LONG TERM PREDICTION OF HIGH ALTITUDE ORBITS by Sean Kevin Collins B.S.A.E., S.M., University of Virginia (1974) Massachusetts Institute of Technology (1977) SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR DOCTOR OF PHILOSOPHY at the Massachusetts Institute of Technology 1981 Signature of by MARCH 1981 Massachusetts Institute of Technology Author Department of Aeronautics & Astronautics March 1981 Approved by Walter M. Chairman of 'Thesis Committee Richard H. Approved by Hollister Battin Thesis Advisor John P. Vinti Approved by Thesis Adv 'sor/ Approved by Paul J. Cefola Thesis Advisor/ Manuel Martinez-Sanchez Accepted by Cliairman, Departmental Doctoral Committee Accepted by Harold Y. Wachman, Chairman, Departmental Graduate Committee ARCHIVES MASSACHUSETTS INSTITUTE OF TECHNOLOGY MAY 5 1981 LIBIRM S 0 LONG TERM PREDICTION OF HIGH ALTITUDE ORBITS by Sean Kevin Collins Submitted to the Department of Aeronautics and Astronautics on 30 March 1981 in partial fulfillment of the requirements for.the Degree of Doctor of Philosophy ABSTRACT This thesis develops a first order semi-analytical theory, based on the Generalized Method of Averaging and making extensive use of recursive algorithms, for the rapid and accurate calculation of the secular and long period changes in the elements of a high altitude caused by the action of the sun and moon. designed to assist the mission analyst testing the long term stability of region above synchronous perturbations are a major and. stability. satellite orbit The theory is concerned with selected orbits in the altitude where "third body" determinant of orbital lifetime A representation of the third body disturbing potential in satellite orbital elements is essential to the development. Non-singular equinoctial orbital elements are used as part of a unified artificial singularities approach to the elimination of in the satellite dynamical equations for near-circular and near-equatorial orbits. potential is the satellite The derived with respect to the reference frame of to. minimize the analytical complexity of the first order theory. Special functions are employed wherever possible to modularize the analytical structure with a view The computation in a numerical program. towards efficient potential retains the parallax factor to an arbitrary power and no assumptions are made on the geometry of the third body orbit. The potential is expanded into the mean longitudes of the satellite and the disturbing body so that resonance can be studied. 2 01 An averaging theory, based on the Generalized Method of Averaging, is developed for removing frequencies from the satellite dynamical equations depending on rapidly varying linear combinations of the satellite and third body mean longitudes. The method for obtaining the analytical forms of the averaged equations of motion and the short periodic recovery functions is detailed. The third body averaging theory has been numerically implemented and compared against Cowell integration for five The principal conclusion of this thesis is test orbits. that the first order semi-analytical third body theory can. be used to accurately predict the long term motion of a high makes it that efficiency with an satellite altitude analysis superior to conventional mission decisively techniques. Thesis Title: Supervisor: Walter M. Hollister Associate Professor of Aeronautics and Astronautics John P. Vinti Thesis Supervisor: Title: Lecturer of Aeronautics and Astronautics Thesis Supevisor: Richard H. Battin Title: Adjunct Professor of Aeronautics and Astronautics Associate Department Head, C. S. Draper Laboratory Thesis Supervisor: Paul J. Cefola Title: Lecturer of Aeronautics and Astronautics Section Manager, C. S. Draper Laboratory 3 6 ACKNOWLEDGEMENTS I wish to express my profound appreciation to the members of my doctoral thesis committee, whose support and This includes Procounsel have made this work possible. fessor Walter M. Hollister, who served as chairman, Dr. who introduced me to astrodynamics, H. Battin, Richard Celestial of whose vast knowledge Vinti, Dr. John P. Mechanics inspired me, and Dr. Paul J. Cefola, who acted as I would like to emphasize my gratitude principal advisor. guidance and technical for his patience Cefola to Dr. I am also indebted to Wayne throughout my doctoral program. during D. McClain (CSDL) for his sage advice and criticisms Thanks are extended to Dr. all phases of this thesis. Mr. Slutsky (CSDL), Dr. Mark S. Proulx (CSDL), Ronald J. Taylor and Captain Stephen P. Bobick (MIT/CSDL) Aaron F. suggestions and for numerous helpful discussions, (USA) Leo W. Early Mr. to extended also is Appreciation support. exploited constantly was GTDS of knowledge whose (CSDL) during the software development. I would like to thank Captain (Dr.) Andrew J. Green The software achiever. a friend and prolific (USA/ARMOR), implementation of the third body theory developed in this thesis was greatly aided by work that he performed at CSDL Special thanks go to Captain as an MIT doctoral student. friendship for his reliable (USAF) Shaver S. (Dr.) Jeffrey and encouragement. I wish to express appreciation to Mr. Bruce Baxter (The Aerospace Corporation) for a useful exchange of ideas regarding the concepts developed in this thesis and for the suggestion of research directions. Karen M. reserved for Ms. Thunderous applause is to ensure the comSmith (CSDL) , who forsook a normal life I am very grateful to her for an pletion of this document. effort that matches the highest professional standards. My wife, Susie, deserves the lion's Her unwavering understanding and accolades. the reasons for my success. share of the compassion are I would like to thank the Charles Stark Draper LaboMassachusetts for providing financial ratory of Cambridge, of my docfor the entirety support and research facilities program at MIT. toral 4 0 TABLE OF CONTENTS 1. 2. INTRODUCTION............................ ........16 1.1 Previous Work.................. ........20 1.2 Overview....................... .........23 THE THIRD BODY DISTURBING POTENTIAL.............. 26 2.1 Derivation of the Third Body Disturbing Potential in Inertial Coordinates.................... 27 2.2 Transformation of the Third Body Potential from Inertial Coordinates to Sate.llite Coordinates............... .35 2.2.1 Reference Frame Choice and Implications............................ 36 2.2.2 Transformation of the Third Body Potential to Satellite Orbital Coordinates............................. 39 2.2.3 Induced Dependence of Third Body Orbital Elements on Satellite Orbital Elements....................... 81 3. 2.2.3.1 The Meaning of h' and k'...............81 2.2.3.2 The Meaning of X'......................86 ISOLATING LONG TERM MOTION IN THE SATELLITE DYNAMICAL EQUATIONS.............................. 3.1 The Generalized Method of Averaging............................... 3.1.1 94 An Averaging Theory for Satellites Moving Under the Influence of a Disturbing Body........................ 3.1.2 91 96 A First Order Averaging Theory......... 110 5 TABLE OF CONTENTS (cont.) Page Chapter 4. MATHEMATICAL STRUCTURE OF A DYNAMICAL THIRD BODY MODEL FOR THE LONG TERM PREDICTION OF SATELLITE ORBITS USING NUMERICAL METHODS............................. .. 118 4.1 0 First Order Averaged Equations of Motion for Third Body Perturbation......................... .. 126 4.1.1 Criteria for Retaining Terms in the Averaged Equations of Motion..... .. 134 4.2 Mathematical 0 Form of the Periodic Recovery Functions.......... .. 137 4.3 Formulation of the Third Body Theory for Numerical Computation..... .. 151 4.4 Calculation of Special Functions.... 4.4.1 Calculation of Zm 4.4.2 Calculation of Jacobi Polynomials n,r .................. .. 176 .. 176 0 and Their Partial Derivatives by Recurrence........................ .. 180 4.4.3 Calculation of the Coefficients Cr, Dr and Their Partial m m Derivatives by Recurrence............ .. 183 4.4.4 Calculation of the Coefficients Ar,m, Br,m and Their Partial s,t s,t Derivatives.......................... .. 193 4.4.5 Recurrence Relations for the Third Body Hansen Coefficient Kernel K-n-l,r and S 4.5 its Derivative.... .. 201 Restriction of Indices in the Third Body Theory.................... .. 211 6 0 TABLE OF CONTENTS (cont.) Page Chapter 5. NUMERICAL VERIFICATION OF THE FIRST ORDER THIRD BODY THEORY............................... 219 5.1 Initialization of the Averaged Equations of Motion............ ...-...221 The Computation of Third Body 5.2 Ephemerides.................... .... Analysis of the Numerical Resul ts. 5.3 228 231 ... 5.3 .1 233 IUE Test Case.................. .... 6. 5.3 .2 ISEE Test Case................. 5.3 .3 VELA Test Case................. 273 5.3 .4 STRATSAT Test Case............. 285 5.3 .5 Lunar Resonance Test Case...... 296 CONCLU S IONS AND FUTURE WORK........ 6.1 Conclusions............... 6.2 Future Work............... Appendix A. ... 262 . ... ... . 306 . ... ... . 310 . ... ... . 312 Computation and Storage of the Newcomb Operators in the Third Body Theory.................................... 316 Appendix B. Software Implementation of the Third Body Theory......................... 322 List of References..................................... 337 7 LIST OF FIGURES Page Figure 2-1 Geometry of the Third Body Problem............... 28 2-2 Orientation of the Satellite Reference Frame with Respect to the Inertial Reference Frame................................. 40 2-3 0 Orientation of the Third Body Position Vector with Respect to the Satellite Frame...... 42 2-4 Geometry for the Rotation of Surface Spherical Harmonics............................. 49 4-1 Admissible Values of the Index m vs. 4-2 Admissible Values of the Index r 5-1 Osculating t .......... 214 vs. s..........217 Semi-Major Axis Comparison within the 60 Day PCE Fit Span for the IUE Orbit/Semi-Analytical versus Cowell.............239 5-2 Osculating Eccentricity Comparison within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical versus Cowell...................240 5-3 Osculating Inclination Comparison within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical versus Cowell...................241 5-4 Osculating Mean Longitude Comparison within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical versus Cowell....................242 5-5 Osculating Semi-Major Axis Differences within the 60 Day PCE Fit Span for the IUE Orbit/Semi-Analytical minus Cowell..............243 5-6 Osculating Eccentricity Differences within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical minus Cowell....................244 8 LIST OF FIGURES (cont.) Page Figure 5-7 Osculating Inclination Differences within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical minus Cowell....................245 5-8 Osculating Mean Longitude Differences within the 60 Day PCE Fit Span for the IUE Orbit/Semi-Analytical minus Cowell..............246 5-9 Comparison of the Mean and Osculating Semi-Major Axis Histories for the 3 Year Integration of the IUE Orbit/AOG versus Cowell..........................................248 5-10 Comparison of the Mean and Osculating Eccentricity Histories for the 3 Year Integration of the IUE Orbit/AOG versus Cowell..........................................249 5-11 Comparison of the Mean and Osculating Inclination Histories for the 3 Year Integration of the IUE Orbit/AOG versus Cowell..........................................250 5-12 Differences Between the Mean and Osculating Semi-Major Axis Histories for the 3 Year Integration of the IUE Orbit/AOG minus Cowell..........................................251 5-13 Differences Between the Mean and Osculating Eccentricity Histories for -the 3 Year Integration of the IUE Orbit/AOG minus Cowell..........................................252 5-14 Differences Between the Mean and Osculating Inclination Histories for the 3 Year Integration of the IUE Orbit/AOG minus Cowell..........................................253 9 LIST OF FIGURES 0 (cont.) Pag Figure 5-15 Osculating Semi-Major Axis Comparison for the 3 Year IUE Integration/Semi-Analytical versus Cowell...................................255 5-16 Osculating Eccentricity Comparison for 0 the 3 Year IUE Integration/Semi-Analytical versus Cowell...................................256 5-17 Osculating Inclination Comparison for the 3 Year IUE Integration/Semi-Analytical versus Cowell...................................257 5-18 Evolution of the Mean Eccentricity for the 100 Year AOG Prediction of the IUE Orbit......................... 5-19 .................. 259 0 Evolution of the Mean Inclination for the 100 Year AOG Prediction of the IUE Orbit...................... 5-20 .....................260 Comparison of the Mean and Osculating 0 Semi-Major Axis Histories for the 8 Year Integration of the ISEE Orbit/AOG versus 5-21 Cowell................................... ....... Comparison of the Mean and Osculating 266 Eccentricity Histories for the 8 Year Integration of the ISEE Orbit/AOG versus Cowell.................................... ....... 5-22 267 Comparison of the Mean and Osculating Inclination Histories for the 8 Year Integration of the ISEE Orbit/AOG versus Cowell..............................................268 0 10 0 LIST OF FIGURES (cont.) Page Figure 5-23 Comaprison of the Mean and Osculating Longitude of Ascending Node Histories for the 8 Year Integration of the ISEE Orbit/ AOG versus Cowell................................269 5-24 Comparison of the Mean and Osculating Argument of Perifocus- Histories for the 8 Year Integration of the ISEE Orbit/AOG versus Cowell...................................270 5-25 Comparison of the Mean and Osculating Semi-Major Axis Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell..........................................278 5-26 Comparison of the Mean and Osculating h Element Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell.............................................279 5-27 Comparison of the Mean and Osculating k Element Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell..........................................280 5-28 Comparison of the Mean and Osculating p Element Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell..........................................281 5-29 Comparison of the Mean and Osculating q Element Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell...........................................282 11 0 LIST OF FIGURES (cont.) Figure 5-30 Page Comparison of the Mean and Osculating Inclination Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell..........................................283 5-31 Comparison of the Mean and Osculating Semi-Major Axis Histories for the 8 Year Integration of the STRATSAT Orbit/AOG versus Cowell...................................291 5-32 Comparison of the Mean and Osculating Eccentricity Histories for the 8 Year Integration of the STRATSAT Orbit/AOG versus Cowell...................................292 5-33 Comparison of the Mean and Osculating Inclination Histories for the 8 Year Integration of the STRATSAT Orbit/AOG versus Cowell...................................293 5-34 Comparison of the Mean and Osculating Radius of Perifocus Histories for the 8 Year Integration of the STRATSAT Orbit/ AOG versus Cowell...............................294 5-35 Comparison of the Mean and Osculating Semi-Major Axis Histories for the 5 Year Integration of the Lunar Resonance Test Orbit/AOG versus Cowell..........................300 5-36 Comparison of the Mean and Osculating Eccentricity Histories for the 5 Year Integation of the Lunar Resonance Test Orbit/AOG versus Cowell.........................301 12 0 LIST OF FIGURES (cont.) Page Figure 5-37 Comparison of the Mean and Osculating Inclination Histories fot the 5 Year Integration of the Lunar Resonance Test Orbit/AOG versus Cowell.........................302 B-i Subroutine Interaction Diagram for the Third Body Software.............................333 13 LIST OF TABLES Table 2-1 (m,r) Form of the Function S2n (P ,q')...... 2-2 Form of 2-3 the Function S(nl,r)(a,S,y)...... 2n Functional Form of the Third Body Elements, h' and k'..................... 3-1 Harmonic Contributions of the Trigonometric Argument tX + sX.......... ........ 4-1 93 Nonzero Poisson Brackets of the Equinoctial Elements.................... 4-2 0 Form of the First Order Averaged Equations of Motion for Third Body Perturbation............................ 4-3 Partial Derivatives of the Third Body Mean Longitude with Respect to the Mean Satellite Elements p,q.................. 5-1 Epoch Osculating Elements for the IUE Test Case................................ ... 5-2 233 PCE Perturbation Models for the IUE Test Case.................................... ... 236 5-3 Epoch Mean Elements for the IUE Test Case.... ... 238 5-4 Epoch Osculating Elements for the 0 ISEE Test Case............................... ... 5-5 262 PCE Perturbation Models for the ISEE Test Case.................................... ... 264 5-6 Epoch Mean Elements ... 265 5-7 Comparison of Cowell and AOG Execution Times for the Eight Year ISEE Integration.... ... 272 5-8 0 for the ISEE Test Case... Epoch Osculating Elements for the VELA Test Case............................... ... 273 0 14 0 LIST OF TABLES (cont.) Page Table 5-9 PCE Perturbation Models for the VELA Test Case.................................. 275 5-10 Epoch Mean Elements for the VELA Test Case...... 275 5-11 AOG Perturbation Model for the Ten Year VELA Integration....................... 277 5-12 Comparison of Cowell and AOG Execution Times for the Ten Year VELA Integration........ 5-13 284 Epoch Osculating Elements for the STRATSAT Test Case.............................. 285 5-14 PCE Perturbation Models for the STRATSAT Test Case.............................. 287 5-15 Epoch Mean Elements for the STRATSAT Test Case....................................... 5-16 AOG Perturbation Model for the 288 Eight Year STRATSAT integration............................ 289 5-17 Comparison of Cowell and AOG Execution Times for the Eight Year STRATSAT Integration... 295 5-18 Epoch Osculating Elements for the Lunar Resonance Test Case....................... 296 5-19 PCE Perturbation Models for the Lunar Resonance Test Case............................. 297 5-20 Epoch Mean Elements for the Lunar Resonance Test Case............................. 5-21 298 AOG Perturbation Model for the Five Year Lunar Resonance Integration..................... 299 5-22 Comparison of Cowell and AOG Execution Times for the Five Year Lunar Resonance Integration..................................... 303 B-1 Datasets and Region Sizes Required for the Various Third Body Options...................... 15 332 Chapter 1 Introduction The order and in elements the Generalized of recursive of term long stability synchronous altitude Method a high the sun and moon. where of Averaging the for long period Earth satellite The theory concerned with the in orbits selected of new and altitude of first a algorithms, secular asset to the mission analyst valuable above use by the action of caused the the is thesis this calculation and accurate changes on extensive making rapid based theory, of result central "third body" is a testing region perturbations are a major determinant of orbital evolution and lifetime. The third work of semianalytical orbit theory. involve of removal of periodic the Parameters formulation size averaged integrated with an equations expanded computational expense. purely since the from a Variation dynamical satellite of a conventional numerical resulting of Semianalytical methods components of frame- These periodic components unnecessarily restrict equations. the step (VOP) the within developed body theory is analytical it permits body models into the of step integration. motion size at then can greatly The be reduced This approach is superior to the use General Perturbations incorporation of (GP) realistic techniques disturbing a numerical orbit prediction program while 16 0 minimizing [1] . complexity analytical the Furthermore, artificial singularities associated with GP theories arising from [2] arguments critical and introduced not are non-canonical variable sets may be employed. The theory of generality in derived this provement over previous thesis represents work. For the a body third semianalytical the remarkable the time first imfol- lowing conceptual components are unified in a single theory: 1) Method of Averaging Generalized In long term dynamics an are motion of equations contained by developed area by Generalized unambiguously and defines furnishes the a an order by order basis. 17 approximation [4]. order the an was the later and Known of in [3] straightforward for obtaining the averaged the The rigorous mathema- Averaging, of to high preci- oscillations Mitropolsky Method the Bogoliubov and Krylov in this non-linear of extended theory of structure averaged approximation sion equations of motion. tical the theory, orbit semianalytical (GMA) as the formalism averaging protocol equations of motion on 0 To a specified provides also Averaging averaged elements. possible through an Method of approximation to the in of the terms is approximation This the Generalized elements orbital precision high the order, construction of made analytical functions of the averaged elements that represent short periodic variations the Short trajectory. sion to essential the in the high preci- periodic initialization of functions the are averaged equations of motion given high precision orbital elements. 2) Third Body Resonance For the case where the satellite and the disturbare body ing commensurable nearly in their mean motions, long period terms arise in the satellite dynamical third body resonance, with the tesseral gravity track. in the potential Third averaged analogous is harmonics caused body phenomenon, This equations. by the a repeating resonance equations resonance to of of terms motion called are Earth's groundincluded derived in this thesis. 18 0 3) Non-Singular Orbital Elements The terms of ments. This choice bility for orbits that near-circular or characteristic is numerical circumvents ele- orbital equinoctial non-singular in formulated are equations VOP satellite insta- equatorial near VOP Keplerian of equations. 4) Special Functions the third permits theory body and coefficients functions The use of special an in com- extremely pact and modular analytical structure. 5) General Disturbing Body Model No number of the third predic- a 'numerical orbit in body terms available tion program on made are assumptions restrictions and no theoretical are placed on the orbital eccentricity of either the satellite or of the disturbing input program parameters tailor the disturbing ments of a is nature of explicit quire extensive third to body reprogramming lities. 19 to the the This "hard-wired" theories to to require- orbit. satellite contrast in attribute sufficient is body model particular Specification body. extend that re- capabi- 0 Recursive Computation 6) The use of recurrence relations for the numerical of computation cated special disturbing rapidly body starting from functions models allows to be compli- evaluated determined simply initial values. 1.1 Previous Work Major researchers have contributions the to study of made been semi-analytical by several techniques for determining the evolution of high altitude satellites moving theories applicable intervals are satellite to over of averaged. Each must a the general the motion. and disturbing of averaging period dynamics in will the its assumed of variables to remove all time the satellite averaging These theories the criticism, extended over angular be judged on satellite double fast and disturbing body components as mission analysis based on successively equations VOP Most of the third body influence of a third body. under the high are the frequency called own merits. double However, independence of the body phase angles for the purposes exclude averaged the presence equations of any of motion long induced by third body resonance. 20 0 A third by developed body Gauss is acceleration perturbation secular the which in [5] are average over the mean anomaly of The eliminated. of system short periodic varia- Gaussian VOP equations from which all tions disturbing a produce to averaged doubly body third was theory the disturbing body is seen to reduce to the purely geometrical exercise of ring of that third matter available to modernize lunar In satellites. numerical could orbital of and effort in Musen [7] given to the in involves elements over high terms precision the numerical an appropriate if on of a 21 long high set to [61 term altitude possibility of of element how Halphen's method non-singular averaged equations elements orbital at epoch One technique, used by Smith high of way will interval precision However, interval. in this the theory, Keplerian original other any Musen the the remove average the contamination by study Initialization of the averaged elements obtained periodic to explained later remains a challenging problem. [81, rederived perturbations an or version of Gauss' programmed solar elements. motion was and reformulated be modified [51, instability formulation, orbit of quadrature numerical A Halphen notation of effects by technique. attributed an elliptical the along is distributed computed is anomaly attraction of the subsequent average over the satellite mean The body. computing is the contain short not precisely A chosen. more effective method, employed [ 91 by Baxter , on a double angle harmonic analysis of high precision relies element histories to identify short periodic components. Ash [10] a developed body third averaged double theory in Keplerida elements, based on Gauss' concept, which was used to of high altitude Halphen's interpret physically method satellite by starting the numerical orbits. It differs from an infinite sion for the third body potential rather integration series expan- than directly from the perturbing acceleration which is closed form. average rather over satellite which expressions third It can be the satellite VOP that are eccentricity this equations in the leaving complex. Furthermore, is to assumed assumption eliminates representing the analytically recognized, not unnecessarily body orbital shown performed Also, Special functions imbedded equations are is orbit than numerically. averaged literal the the from be terms zero. from dynamical significant contributions. Sridharan Lidov theory [12] Seniw [11] to derive an explicit based expansion and on of the the first term followed of double averaged third in Legendre polynomial disturbing 22 the development the acceleration. body The Gaussian VOP tions are formulated in terms the lacks the theory high altitude able to Keplerian moving in The the orbital ele- truncated force to handle flexibility orbit. satellite satellites of of the dramatically As a consequence ments. model equations and the short periodic recovery func- general is most theory region a below applic- synchronous altitude. general theory A more [13]. It includes an analytical based on Kaula's model in extensive use of special been double relations to simplify computation. assumptions are made to facilitate panying short periodic body disturbing makes theory The and attendant recurrence Furthermore, no a priori truncation the However, averaged equations of motion. Cook averaging capability [14]. functions by developed third the elements Keplerian potential for has deyelopment, is there thereby no of the accom- making the initialization of the double averaging theory from high precision orbital elements an extremely difficult and uncertain task. 1 .2 Overview The Generalized Method of Averaging is applied to the conservative VOP equations describing the motion of an Earth satellite under the influence of a third body. 23 Chapter In third body the 2, disturbing potential developed in non-singular orbital elements using taken is and satellite as the the disturbing both can resonance that so body for variable angular fast satel- the The mean longi- lite orbit plane as the frame of reference. tude is the be accomodated. Chapter In Method of 3, the Generalized Averaging is used to create an averaging theory applicable to a system of rotating rapidly two containing equations differential The The theory is then specialized to first order. angles. formal method tions of the for obtaining motion functions periodic short the and equa- first order averaged is presented. Chapter 4 details the results of applying the averaging on theory the disturbing form mathematical the short periodic tives, are given. values for all atives are 3 to of Chapter a system of VOP potential of the special presented. including recurrence functions in all of Truncation their The motion and partial relations and 2. Chapter equations averaged functions, The derived equations based and partial procedures derivastarting derivfor the dis.turbing body model are discussed. 240 0 The and equations interfaced Determination Draper bed a System Laboratory program, lation with expressed GTDS algorithms version (GTDS) in for the between theory high developed precision in this of the at 4 are Goddard the short programmed Trajectory Charles Massachusetts. numerical auxiliary perturbation models. sons Chapter modified Cambridge, furnishes in As integrators, periodic thesis are a and presented the test interpo- variations Speed and accuracy integration Stark and compariaveraging in Chapter 5 for selected orbits. Chapter areas 6 formulates conclusions for future investigation. 25 and suggests some 0 Chapter 2 The Third Body Disturbing Potential This potential chapter in formulates terms of the third satellite body orbital disturbing coordinates. Mathematical operations on the potential produce a system of high precision equations form Variation the of Parameters cornerstone of equations. third the body These averaging theory developed in this thesis. The tial potential orbital elements numerical instability orbits that formulated is in The equinoctial is as expressed part of an non-singular approach for near-circular characteristic terms in of the of elements are classically a = a h = e sin(w + IQ) k = e cos(w + IQ) p = tanI(i/2) sing q = tanI(i/2) = M + w + IQ cosQ 26 circumvent and near-equatorial satellite classical to equinoc- VOP equations Keplerian elements. defined as [15 ] a, where i, e, Keplerian and elements I is The retrograde factor is present to the retrograde factor. eliminate a the M are w, Q, in singularity element the for orbits with set It is discussed in detail in an inclination of 180 degrees. Section 2.2. 2.1 Section in tial inertial disturbing to potential the poten2.2 Section coordinates. rectangular transformation of the details third body the derives equinoctial orbital elements. Derivation of the Third Body Disturbing Potential in 2.1 Coordinates Inertial The expression an with Newtonian strictly may be referred. metry. body r the disturbing XYZ Figure R with respect to 2-1 depicts the denotes the (S) represent respectively and the disturbing body ter of the central body. difference r - r', begins In acceleration. the implies this formulation, potential body third position three geo- central The vectors the positions of (D) measured motion body the of a postulate all which (C) relative to the origin of coordinates. and r' lite vector The the of for frame inertial an of development the satel- from the cen- The vector d, which is simply the establishes 27 the relative separation of Figure 2-1. Geometry of the Third Body Problem s0 S z 00 0 x 28 S the satellite and the third body. Another useful parameter, soon to be employed, is the angle * between r and r'. commonly referred to as elongation the geocentric in It is Earth centered orbital analyses. of dynamical equations describing the motion of the three body system may on Based the geometry, stated a set be written as m (R +r) --GMM r r- G m m dd (2-1) and SG -r3 where the double dot Mmr+ G Mm' r' 3 notation (2-2) indicates the second deriva- tive with respect to time and ml mass of satellite (kg) mass of the third body M G (kg) mass of the central body E universal constant 29 (kg) of gravitation (km 3 /kg-sec2) 0l From eq. (2-1) mass the of (2-2) the inertial accelerations per unit and body central and satellite respectively are given by R + rM G- 1~ r d r (2-3) d 3-7 0 and = Subtracting eq. Gm r (2-4) 3r' (2-4) from eq. (2-3) yields _ r GmI + -T r r G (M 3 + m)r-Gm m r- d r Eq. (2-5) (2-5) 3L)3 + may be simplified by defining the quantities y' = (2-6) G(M + m) (2-7) = Gm' Transposing (2-5) and the first invoking eqs. term + right hand (2-6) and (2-7) leads d .. r the of of eq. to r' + -r r3-d3 side r3 3 (2-8) 30 0 Eq. a disturbing body third the by forced as body central about satellite a of motion the represents (2-8) acceleration a = potential eq. (2-9) function. This can be satellite to the the conservative, are forces respect with (2-9) r 1 by force represented the gradient, scalar d r' -- 3 3 -+- gravitational Since specific d ( -' function expressed position, of the as of a satellite coordinates has the form U' U11 = (- y' - r'-E - . ) (2-10) r Subsequent of eq. analysis require Manipulation (2-10). d2 will = d = r2 d - - = 2r a more convenient begins by recognizing - (r - (r - r') - r' + r, 31 2 version that r') (2-11) a If is $, elongation, geocentric the into introduced eq. 6 in distance of the relative 2rr' cos * + r' 2-1/ inverse the then (2-11), eq. (2-10) is seen to be 1 (r 2 = developed in orthogonal the of terms (2-12) eq. coordinates, orbital 2 (2-12) into of the third body potential the expansion To facilitate satellite - more naturally is Legendre 0 polynomials defined by [16] 1)-1/2 2hX + (h 2 - - I hn P ( X) n=0 n (2-13) 0 where Legendre polynomial Pn(X) of degree 0 n and argument X parameter less than or equal h Eq. be (2-12) may by factoring out r' in placed 2 correspondence with {( eq. (2-13) so that 2 = to 1 ) ( -2 cos s )c - 1/2 *+ 1} (2-14) 32 0 Comparing with (2-14) eq. (2-13) eq. yields identifica- the tions h=( (2-15) r) and X = (2-16) cos * (2-14) to take the final form This allows eq. 00 1 d r n ) n0 p (2-17) (Cos Note that this representation assumes that the satellite of describes the an perturbing required. body. However, obviously violated. eq. (2-12). Only orbit interior for This with ensures an exterior respect the the orbit 1 as condition is (r/r' that orbit, to ) < In such a case r 2 must be factored from interior sidered here. 33 satellite orbits will be con- (r' 3 - r)/r' U1 as (r/r' iU = r -r 2) Further eq. recognizing (2-18) becomes, 1= U' 6 cos * yields n (cos F- )n n n0 (r (- - nT r n=0 (2-10) and rewriting (2-17) into eq. Substituting eq. PO(cos that *)=1 and potential position with on solely respect vector. $, to (2-19) Pn (cos *) ] the gradient in cartesian coorof elements the Accordingly, 0 0 The satellite equations of motion depend *)=cos 6 n [1 + n=2 dinates Pi(cos (-18) terms, cancelling after s2 ~] Cos the of leading the the disturbing satellite term in eq. (2-19) will not contribute to the satellite motion by virtue of having no satellite dependencies. In view of this the third body disturbing potential may be rewritten in fact the commonly used form , ) 2 n=2 34 n Pn (cos *) (2-20) 0 Transformation of the Third Body Potential from Iner- 2.2 tial Coordinates to Satellite Coordinates formulation VOP Lagrangian The tion problem requires partial of predic- orbit the derivatives of the disturbing potential with respect to the orbital elements of the satellite. It is therefore highly desirable to express the third (2-20), directly in terms body potential, represented by eq. of , One elements. satellite identities standard it in to tends special functions such ignore a the in the satellite by typified method Kaula application tedious trigonometry spherical Although manipulations. correct, but straightforward a entails approach, is presence of theory and [14] of and algebraic in principle mathematical the reduction in analytical complexity that derives from their use. alternate An technique involves employing a powerful transformation theorem for spherical harmonics under a rotation of tial has coordinates which been is to provide an expression more substantially used with success compact. by McClain [17] and will be adopted in the ensuing analysis. 35 for the potenThis technique and Cefola [18] ] Reference Frame Choice and Implications 2.2.1 0 potential body third the transforming Before to satellite orbital elements, a reference frame must be chosen for must numerically be a is potential The (2-20). cosine of the geocentric elongation in the computing invariant under a change of coordinates Hence, the selection of a that leaves the datum unaffected. venience tical can be made principally as a matter of con- frame reference or practicality of form therefore and quantity scalar eq. the provide to or potential a more computational the to reduce analy- elegant load in a numerical orbit prediction program. In be made terms, broad absolute between and a of choice the relative. reference frame may Absolute frames are the equato- inertial reference systems commonly oriented in rial plane of the Earth or in Within plane. the ecliptic the context of developing the third body disturbing function such frames the have advantage of maintaining dence of the third body orbital elements elements. turbing body elements from an external with the notion affected by the are ephemeris. that the movement constant simply This of reverse. 36 the satellite third body step the dis- parameters decoupling integrated indepen- from the satellite Hence, at each integration orbital the is taken consistent elements are than the rather On the debit side of the ledger, the use of an abso- lute frame may be undesirable from the viewpoint of a numerical In program. potential torial the of expansion the Earth's gravity in equinoctial variables, as referred to the equaframe inertial [18 ], inclination an is function introduced relating the satellite orbital plane to the equatorial system. a second results in the tion, potential duct However, in the case of third body perturbafunction inclination be introduced. This appearance of an additional summation in the and extra computational could is a reduction in numerical prediction program. 37 complexity. the overall The end pro- efficiency of a U1 Selecting a relative reference frame in the satellite or disturbing body orbital plane serves to eliminate one or the The summation. the the of other an is result then to referred were in derived third body be respect to equations chained the to the Hence reference. satellite of the the motion through will body dynamical frame of be must elements body third with motion in the satellite inertial an the the disturbing is that However, absolute space. if For example, elements of frame a of using the satellite reference system, is developed the orbital form simpler analytically to be induced dependencies. potential associated the An obvious drawback would appear potential. disturbing and functions inclination frame inertial Similarly, frame. if the third body reference frame is chosen, then the elements of the orbit satellite will consequently to related be the integrated through the motion of the disturbing body of characteristic This non-inertially referred demonstrating problem, a the satellite frame it the leaves frame relative is selected satellite framework exists for to for the inertial the purpose third in the chosen. In particular, to develop the potential is elements system of integration. 38 not does averaging of power elements [1. frames elements Accordingly, dynamical reference frame. system relative preclude their use since an analytical relating defined and be non-inertially will expressed directly of body the since in the Body Potential to the Third of Transformation 2.2.2 Satel- lite Orbital Coordinates eq. The transformation of the (2-20) to equinoctial elements of the satellite begins by expressing the cosine of the geocentric elongation as the dot product, where = symbol 1 denotes the cos * 1 r - 1 r a unit 1 tors f, g, frame, the cos(L) f + sin(L) g + 0 w the true L is coordinates r has the form, = where In vector. satellite reference measured with respect to the unit vector (2-21) . , w are (2-22) longitude of the satellite and the vec- the in Figure unit vectors depicted graphically frame satellite referred inertially 2-2 and defined by f = 272 [1 p2 , 2pq, -2pI] + q (2-23) 1+p +q T g = = 2 2 2 1 2 1+p +q [2pqI, 39 (1 + p - q )I, 2q] (2-24) 0 Figure 2-2. Orientation of the Satellite Reference Frame with Respect to the Inertial Reference Frame z A f W1 9V y0 L-f+W+ 12 x 40 w T [2p, -2q, (1 - are the equinoctial p2 (2-25) q2)I] - 1+p2 +q2 The variables the specify p of the orientation the inertial frame. a circumvent q and in for factor is +1 when the orbital inclination is the inclinations with motion the frame to relative The retrograde factor, I, is present to singularity orbits satellite that elements 180*. In of inclination between of equations satellite The degrees. 180 is 0* either and -1 when value may be used. The third body unit vector is given by 1r'= cos6 cosa f + cos6 sina g + sin6 w (2-26) where a and 6 are the right ascension and declination of the third body relative to the satellite frame. shown in Figure 2-3. Substituting eqs. The geometry (2-22) and is (2-26) into eq. (2-21) yields cos* = cos6 cosa cos(L) + cos6 sina sin(L) + sin(0) sind (2-27) 41 Figure 2-3. Orientation of the Third Body Position Vector with Respect to the Satellite Frame A w r AA fg 42 the Apply cos(y)+ trigonometric standard eq. sin(x) sin(y), cost sin(O) = identity cos(x-y) = cos(x) (2-27) becomes sinS + cos6 cos(a - L) (2-28) At this point the Addition Theorem for spherical harmonics cosS should cos( a - be L)] into simple third body coordinates. decomposes It invoked. functions of Pn[sin(O) the sin6 + and satellite The Addition Theorem has the form [19] Pn [sin(y) sin(y') = n [sin(y)] + cos(y) cos(y') cos(x - x')] = Pn [sin(y')] n + 2 (nm)! P [sin(y)] P [sin(y')] cos m(x - x') m=1 (2-29) 43 The function defined by is Pnm(z) associated the Legendre function 4 (16] a ( = n (z - z2)m/2 P (z) (2-30) dzm identifications If one makes the sin(y-) = 0 sin(y') = sinS cos(y) = 1 cos(y') = 0 cos6 x a x' L 0 then eq. (2-29) becomes Pn(cos *) n + 2 m=1 = Pn (0) Pn (sin) (n-n P (n+n)! nrnm(0) 44 Pnm(sin3) cos [m( a-L)] (2-31) From eq. (2-30) it is clear that PnO(z) Hence eq. (2-31) may be rewritten as Pn0 = Pn (cos *) + 2 n M=1 (2-32) P n(z) = (n-m)! PnO(sinS) (2-33) nm(0) Pnm(sino) cos[m(a-L)] Def ining m = 0 K m allows the m > 0 2 summation in eq. (2-33) to begin at zero, producing Pn (cos*) = n I m= 0 K Km (n-) (n+m)! nm (0) P nm (sin6) cos[m( a-L)] (2-34) 45 the function Vnm is If V n,m = defined (n-m)! (n+m)! to be, (2-35) P nm (0) 0 then eq. (2-33) may be restated as, 0 n Pn (cosM) n = Substituting eq. 0 KM Vnm Pnm (sinS) m n~m=n (2-36) into eq. cos[m(a-L)] (2-20) (2-36) produces the intermediate form of the third body potential, U' KmVm = n=2 Pnm (sind) cos[m(a-L)] m=0 (2-37) 46 0 In order to use the rotational transformation theorem for e j[m( a-L) in) Re{n = (-Er) ro n=2 is (2-37) Doing so yields rewritten in complex notation. T eq. in potential the harmonics, spherical (sin(s K mV nmP m=O (2-38) where Re sion and { } denotes j V'". = the real part of Breaking apart the bracketed the expres- complex exponential produces U' 1 = Re 1 nm (sin6)je emm [Km V m=O n=2 (2-39) surface The will now the third be rotated from the body frame. transformation harmonics spherical under A theorem exists simple origin is held fixed. Pnm(sin6)ejma, satellite reference of any linearly a harmonics, which describes independent rotation of frame into the set of spherical coordinates when the With appropriate changes of nota- tion, the theorem is formally stated by[20], 47 nm = m (cos r=-n (n-r)! S(m,r) (n-m)! 2n - P (cosO') ejr' (2-40) The unprimed quantities of a point as measured, frame. The primed dinates of the 8 and E are the angular coordinates angles same from O'and as point from measured referred axes of the third body frame. satellite spherical the are E' the of axes the the coor- satellite The parameters p,a,T are related to the Euler angles defining a rotation of coordinates from the third body reference frame to the satellite frame. These parameters will be discussed Eq. cal (2-40) is now used to express the surface spheri- harmonics, spherical frame. Pnm(sind )ejma, as a expressed in the harmonics This is done by identifying ties shown in Figure 2-4. the shortly. colatitude in linear third combination body of reference the. geometrical quanti- The parameter 6, generally called spherical coordinates, is measured from the positive w axis of the satellite coordinate frame to the 48 Figure 2-4.' Geometry for the Rotation of Surface Spherical Harmonics A W A w ' A g %N {f, g, w } = satellite frame unit vectors A f f^',, IA f' 49 third body frame unit vectors! a disturbing the plane of third body declination, The angle right E in eq. ascension, 6, through In the coordinate the related 0 = relation the place of (2-40) holds a. is It body orbit. the 7r/2-6. third body the system to of the per- turbing body, the angle 0' has the value w/2 since the third A body orbital plane parameter, ', corresponds the to The angle, L', third body, L'. the w' axis. is normal to true Finally, the of the longitude is measured from the f' axis in the plane of the perturbing body orbit. Making indicated the substitutions, eq. (2-40) becomes P nm (sin6) eJma r=-n (n-r)! S(mr) (n-m)! - nr (0) 2n (pyajT) jrL' (2-41) I Making the definition V n,r =m (0) (n-r)! P nr (n-m)! (2-42) 50 i eq. (2-41) may be rewritten as n e ma (sine) P , n,r r=-n ejrL' (m,r) (paT) 2n (2-43) U' = Re{l 1 00 1 (2-39) produces, (2-43) into eq. Substituting eq. n n n (r) 1 n =2 ,e jrL' Km n,m r=-n M=0 2n nr -jmL} (2-44) The known explicit quantities dependence will Courant and Hilbert now [20], be of S ,r) (p,,T) on determined. As defined S (r,r)(prg,T) has the form 2n 51 in a S(m,r) s2n ( p,a, T) - Um ,r (T) exp{-j[(r+m)p + (r-m)a] } (2-45) 6 a where n+m U(m,r) 2n - 2F n-m) n+r (-n-r, n+1-r; sinT ) m-r (COS T) -m-r (cost) (sin'r 1-m-r; , cos 2 a m + r < 0 (2-46) U6 and 01 01 0 52 0 2n (cosT)m+r n+m) n+r U(m,r) (sint)r-m n-r SF 1(r-n, 1+m+r; n+r+1; cos 2T (2-47) r + m > 0 The expression in function the 2 F 1 (a,b;c,4cos 2 T) argument (cos 2 T) is a ( ) and e hypergeometric is the binomial p, a, coefficient. In related the (2-43), view of eq. to a rotation satellite orbital coordinates defining rotation matrix from a the quantities from the third plane. They the third body frame, viz., 53 body orbital are four parameter and actually plane to the are to orthogonal representation frame T of the satellite a q2+q M = 1 q2-q 2 2(qlq 2(qlq 2 -q q ) 3 4 - 2(q1 q 3 +q q ) 2 4 2 +q 3 q 4 ) 2(qlq 3 -q 2 q 4 ) 2 2 2 2 q 4 +q 2 -q 1 -q 3 2(q 2q 3 +qq4 ) 2(q 2 q 3 -q1 4) 2 2 2 2 q4+q 3~91~-q2 0 / (2-48) g 0 Is where v + q 2 + q32 + q 2and q = 0 = sinT sina (2-49) q2 v sinT Cosa (2-50) q V COST qi -v 3 V The parameters qi, parison of eq. sinp COST COSP q 2, q 3, 0 (2-51 ) (2-52) q 4 are determined through a com- (2-48) with the rotation matrix 0 54 0 ,2 1-p' 2+ M 2 2p'q'I' (1+p'2 -q' 2 )I' 2p'q' p' -2q' 1+p' +q' (1-p' 2-q, 2 )V -2p' I2q' (2-53) The p' quantities q' are elements equinoctial the the of orientation the specify and third reference body that frame Hence, they are related to relative to the satellite frame. the mutual inclination of the third body and satellite orbit The planes. set ordinarily mutual +1 inclination singularity moves to in opposite Instead, in the but 180*. is plane of the assumes This third the The value of body singularity when an the orbit, is when -1 circumvents of motion which factor, retrograde the the equations direction. it is I' symbol not is the apparent satellite but in the dynamical. appears because the satellite frame was used to develop the disturbing potential. Taking cases of eq. into (2-53), account both the the parameters, found to be, 55 direct and retrograde of eq. (2-48) qi, are 4 [(1 q,= 4 p + = (2-54) I') + (1 + I')q'] - (2-55) a q = (2-56) p 2 a q = + + I') + (1 [(1 - (2-57) I')q'] a Also, it is evident that v = (1 + p, 2 + q,2)1/2 (2-58) a Now it is that possible the parameters, to determine the elements p' and q' . eqs. and into (2-49) the qi, have dependence Substituting eqs. (2-50) yields been of identified, p,a, and (2-54) an expression and T on (2-55) a for sinT, after squaring and adding, viz., a sint = 2 (1 + p, 2 + q, )-1/2 (p'2 + q,2)(1+I')/4 (2-59) Automatically, IM cosT must be 56 41 4 cost (1 + p' 2 + q, 2 )-1/ = (p, 2 + q1 2 2 (1-I')/4 (2-60) The through of plus or minus (+) designation over the parameter set will satisfy of the rotation matrix given in eq. being adopts eqs. (2-54) (2-57) does not imply that an arbitrary distribution signs nations in of (-,-,-,+) the signs will and former produce (+,+,+,-). convention (2-53). the conditions Only two combi- the desired The analysis although result, that those follows the other would and (2-59) into eq. be valid. Substituting (2-49) and solving sin a eqs. (2-54), (2-58) for sina yields (1-I) I 2 Vp' + 12 I)q + q' (2-61) 57 a Substituting eqs. (2-55), (2-58) and (2-59) into eq. (2-50) 4 produces Cosa(1 + I')p' 2 /'p' 2 Similar manipulations the desired forms of = sinp with (-2-62) eqs. (2-51) sinp and cosp, - 6 + q'2 and (2-52) provide 6 viz.., ( 1 I'I)p (1__ (2-63) a 2 /p,2 + q'2 a and a cosp = (1 + I') Vp' 2 + q' 2 + (1 2 - )q p 2 + q' 6 (2-64) 6 58 01 Making use of eqs. exponential in eq. exp{-j[(r through (2-64) , the complex (2-45) is seen to be + m)p + (- 1)mr = (2-61) (r - m)a.} = 2 (p'2 + q1 2 )(m-r)/ (p'I' + jq') r(p + jq')-m (2-65) The will dependence now first. be of U nr) (T) determined. Substituting eqs. The on range (2-59) and 59 the elements r<-m will be p' and q' considered (2-60) into eq. (2-46), 4 U (m, r) n+m (n+) [(1+p ,2+q, 2)- 1/2 (p,2+q,2 ) (1 -I'1)/4 1-m-r 1 (p, 2 + q12 )( +I 2 + q,2 -1/2 - (1 + p, [-n-r, n+1-r; (P, 2 + 1-m-r; )/4 m-r a ,2) (1-I')/2 2 2 I (1l+p'2 +q,2 r < -m a a (2-66) a After some manipulation, eq. (2-66) becomes 6 (m,r) U2n = (_,)n+m (n~) (1+p,2+q' 2 )r(P2+q,2)(I'm-r)/2 , IM (1-I' )/2 S2F 1[-n-r, n+1-r; 1-m-r; 2 (1 + p' 2 + q' ) I IM r < -m (2-67) 0 60 01 40 The hypergeometric gonal tion Jacobi function polynomials may be replaced- by P (a,b) (x) n by the the using orthodefini- [16] P (a,b) I _ (x) ta+a) 2F 1 (-, +a+b+1; a+1; ) (2-68) if X = n+r, 1 a = -m-r, and b = m-r. Hence, (-m-r,m-r) (-m-rm-r)1-x X) 2 F (-n-r, n+l-r; 1-m-r; ) n+r (2-69) The argument of the Jacobi polynomial, x, may be determined by solving the algebraic equation 1-x (p 2 + (1 + p' (12 + q') The solution is given by 61 )/2 (2-70) 4 ,2 - p' 2 . 2 (1 + p' + q' 2 ) _(1 - (2-71) 41 a is (2-71) of eq. An interpretation made by :..amining the dot product representation of the rotation matrix in eq. (2-53), viz., f') (f -g') (f - w') (g - f') (g - g') (g - w') (w f') (w - g') (w w') (f a M = (2-72) 61 The body columns frame frame. of eq. (2-72) vectors basis Comparison of the the same element of eq. are as the components coordinatized (3,3) element of in eq. the of the third satellite (2-72) 6 with (2-53) shows 61 A 0. p A ' 2 _q12 ' = (1 -+p 2 1 + p' + q 1 (2-73) 0 62 0 0 The dot third product body orbital of the unit planes, normals denoted in to the eq. satellite (2-73), and is equal to the cosine of the mutual inclination and is evidently the negative of the x in eq. (2-71). duct by the symbol y, (2-69) eq. P (-m-r,m-r) (-) 1 n-r) Representing the dot procan be rewritten F as (-n-r,n+1-r;1-m-r;)+Y n+r (2-74) Replacing the hypergeometric function in eq. (2-67) by eq. (2-74) produces U(mr) (-1)n+m (1+p,2 +q2)r (p12 +q1 2 )(I'm-r)/ 2 . S +(-m-r,m-r) n+r r Using < -m the identity for Jacobi polynomials 63 (2-75) [171 a P(a,b) n transforms eq. -_) (2-75) U (,r = (-1)n p(b,a) n (2-76) (x) into 41 a 2 (-1)mnr (1+p,2+q1 )r (P, 2 +q 2 ) (I'm-r)/2, , p(m-r, -m-r) n+r 6 r (2-77) < -m 09 Substituting eqs. an expression S ( p',q') (2-77) and (2-65) into eq. (2-45) provides for S (m,r) (p'q') 2n = (1+p, 2 +q )r (p, 2 +q 2 0 2 )[(I'+1)m/2]-r n+ r r < -m 0 CT) 01 2-78) 64 0 Examination of the direct and retrograde cases of eq. (2-78) leads to the more compact expression, S (mr)(p,,q,) r (1 + p, =(I') jq, (p 2 + q1 2 )r (m-r,-m-r) n+r ,)I'm-r r < -m (2-79) A similar procedure is used to determine the function S (m,r) (p',q') when 2n portant eq. proviso. r > Whereas -m. However, the there hypergeometric is an function imin (2-47) is valid over the entire range r > -m, care must be taken to ensure that the Jacobi polynomial representation is also valid. r > -m into In fact, it is necessary to break the range the subranges -m the requirement. A different corresponding each strated. (2-47) to Substituting < r < m and r > m to satisfy Jacobi subrange. eqs. polynomial This (2-59) will and leads to, after some simplification, 65 is now (2-60) required be demon- into eq. - + p,2 + ( m,r) U 2,2 (P, 2 + q' 2 ) (r-I'm)/2 61 (Y) , p(r-m,r+m) n-r a (2-80) The validity determined by of the the Jacobi polynomial restriction satisfy the constraints that the in eq. two (2-80) is superscripts 6 [16] r - m > -1 (2-81) + m > -1 (2-82) r a 6] Since r and m can only be integers, the constraint relations may be rewritten as r - m > 0 (2-83) r + m > 0 (2-84) a 66 40 Only r > eqs. (2-83) m will and satisfy the (2-84). As valid over the range (2-65) into eq. (2-47) yields S (mr) (p',qI) r a > m. inequality result, eq. Substituting m-r (1+p, 2+q (. 1 ) (' ' (p' I '+jg' ) 2 relations (2-80) eqs. )-r (P 2 +q )-m 2 is in only (2-80) and ) (1-I')m/2 . (r-m,r+m) ( r > m ) (2-85 ) Examination of the direct and retrograde cases of eq. (2-85) allows the more compact expression S mr)(pq,) (_.fl m-r =r + ( (P r > m 67 2 (1 + p' 2 + q 1 )-r j'I)r-I'm () P(r-mr+m) n-r (2-86) 4 a form Finding range, -m < m, is < r (2-47) of eq. sub- remaining the by using accomplished the hypergeometric formation of over a function, [16], linear trans- viz., c-a-b 2 F 1 (a,b;c;z) = (1 - a 2 F 1 (c-a,c-b;c;z) z) (2-87) After eq. matching the parameters in 4 eq. (2-47) with those a of (2-87), one obtains 4 2 F 1 (r-n,n+r+1;1+m+r;cos2 = (sin2 T)m-r 2 6 T F 1 (1+m+n,m-n;1+m+r;cos2 T 6 (2-88) 61 Recalling function that may be the first two interchanged arguments and of applying a eq. hypergeometric (2-68), leads to 6 68 09 (r~m~-m)((n+m) n+r p(rmrm_ n-r (n+r) n-m m-r P (r+m,m-r) n-m (sin2 (2-89) Finally, substituting Jacobi polynomial eq. identity of eq. (-)r-m P(r-mr+m)(y) n-r (2-59) for sinT (2-76), eq. (n+m)!(n-m)! (n+r)!(n-r)! and using the (2-89) becomes (1 +p12 +q1 2 )r-m (p12 +q 12 )(1+I')(m-r)/ 2 p(m-r,r+m) ( n-m (2-90) Replacing P nrm,r+m) (Y) hand of side eq. (2-90) in yields plification, 69 eq. the (2-86) result, by after the some right sim- a S (m,r) 2n 2 r (n+m)!(n-m)! (1+p12 +q1 (n+r) !(n-r) !g () ,) m , ,-q m-I'r P(m-r,r+m)() ,P (p-jq )fl Prn-m 0 -m < r < m A collection of S (mr) (p',q') the final (2-91) expressions for the function is given in Table 2-1. hand sides of the The right Lagrangian VOP equations contain partial derivatives of the disturbing potential with respect to the satellite tial the inertially referred p and q orbit. variables The is Earth's gravity potential already p and q elements. elements formulated By contrast, in in directly of the equinocterms of an inclination function that depends on the relative quantities p' and q' was intro- duced when the third body disturbing potential with respect (p',q') set of to the satellite frame. The must be related to the element pair intermediate so quantities, that the was derived element pair (p,q) through a dynamical par- 70 40 Table 2-1. Form of the function S(m, S ' 2n - r p(m - r, - m - r) , jq,)I'm n+r + p,2 + 2)r (p 0 (p', q') (p, q'). r < -m S 2n S 2n , )r (n + m)( (n - m)! (n + r)! (n - r)! ((m, r) (p', '( (p', q') = (P)r(m- 1+ p, 2 2 + q, )- (p,- j qI)m - I'r ,(m - r, r + m) n - m 2 r( 1 +p,2 + q, )-r (p'+ jq' ,')r - l'm p(r - m, r + m) n -r r 71 > m that recognizing under may a a change of appear taken. The product is be can derivatives tial dot coordinates The different. problem is numerically although direction the invariant form analytical cosines of by solved the third body orbital plane unit normal with respect to the satellite 6 reference frame are formally represented by the dot products ^ a f A A = g - w' (2-93) = w - w' (2-94) y The right ^ 14 = hand aw sides (2-92) of eq. (2-92) through (2-94) form the third column of the dot product rotation matrix that relates the third verified body by to the frame looking at eq. its counterpart in eq. a = frame. satellite (2-72). Matching can be that column to This (2-53) leads to 2p' (2-95) 1+p' +q' 72 4 -2q 1+p' (2-96) +q' 2 (1-p, _q, 2)11 ,2 1+p' 2 Eqs. (2-97) (2-95) through (2-97) are the result of using satellite frame coordinates to compute the direction cosines. trast, if inertial coordinates are used to By con- compute the direction cosine dot products, then the elements p and q are introduced naturally lite frame. Hence, (p',q') space body potential would allow through and the a, 8 the unit and (p,q) space. inclination dynamical y vectors of the satel- form the bridge between Thus, transforming.the third function partial to direction derivatives to cosines be taken through the chain rules, as(m,r) 2n ap _ + as(mr) 2n - 9a as(mr) 2n ay(-8 3a ap as(mr) + __2n a0 5p + ay (2-9 8) 73 a and a as(m,r) 2n as(m,r) 3a 2n. Da _ aq + as (m, r) 2n aq aa 01 as(m,r) + 2n 37 9q 09 (2-99) The transformation from p' manipulating eqs. and q' to a, (2-95) to (2-97). 8, and Eq. y is made by (2-97) leads to the 61 relation (1+ p' 2 + q' 2 2 1+I y (2-100) g 61 Using eq. (2-100) in conjunction with eqs. (2-95) and (2-96) produces the set of identities (P' - jq'I') = 'il) 1 + I'-Y ___+ (2-101) 74 01 (p' = jq') - yields Table 2-2 jOI') 1 + V' y through (2-100) after in used the analysis body frame the which the to cosines. direction into Table 2-1 The and follows, the the aid To relating should newly both formulae in Table 2-2 matrix frame satellite for regard implementation. numerical Using (2-103) (2-103) .simplification the direct and retrograde cases. are (2-102) y ca (P I + jq'I') Substitution of eqs. ' (a + 1 +I be the third converted developed in to identities, the result is 1+I'y-a 2 M 1 - +- - aa a(y+I') a(1+I 'y) UI+Y-s25, a (1+I'y) -(+-f)I'y) y(1+I 'y) / (2-104) 75 a Table 2-2. Form of the functior. S(m, r) 2r (1 + l'Y)-I'm 6 (a+ j Al')I'm - r ,(m - r, - m-r) n+r s(m, r) ,)r s(m, r) 2n , r 2-m (n + m)! (n - m)! (1+ 'Y) 'r (n + r ! (n - rl 2n -m m - I'r ,(m - r, r + m) n- m < r< m 09 s(m, 2n r) ,,)r m -mr 2-r (1 + V'y) I'm (a,- r Il r- I'm ,(rn -r- m, r + m) > m 6- 76 0 09 At present the potential is expressed in terms of the true longitude. high This formulation is particularly useful for eccentricity orbital times eccentricity when essential changing mensurable it than is closed to the is mean true in and true longitude motion is nonlinear. collateral effect of case disturbing choice whose retains the there are However, the Since the mean longitude of it longitude, motions. a more natural the since form. mean satellite their derivative motion, nance in the orbits, in This choice. resonance where time satellite X, can of third body the is equal for be body are com- unperturbed to the the study of dependence an mean reso- on the mean Using the mean longitude also has the simplifying the structure of the short periodic recovery functions that are discussed in Chapter 3. The mean transformation longitude is made from through the true longitude the Hansen to expansion the which has the form [18] n. ( a )emL0 t=- 77 n,m t0 jt( 2-105) 4 where the index t is an integer and the modified Hansen co- I efficients, Yn,m, t are in polynomials the eccentricity defined by 61 Yn,m t = (k + a=0 t Y ,m t = (k - Newcomb (2-107) are recurrence 2 -nm (h + k2 a 0 X n,m in eqs. (2-106) constants which are governed For a (+t-m,2 further discussion and by U1 by simple of these U1 operators see Appendix A. Multiplying 0 (2-107) >11m operators, relations. (2-106) 0 > numerical (h 2 + k 27 < m jh)t-m t The Xn,-m a+m- t,a jh)m-t I numerator and denominator of eq. (2-44) (r/a)n produces 01 78 01 n U' =Re r -S ( r) =2 n e jrL, ,0 ( n r = K V (a FrM7-0 m n,m r=-n m n, ()n e-jmL (2-108) Applying the Hansen expansion of eq. (2-105) n VK M-0 V m n,m with appro- priate changes yields n U' = (a Re { 1 (F n= 2 -S (m,r) (a,6,y) ejrL' ' t=-O t ,-m n Y9v nn,r r=-n (k,h) ejtX} (2-109) Similarly, multiplying (2-109) (r'/a')n+l by numerator and using and eq. denominator (2-105) with quired notation changes leads to the final result 79 of eq. the re- a n U' =Re a - (2)a n=2 n I m=0 Y) - S(m,r) 2ns=- t=-- n ,m Km r=-n -n-1,r s (k' n,r 6 h' 0 (2-110) - Yn,-m (k,h) exp[j(tX + sV')]} t Compare with this the frame which contains potential derived in the 0 equatorial the additional inclination function and corresponding summation, viz., 0 n U' = Re{ -- . I n=2 y n n m=0 r=-n g *(ms) (p, q s=-n Y - n,r u=-W (k,h) t=-- ,r mnr) 0 y-n-1 u s(k',h') exp[j(tX + uX' (2-111) 80 0 The asterisk primed (*) represents parameters elements the of reference frame complex eq. (2-111) body as computed are not to be in third and the The of geometry third body satellite the equinoctial the in confused with equatorial the third Body Orbital Elements on Induced Dependence of Third Satellite are The (2-110). body elements of eq. 2.2.3 conjugate. Orbital Elements primed the parameters perturbing potential frame, was these in body eq. (2-110) describe However, orbit. developed with parameters are since respect not to the the the inertially referred.The next sections discuss the functional dependence of the third body elements on the satellite elements that is induced These by the results choice are of a non-inertial necessary before eq. reference frame. (2-110) can be used to develop the satellite equations of motion. 2.2.3.1 The Meaning of h' and k' The elements h' and k' are formally defined by k' = e' - f' (2-112) 81 a A h The = body third and be computed vector can eccentricity position inertial (2-113) - f' e' (v') 1 , and (r') 1 vectors, velocity from the through the formula (e') (- = 1 The symbol vector - I magnitudes reference frame. universal gravitational The the P* parameter is expressed unnecessary is are they constant - vector notation The since (r')1 '-I' (v(r')') ~(2-114) * ( )i indicates that coordinates. inertial 7) - v' of independent is the sum of and the of product the in for the the masses of the central body and the perturbing body. The vectors in eqs. (2-112) and (2-113) must be expressed in a common coordinate system for the dot products to be performed. The first two columns A matrix in satellite eq. (2-104), give the f' and of the rotation A g' unit vectors in 0 (S) coordinates, viz., 82 0 A (f'T) [1+I'y-a2 1+I 'y -a, -a( y+I' ) (2-115) (g T) = [-ac I', +y-a2I' -a(1+I Y)] (2-116) The eccentricity is transformed from inertial coordinates to satellite coordinates by the operation I (e')S (fT (gT = (e_')I (WT (2-117) Eq. (2-117) can be rewritten 83 in terms of dot products as, (e' the Using = transpose (g) - (e' (w) (e operator (2-118) scalar the to denote product and recognizing that the order of the vectors is immaterial, eqs. (2-112) and may (2-113) be written in frame satellite coordinates as k' = (f' h' = (g' T) S (e') -S (2-119) (e') (2-120) and Finally, eqs. substituting eqs. (2-119) and and k'. (2-115), y = 1, into For the special case the third body frame with those of the satellite. and k' and (2-118) (2-120) yields the final expressions for h' They are given in Table 2-3. of a = a = 0 and for h' (2-116) In that case, axes coincide the expressions assume the well known forms 84 0 k' - h' = 1 1±I'y {- +I'y- ' 2 A ctM[(f), - a(y + I') (g) - w SS e e [(w)- (e')I]} 00 UL 1+I'y I Table 2-3. + [I' + y - 2 [(g)- (e')] - (1 + Iy)[(w) Functional Form of the Third Body Elements, h' and k' 4 kA k'= (f)1 S (e' ) (2-121) and a 0 A h' - (e') =(g) (2-122) a 2.2.3.2 The Meaning of The mean ' longitude of the body, third ', is deter- a mined from Kepler's equation in equinoctial elements a = where F' is the F' - k' sin F' + h' third body (2-123) cos F' eccentric longitude defined a through the relations [15] cos F = 2 k' + (1 + k' V) a' /1 - X' 01 - h' 2 - k, 2 (2-124) 0 0 86 sin F' h' = + (1 h' 2 - a' /1 Y' - h' a -k' (2-125) The parameter a' has the meaning (2-126) = ' 1 + /1 - h' 2 - k,2 while X' and Y' are formally represented by X = r' - (2-127) = r' - (2-128) and 87 a The procedure leading decomposition of third body to Table any vector that Hence, orbit. 2-3 by is lies applicable in analogy, the X' plane and Y' to the of the may 61 be computed according to 4 X= {[1 + Vy - a2 1 [(f) 0(r') I] - 0 - (r')I] a$[(g) 1 - - a(y + ')[M) - (r')I]} 0 (2-129) 0 and Y 1+I'y + [I' - (r')1 ] + + y - a21'] 0 - (1 + I'y) [w - (r') ]}. (2-130) 88 0 40 2.2.4 Steps for the Evaluation of Third Body Quantities The following steps are body parameters a, 8, y, h', 1) used to k' and compute ' in eq. the third (2-110): Given the position and velocity components of the third body in (v') 1 , compute vector, (e') 1 , normal inertial coordinates, from (2-114) eq. and eccentricity body third the (r')1 and the unit body orbital plane from to the disturbing the cross product, (W) 2) Given = the construct (w)1 Unit p and the unit [(r') 1 q (V)I] X elements inertially vectors of (2-131) of the satellite, referred the (f)1 , satellite (g)1 , reference frame using eqs. (2-23) through (2-25). 3) Compute the the direction disturbing respect to the body satellite through (2-94). 89 cosines, unit a, a, orbital frame from and normal eqs. y, of with (2-92) 4) Compute the Table 2-3 third body using the results elements h' of steps and (1) k' from through (3). 5) Compute the third body mean longitude, X', from the expressions presented in Section 2.2.3.2. 90 0 Chapter 3 Isolating Long Term Motion in the Satellite Dynamical Equations The previous body disturbing elements. chapter potential the complex that { Re = the quantity depend satellite precision form in non-singular and the of the third equinoctial orbit slow directly into constants elements equinoctial equations body. are the (31) ej(t+ consolidates disturbing the dynamical potential *t,s on * to' t s=- t=-c tors a The result has the structure U' The developed A system and fac- of both of high obtained by Lagrange Planetary substituting equa- tions. The harmonic content of the high precision satellite equations is determined angles + sX' - as tX Contributions to the well by as the the satellite linear more motion combination slowly of varying stemming from fast $t,s*t,s are most noticeably a result of variations in the third body orbital parameters. Examples are the thirty day oscillation 91 a in the lunar eccentricity perigee advance. several classes The and the 8.9 combination year tX + period of lunar contributes sX' frequencies, each of which has of dynamical an analogous counterpart in the theory of a satellite moving under the influence of the Earth's non-spherical gravity potential. These classes are summarized in Table 3-1. of a satellite s'olely to tion. In to of equations the restrict mission analysis, constraints over satellite. On comparison In either other the to case, a numerical integraprior a geometrical satisfy lifetime operational to be the goal may time span that is of the utility anticipated knowledge will orbit hand, height over a serves and the goal may be to verify the projected the minimum perigee in satellite a that launch of size step of the long term the in information dispensable is motion illustration excellent harmonic the of much where case an provides analysis Mission the of ensure quite a long satellite. evolution of the satellite orbit is sufficient. 92 6 a w 0 w w 4p w CONSTRAINTS ON INDICES IN tx + sx' PERIOD OF TRIGONOMETRIC ARGUMENT, tX + sX' P = SATELLITE PERIOD P' = DISTURBING BODY PERIOD ZONAL ANALOGS t # 0, s = 0 P/ItI, "M-DAILY" ANALOGS t TESSERAL ANALOGS t # 0, s DESIGNATION L~J 0 = 0, s # 0 0 P'/ s t = 0, s Table 3-1. = 0 IsI, = 1,2,3,... s = 1,2,3,... P/ It + sP/P' Itl SECULAR iti = 1,2,3,... = 1,2,3,... 00 w w REMARKS DEPENDS SOLELY ON SATELLITE MEAN MOTION DEPENDS SOLELY ON THIRD BODY MEAN MOTION RESONANT TERMS (i.e., t+sP/P'~ 0) PRODUCE OSCILLATIONS WITH LONG PERIODS IN RELATION TO THE SATELLITE PERIOD DOUBLE AVERAGED TERM Harmonic Contributions of the Trigonometric Argument tX + sX' w 4 high tions equations of X and X'. arising from Methods for precision rapidly varying combina- smoothing $t,s are outside thesis. the scope of this The Generalized Method of Averaging 3.1 The technique the in use study of the theory, context of satellite remove short periodic motion that restrict differential developed was from by [4 ], In the is employed to the equations of method oscillations an eliminate oscillations. non-linear is by Mitropolsky and extended Krylov and Bocoliubov [ 3 ], of system formalism mathematical The equations. to used be a from (GMA) Averaging can which frequencies dynamical of Method Generalized asymptotic for on high the from components frequency dynamical based theory, averaging Method of Averaging, that can be used to re- the Generalized move an derives chapter This I integration. mean elements expense. the short averaged the The resulting may be integrated of of the numerical equations of motion averaged at reduced in computational The GMA also allows for the analytical recovery of periodic at the Hence, an variations orbit generator. high precision orbital elements time size step the averaged is output approximation of the to the available at each output generator orbit points by evaluating 6 the 94 4 periodic corrections depends on Chapter 5 the to order the of demonstrates mean the how elements. asymptotic this The accuracy averaging approximation theory. is used to initialize the averaged equations of mot-ion. The Generalized used for the high determination of , 221. of fast satellite average is central body algorithms depend essential have rate in the short to on an the single of area where frequencies an that body, central the a the examples to remove [21 remove cases in arc orbits been based some found of already been satellite Researchers to algorithmic ef f iciency is [23 1 . is an analogous consideration for high altitude There moving satellites and averaging of operation, rotation has usually have However, perturbations the prediction appropriate. averaging on method the variable. not additional precision of Averaging low and medium altitude Efficient application Method under the influence of the sun and moon when extensive mission analysis and very long term stability studies are induced by step . size attempted. the of Similarly, Variations in the in orbit moon moving numerical the its integration apparent motion to of at satellite can restrict most the motion sun 3.5 the days about [23] the Earth can place an upper bound on the step size of around 45 95 a days. Any averaging goperation that removes the satellite . variable fast from the An of motion, but ignores the motion of a third body caused by periodic variations inappropriate. equations satellite the of average effective is dynamical equations must be based on eliminating the rapidly varying in members of combination the where {#t,s} set the a is $t,s linear and third body mean longitudes satellite given by, The an averaging section derives following the (3-2) tx + sX' tos= $t,s- frequencies associated with the composite angles, 3.1 .1 An Averaging Theory removes that Averaging, of Method Generalized based on theory, Under Moving for Satellites the Influence of a Disturbing Body Given eq. (3-1), evolution the the equations of the motion describing by a third body perturbed for a satellite represented schematically as potential in orbital have the form [15] 6 da. 00 (a.a S- k=1 j$ 00 Re t=-0o s=-co k 9ak i e = 1,...,5 t t,s S (3-3) 96 61 and dt - n(al) 6 1 - a k=1 (a6,ak) 0 00 t=-oo s=-- Re{ k *tsejt,sI (3-4) where (aiak) is a Poisson bracket and n(al) is the mean motion. satellite The asymptotic formalism of the Generalized Method of Averaging Hence, presence depends on the the high precision of dynamical a small equations parameter, are v. required to have the form, da d. = v F (a, { t i (a, ) };a'(a) to's_ - = 1,...,5 and 97 _ (3-5) 4 dA_ n(a1 ) + v F 6 (a = , s(a,X)};a'(a)) (3-6) where 4 a a E vector of orbital elements; the slowly varying satellite a A aT = [a,h,k,p,q] 3mean longitude of the satellite 4 a'(a) vector of satellite ing orbit; t,s parameters a'T = dependent slowly varyof the perturbing body a [a' ,h',k',ary] (a,A)E tX + sX'(a) a A'(a) satellite dependent mean longitude of the third body 0 98 The dependence orbital satellite Chapter of to 2 $t,s and on reflects elements develop a' the the the disturbing slowly decision varying potential in the averaging theory developed in this chapter can be specialized to the case of satellite non-inertial The in made frame. a potential developed in coordinates by neglecting inertial the induced dependencies. In two the analysis subsets. {ag,m}. {Pj,k}. One other The The so determined is that the follows, is set the averaged set is broken into rapidly varying angles, slowly varying angles, of of equations members no that of {$t,s) motion of are {aIm} to be appear. Accordingly, the assumed form of the averaged dynamics is da. N v Ai i = (a, {pj,k(a,~X)};a'(a)) 1,...,5 and 99 (3-7) 4 - N ) + n(a - 1 v A6,p Vj,k 4 h a'(a)) (a,) p= (3-8) a where (-) the symbol denotes the mean and 4 y. (a,X) j,k -- jX = + kX' (3-9) (a) a The existence of a parameter that of Method Generalized transformation near-identity connects element the mean assumes Averaging in space the to the small the high a The transformation equations are precision element space. N VP n a. + = a (a, {~yX a (a,~1) }; a' (a)) P=1 i where ni,p periodic interval in is a the [0,27r]. (3-10) = 1,...,6 function that members of is the required set to be {5',m(a,T)} jointly on the Also, a 100 68 a L,m The as yet objective The precision is to Ai,p of equations (3-11) create expressions and is approach to to Ti,p in motion relating functions both develop in the which are the high of sides of terms transformation, identity near LX + mA'(a) = -- undetermined known. The (a,) elements. mean the with conjunction assumed form of the averaged equations of motion, is used to the transform sides hand left the of precision high The right hand sides of the osculating equations equations. are expanded in a Taylor series about the mean elements with the aid of the near identity transformation. the transformed order relating all remove functional dependence form small expressions set the on The then equated to parameter Ai,p functions Ai,p. of are are and ni,p to yield recovery periodic produce to averaged then {~X,m} on an to the function then known. nli,p is To the begin, differentiated there the These quantities. equations the in basis order by expressions known dynamical Both sides of with near respect identity to time. is no explicit time variation of orbital elements and that transformation It is assumed that the slow third body whatever change occurs the motion of the satellite orbital plane. 101 is comes from Accordingly a da. an. 5 N da. 1t 9a an. a 1 _ p=1 an. 5 aa' - ,p + q q=1 n=1 9an (Xm) am + n +t~ an = a an. da i n (xm) a at m 1,...,6 (3-12) 0 The with respect to of consequence potential of derivatives partial in the expressing is not are the disturbing body third the frame which a coordinate elements orbital satellite the parameters body disturbing the reference system of the numerical integration. The function of Ai,p is averaged the the assumed form eq. (3-12). The result now introduced equations 0 by of substituting motion into 0 is 61 40 40 102 40 da. N dt p= 1 N VP A. I + lip p= 1 an. + ( ,,m) a irp 3a I' i + 3an 5 an n=1 aa + aa' an. 5 X N 9 q=1 a q n r= 1 3an n, r + N an. + ( -tm) X I [(xn + mn' ) r r=1 i = 1,...,5 and 103 A 6 ,r (3-13) 4 dX N =N I n + P=1 = d dt A6,p v (,m) -,m aan aX,m { vP 5 I + (X,m) _6(, aaXm q=1 an aa' q ar= 9a -n + mn') + 4 + 6,p ,p N ] I vrA n rI n [ r=1 4 r N [ an an 6, an6p+ + [ n=1 p=1 3a an + 5 I + v A]6 41 (3-14) where n' and (3-14) viz, [15] is the disturbing can be expressed body mean as a pure motion. power Eqs. series (3-13) in v, I I 104 a a da. an. N dt 1 VP {A. P= + (. (Xm) ',p +ri +mn') + 3a1 p-1 5 + + an I[ I,p-w n=1 w=1 5 an. aan 1,p-w Ba' q=1 q I ( Irm) an. 2 xI'm 3aa (£,m) + an aa' + n an. P-1 w=1 + A6,w} + O( a.- i = 1,...,5 and 105 v N+ 1 (3-15) a d - N + dt 5 p-1 + w1j 5 an + mn') P.3"M g P + q + am 6,p-w Tm6 Dan ( A~m) am Dan aa' q=1 (Zn+ (tXm) a 6,p-w 1 + {A 6,p1+ an6 w=1 n1-1 v a _q ]- An,w + an a an P-1 _6,p-w a + w=1 (Xm) A6,w} + O(vN+1) a (3-16) 6 The summation on w is not performed when p = 1 so that no contribution is made at first order. The of motion right hand are Substituting now the hand sides of eqs. sides of the high precision equations expressed in transformation (3-5) and terms equations (3-6) yields 106 of mean elements. into the 61 right is a a da -i dt N = vF[ a+ VP I p= 'n 1 N N I ( ts + X VP P= 1 n + I p=1 VP n6,p ' N a (a + X VP n ~-P P= 1 )] i = 1,...,.5 (3-17) and dAX N = n(a + v I 1 P= n ) + N N N + vF[a+ V p , t,s VP -. + P= a ,~\+ = vp6,p P= N a' (a + P= 1 vP n )] (3-18) 107 4 where .p is a vector of periodic recovery functions asso- 4 with ciated the in Expanding elements. satellite slow a Taylor series about the mean elements, a da. = v F {its (, a'(a) +X) 5 + Vn= n=1 + { n! 5 Da' 1 q=1 aa k N pI k= 1 p= 1 (a,, VP n k,p (Dak + t,s (t (t,s) aak a ts q a + N I 1 p= t vp n 6 s) a 0t Fs }n F. 1 a = a to's i = 1,...,5 ts t" (3-19) a 6 and 6 6 108 a =X dt + v F6 Nn 0 = n=1 ( t a)) ),)} 5 1 }n -3a n(a)1 n=1 N k=1 5 a' I q= 1 aa + a a + at- n! +v + a 1,p n (t,s) k p=1 Dak 4"s N aq k ) + v2 t s6,p t p=1 4trs (ts) }n F6 (3-20) The right hand sides of eqs. osculating hand sides follows Equating element of that eqs. these them and rates. (3-15) (3-19) and The same and (3-16). express'ions must matching is (3-20) represent the true the right Consequently, be equal coefficients of of to each like it other. powers of the small parameter leads to equations that relate the A and n- functions to the known F function basis. 109 on an order by order 4 In many instances, the first order approximation produces results of complexity. striking A first accuracy order with formulation minimal analytical of the averaged equa- tions of motion and periodic recovery functions will now be developed to provide the basis for the numerical demonstra- tion. 3.1.2 A First Order Averaging Theory Using the methods described in the preceding section, the set of first order equations for Ai,p and ni,p are found to be Fi(a, AA. + {~t, 5 Qa.,,X)}; a' _, J1jl 1 (Zn + mn') (X ,m) -,X _' Ia (a)) I 6 a' (') + (a, {~lm(a,X)}; i = 1,...,5 a' (a)) (3-21) 110 a and, recognizing that n(a 1 ) = 1 3 n a1 + F6 SA + n- ,1 (a, - -X)}; a' (a) + j,k(afX) }; as (Xn + mn') (X,m) I- -3/2 al }; a' (a)) - ' 6 1/2 an 6 1 _ ' = (a)) + (a, {a Xm (a, Ax)}; a'(a)) (3-22) 111 The by desired expressions averaging successively of member on dependence all the A the are determined and (3-22) over interval [0,27r] to varying rapidly the functions (3-21) eqs. {a t ,m} on set the for remove first At angles. each order, the slow elements of the satellite and the third body held are of independence the over fixed is angles the interval averaging and The assumed. mutual periodic recovery functions are required to be jointly 2w periodic in angles the of set the the are set Hence {at,m}. then the following properties hold f 11 f 0 2w 2 da 1 [- 2 2 ] 1, f 0 ... 0 da ] ,m n-1,mn-i { elements - inrmn' of [151 I (in (Lm) daX the {a1,m1 by denoted if ,m - + mn , Da3 m 0 n mn i = 1,... ,6 (3-23) and 112 0 1 [ 2xi f 2w 0 ... 2w 2w 2w 1 f ... 0 f 1[27r 0 daxnmn da n-1mn-1 3 n 2 - ni1i }da 1 tam ] - =0 (3-24) The right hand sides of the averaged equations of motion are then seen to be A i ,1(a2, {ii. k( a,,X)}I; 27t - 7r - da a' (a) ) 0 X ,m1 2w 2w [L -. 1[ da Xn-1,Im F (a,{t, , };a' (a) ) - 0 0 ].. f n- 1 i ] dan ,mn = 1,...,6 113 (3-25) 4 Eq. (3-25) shows that at first order, the averaged equations of motion are obtained by substituting mean quantities the right hand of sides equations, followed by a the high removal of precision into satellite terms depending all on any of the rapidly rotating phases. Now recovery that the functions Ai,i are functions known, the partial =l F -A9 by given are the periodic differential equations, (in + mn') (Z , m) aM X i = 1,...,5 (3-26) and. ( Zm) +mn') 6,1 aa ,m ( 6 F A ,1 3 2 n a 1 1 (3-27) 114 a If the notation sides hand right [I ] ( ,m) of eqs. is used and (3-26) to denote (3-27) a term in the that depends on 72 ,m, (in + mn') = aa~,m (,m) i (Zm) [Fi - A il] (Lm) = 1,...,5 (3-28) and 6,1 (Yn + mn') (Z,m) 3~IM al (Im) (3-29) For a (3-29) given pair (Z*,m*) , the solutions are 115 to eqs. (3-28) and 4 T).1- ~ Ti,1 f - m F -A , Z*n+m*n' ] d+ + f 4 i = 1,...,5 (3-30) 4 and 4 1 161 f Z*n+m*n' 6' F [(F - 3 7 A 6 1) 2 ' n ~~ a l 1] ' (1*m*) 4 - ~+ (3-31) where of f({at,m}') fast forward angles to show and g({a,,m}') that excludes that each of which depends these are of functions -t*,m*. It functions must be a is the set straight- sum of terms on exactly one of the angles 116 4 in the I01 set {[a,ml' tical to (3-31). be Further, that of the each term leading has term a form that of eqs. is (3-30) idenand This shows that the periodic recovery functions may separated into a sum of functions, the form 117 'ni,1, ,m, that have 4 Chapter 4 Mathematical Structure of a Dynamical Third Body Model for the Long Term Prediction of Satellite Orbits Using Numerical Methods The goal numerical orbits tool for to construct this thesis for the long term third body perturbation which 3 and is of furnish Chapters 2 chapter synthesizes the analytical these prediction algorithm that prediction of is flexible satellite significant. components. components is a into an This orbit numerically efficient and free from singularities. I In Chapter It derived. noctial the is orbital satellite 2, the formulated elements dynamical potential is expressed governed by recurrence eliminate the calculations. respect frame in terms of non-singular in order to avoid equations. in terms relations. inefficiency equi- singularities in Wherever of potential was possible, functions This was with associated which done I the are to explicit Furthermore, the potential was developed with to the choice third body disturbing This reference satellite reference frame. eliminates a summation and the corresponding 118 a function. inclination the third body elements on the satellite side-effect of A h', k', orientation and this choice X' acquire elements p a is that dependence and q. The potential is restated here in the functional form, U' = Re{ I t=- sP1F~ -e ts 1 s=-I [a; a',h'(p,q),k'(p,q),a,O,y] } (4-1) where Re{ } real part of a complex quantity aT {a,h,k,p,q} tS[p,q, X] tX + sX'(pq) J 119 4 and *t,s has the structure h'(p,q), a', an= 2 * Ysn-1,r 5 n nI r=0 - [k'(pq), a,O,y] k'(p,q), n L KV r=-n h'(pq)] Yn,-m t = Vm n ,r S (m, r) 2n (~,Y (k,h) (4-2) The definitions of the various blocks in eq. (4-2) are found 6 in Chapter 2. The high precision satellite equations for third body perturbations are potential of eq. obtained by substituting the 1 disturbing (4-1) into the expressions, 4 6 da =k- 1 (al,ak) k=1 Ta~ k ak 6 i = 1,...,5 (4-3) a 120 a and 6 dX n - t (X,ak) x k=1 (4-4) - k where [a ,,a2 ,a 3 ,a4 ,a s a 61 E [a,h,k,p,q,XI third U's body disturbing potential A table orbital of the E Poisson bracket n = satellite mean motion non-zero elements is in Table 4-1. (ai ,ak) Poisson found in brackets Reference in 16 and is The result of the substitution is 121 equinoctial reproduced 4 I Table 4-1. Nonzero Poisson brackets of the equinoctial elements. (a, ) = (X, h) = (, k) = -ks (, p) = (X, q) (h, k) -2as 1 (h, p) = -kps5 (h, q) = -kqs 5 (k, p) = hps5 -Ps 5 (k, q) = hqs 5 = -qs (p, q) =- = -sl S3 4 5 I 4 s2s5 where na2 s2= s3 = s4 - S4 s5 41 1 Si 1+p 2 +q 2 1 - h 2 -k 2 S sg3 5l S 3 2 S----2s3 122 6 a. i16 + = ni. 6 - Re{ CO I 5 k=1 t=-co0 (ai,') it t,s 5 t=-00 s=-00 i = 6 t's + _ e, t,s (a ,p) Pt, s + (aiq) Qt,s -Re{ where (a.,a ) -2 1 k)a k e ts } 1,.,6 (4-5) i6 is the Kronecker delta function defined by i 0 6 i6 = = 1,...,5 (4-6) ; i = 6 Also, Ptrs * t,s ~9h' ak' + a3k' + j * t s t (4-7) and 123 ,p 4 ah, *ts ah'- -q- + 3*t,s -3k' Wk' 31 - 3q j. 41 3q t~s (4-8) a The form of eq. (4-5) hinges on the auxiliary expressions, 61 *t 'ws *t Is 3a + ast is 3 + 3Y ths ay 0 (4-9) a and t s 3*t s 3q-9 Da q *t's + a~ 36 -- a 1t Y s -3Y aq 0 (4-10) The partial Table 2-3. derivatives 3(h',k')/D(p,q) are obtained from The specific results are given in Section 4.3. 124 0 0 The operators 3/3a, the explicit appearance inclination Pt,s orbital function of the the frame through the on *t,s solely direction a,y). The third body elements orientation When the disturbing through cosines (a, S(mr)2 n connect plane. act 9/3y Qt,s and inertial a/Da, of the potential in the functions the to satellite is developed with respect to an inertial frame, Pt,s and Qt,s vanish. In Chapter developed, of for 3, a the differential that with equations much equations. are fast angles. larger step averaging of frequencies that the averaged equations a order elimination combinations of two is first theory from a system produced by can be numerically integrated size than the high precision Initialization of the averaged equations is made theory that allows recovery of the short periodics at the output by linear The benefit of the theory of the possible was the feature for the times of the numerical integration. The results high of applying precision mathematical explored. of remainder first order satellite form of Finally, this the the chapter averaging equations partial recursive prediction algorithm is detailed. 125 in discusses the methods the eq. (4-5). derivatives nature of to The is fully the orbit 4 4.1 Order First Averaged Equations Motion of for Third a Body Perturbation The first order averaging 3 transforms a system of theory developed high precision in Chapter differential equa- a tions of the form, da. = v F (a, i {$,s (a,X); a' (a)) = 1,...,5 (4-11) 61 and dX = n + v F ' It dta s(a, A)}; a' (a)) (a))' (4-12) a into a system of averaged equations of motion in mean ele- 6 ments having the form da. = V A {ij,k (a, ( i = 1 126 , ' (a)) (4-13) and dX = - dt6,1n + vA ~- jk k 11j, ' - - (a, - a' (a)) (4-14) where ni is the mean mean motion defined by n = n(a) 1/2 - = and -3/2 (4-1 5) {Pj,k} is a set of slowly varying mean angles. The transformation hand sides of eqs. of eq. (4-5). (4-11) comparing the is begun by and (4-12) to the right hand right sides This leads to a representation for the high precision forcing function, viz., 127 4 v F S 5a = - Re{ s=-0 t=-0 + (a., X) - Re{ jt $ I [ X - 4 t,s + k _ t,s s I (a ,ak k= 1 - [(a ,p) Pt,s + I (ai,q) Qt,s t=-- s=-- ] te 4 i = 1,...,6 (4-16) 4 Mean elements are then substituted directly in place of high precision satellite elements in eq. 0 v FI = - 00 5 Re{[ (a t=-ew s=-co . (a , A) Jt$t,s]e - Re{ a (4-16) to yield ikas k=1 t + Baak t s 6 [(a.,p) P 1=-s- i =1 128 a t,s ,6 + (a.,q) Q 0 t,s i ] e t,s 0 (4-17) 6 01 the of the interval and satellite the averaging {Ft,s} taken stipulation of In an to set {ct,s} on for the slow held the the set in The independent. in that terms qt*,s* are unaffected average over a cycle of that angle. Hence, one of over ensures angle mean elements fixed angles the mutually be to the are body addition, independence contain expressions order, first disturbing interval. are not produces At vAi,3. functions, do [0,27] the of respect with (4-17) members varying rapidly each eq. averaging Successively vFi by that an is concerned with evaluating integrals of the form I - f - 2w 0 + (a,)j 1 5ts Re{[ (a1 ,ak) k=1 *t*s* 0 2 t*s* 3ak } ts jtt* __ Re([(a ,p)Pt*,s* + i = dcpt*,s* (a1 ,q)Qt*s* 1,...,6 129 s* - dt*s* (4-18) According integral also some to the of eq. rules of (4-18) vanishes. The second first is integral identically zero, although the reasons for this deserve consideration. definitions for f2 Tr 1 Eqs. #~t,s into eq. definitions (4-7) and + _ S, integrals and can *t*,s*- be ____* t * Differentiating of if t*s* ',} - dct*,s* returning this (4-19) partial the are these + ap e the the form, 1,...,6 = 9~t*,s*/aq by _s ] vanish shown provide Substitution t*,s* i These (4-8) (4-18) produces integrals oi Re{[(a,p)j (aq)j - and Ut's- 0 This averaging, the first order independent to relation the derivatives of $t*,s*. expression with respect for to -p and q leads to, 130 01 d - * [t*X + s*X'(p,q)] = s* 4-)ap (4-20) and _'__ =_- q a [t*X + = s*X' (p,q)] - s* aq 3q (4-21) The mean as the longitude of the third sum of a dynamical A' (t,p,q) = ' body, A', may be thought term and a geometrical ar (t - DYNAMICAL t 0) + X' 0 term, of viz., (p'q) GEOMETRICAL (4-22) where 131 4 t E current time to m reference time reference -alue of the mean longitude X'O The dynamical as X' changes third the is reference frame independent It in its orbit. body moves how term describes since it depends only on the elapsed time from a reference and third the on semi-major body X' as resulting orbital vectors, plane map f' and in in in the invariant the the variation of satellite the orientation of a rotation into g', term reflects changes from Variations elements. plane and p the q satellite body unit of the third of the disturbing body The rotation changes the datum with respect to which orbit. X'0 the geometrical is which At a point in the third under coordinate transformations. body orbit, axis is measured, causing X' to vary in turn. Differentation of eq. (4-22) with respect to p and q yields the intuitively satisfying results 0 (4-23) 132 0 and a' ax10 aq aq Substituting eqs. (4-23) (4-24) and (4-24) into eqs. (4-20) and (4-21) leads to the desired relations t*,* ap -s* ax' 0 (4-25) t*,* =s* ax' 0 (4-26) and __ __ _ 133 I t*,s*/3p Hence, angle by change At measured. '0 /a4 and that in the first order, the int,.egral of eq. preceding for procedure averaged {Ft,s} that motion to map be into the the for on from which ' is Da' 0 /p derivatives averaging the caused simply leads to vAi,1 functions of an motion. retained in interval, extremely of Those the members so of vAi,1. At first in equations index set s eq. and those index pairs gives first angles the t simple the averaged on summations the produce only expressions the specific Restricting {(ts)}. (4-17) to result equations are line partial over depend is $t*,s* of the not (4-19) vanishes. obtaining order do reference constant are The of 3 t*,s*/Dq variation The *t*,s*- the and in the defining terms order, depending on other indices cannot contribute to the averaged equations of motion. 0 A philosophy for retaining index pairs in the averaged equations of motion will now be developed. 4.1.1 Criteria for Retaining Terms in the Averaged Equa- tions of Motion Averaging ing dynamical is merely frequencies a formal from a technique system of for eliminat- differential 134 6 to is It equations. judiciously retained in third period double averaged problem, dynamics in of that motion, can be entails are so be to that the realized. identifying the For long (4-17). terms. linear this analyst the mission frequencies averaging kernel dynamical averaged trivial eq. task of equations advantages of body The the those specify the computational the therefore of eq. (4-17) consists of the These are terms which depend on combination of the satellite the and disturbing body mean longitudes, viz., If no further represent as transformations the irreducible in embodied j0,0. step admissible Accordingly, (4-27) 0 t=0,s=0 size additional are made, minimum Hence, for terms of harmonic they a then these dynamics determine the maximum integration. numerical considered information, for inclusion in the averaged equations of motion should have periods that do not restrict dictated satisfying by the the such integration double step size averaged a requirement 135 could to less dynamics. be than that Candidates introduced in the 4 the when case the and satellite third commensurable in their mean motions. N where and geometrical repeat long This phenomenon, known N N' are (4-28) N' of linear combinations of the X and third to disturbing satellite in the that states (4-28) satellite of revolutions variations periodic Eq. integers. relationship every nearly may be expressed mathematically as as third body resonance, n are body motion will body body. the Since occur 6 for X' that are slowly varying, one obtains the auxiliary condition S If two body = relations are (4-29) 0 tx + sx' used, then eq. (4-29) can be 0 rewritten in terms of the mean motions of the satellite and third body, viz., $t's= tn + sn' ~ 136 0 (4-30) The union of eq. (4-30) eq. (4-28) leads to the constraint relation tN + sN' with the statement of resonance 0 = in (4-31) which provides a filter for the values of t and s that give rise to included eq. long in the (4-31) averaging terms period averaged in eq. equations (4-17) of motion. is a generalized constraint that a as special Hence case. are found by restricting the indices satisfy eq. motion are 4.2 Given (4-31). this, the seen to have the form found be Notice that includes double functions vAi,1 (4-17) so as to in eq. the could that averaged equations of in Table 4-2. Mathematical Form of the Periodic Recovery Functions Those terms in eq. tribute periods to the unecessarily tion. (4-17) for which tN + sN' satellite motion restrict the step that are * 0 condeemed to size of a numerical integra- In accordance with the methods detailed in Chapter 3, the amplitudes of these periodic variations can be recovered as a orbit function of generator the mean through element the integrals 137 output evaluation of of the the averaged indefinite I 6 Table 4-2. Form of the first order averaged equations of motion for third body perturbation. 5 (aii, ak) A Re S5i6- k=1 5) PO,0 + (ai 00 + ( k 0,0 I DOUBLE AVERAGED TERMS cc - Re cc 5 (ail ak) A E2E t=-o= s=-0o k=1 ak 5) rP ~ +(ail X)it t s+(ail 5 tN + sN' = 0 t # 0, s, 0 jot3,s + (i;,ii (4-32) 5,s RESONANT TERMS a40 ,ah' 0 0, h' aji aPo ak'. ak' I a5 ' 0 ' 0,0 ah' ah' ai q ak' g 4 61 138 61 00 V,1 t=-o 0 v0 i ,1,t,s s=- tN+SN'#0 1 f Re{[ - t=- S=-- tn+sn' 5 I k=1 - k t (a ,a s + aa k tN+ sN '#0 + (.,~\) jt ~p + (a., + (ai .,) )P i = 1,...,5 and 139 ] e Its}d~ts (4-33) 4 = v n6,1l 0 o v n6,1,t,s t=-co s=-m 4 tN+sN' *0 co s1n s=co t=-" a 5 f [Re{[ tn+sn' 0 I (X k=1 ,ak) aak t, s + tN+sN' #0 a + ( ,P)Ptf + (,~q) 5 ,, S + 3. ] e t a V nl 1 ,1,t,,s] ts a (4-34) a where V,n Ah Ak 0 1 v21 vn 3,1 Ap vn Aq vn5, 1 Ax vn6 , 1 (4-35) 01 1 61 and a 140 a Aa. 1 Notice that = a. 1 eq. - i = 1,...,6 a. 1 (4-34) has taken into Poisson bracket (T,T) is equal to zero. notation can be achieved by complex quantities 141 defining (4-36) account A that the simplification of the slowly varying a and (4-33) Eqs. (4-34) may then be rewritten as 4 1 V nl, t=-w f Re(Miets.t,s dt s s=-w tn+sn 4 tN+sN' *0 i = 1,...,5 (4-39) and 4 V n 6,1 f = t=-cc s=-c0 [ReM tn+sn, s e 6 ,t,s a tN+sN' #0 3 n 2 - a v 48 dit,s 1,1,t,s (4-40) Expressions varying for variations the periodic satellite elements forward integration of eq. are obtained (4-39). 142 in the by five the slowly straight- 01 The result is: 61 a vn. = - i,1 t=-oo Re{j M. s=-oo t1 tn+sni 1, t,s e tjs tN+ SN' #0 i = 1,...,5 The periodic correction for the satellite mean longitude is determined in two steps. V n = (4-41) From eq. - trn+sn, (4-41), one finds, Re{j Mts ,' e ftFs (4-42) Substituting eq. (4-42) into eq. (4-40) and 143 integrating, 4 v fl 1 6,1 3 2 = n a t01 CO Re{M e ts _ g (tn+sn') tN+ sN' *0 4 Retj t=-0 s=-O M 6 ,ts e t, s tn+sn' tN+sN' *0 a (4-43) a Eqs.. and (4-41) into its (4-43) can be rewritten by breaking Mi,t,s real and imaginary parts, viz., a M. 1, t,s 5 = ) Re(M. + j Im(Mi. (4-44) ) 41 and by recalling e jt, s that - cos *t's + j sin (4-45) t s 4 After performing the complex multiplications the real part, one obtains, and extracting 4 144 4 00 v fnl Im(M.,, ~ - 0 { ={ 1 t=- s=-w Im(M. ) it~s tn+sn' Cos + $ tN+ sN'1#0 Re (M. ItI) _ + sin tn+sn' i (4-46) =5 and 3 v n6,1 t=- {0 s =S Re(M n a 1,t,s ) tn+sn' + Im(M)6t s ',' tn + sn' tN+sN'#0 3 Co - + - n a Im(M _ -1,t,s tn+sn' ) tn + sn + Re(M sin t,s (4-47) 145 4 in formulated of problem problems of a into functions, to those to simplify the found eqs. Accordingly, forms of which in the central are shared the the as (4-46) and the by the and both (4-47) may be short periodic mathematically identical body of problem. I computational includes that classes distinct longitude structure package software three mean common The to perturbations, body the satellite angle. analogous is central can be exploited perturbations. cast variables, fast terms of hour Greenwich flow two as perturbations, body third non-spherical in formulated ,wo of problem The The results are: Zonal analogs; t #0, [v-lil]zonals I t=1 s = 0 it,0 i cos it,0 = 1,...,6 + Si't, sin t,0 (4-48) where I t,o (4-49) =t~ and 1 146 a [Im(M 1,t,0 tn ) - L,t,0 Im(M i,-t,0) i 1,... = 5 (4-50) [Re (M Si,t, 0 tn ,-t, ,t,0) + Re(Mi 0)I 1 3 C6 ,t,0 tn + Im(M 6 ,t 0 ) - Im(M 1 1 Re (M6 ,t, ) + Re (M6 0 ] _o 1, t ,0 ) + (4-51) I + Im(M1 ,-t ,0 + tn t s-monthly or s-yearly terms; [v n ) - Re(M1,r-t,0 - Im(m 6 ,-t, 0 n a tn + 1 ,t,0 a _1 t, 0 Re (M a -o i,os i = (4-52) t0 ) = 0, s 0 cos I0,s + gi,0,s sin *O,s} 1,...,6 147 (4-53) a where a (4-54) SsX' p0, s 4 and c1,0,s = ( 1m(M 1 ,0 ,s ) ] + -m(M 10 0 = (4-55) s1,0,s = 1 Re (M1 , 6b 01 ) + Re (M1,,- (4-56) a ci,o,s = (~+Im(M, 0,s - i,,-s I i =2,.,6 i si,0,S S[ Re(M,0 ,) + Re(M,0 ,) ] (4-57) 6 148 4 Tesseral t analogs; [v n 0 _s * 0, ]tesseral - i,t,s Cos s-i t=-t#0 tN-sN' -s + 0 + Sivt s sin it,-s i = ... (4-58) ,6 where t-S = (4-59) tx - sx' and ci,t,s - tn2 sn' [ I(Mi,t,-s) - Im(Mi, ts i=1,...,5 (4-60) 5. i~t~s = tn-sn, [ Re(Mi..- ) + Re(Mi. ,s1-~ ~ 149 ~) a 1 tn-sn' 3 2 S 6,t,s + Im(M 6 Re(M1r t,-s)- - a- - ,t,-s) Re(M1,-trs) tn - + sn' 4 Im(M 6 ,-t,5s) a (4-61) 1 _ _ tn-sn 3 - 2 a + + Im(M1,t,- s)+Im(M1,t,s tn sn' - a + Re(M 6,t,-s 5 ) +,s (4-62) functions the Eqs. expansions of classes and variations periodic periodic short of 6 reproduces (4-53) (4-48), the three exactly just described (4-47). problem. of union The a the and Fourier are (4-58) for (4-46) eqs. third body 6 The ~ and coefficients expansion S are functions of only the slowly varying elements of the satellite and the disturbing be body. calculated averaged explicitly orbit intermediate This property allows the the on and generator times. The form coefficients to integration grid interpolated of the Fourier of at the any series 150 a developed for compatible with Early [24] the third body interpolator for the perturbation software already central body theory so that problem is created by implementa- tion is straightforward. 4.3 Formulation of the Third Body Theory for Numerical Computation Sections 4.1 and 4.2 described the formal representations of the third body averaged equations of motion and the short periodic implementation requires a computed functions. of an detailed and an averaged knowledge For third understanding of and its the partial mean longitude, A', of the a numerical prediction the properties methodology of with the to It also involves establishing the be their entails an complex of to for respect derivatives theory quantities body perturbations, this form of the partial elements of derivatives related quantities. tional orbit efficient computation. t,,s However, function satellite the func- third body with respect to the mean equinoctial p,q satellite. The nature of considered first. For convenience, Tt,s is restated here 151 Tt,s will be 4 (- I, t, s Y n n Y-n-1 ,r [k'(piq), h'(pq)] ,r) (a,,Y) nr m=0 Km n,m r=-n n=2 Ytn- 41 (k,ih) a (4-63) a The complex factors inclination coefficients may be t,s of S (m,r) function Y -n-1,r formally broken into imbedded and 2n Yn,-m, t ' and s are its real the the Hansen S function The and in a imaginary parts to yield the expression, I S (m, r) (a,a, y) = C (a, a) j D r(a, + a) ] A(y) (4-6m (4-64) where depending on the following definitions relationship of r to m, one of the is used a 152 S(m, S2 n , r2 r (1 +I') r)I')Im-r aj2(+, Pn+r() Cr+Dr m r) A(y) m (4-65) r < -m S(m,r) 2n -( m-Ir W)r 2 -m (n+m)!(n-m)! (1 +I'Y)Ir (n+r)!(n-r)! P(m-r,r+m)() n-m Cr +D rA(y) m m Ay -m < r ()r()m-r (r-jOI')r-I'm S(mr)= 2n (4-66) < m 2 r( 1 +IY)I'mP(r-m,r+m) n-r jDr m Cm + A(y) r > m The third product real of body a power Hansen complex series in (4-67) coefficient polynomial the may be broken into a in h' and k' and square of the disturbing the purely body orbital eccentricity, viz., s = (k' - jn'h') |r-sI K sn-l,r s 153 (4-68) where a K- n-1 ,r s X-n-1 _ U ,r e 2i ,g1i+ \Gtq i+ a (4-69) q = s - (4-70) r a (4-71) = sign(q) n' 61 The expansion Their coefficients, computation Appendix A. The and X, are storage are satellite Hansen the Newcomb discussed in coefficients operators. detail have in the a similar form n,-m t _ m-tI -- Kn, -m t (4-72) 0 where a 154 69 S0 gn,-m 2 Kn,-m t i=0 i+2 - 2 i' 2i (4-73) 2 q = t + m (4-74) n = sign(q) (4-75) Substituting eqs. (4-64), (4-68) and (4-72) into the expression for *t,s yields n I n a-) n= 2 m=0 n KmV 0 (k - t m j-nh)|-m-t|} If the designation is made 155 m A(y) r=-n - K-n-1,r KnF-m {(Cr + j D r) (k' s m - jnlh') r-s I (4-76) a j B r,m Ar,m + s,t s,t = (k' - jn'h')|r-sI (k - jn -)m-t| I (4-77) a and the complex then Tt,s is multiplication a ts n= 2 - eq. is (4-76) performed, form seen to have the - in n a ) a n n m=0 ,m K K-n-1,r Kn,m {(ArIn st t s r=-n ,r A(y) - a C m -C Br,m s,t a + j(B rm s( t Cr s t D m )} m + Ar,m 4 (4-78) a If Vnm and Vmn,r are grouped into the aggregate function 61 Zm n,r mV n,m n,r (4-79) a 156 4 then eq. (4-78) becomes - y, sa t s n=2 (ta n n n I m0 K m r=-n s(Ar,tm m s{rt Kn,-m t B st ,m Dr) m + m- , r m n,r A(y) Kn5 j(Br,m st C m + Ar,m s,t Dr)} m (4-80) The final form considerations. of is Tt,s The Jacobi by shaped polynomial practical embedded in A(Y) is governed by a recurrence relation which will soon be introduced. It is employed to ensure that the recurrence advantageous to compute Jacobi increasing subscript, polynomials it since is for in the direction of that direction convenient starting values can be determined. the summations summation purposes restricted over of a of n eq. is (4-80) are innermost. numerical program, to run over finite that Accordingly, so that the Furthermore, for the the must reordered ranges. indices Hence, the *t,s used in the numerical implementation is 157 is be form of 01 M Xj r=R%1 m=0 N x R2 t, Km t - a n=max(2,m,r ) ,r Kn,-m {(Ar,m C K-ns (a/a')n Zn,r A(y) st B r,m Dr) + m st m Dr)} (B rm m st s,t C mr+Ar,m 40 (4-81 ) a The requires software implementation of the derivatives: the following partial third body theory 01 40 01 09 158 h partial t,S R2 = aiE at r=R - -n-1,r [ 2K S + M N - j(Brm s,t m= 0 dKn, -m t de (a/a') n=max(2,m, n A(y) - Ir) {(Ar~m Cr - Br,m Dr) + s,t M s,t M r m + A rm s,t DMr)} + + Kn,-m t K mi { s,t 9h, CrAr,m 3B r,m DrB s,t m M _ + aih j( rm Cr 3A ,m Dr St m + M sot ah aih (4-83) Eq. (4-83) has been derived by employing 3 Kn,-m t h d Kn,-m t d e 2 - 2 9e 3h where 159 the relation (4-84) -2 ae a (4-85) 2h = + - 2) -2 6 k partial R2 a3K 01 a -K-n-1 ,r[ s N M (a/a')n Z r=R1 m=0 2K n=max(2,m, Ir dKn, -m t de 2 r A(Y) - ) 61 Cr {(Ar,m s,t m - Dr) + Br,m s,t m 01 + j(B r~m s,t + K ,-m t Cr + Ar,m Dr) + s,t m m 9Ar,mCr s,t m ak B r,m Dr m s,t ak 3B r,m + j( _st + 9Ar,m Dr m s,t qk (4-86) 01 01 4 61 160 09 apartial t,s a -Kn-1,r s - R2 ir M a M0 Kn,-m 1 t Br,m a +(sot -+ + N n,r m n=max(2,m, r) A r Fm aC r Br,m aDr s,t m _ st 3a a7 ) + Ar,m 3Dr s ,t a (4-87) 161 Spartial a t, s 8 _ R2 y. a-' r=R SK- n-1,r Kn, t s Br ,m + ( s "t m aCr M m= N m nmax(2,m, Ar ,m (s t acr m _ Brm s,t n,r |r|) 6 3Dr + 0 A rm 9Dr + s Ft a 6 (4-88) 162 4 DT t,s = y-, R2 M N , K r=x mn=max (2,m, Ir m= 0 K- n-1,r Kn -m((Ar, m Cr s t sit + j(Brm s,t m - n I) Brm s,t Dr) m m dA + r r)} m + A rm s,t Dm (4-89) 163 0 h' partial = BhI Kn,-m 6 2 M r=R m=0 N Km dK-n 1 ,r 2h, dms | |) n=max(2,m, (Arm r - (aa ) n ,r A( y)- Br,m Dr) + + j(Br~m c r + Ar,m Dr)} + ss m sdt s~t m + -n-,r s 3B r,m Dr 9Ar,m Cr m) + m _ ( st h3h' Mh' 3B r,m Cr m j(asht 3Ar,m Dr m st 3h'. (4-90) 6 6 6 164 4 k' partial M N Zn ,r A(y) (a/a') n z K m= 0 r=R "n=max(2,m, r - ) mI Kn, -m t + [2k, j(Brm s,t Cr mf + K-n-1r{ s + dK-n-1 ,r s de' 2 - Br,m Dr) + C (Ar,m s,t m s ,t m + A rm D r)} + s,t DAr,m s,t 3k' m Cr m aBr,m ak aBr,m Dr M) + s,t 3Ar,m Dr m) s,t + ak' I (4-91) In view of eqs. (4-7) through (4-10), the ary partial derivatives are also required: 165 following auxili- 4 ap -- (T+I'y) c + 2 ' " '"' ~ ~ a ' 4 (4-92) I I' q k' where 9h' - 3q 2 I I'{(1 c I I 1+Iv y-- + 2 c (4-93) >2 + q 2 + = - I'Y) (h' (w - e') y[a(f - - p k'} + - e') + 0(g e' (4-94) 9k' 2 1 r -. ,. . ,. - ,,1 166 is --- = 2 9q {8k' + a(g - e') (1I' - 8(f - e')} + c I I' (4-96) h' c and [17] ga 2 apc c 3a 3q 2 = I c [q I 8 + y] (4-97) p8 (4-98) (4-99) c 2 I (pc - y) (4-100) c 2 (4-101) c ay 2 (4-102) C 167 4 partial The derivatives of longitude with respect to the mean q are determined as follows. the third body mean satellite elements p and dependence The functional of X' may be given by, 4 'I = '[(r') (4-103) , (v') S] 41 where (r')s and are (v')s third the position body By the velocity vectors in the satellite frame coordi'nates. the partial chain rule, derivatives X' with respect of and to p a and q have the form a 3 -- [T 3r' (r r'_)_ s T s [3X']T [ - s T 3(v') 39 (4-104) a and 3;1' 3 I(r' [ 3(r Ax']T - ) s+[ 4 3(v' s 3'T s05 3(r')s (4-105) 168 4 4 4 where the superscript denotes third body ephemerides are tial coordinate the generally eqs. system, Since transpose. available (4-104) and in an (4-105) the inerare rewritten using the transformation relations: (r' )s = [f g w]T (4-106) (v' )s - = [f g w]T (v) (4-107) and where vectors result (r') 1 of of and the (v') 1 third substituting are the in body eqs. inertial (4-106) (4-104) and (4-105) is, 169 position and and velocity coordinates. (4-107) into The eqs. 4 A AA AL ap- - [ax 7 (r )J ]T [.2- s ] p p (r') 1 + I _p A A A + [a] [a) a ap (v - )s ap ap - ]w IT (v) 6 - (4-108) 4 and -(r') s aq- [ aq- T e aq aq a A 'a 3(v )s ' aq T (v'I aq aq aq 4 (4-109) 11 Analytical the satellite lite p and [17] expressions exist frame for derivatives the partial of unit vectors with respect to the satel- q elements. As taken from a work by McClain a they are, 4 170 0' af = --- 2 - (q - ap I (4-110) g + w) c AC af 2 - - 39 c ap = c I p g (4-111) I q f (4-112) I(p f-w) (4-113) =_ aq C = f W (4-114) aw 2 _ Making use 4-3. The longitude of C eqs. partial with (4-115) I g - aq through (4-110) derivatives respect to the velocity vectors have closed found in a work by Shaver of (4-115) the disturbing leads third body to Table body position mean and form representations which are [25]. 171 They are: 0 0 Table 4-3. Partial derivatives of the third body mean longitude with respect to the mean satellite elements p, q. 01 2 = ap c ax' [q lg+w Iqif -f | 61 + 51T ] T[ q |I g+ w -lq -T (~)l} (4-116) Is aq [ai )S] T 2fF S c[ar')sJ (v')s] - I - ^p- ) I-w T I7 pg I-1(pf -W) -1g L lpg 0 -f (p-w)I lg] (4-117) 0 0 172 01 0 axv'= - -n =r + -s , a ,2 1 ~ + k' (h' 1 (q' i'f - 1-h' -k' n , a 12 I' ) a - p' g' ') (h' [h'g ] + ks 4) f + - w' (4-118) and 3a' 6'/1-h'j -k'1 2 n a2 n a - + ax (h' + (h' 1= ay + k' aX' k) fI g'] + k' + + 1 g (q'Y'I' - p'X' )w' (4-119) 173 4 where it is all that understood calculations performed I [25] in satellite frame coordinates and 8' = are 1 (4-120) 1+/1-h' 4 (4-121) 41 2 -k'2 A X' = r' cos L' = r Y' = r' = r' sin L' -f' (4-122) - 4 -n' a' (h' + sin L') , h' 2 - 1- (4-123) k 4 n'a'(k' + cos L') ,s 2 /1 - h' - (4-124) k a G' n'a' 2 = /1 h (4-125) k i k' ' k ni ax' = - + a' + g Y' I' (4-126) a ay' = - a' k''fi'g k (X'Y' + G' ) (4-127) 174 01 ax, =l h' S'X' ,f (4-128) - G') aT' n'S ' = ay' X' x' - 2 + a ', a r 3 (4-129) _ (G'k' a'X' - n'a'Y, 2 2 -h2 (4-130) =i- al j'i' a' + G' 3h' r' 3 /1 -h' (G'k' 8'Y' 2 + n'a'X'Y' ) 2 -k' (4-131) 3A' 3kT , , a' _ r' /11-h' (G'h' a'X' + n'a'X'Y') 2 -k' 2 (4-132) =- ar '2 3 r' 1 v1 -h' (G'h' S'Y' 2 - n'a'X'2 ) 2 _k'1 (4-133) 175 41 4.4 Calculation of Special Functions 4 Calculation of Zm n,r 4.4.1 Zn,r = m 41 is defined by The coefficient Zm' n,r n n,r n,m (4-134) a where a V n,rn S(n-r) (n+n)! (4-135) m (0) n,rn a Vm n,r - (4-136) (n-r) (n-m)!! P n,r (0) 01 and the Legendre (4-135) functions functions (4-136) and Z r n,r Pn,m( 0 ) of and argument into eq. Pn,r(0 ) zero. are associated Substituting eqs. a (4-134) yields (n-r)! (n+rn)! P n,rn (0) P n,r (0) (4-137) 0 0 176 61 The indices positive n and are m constrained However, integers. the positive and negative values. eq. (4-137) to computational positive r. consider, form for index being when r is r over may only assume the both (4-137) r > 0 and 0. A is now determined for A simple symmetry relation compute Z m , n,r run Hence, there are two cases of those eq. to r < will then be used to negative. r _> 0 Eq. [17] (4-137) is written in terms of double factorials by recognizing that P n,m (0) = (-1) (n-m)/2 (n+m-1)!! (n-m)!! (4-138) (0) = -(-1) (n-r)/2 (n+r-1)!! (n-r)!! (4-139) and P n,r where the definition is made (-1)!! = (4-140) 1 177 4 Substituting eqs. (4-138) and (4-139) into eq. (4-137) 4 yields Zm n,r (n-r) ! (n+m) ! 1) (n-m) /2 (n+m-1 )!! (-1) (n-r)/2 (n-m)!! (n+r-1 )!! (n-r)!! 4 (4-141) 4 or after simplification I n[(r+m)/2] Zm n,r r > 0 (n-r-1)!! (n+m)!! (n+r-1)!! (n-m)!! (4-142) r < 0 I a Replacing r by -r in eq. (4-142) produces the expres- sion 178 6 n+[(r-m)/2] Zm n ,-r (n+r-1)!! (n-r-1)!! (n+m)!! (n-m)!! (4-143) Comparing eq. The ty. The (4-143) Zm coefficient exploitation calculations in a (4-142) to eq. has n~r of this numerical leads an interesting property program. immediately to It helps is to easy properminimize to show that the following relations are true P n,r(0) = 0 ; |n-ri = odd (4-145) Pn,m (0) = 0 ; In-ml = odd (4-146) and 179 4 Hence, all 2P n,r even or must have all odd. the if vanishes indices r, m and Thus the members of the triad if a term in the same parity n are not (r,m,n) -corresponding ii to that set of indices is to be non-zero. 4.4.2 Their Partial and Polynomials Calculation of Jacobi Derivatives by Recurrence The function A(y), (4-65) eqs. m P (E) a to (4-67) through r, the contains (y), the forms of which can be found in depending on orthogonal the relationship of polynomial Jacobi where a= n + r m -r =-m r < -m (4-147) r a= n-m m -r S= T=r a T The Jacobi = = = + -m < r < m (4-148) m n- r r -m r + m polynomial r and > m its derivative (4-149) with respect to are governed by the standard recurrence relations 180 [161 Y P E (y) = (a 2 a + a 3 a Y) 4 E(S T)ay T) E a 45a 0 (4-150) and dP( ,T) a+l dy (a 22 aa + a 3 a ) ) + al P ' T) dy+ a3 3 dP~ E ( Y) a a a- a dP , ) a-i dy (4-151) where 181 4 a + 1) ( a + E + T + al . S2( a2a = (2a + C a3 a = (2a + e + + T + 1) (2 a + 1) (C 2 T) (2a+ s+ E + (4-152)' T) (4-153) 2) T + 2) (2a + E + T + 1) (4-154) a4 a = 2(a + e)(a + t)(2a + e + T + Starting values for the recurrences explicit expressions (4-155) 2) are given by the g [16] a 182 01 P , T) 0 P T) P , 1 = (4-156) =1 [C - (C + T + 2)y] T + (4-157) T) 0 (4-158) 0 = dP~ C, T) dy 4.4.3 Calculation = 1+ the of (4-159) 2 Coefficients r CCm coefficients m , Dr m and by Recurrence Their Partial Derivatives The C and Dr are defined ac- cording to + jD (a + jaI')I'm-r r < -m (4-160) (a + j6)m-I'r -m < r < m (4-161) (ca - jaI)r-I'm 183 ; r > m (4-162) a This section develops recurrence relations partial coefficients C , M Dr m and their with to a 6. Starting respect recurrences and are also determined. that recognizing eqs. (4-160) for the derivatives values for The task is through (4-162) these simplified can by be collapsed into two cases, viz, C + j m D (a + jgI')I'm-r = m r < I'm (4-163) > I'm (4-164) and Cr + m j Dr m (a r r-I'm - The exponents of the complex polynomials of eqs. are (4-164) recurrence positive that exponents. r indices recurrence corresponding because are relations the the same parity than greater sum must be required only for it and have the m must that increasingly has differ shown parity, coefficients two. integers This difference of even. recurrence relations The two by been same connect should Hence, zero. since exponents or to equal Furthermore, relations to or (4-163) and having is the follow directly: 184 6 Case I For clarity, it is appropriate to rewrite eq. (4-163) as CI'm-r + Incrementing C (I'm-r) +2 + j D I'm-r = (a + jai')I'm-r r < I'm (4-165) I'm-r by 2 leads to j D I'm-r)+2 + = (a = (a + jaI')(I'm-r)+2 jaI')I'm-r (a + jai')2 (4-166) Substituting eq. (4-165) into 185 (4-166) 4 C (I'm-r)+2-+ j D I'm-r)+2 " (CI'm-r + j DI'm-r) 4 [(a2 2) + j 2a W (4-167) a Performing the complex multiplication and equating the real and imaginary parts yields the recurrence relations I 0 0 6 The recurrences at the point r of eq. (4-168) and (4-169) are initialized = I'm, where a 186 6 01 CO (4-170) =1 r = I'm D 0 0 Recurrence CI'm-r and (4-171) relations with DI'm-r differentiating eq. 9C Im-+ 3a( for the respect partial to a may derivatives of found by be (4-165) jD.Im-r (I'm - + r)(a + jSI') I'm-r-1 4 (4-172) Incrementing I'm - aC (I'm-r)+2 + r by 2 jD(I'm-r)+2 = = (I'm-r)+21(a+jOI')(I'm-r)+1 [(I'm-r)+2] (a+j IW)I'm-r (a+j6I') (4-173) Substituting eq. (4-165) into eq. 187 (4-173) 4 3C(I'm-r)+2 .3D( + 3 3a I'm-r)+2 3a , =[(I'm-r)+2] (C I'Im-r +jD I'Im-r) I - (a 6 + jaI') (4-174) a After performing the complex multiplication and equating the real and imaginary parts, one obtains the recurrence rela- tions a(I'm-r)+2 = [(I'm-r) + 2] (aCI'm-r - I'DIm-r) 6 (4-175) 40 (I'm-r)+2 a = [(I'm-r) + 2] (IC (I I, 0 r < I'm (4-176) 0 Again, the initialization is found at the point r = I'm 188 = 0 (4-177) r 3Da = I'm 0 0 0 (4-178) 9a In similar fashion, the recurrence relations for the partial derivatives with respect to a are given by 3C( I'm-r)+2 -I'[(I'm-r) + = 2 ](aI'CIm-r + aD I m-r (4-179) D( I'm-r)+2 = I' I'm-r) + I'm with initial conditions 189 2] ( aC I Im-r - WI'DIm-r) (4-180) a =0 0 (4-181) g r = I'm =D 0 (4-182) 6 Case II Having rewritten eq. Cr-I'm + j Dr-I'm S(a (4-164) as - jaI')r-I'm r (4-183) > I'm a the recurrence relations for Cr-I'm Dr-I'm and are found to be 01 C(r-I'm)+2- (a2 _ 2)Cr-I'm + 2a$I' Dr-I'm (4-184) D(r-I'm)+2 = -2aaI' r Cr-I'm + (a > I'm - 2) Dr-I'm 61 01 (4-185) 190 0 with the initial values C = 1 (4-186) 0 (4-187) 0r DO0 The recurrence relations for the a partial deriva- tives are given by 3C(r-I m)+2 = [(r-I'm) + 2](aCI + SI'DrI' (4-188) D r-I'm)+2= [(r-I'm) + r > I'm The initialization is furnished by 191 2] (-aI'CrI + aDr-) (4-189) 4 0 = (4-190) 3D r aD0 = I'm 0 (4-191) 0 = I I Finally, the recurrence relations for the S partial deriva- a tives have the form aC(r-I'm)+2 = -I' [ (r-I'm)+2] ( IC r-I a 'm (4-192) 6 r-I'm)+2 ID = -I' [(r-I 'm) + 2] ( aCr-I 'm + SI 'D r-I 'm) 6 r > I'm (4-193) 01 The initial values are ac = 0 (4-194) r D0 61 = I'm 0 (4-195) 192 0 4.4.4 definition B r,r s,t the of Arm As,t Coefficients Derivatives Partial and their B r,Im s,t__ The the of Calculation Ar,rm s,t coefficients and come from the expression Arm + s,t jBr,m s,t k' = - jn'h') Ir-s I(j - jh) -ur-t| (4-196) where = sign(s - (4-197) r) and n = (4-198) sign(t + m) If the following definitions are made 193 a e r-s I+ jf Ir- = (k' r-s| -j'h') (4-199) and a g g |-m-t| + (4-200) -j jhl-m-tI 4 then, after equating A r,m s,t the performing real and Br,rm s,t and the complex imaginary multiplications parts, the and coefficients a are found to be 6 6 0 194 A rm = e |r-s1 9 m-t|- ~ f |r-sj -- t| h I-m- (4-201) B ,m s vt - e |r-s h |m-t| + f jr-s 9 -m-tj (4-20 2) From eq. (4-201) and (4-202), relations 195 one obtains the following a aA rm I e ir-s sot ag I-n-t| ah|-m-tl Ir-si (4-203) 4 3Ar,m st ah ag~1 e9 e -m-t e r-s h-m r-s| I 4 I4 (4-204) ae 9A r,m s 3h' tjr-s h' afr-s ~ ah |-m-t| 9 1 h 61 (4-205) a 3A r,,m -A Wk e e r-s ak' - a |_ 9 |-m-t| I r-s| k' 01 hti (4-206) and 41 0 0 196 9B r,rn s t = aiR e |r-s 9s -m-tI 3 r-s| ah (4-207) 3h -- t s t 3R~ = er-s r-s 9 -i I-m-tI 3i (4-208) 3Brm s t 3e r-s 3 h' h I-m-tj + af r -m-t 9 I (4-209) 3B ak' ' m ae |r-s ak afr-s hI-m-t + I 3k' 9 -m-ti (4-210) 197 a The coefficients eqs. of (4-199) and and (4-200) 0 their partial Since there between m derivatives are and coefficients The t, the be computed constraints parity recurrences corresponding techniques the desired no can to )t the prior are exponents section may by recurrence. between designed that be r and to differ used to s or relate by 1. achieve results: 0 e |r-s| +1 - k' e Ir-sl + n' h' f |r-sl (4-211 ) 0 f r-sj +1 e = 1 f = 0 - -n' h' e r-s + k' f ir-s| (4-212) (4-213) Ir-s =0 (4-214) 0 9 |-m-t| +1 h |-m-t| +1 ~ 91-m-t| - h gm-t + n h h-m-t| + k h |-m-t| (4-215) (4-216) 0 (4-217) -m-ti h0 0 = 0 (4-218) 0 198 0 s + = r - sj -s+ - (|r-s| f + 1) e(r- + 1) s|9 (4-219) fjr-sj (4-220) (420 3e 0 (4-221) 0 S= jr-s = 0 af0 07 D = (4-222) 0 -se+1 = ( -|L+ = -( jr-s| + 1) n' f r-s| (4-223) e2r-s24 (4-224) af r-s| + 1) n' 9e0 07= (4-225) (425 0 r-sj Sfo = = 0 0 (4-226) 199 a ag I-m-t +1 = ( |m-t| = J-m-t 1) + g (4-227) 3h -m-t +1 + 1) h I-m- ti ak = (4-228) (4-229) 0 1-m- t = 0 ah0 = +1= 9h= ag (4-230) 0 ( -m-t| -( = 0 = + 1) h-t| T n (4-231) (4-232) (4-233) I-m-t | h0 -m-ti 1) + = 0 0 (4-234) 9E 09 0 200 4 4.4.5 Recurrence Relations for the and Kernel K'-n-lr efficient S The modified Third its Hansen coefficients (k' - in' h')|rsI Body Hansen Co- Derivative for the third body have the form Y-n-1r S = Mathematical expressions polynomial already in been (4-235) introduced. of computation derivative eq. the for the The recurrence function the complex derivatives partial its are now examined. S calculation of and kernel (4-235) Kn-,r relations K ' for and have the its The two cases corresponding to s # 0 and s = 0 are considered separately. Case I; s * 0 The recurrence relation governing the third body kernel functions when the subscript is non-zero may be taken from an 1855 Hansen manuscript 201 [26]: 4 I I I where a = C -n - (4-237) 1 a and a e' 2 )-1/2 (1 - x' (4-238) a The evaluating Kc.r s -nX- of initialization 3 , the the power explicit given in eq. -nk-4, where recurrence (4-69) ny is the series for lower c is accomplished by representation of = -nt-1, bound on 61 the index n given by a 202 61 = Ir) (4-239) 2 initialization this that Note max(2,m, singularities in eq. ensures (4-236) for c = - Ir | that - the apparent 2 and c = -4 are never encountered in practice. The derivative of the kernel function with respect to e' 2 is seen to obey the recurrence relation, dKc,r s _ 2 de' ,2 x, Kc, r + s 2 {(c+2)(c+4)(2c+5) -- dKc+1,r de' + s r 2s - (c+3) (c+3) x' dKc+ 2 ,r 2 s de' [(c+2) (c+4)+2sr V1-e, Kc+ s - (c+4)[(c+2) -r2 2 ,r + s2 (c+2) 4 dKc+ ,r s de' 2 + I (4-240) The recurrence is derivative of eq. explicitly initialized (4-69), viz., 203 by evaluating the 5 dKc,r = de' 2 j=0 ((j+1) Xc,r +1 , j+ j+- e,2j 4 2 (4-241) 4 for c = -n - 1, -n -2, -n -n -3, -4. 4 Case II; s = 0 4 If s is set equal to zero in eq. (4-236) then the following specialized recurrence relation results: a Kcr 0 _ (c+2)x'2 2 2 [(c+2) -r ] (2c+5) {c+) Kc+1,r 0 c - c+3) ( Kc+2,r} 0 I (4-242) 6 The zero series subscript kernel which terminates function can be represented by a a finite after hence may be computed in closed form. tial values for eq. (4-242) number of terms and Accordingly, the ini- are given by the simple expres- 6] sions 204 61 K- rlr = 0 (4-243) K- Irl-2,r = (1 / 2 )1 1 x' 2rIl+l. (4-244) 0 0 The derivative to zero in eq. recurrence is readily setting s dKc+1,r 2 02 de' 2 by (4-240) dKc,r ,2 2 (c+2) 2 [(c+2) -r ] K0c,r + - The obtained {(2c+5) 2 dKc+ ,r (c+3) d '2 de' } 0 de'2 (4-245) initial conditions are given by dK~0|rl-1,r 02 = 0 = (1/2 )IrI+1 (2 Ir + 1) x,2|rI+3 (4-246) de' dK-I ri-2,r dO de' (4-247) 205 4 4.4.6 Recurrence Relations for the Satellite Hansen Coefficient Kernel K n, -m a and its Derivative t The modified Hansen coefficients for the satellite 41 have the form Y= The and recurrence (k - jnh) -m- relations for the t Kn,m (4-248) kernel function K n,-m t its derivative are now discussed for t * 0 and t = 0. 6 6 Case I; t * 0 The recurrence relation governing the satellite nel functions when the subscript is non-zero ker- is given by: 61 01 01 206 Kn,-m t - {(n-1) [n(n-2) 1 t2 (n-2) _ n(n-2)(2n-3) Kn 3 , m + n[ - ] 2tm Vi-e 2 2 - n- 2, -m t Kn-4 (4-249) The of initialization evaluating Kn,-m t nX+3, tialization in where the explicit nX power for (4-73) eq. is ensures in defined that accomplished by series representation of n nt, is recurrence the the eq. apparent = (4-239). ny+1, This np+ 2 , ini- singularity at n=2 is not encountered. The derivative of the kernel function with respect to e2 is seen to obey the recurrence relation 207 4 dn, -m t 2 * de t 2 1 (n-2) {tm(n-1) X Kn-2,-m t + dKn-2, -m + (n-1)[n(n-2) - 2tmV1 -e t- 2 de n(n-2) (2n-3) - n-3, -m -d- - (n-2)2 - m 2 2]Kn-4,-m + n[(n-2) 2 - m2 , -n 4 dKn- ,-m t de e 2 1 (4-250) where x The = recurrence (1 _- is (4-251) 2) -1/2 6 explicitly initialized derivative of eq. (4-73), viz., 208 by evaluating the a a a dKn, -m t d- 2 j=0 - (j+1) Xn,-m j+ e 1 2j ,j (4-252) for n = Case II; n+l, n + 2 , n., t If n k+3. = 0 both sides of (4-249) eq. are multiplied by the factor t 2 (n-2) and the index t is then set to zero, = 0 + Setting n = - (n-1)(n-2) Kn-2,0 m 2 ]1 [(n-2)2 + [(- -2 n+2 in eq. - - e (4-253) + Kn-3,-m (n-2)(2n-3) K 0 2) Kn- 4 ,-m ) K0 leads to (4-253) the specialized recurrence relation: Kn,-mK 1 n(n+1) {n(2n+1)Kn-1 , -m o - (n2 m2 - 2) Kn-2, -m 0 ( 4-254) 209 4 The zero Hence, subscript the initial kernel values may be computed for eq. (4-254) in are closed given form. by the 4 simple expressions I Km,-m 0 (-1)m m+1,-m The derivative (2m+1)!! (m+1)! m recurrence +! is (4-255) [2(m+1)+e 2 obtained by (4-256) differentiating I I eq. (4-254) dKn, -m 0 1T- de 2 I dKn-l,-m {n(2n+l) -2 n(n+1) de I1 dKn(n 2 ,-m d0- 2 de(-27 - m ) - n-2,-m (4-257) U1 The initial conditions are given by 210 41 6 dKm, -m 0 . 0 (4-258) de dK m+1,'-m 0 1 - (4-259) (m+2)! Restriction of Indices in the Third Body Theory 4.5 In a numerical must be established third )m m( (2m+1)!! 2 body orbit prediction program, a procedure for disturbing limiting potential the number of the minimum to the terms in required to accurately predict the motion of a satellite in a particular orbital regime. Once free truncation parameters have been set, this task entails the determination of constraining relations governing the indices of the multiple sum T2 S2 R2 M t=T 1 s=S r=R m=0 N (4-260) 211 n=max(2 ,m,I r) 4 In the numerical of implementation the third body theory 4 derived in this thesis, the truncation parameters are: 1) Maximum N power of the parallax factor, 4 (a~/a') 2) M* Upper bound on the satellite Hansen coefficient d'Alembert characteristic, 4 I-m-t|. 3) R* E Upper bound on the third body Hansen coefficient d'Alembert characteristic, I. r-s a The bound on the satellite Hansen coefficient d'Alembert characteristic may be mathematically expressed by a < I-m-ti (4-261) M* which translates directly to an inequality on m: -M* - t < m 212 < M* - t (4-262) 6 6 The index m is not allowed to take on arbitrary values since the application of the Addition Theorem introduced the additional constraint: 0 < m The intersection parallelogram is special case of substituting eq. M* admissible region of displayed graphically region < (4-263) (4-262) with eq. of eq. shaped < N Solving N. in (4-263) leads to a m versus Figure eq. 4-1 (4-262) same that eq. for the t and (4-263) yields the necessary bound: (4-264) solution can be derived using Figure 4-1. (4-264) The for -M* - N < t < M* This t. shows that an increase in the Notice number of multiples of the satellite mean longitude can be accomodated only by retaining more powers of the satellite eccentricity in the disturbing potential. accordance with eq. (4-264), With the t index restricted in it is well behaved constraint on m, viz., 213 now possible to write a 4 Figure 4-1. Admissible Values of the Index m vs. t N M*i -M* \, 2144 a The max( 0, on the bound -M*-t ) < m < min( third body Hansen N ) M*-t, coefficient (4-265) d'Alembert characteristic takes the mathematical form: (4-266) Ir-sI < R* which leads to -R* As in the satellite + s < r < R* the case, (4-267) + s index r cannot vary arbi- trarily because the rotation theorem for spherical harmonics provides the auxiliary inequality: -N < r < N 215 (4-268) 4 The shaped case special of substituting eq. R* N. < with region graphically seen is region The (4-267) eq. parallelogram another S. of intersection Solving eq. of in leads (4-268) Figure eq. versus r admissible 4-2 for the s and for (4-267) to 4 I (4-268) provides the required bound: 4 With the s index restricted in this way, a uniformly valid 4 constraint on r can be written, viz., I I Making (4-265) , (4-260) use (4-269) the of (4-270) , and can be recast constraints the of eqs. multiple sum (4-264), of eq. as I I 41 216 41 Figure 4-2. Admissible Values of the Index r vs. s R* 217 4 M* min(R*+s,N) R*+N 4 r=max(-N,-R*+s) s=-R*-N t=-M*-N N min(M*-t,N) m=max (0,-M*-t ) 4 n=max (2, m, I r (4-271) I Of course, necessary for to a given use the (4-271 ) simply shows selection full range the maximum of N, of t, M* and s, allowable r, R* and is it m. not Eq. 4 ranges. I I I 218 4 41 Chapter 5 Numerical Verification of the First Order Third Body Theory The first order third body averaging theory developed in was thesis this studies of results of orbital a theory that tests theory can be motion of a makes stability. numerical the used high altitude decisively it This of The predict satellite with to superior the long term presents the third show results accurately reduce and chapter implementation design. to substantially mission - analysis of expense computational to designed an that the the body the long term efficiency that conventional mission analysis techniques. The theory is applied to the long orbits five test and semi-major conditions for which span axis. the a For averaged term prediction of broad range of each test orbit, equations eccentricity of initial motion are determined from the high precision orbital elements at epoch using The a least averaged squares equations differential of motion are correction then algorithm. integrated and compared for speed and accuracy against Cowell integration. 219 4 The equations averaging version (GTDS) theory of the for are at the Amdahl 470 V/8 test furnishes order and Trajectory Charles Cambridge, Massachusetts. CSDL's first programmed Goddard modified the third interfaced with Determination Stark Draper body a System Laboratory in This version of GTDS operates on digital facilities computer. GTDS include that numerical integrators, interpolation algorithms for the short periodic coefficients, and auxiliary perturbation models. The consists software of an Averaged Periodic Generator for routines software right third hand GTDS. AOG the perturbation averaged that coefficients third (AOG) body and interface with the theory a theory of constructing equations correspond dynamics. of to motion the The SPG for the zonal, times Since the periodics SPG the coefficients averaged have a share a great equations similar many are of analytical subroutines. 220 motion and structure, for computes tesseral interpolated the double m-daily analogs on the integration grid of the AOG. other Short executive satellite is capable and resonant satellite short periodic the semianalytical The of of Orbit Generator (SPG) which the sides body averaged the in implementation and At all by GTDS. the short the AOG and the two Nevertheless, components of different the averaging fields of discussion of the indices program software can flow are independent be specified for and subroutine and each. A interactions can be found in Appendix B. Section 5.1 determination describes the of precision data. the AOG method initial employed conditions for from the high Section 5.2 presents a method for computing disturbing body ephemerides over the time long term satellite orbit prediction. spans required for The numerical results of applying the averaging theory to selected test orbits are discussed in Section 5.3. Initialization of the Averaged Equations of Motion 5.1 Given elements a at set epoch, of a high precision satellite set corresponding of orbital initial mean elements for a long term integration must be determined in a way which is consistent the with averaged equations of motion. harmonic content of the This requires the elimination of contributions to the high precision elements arising from frequencies equations element that of motion. space divergence have is to mean been If the element apparent removed conversion space between 221 from is the the satellite from osculating inaccurate, averaged then a element 4 histories and the trajectory [27]. term long trends of the high precision For the test cases discussed in this chapter, the AOG was initialized (PCE) capaoility squares epoch using of elements to trajectory integration. the The GTDS. differential mean Precise the on output of Elements procedure is a PCE algorithm correction based Conversion the of fit of high a that a least solves for semi-analytical precision I Cowell The PCE can be performed over any time span. The exact initialization procedure is as follows: 1) Given a set of initial osculating elements and an appropriate perturbation model, a high precision trajectory is produced by Cowell integration. At the integration span, the the satellite fixed intervals inertial position within rectangular and components velocity are of output to a file to represent actual observations. 222 4 2) With a and field perturbation compatible epoch, priori estimate of the mean elements at 5*0, a an where a 0 ~ (5-1) X0 ] k0 , p0 ,0 q h 0 to the osculating a semi-analytical approximation element histories is generated over the same span as the recover first the must be stressed recovery model of convergence an is essential the used to periodic short order that is SPG It elements. integrated mean the to corrections The integration. Cowell short periodic accurate ensure to the correction differential algorithm. 3) At each observation employed to velocity components determined of step compute two body relations are from the the residuals, 5b, observations from the actual 223 and position satellite orbital by semi-analytical methods. observation subtracting time, is A vector obtained computed observations. elements in by this For a single 4 observation satellite time, where T, position and the six components velocity are of computed 4 through the equations 4 S[a( T)+vn rE ( T ) rc (T - ,( 1 )+vn ( ) v 2,1 V 1,11 (T) 1 ,...,~(T)+vni X(T +V 6,11 4 (5-2) 4 the correction to the mean elements at epoch is given by the expression 4 - a* (A = T WA) -1 A T W6b (5-3) 41 In the eq. (5-3), W is Jacobian of a X weighting and X with matrix and respect A to is 7*0 evaluated at the observation time, viz., AA = 3X(t) I 9X(t) 1 (5-4) _ i* - i* - 0 0 a t= T a I a 224 Eq. can (5-4) expanded be by chain rule partial differentiation to yield: I 9X(t) 3Zt) a* (t) 3a*(t) 3a*(t) aa*(t) A I I 0 6x6 0 I- aa*(t) 0 Ba_*(t) 0 6x6 a*(t) 6x6 - 0 0 aa*(t) 0 6x6 - a* t= -r (5-5) where a*(t) is a*(t) the vector of osculating = 225 [a, h,k, p,q, ] elements (5-6) 4 At first order, aa*(t)/a3*(t), is the partial derivative 4 given by an aa*(t) I6x6 a_ =a(t I6x6 + ga*(t) where matrix, is a 6x6 (5-7) t~ 9a*(t) identity matrix. The least I I squares differential correction algorithm in GTDS is to found estimates thesis, of converge eq. eq. even (5-7). (5-7) was For for all very runs approximated identity matrix, so that eq. crude in this by the I (5-5) reduces to I K aX(t) I 0 aa*(t) aX(t) 06x6 aa*(t) ' - A= I I 3-*(t) 6x6 -; 0 t=T 41 (5-8) 41 The partial differential derivatives, equation aa*(t)/a *0 , are governed by the [22] 226 I d [a* (t)1[ -aa*(t) a* 0 a* (t)1 a* (t) 0 (5-9) with the initial conditions a*(t0 The partial observation integrated derivatives times output 3[f*(t)]/a1*(t), double-sided (5-10) 6x6 a* by of is eq. are obtained interpolating (5-9). computed in The GTDS at on the the matrix, using a finite differencing algorithm where the mean elements are varied by an amount 227 [221, 4 = Aa*(t) 10- (5-11) a*(t) 4 4) After the all the revised observations estimate to have the been mean processed, elements at 4 epoch is given by 4 a* = a* 0+ i* (5-12) 4 This new estimate in replaces the a priori estimate Step 2. 4 5) Steps 2 through 4 are until repeated a convergence criterion is met. 4 5.2 The Computation of Third Body Ephemerides In GTDS, the geocentric position and velocity I components of the sun and moon are usually obtained by evaluating Chebyshev polynomials. The coefficients of these polynomials ephemerides are computed from supplied on magnetic tape by the Jet Propulsion Laboratory (JPL) and are stored on permanent files. At the present time, I these files can accomodate requests for third body ephemerides that fall 228 4 within If a period between 1 January long numerical integrations to arbitrary very option choose an 1971 and 14 January are necessary or epoch of 1984. if the integration is desired, than an extended capability is required. For chapter, the the analytical moon. numerical extended theories capability for the theories These integrations secular are Supplement to the ,Astronomical on the solar tables of Newcomb taken provided motion Ephemeris by of the from [28] in the the this use sun of and Explanatory and are based and the lunar tables of The mean equinoctial elements Brown. moon, is discussed for the sun and in mean ecliptic of date coordinates, are given by: Mean Solar Elements a = km h'= 0.01675104 sinr k'= 0.01675104 cosr p 0.0 1= = q '= where 149598412.7 r is 0.0 2790.69668 + 0*.9856473354 d + 0*.000303 C 2 the longitude of pericenter according to 229 which is computed 4 2810.22083 + 00.0000470684 d + 0*.000453 C 2 = r 4 and 4 d = Julian days from 1900.0 C = Julian centuries from 1900.0 (C = d/36525) a Mean Lunar Elements a' = 4 km 384388.1743 h'= 0.054900489 sinr' k' 0.054900489 cosr' p' = 0.0449322554 sinil q = 0.0449322554 cosQ '= 270*.434164 + g 13*.1763965268 0.001133 C 2 d - 4 where r' is the longitude of pericenter given by, r = + 00.1114040803 d - 3340.329556 C2 00.010325 4 and 9 is the longitude of the lunar ascending node on the ecliptic, a S= 259* .183275 - 00.0529539222 d + 00.002078 C2 a 230 At each elements, two evaluation body mean ecliptic velocity of vectors equatorial the relations rectangular components in of third are T date are coordinates coordinates. then by transformed rotating Further 23*.452294 - - 00.00000164 T 2 + + 100.000000503 T 3 the to compute the them depend Julian on the position to mean through and of date the mean [28], T - 0*.0130125 of The centuries since 1950.0. reference system of the integration. Analysis of This order number rotations numerical 5.3 = is used equinoctial of the position and velocity vectors obliquity of the ecliptic given by where body the Numerical Results section describes third body averaging integration, for five test the theory, orbits. performance in of the first comparison with Cowell These test satellite orbits demonstrate the ability of the theory to predict long term motion accurately and efficiently over a wide range of orbital geometries. 231 4 For each computed by and Cowell the ephemerides the does test same of the the third body method for integration. not Except for the ISEE all orbit, enter both the any averaging the Hence, into ephemerides of source the were theory of the comparisons. test case, which used the JPL ephemeris, resulss of this section were obtained using the analytical ephemeris described in Section 5.2. 232 4 5.3.1 IUE Test Case The International (IUE) Explorer Ultraviolet orbit provides an accuracy baseline for the third body AOG and SPG before initial moving on osculating to more elements demanding of the cases. test orbit are defined Table 5-1. Table 5-1. Epoch Osculating Elements for the IUE Test Case a= 42143.48243 km e= 0.2353378723 Epoch = 7 March 1972 Ph.0,0m.0,0s.0 28.301165210 i = 199.61370900 Period =0.996 day 264.69887660 270.4208456* Radius of Perigee = 32225.5 km Radius of Apogee = 52061.4 km Lunar Parallax Factor (a/a') Solar Parallax Factor 233 ~ 0.1 (a/a')s ~ 0.0003 The in 4 The IUE orbit was chosen to demonstrate the following points: 1) The validity of the PCE procedure for obtaining I epoch mean elements from osculating elements. 2) The ability of high precision long in the AOG to trajectory comparison to track over the the an time mean arc span of a which is the PCE of initialization. I 3) The accuracy of the third body short periodic model. I 4) The remarkably long integration step size that is permitted by the third body averaging theory. The initial mean elements for the averaged of motion were obtained by performing a PCE of high spaced precision over initialization sixty days. were osculating-to-mean quadrature position to fit equations to 184 and velocity components The a priori elements provided by the GTDS sets evenly for the numerical conversion which used a 96 point Gaussian average period of the satellite the osculating t29]. trajectory over one The perturbation models used 234 61 in the PCE are given in Table 5-2. The truncation parameters N, M* and R*, in the lunar and solar models, were chosen on the basis of experience and the relative parameters such as eccentricities. the third Given the maximum ranges on the by the 4. reflects The frequency symmetry of the present to handle only indices, noted that models in the parameters Table truncation improving 5-2 are studies numerical the capability symmetrical and satellite truncation inequality relations in eqs. Chapter Model body actually are efficiency (see Chapter 6). 235 parameters, and the are given (4-264) and (4-269) of of the specified t orbital s, ranges frequency sizes of chosen third body fields. for for the without with PCE software It should be lunar and conservative required the a sacrificing view solar choices. towards accuracy 4 Table 5-2. PCE Perturbation Models for the IUE Test Case 1 ) AOG + SPG Perturbation N M* R* -5 < -5 7 N Model: EARTH MOON SUN =6 =6 =4 t < 5 s 7 5 N = M*= R*= -5 < t -5 7 s E 10 8 4 < 5 7 5 J2 NOTE: AOG retains only double averaged terms for the third body S maximum power of the parallax factor, (a/a') Hansen coefficient M* upper bound on the satellite d'Alembert characteristic R* upper bound on the third body Hansen coefficient d'Alembert characteristic 2) Cowell Perturbing Acceleration: point mass sun- point mass moon J2 236 a Since the IUE orbit is non-resonant with respect to a body, third averaged the double only are terms retained The mean the third body AOG for the initialization process. elements determined in order solution, these judge the quality of the converged to In Table 5.3. are shown in the PCE in mean elements were used to initialize an integration of the Short periodic recovery at the output times of the the PCE. approximation to to the osculating a Cowell Representative element through The symbol by the within 5-4. (+), (*) . (*). the averaging oscillation in are trajectory Whenever of the the the over semi-analytical resolution overwrites the of the while symbol the Cowell which trajectory prediction histories semi-analytical a produced integration numerical compared span of the sixty day fit of motion over averaged equations is Figures is trajectory by then 5-1 the denoted agree histories scale, then span. same represented element plot in shown was the to (+) The plots demonstrate the high accuracy orbital the particular, In theory. eccentricity the semi-monthly and inclination, induced by the motion of the moon, is seen to be reproduced by the third demonstration element body short of the fit difference plots periodic model. span accuracy in Figures 5-5 is A more graphic provided by the through 5-8. The element differences are very small fractions of the elements themselves. For example, the semi-analytical semi-major axis 237 41 from differs its generated at point meters than fifteen span. Similarly, degree of any counterpart within the by more no computed the PCE fit was longitude. mean is the accurate fit sixty day the averaging theory holds to within Cowell the that evidence Cowell 4 10-4 Further absence of an 4 appreciable bias in the element difference plots. Table 5-3. Epoch Mean Elements for the IUE Test Case Keplerian Equinoctial a = 42143.09386 km a = 42143.09386 km e = 0.2357026946 h = 0.2284825453 i = 28.27923713* k = 199.67553290 = -0.0578920263 p = -0.0848190305 = 264.5426255* q = -0.2372094942 7 = 14.70681220 M = 270.4886538* 4 elements The PCE procedure adjusts the mean satellite at epoch to produce generated data. averaging theory the "best" semi-analytical fit to Cowell As a result, the observed accuracy of an sufficient to over the fit span is not a I 238 a Osculating Semi-Major Axis Comparison within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical versus Cowell Figure 5-1. GTOS COMPARE PROGRAM 1000000 SATELLITE IUE KEPLERIAN ELEMENT HISTORIES I.------------------------------------------------------------------------------------------------42145.484 - I I I 42144.884 42144.284 4* ++4 .+ .I 4. ++, 'I - + I+ + I+ I+ 42143.084 - + 4.+ 4. 42143.684 + + +. + + . + 4+ + +. +. +. +. * + - + I+ +. +. 42142.484 I +4 I ++ 42141.884 I ++ . . 42141.284 + I . 42140.684 4 + I . - I -. 42140.084 42139.484 0. ---- 7.5-00 15.s*_00 22.-,5-0--- 3 0._0 0 --- 00 37.5S_0--- 45*. TIME FROM YYMMOD 720307 5--s2.50o--- HHittSS IN DYS 0 ()=Cowell ()=AOG & SPG 239 60.00 --- 67.5-0 --- 75.00 4 Figure 5-2. C Osculating Eccentricity Comparison within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical versus Cowell C GTDS COMPAREPROGRAM SATEL.ITE KEPLERIAN ELEMENTHISTORIES IUE 1000000 I.--.------.---------.---------.---------.---------.---------.---------.---------.---------.---------.- I 2.354999E-1 2.352999E-1 . I +++ I+ * ++ I .I I I I I 2a50999-1 2.348999E-1 E C C E N I I I I . + + I I I I + + +.++4 + +4 + +4 +++ + 2.344999E-1 44 44 4 +4 ++ ++ C I T Y + +++ 2.342999E-1 2.340999E-1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 2.338999E-1 2.336999E-1 I 4+4+ 2.346999E-1 T R a is a 2.334999E-1 I.---------------------------------------------------------------------------------------------------I 67.50 60.00 52.50 45.00 37.50 30.00 22.50 15.00 7.300 0. 4 75.00 TIME FROMYYMMDD HHMMSS IN DYS 720307 0 (+) = Cowell a (*) = AOG & SPG 240 C C Figure 5-3. Osculating Inclination Comparison within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical versus Cowell GTDS COMPARE PROGRAM SATELLITE KEPLERIAN ELEMENT HISTORIES I ---------.-----------------28.31499 I + 28.30749 + +4 +++ .+ I+ I ++ ++ + 4 2+ 28.29999 + 4+ +++++ + + ++ + I - - - - - - - - - - - - - - .I++ + I 1000000 IUE ---------------------------------------------------------- I- + +4+4 ++4 + +++ + 28.29249 I I I 28.28499 I I . I I +++4 28.27749 + I- I I. I I 'I . 28.26999' I I I I I I I I I I I I I I I I I I I 28.26249 28.25499 28.24749 I I I I 28.23999 I .--------------------------------------------------------------------------------.------- 0. 7.500 15.00 22.50 30.00 37.50 45.00 TIME FROMYYMMD0 HHMMSS IN- DYS 720307 0- (+) = Cowell (*) = AOG & SPG 241 52.50 60.00 67.50 --. I 75.00 4 Figure 5-4. 4 Osculating Mean Longitude Comparison within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical versus Cowell 4 GTDS COMPARE PROGRAM SATELLITE EQUINOCTIAL ELEMENTHISTORIES IUE 1000000 I.---------.---------.---------.---------.------- ------- ---.---------.---------.--- ------.---------.- I 200.0 I 160.0 I I I I + r 41 I I I I 120.0 I I I I+ + 80.00 41 I I I I 40.00 I I I I I 0. I I I I I I I I + -40.00 I I I I I, I I -80.00 I I I I -120.0 4 .+. I I I I -160.0 I I I a -200.0 .---------.---------.---------.---------.---------.---------.---------.---------.---------.----------75.00 60.00 67.50 52.50 37.50 45.00 30.00 15.00 22.50 7.500 0. TIME FROMYYMMD0 HHMISS 720307 0 IN DYS I (+) C*) 242 = = Cowell AOG & SPG a a Osculating Semi-Major Axis Differences within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical minus Cowell Figure 5-5. STDS 15.00 COMPARE PROGRAM KEPLERIAN ELEMENTDIFFERENCES I--------------------------------------------------.' SATELLITE --------------- - IUE 1000000 £ I I 12.50 I I I I I I *1 I I 10.00 I I I I I I 7.500 * * 5.000 I I I I I N * N I * I * NN N * * * N ** * * 2.500 I I I I N N I I * * * ** NN N N N I I I I N N I I N * * -2.500. I I I I.. N N -5.000. -7.500 -10.00 IN I I I I N . N I I I I .-----0. 7.500 15.00 22.50 30.00 37.50 TIME FROM YYMMOO 720307 243 HHMMSS 0 45.00 IN DYS ---------------60.00 52.50 67.50 75.00 4 4 Osculating Eccentricity Differences within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical minus Cowell Figure 5-6. 4 COMPARE GTDS PROGRAM SATELLITE KEPLERIAN ELEMENT DIFFERENCES ---------------. I. ---------.- 1000000 IUE - 1.500E-6. I I I I 1.200E-6 I I I I 9.000E-7 I I I I * * 6.000E-7 w** * * I. * *** w** * * ** ** * * * * * * * * I I I I * * * ** I I I I -I -6.000E-7. I* I I I * * I I I -1.200E-6 I I I I * -9.OOOE-7 ** * * *** *N~* i * I I I I * ** * * * .* a I* -1.500E-6 41 I I I I * I a I I I I ** * * ** * C C C E H T R I C I T Y 48 . I.------------------15.00 7.500 0. 30.00 22.50 37.50 45.00 HHMMSS IN TIME FROMYYMMDO0 0 720307 52.50 60.00 67.50 75.00 OYS a 244 41 Osculating Inclination Differences within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical minus Cowell Figure 5-7. GTOS COMPARE PROGRAM 1000000 SATELLITE IUE KEPLERIAN ELEMENT DIFFERENCES I.------------------------------------------------------------------------------------------------ I . I I I I NNNNN * NNN* 3.000 2.350 I I I I *** 1.700 I I I I ** NN N C L * 1.050 I I I I N A T I 0 N N I N N 4.000E-1 . I I I I * * -2.500E-1 .1 I I I * * C R 0 R A D I A 4, 3 * -9.000OE-1 * I I -1.550 I I I I -2.200 I I I I N N -280 I * I* I* * -3.500 I I. I I . I.---------.---------..-.--.---------.---------.---------.---------.---------.---------.--------. 75.00 67.50 60.00 52.50 45.00 37.50 30.00 22.50 15.00 7.500 0. TIME FROMYYMMDDHHMMSSIN DYS 0 720307 245 I I Osculating Mean Longitude Differences within the 60 Day PCE Fit Span for the IUE Orbit/ Semi-Analytical minus Cowell Figure 5-8. 4 GTOS COMPAREPROGRAM SATELLITE EQUINOCTIAL ELEMENT DIFFERENCES I.---------.---------.------------------. - ------.----. IUE 1000000 ------. I 2.000 I I I I I I I I - * 1.650 I I I I 44 * 1.300 I I I I 41 9.500E-1 I I I I * * * 6.OOOE-1 I I I 1* ** ** * * ** * 4 ** 2.SOOE-1 * * I I. I * -1.000OE-1 .* * I * I * * * I I I I I I I ** -1.150 . * a I I I I * * I I I I 4 -1.500 I.--------.---- - ---- .---------.---------.----------.---------.----------.----------.---- ~--.--------.-I 75 00 60.00 67.50 45.00 52.50 30.00 37.50 15.00 22.30 0. 7.500 TIME FROMYYMMDDHHIISS 720307 0 IN DYS 4 4 246 4 ensure acceptable mean elements year AOG behavior in Table prediction for 5-3 to a were test longer used the integration. to initialize ability of The a the three averaged equations of motion to predict the mean of the corresponding high precision than the trajectory time span of truncation parameters models are compare the plots inclination symbol (*) same for as semi-major satellite axis the that much longer initialization. The for given in the Table axis, through Cowell trajectory output of since element inclination are motion of high the sun. 5-12 differences to all for the trajectory very interval. is The 5-9 5-14. further 5-11 and The the on the averaged in the high and the over the mean of the difference 5-11 verification mean introduced by the follows symmetry the symbol The from the element and where dependence closely through solar Element eccentricity the AOG through 5-2. day oscillations Evidently, Figures lunar and AOG. the the semi-annual variations integration Figures 180 histories precision corresponding The is eccentricity, mean longitude has been removed precision year and R* constant perturbation models. the PCE Figures 5-9 mean is arc semi-major in (+) represents the M* those the an the N, are given represents over are of of three plots found the in element the PCE initialization and the accuracy of the averaged perturbation 247 a a Comparison of the Mean and Osculating SemiMajor Axis Histories for the 3 Year Integration of the IUE Orbit/AOG versus Cowell Figure 5-9. a GTOS COMPAREPROGRAM SATELLITE KEPLERIAN ELEMENTHISTORIES ------------------------I I I I I+ I a ++ 4 42144.534 I I I I I + I+ 42144.084 + I I I I + + + I + I 42143.634 1000000 - + 42144.984 IUE ---------------- - - I + + + + I I I I I+ + I 42143.184 I I I I 4 + 42143.184 + 44 a 4 I+ 42142.734 I I. I .4 4+4 I 4 + +4 ++ 42142.284 I I I I' 42140.934 4 I I I 42141.834 42141.384 C1 4 + + 4 I I I I a I I I I I I I I I I I I I I I 42140.484 61 I------------------ ------------------------------------------------------------------------1500. 1350. 1200. 1050. 900.0 750.0 600.0 450.0 300.0 150.0 0. TIME FROMYYMMDD HHMMSS IN OYS 0 720307 6 (+) (*) = = Cowell AOG 6 248 6 Comparison of the Mean and Osculating Eccentricity Histories for the 3 Year Integration of the IUE Orbit/AOG versus Cowell Figure 5-10. GTDS COMPAREPROGRAM SATELLITE KEPLERIAN ELEMENT HISTORIES I.---------------------------------------------------------------------------------.----------I 1000000 IUE 2.4000E-1 2.3700E-1 I+** I 2.3400E-1 I I + +***++ **++4 +***I ++****++I I ++ +++ 2.3100E-1 E C C 2.2800E-1 I . +44* +++++ -4 C*+. T R I I 444 2.1600E-1 I4 T I *+4+ +I I I I 4+I 4+I 4*I 2.1300E-12.1300E-1 - . I I -------------------0. 150. 0 --- 3 00. 0 --- 450. 0 --- 600.0 --- TIME FROM YYMMDD 720307 ()= ()= 249 900.0--- 105-0. 750.0 --- HMMS IN DYS 0 Cowell AOG 1200. 1350. 1500. Comparison of the Mean and Osculating Inclination Histories for the 3 Year Integration of the IUE Orbit/AOG versus Cowell Figure 5-11. 0 GTOS COMPAREPROGRAM IUE SATELLITE KEPLERIAH ELEMENTHISTORIES I --- ------------------------------------------------------------------------------------------28.3500 28.2900 I I I I++ I+ + * I* + I I I I1* I * I I I 28.2300 I I 28.1700 I I I +4** ** + 4 + *+ + + I I I I + +4+ + * + * 28.1100 1000000 I *+ .- I I I I *+ +* 28.0500 I I I I Z7.9900 0 I I I I *4* 27.9300 +44 + + +4 44*4* 4 +4 44 27.8700 I I I I + + +4 + +44* 44*44 + + + 4+44*44*4 4 *4*+4******* + + 44 I I I I 4 +4 +44 +4 I I I I 27.8100 0 27.7500 0. 150.0 300.0 450.0 600.0 750.0 TIME FROMYYMMODHMMSS 0 720307 900.0 1050. 1200. 1350. 1500. IN OYS (+) = Cowell (*) = AOG 40 250 Figure 5-12. Differences Between the Mean and Osculating Semi-Major Axis Histories for the 3 Year Integration of the IUE Orbit/AOG minus Cowell GTDS COMPARE PROGRAM KEPLERIAN ELEMENT DIFFERENCES SATELLITE IUE 1000000 I---------.---------.---------.---------.---------.---------.---------.---------.---..------.------..- 1900. . 1525. . * I * I I * * I I I I I 1150. I I I I 775.0. I * * 400.0 I I I I * * * *I .* I * * * * * ** 25.00 . * I * * * * -350.0 I I I I * I I I I * * .* * * -725.0 -1100. . . * I I I I * * I I I I ** I I I I * * * * -1475. I I I 1* I I I I I' -1850. I-------------------.---------.---- -----.-------0. 150.0 300.0 450.0 600.0 - ---------.---------.---- 750.0 900.0 TIME FROM YYMMODHNMMSSIN DYS 720307 0 251 -----.-------------- 1050. 1200. 1350. 1500. 0 0 Differences Between the Mean and Osculating Eccentricity Histories for the 3 Year Integration of the IUE Orbit/AOG minus Cowell Figure 5-13. a GTDS COMPAREPROGRAM SATELLITE KEPLERIAN ELEMENTDIFFERENCES 1000000 IUE I.---------.---------.---------.-------------------.---------.---------.------------------------------- 1.000E-3 - a I* I* 8. 000E-4 ** . I * 6.OOOE-4 I i - 4.OOOE-4 .* I 2.000E-4 E C C E N T R * * w - - I I w * * * 0. I I I I C I T y * .* - * - -2. 000E-4 I I 0 * * * * I 0 -4. OOOE-4 I I I I -6.OOOE-4 I I I I * * -8. OOOE-4 I I I -1. 000E-3 . 0. 150.0 300.0 450.0 600.0 750.0 TIME FROMYYMMDD HNMSS 720307 0 900.0 1050. 1200. 1350. 1500. IN DYS 0 0 252 Figure 5-14. Differences Between the Mean and Osculating Inclination Histories for the 3 Year Integration of the IUE Orbit/AOG minus Cowell GTOS COMPARE PROGRAM KEPLERIAN ELEMENTDIFFERENCES I.-----------------------------------------------------------------------900.0 . I ** I .4 I SATELLITE IUE .---------------- * * 1000000 -- I I I I I 715.0 530.0 I I I I 345.0 I I I I .4.4 * I I I I I * *4 160.0 *4 * * -4 I I I I -25.00 I I I I .4 -210.0 .4 .4 I-9 . . -395.0 *4 -I I I I I * I I I I -580.0 '.4 -765.0 I I I I .4 .4 I I I I .4 .4 -950.0 0. ------.----------------------------------------------------------------------------..---.-..... 159.0 300.0 450.0 600.0 750.0 TIME FROM YYMMOD 720307 253 HHMMSS 0 900.0 IN OYS 1050. 1200. 1350. 1500. 0 the element history plots the altitude semi-major axis caused by third body perturbations amount to about of comparison periodic have reproduced resolution of three short Similarly, in eccentricity variation the induced to by within the notably 5-10, sun, produce eccentricity the resolution evidence that in of an working well. the mean to corrections periodic Figure is model semi-annual the approximation to that is 5-16 Figure the the in but two points is powerful This periodic short generated Cowell exact scale, at all the plot body to within the Cowell generated element, prediction span. year third the the axis semi-major mean constant the to corrections short that shows 5-15 Figure with 5-9 Figure A kilometer. 1 as vary to axis semi-major much as by value mean its the cause themselves by lunar short The a large percentage of the total variation. periodics the in variations periodic short to At through 5-17. in Figures 5-15 the IUE, of leads AOG the of precision high the of times compare the at elements orbital recovery semi-analytical A models. plot scale. A comparison of the inclination plots in Figures 5-11 and 5-17 another example of the accuracy with which the provides yet semi-annual SPG. variations have been modelled Hence, indications predictions the that that three year the the third body integration provides accurate extremely include in long third body models 254 term the first orbital developed in 0 0 Osculating Semi-Major Axis Comparison for the 3 Year IUE Integration/Semi-Analytical versus Cowell Figure 5-15. STDSCOMPARE PROGRAM KEPLERIAN ELEMENTHISTORIES 42144.984 SATELLITE I.---------.----- ----.---- -----.----- ----.---------.--- ---. + I 1000000 It ----- -----.---------.---------.---------. I I + I+ 42144.534 . + + I+ I I I +. I+ I +. + I + + 42144.084 S E 0 I I I I I + ++ + - M 42143.634 . + A * I + + X 42143.184 A, x II + 1. I I + +.+ + + + .+ + + + K I .+ 42142.284 . + + ++ + 42142.734 + + + I R + + 4+.4 + + +.4 + + + + ++ L + 0 + - + M E + 42141.834 T + E I I S S I 42141.384 . + + +4+++ . . + - +. + 42140.934 42140.484 I.0. ---------.------------------------------------.- 150.0 300.0 450.0 ---------------------------------- 600.0 750.0 TIME FROM YYMttDO HHSS 720307 0 (+) (*) 255 = = 900.0 1050. IN DYS Cowell AOG & SPG 1200. 1350. 1500. Osculating Eccentricity Comparison for the 3 Year IUE Integration/Semi-Analytical versus Cowell Figure 5-16. OTDS COMPAREPROGRAM KEPLERIAN ELEMENTHISTORIES --------------------------------------I. ---------. - -------- SATELLITE IUE - ------------- 1000000 - ------- 2.4000E-1 2.3700E-1 I+ I++ 2.3400E-1 I+ . +++ ++ + ++ +. I I +4++ ++++I++ I 2.3100E-1 - ++4 - . I I + I+ E + 2.2800E-1 C C I E I T R I I+ C I + II T Y I 1 ++ I 2.2500E-1 I ++++++ . ++ 2.2200E-1 I.+ 2.1900E-1 +++++++ .. 2.1600E-1* 2.1300E-1 2.1000E-1 - . 0. 150.0 300.0 450.0 600.0 750.0 TIM FRMt YYMD 720307 900. 0 HHM0SS IN DYS 0 ()= Cowell ()= AOG & SPG 256 1050. 1200. 1350. 1500. Figure 5-17. Osculating Inclination Comparison for the 3 Year IUE Integration/Semi-Analytical versus Cowell GTDS KEPLERIAN ELEMENTHISTORIES ---------. ---------. ------------28.3500 I. COMPARE PROGRAM ---- - -----. . . SATELLITE IUE . -----.--------- I 1000000 I I I I+ .4 28.2900 I++ I . + + 28.2300 I I 28.1700 .I I I + + + +. + +. +++.4 + I I I I 28.1100. * I I I I 4.4. 28.0500 .4.4.4. 4. I I I I 4. 27.9900. 4. + * 27.9300 . I I I I 4.4 4. 4.4.4. 4. 4. 4. 4. 4. 4. 4.4. 4.4. * 27.8700 . 4. 4. 4. 4. 4.4. 4.4. 4.4. 4.4. I I I I 4. 4.4.4. 4.4. 4. 27.8100 I I I I 4.4. 4. 4.4.4. .I.I 27.7500 0. 150.0 300.0 450.0 600.0 730.0 TIME FROMYYMOO 720307 (+) (*) 257 HHMSS 0 900.0 IN 1050. DYS = Cowell = AOG & SPG 1200. 1350. 150s. a can thesis this spans short from relatively initialized be of high precision data. for file Cowell The 150 time regularized generated from an integration that used steps a AOG possible from a used by circulation fast variable frequencies dependent motion. of equations Since the as the such angles, satellite made was This year. one contrast, In eccentricity. of for periods a it is not unreasonable for size body is This satellite. although moderate step removing third the of orbit satellite the size, step conservative tne of revolution per was comparison year three the argument of perigee and the longitude of the ascending node, generally are quite the AOG was retained in perigee. Hence, an AOG size has the the altitude of considerable 8.9 year the IUE, of amplitude of advance lunar step size of one year was permitted without loss of accuracy. step at oscillation period shortest long enormous This remarkably large integration consequences for the efficient analysis of high altitude orbital stability over decades or centuries. A one hundred year AOG prediction of the IUE orbit was made with a one year integration step size, using the epoch 33 seconds mean elements of Table of CPU time. The 5-3. element eccentricity and inclination are plotted 5-19. The AOG executed histories for in the in Figures 5-18 and At present, there are no precision benchmarks against 258 Figure 5-18. Evolution of the Mean Eccentricity for the 100 Year AOG Prediction of the IUE Orbit GTDS COMPAREPROGRAM KEPLERIAN ELEMENTHISTORIES I.-------------.---------.----------------------------------2.5000E-1. I I* 2.3000E-1 I * . I * I SATELLITE IUE 1000000 ----------------------------. I * ** N N -I 2.1000E-1. I 1.00E1 . I 1.7000E-1 E C C E N T R I C I T y . *I I * * * -N . I I N* ** * I 1.5000E-1 I I * * ** ** N**** I I ** *** * * I * * I * ** I I * * * -I I * * I I I I * ** 1.3000E-1 . 1.1000E-1 . 9.OOOOE-2 I. I. -- - - - .. . 50I 7.0000E-2 5.0000E-2 I259 - - - - ..0E4 150+ - - - -I-.0E4 250+ TIEFOIY 72007I - - .300+ I Y .0E4 400+ .0E4 500 IDHMMS - -- - . - - - 0 6 Evolution of the Mean Inclination for the 100 Year AOG Prediction of the IUE Orbit Figure 5-19. GTDS COMPARE PROGRAM SATELLITE KEPLERIAN ELEMENTHISTORIES IE 1000000 ----.-------. ------------------.---------.---------. I .---.------.------.....--------...----- 45.000 * . 42.500** *- 40.000- N 37.500- CI I * L I ** I A T 0 N G- * ' DI * 35.000 I * * * * * RI EI* I - 32.500 N E 30.000 E S . - * I * 27.500 . - 25.000 . - 32.500 20.000 - . 0. - 5000. 1.000E+4 2.500E+4 3.000E+4 2.800E+4 1.500E+4 TIME FROM YYMMOD HHMMSI IN DYS 0 720307 260 3.500E+4 4.000E+4 4.500E+4 5.000E which the correctness this of be can prediction measured. is However, the basic regularity of the element histories a good indication that their deviation from the physical world Furthermore, the 54 year period is at least a slow process. of oscillation for inclination, predicted integrated. addition, associated Cowell corresponding The 5-19. It the with computer, would be build-up numerical of computations make the suspect. 261 output time seen in Figure cannot consuming. error on [30] by Kozai trajectory prohibitively intensive would clearly is orbit, geosynchronous the length in the a points over fixed be In time, word increasingly 0 ISEE Test Case 5.3.2 61 Sun-Earth International The demonstrates the accuracy when the satellite first the of orbit (ISEE) Explorer body third order S theory orbital eccentricity is large. The initial orbital elements are shown in Table 5-4. Table 5-4. Epoch Osculating Elements for the ISEE Test Case Epoch = 7 March 1972 a = 70850 .0 km oh.0,0m.0,0s.0 e = 0.89 i = 29.0* = 49.50 i Period = 2.2 days = 0.21* S M = 0.0 Radius of Perigee = 7793.5 km Radius of Apogee = 133906.5 km Lunar Parallax Factor,(a/a')~ 0.18 Solar Parallax Factor,(a/a')s~ 0.00047 The epoch mean elements for the AOG were obtained by a PCE procedure over sixty days. The a priori elements 0 for the initialization were provided by averaging the osculating over trajectory numerical models one of the period osculating-to-mean used in the PCE are satellite conversion. shown in Table using The the GTDS perturbation 5-5. The ISEE 262 0 orbit is non-resonant only the double retained PCE with respect averaged in the AOG. are given initialize in an A Table time was of the for These year the third Cowell using elements integration A one year precision performed revolution 5-6. eight high a third body so that body The mean elements determined equations of motion. used. terms to 200 of are from the were used the averaged to integration step size integration the same steps per time satellite. over regularized The five slow was Keplerian element histories are shown in Figures 5-20 through 5-24 for both the AOG and Cowell are represented by the are designated (+) within are the seen element This to order axis point point of orbital effects. epoch occurs in 400 variation at the at perigee period, is the Since extremely PCE axis of was set short the procedure by by J2 over to the kilometers. periodic is on which comparison tended of the single short time in to osculating scale 70850 caused the the the to where agree the The mean elements that 5-20 elements test case, histories mean corresponding semi-major Cowell the mean elements scale. note Figure kilometers. acts two the will plot in while the follow One The in the previous when (*) closely histories. variation As resolution of the plot semi-major Cowell the (+), symbol a (*) by overwrites predictions. to smooth the this the its This accounts for the apparent discrepancy between the single Cowell point and the predicted mean. 263 The absence of any further points selection phenomenon. Figures 5-21 the lunar the in evidenced The argument of is caused and behavior inclination by the perigee which was second not a point is 5-20 oscillatory pronounced eccentricity and 5-22 in Figure at perigee plots of multiple of removed by the averaging operation. Table 5-5. PCE Perturbation Models for the ISEE Test Case 1) AOG + SPG Perturbation Model: N M* R* -5 < -5 7 EARTH MOON SUN = 5 = = t s 5 4 < 5 7 5' N M* R* -6 < -6 7 = 12 = = t s J 2 ,J3 J 4 12 6 < 6 7 6 NOTE: AOG retains only the double averaged terms for the third body N maximum power of the parallax factor, (a/a') M* upper bound on the satellite Hansen coefficient d' Alembert characteristic R* upper bound on the third body Hansen coefficient d'Alembert characteristic 2) Cowell Perturbing Acceleration: point mass sun point mass moon 3,J 4 J2 I.J 264 01 Table 5-6. Epoch Mean Elements for the ISEE Test Case Keplerian Equinoctial a = 70405.55206 km a = 70405.55206 e = 0.8908091435 Ih= i = 29.24922760* k = 0.5734846282 = km 0.6816570336 p = 0.1984228809 49.501046560 W = 0.42472839970 q = 0.169462882 M = 359.2566209* T = 49.18239586* A argument look of at the perigee element and plots longitude of for the the ascending satellite node reveals that their circulation periods are approximately 16 years year and 21 years respectively. integration step size for an orbit the low perigee benefit of with strong height. retaining only for This indicates that a one the AOG is appropriate zonal perturbations Hence, the it arising from would appear double averaged even that third the body terms in the AOG is not diminished by the inclusion of other 265 0 6 Comparison of the Mean and Osculating SemiMajor Axis Histories for the 8 Year Integration of the ISEE Orbit/AOG versus Cowell Figure 5-20. GTOS COMPARE PROGRAM SATELLITE KEPL.ERIANELEMENT HISTORIES 70850.00 ISEEAU 1000000 .+ I . I . I . I 0 70795.00 70740.00 70685.00 I . I - - I 70630.00 I 0 70575.00 70520.00 70465.00 I I 4 4 4 70410.00 70355.00 .I I + 444 +++ 4 ++4+++++ 4 44 +4+ +4 4444 + +4 ++ +4 ++ + + I I I I 4 4+4+ + + ++ I I I I ++ I I 70300.00 --------------.---- -----. I.---------1500. 1000. 500.0 0. --------. 2000. -------- 2500. .--------- 3000. TIME FROMXYMMDD HHMMSS IN DYS 720307 0 (+) = Cowell (*) = AOG 266 .--------.-- 3500. 4000. 4500. 5000. Figure 5-21. Comparison of the Mean and Osculating Eccentricity Histories for the 8 Year Integration of the ISEE Orbit/AOG versus Cowell STDS COMPARE PROGRAM SATELLITE KEPLERIAN ELEMENT HISTORIES ISEEAS 1000000 ----.------ ---.------------------------------ I -.----------------.----- I.-------------------------- 8.95000E-i I I I I I++ I+ 8.89000E-1 .+ I4* I+ I I I I 4*++ 8.83000E-1 . I + I+ E C C N T R I C I T y 8.83000K-i1 8.77000E-1 I I .+ I I 4 + +* I 8.77000E-1 + *a* + + + +' ** + + +* + I I I I +* * + 4 +4 * + * 4 * *+ * I I I. I + ++4 + * +* + 44+ * +w* a *+ *4 +4 8.7000E-1 +' ++4 + + ++ * *4 + I I I I +4 * I I I I 0 * * + * I . I I I I +4 *+ 444 + +4 8.47000K-i . 4 + 444 +4 * ,I 4' +4 4+4 4 4 I I I I +44 * 8.59000K-i I I I I 4 *444*4 + * + + 4 I I I I I I I I 8.35000E-1 -- -.-------------------------------------------------------------------------------------------. 4500. 5000. 4000. 3000. 3500. 2500. 1500. 2000. 1000. 0. 500.0 TIME FROM YYMMOO 720307 HHMMSS 0 IN DYS (+) = Cowell (*) = AOG 267 Comparison of the Mean and Osculating Inclination Histories for the 8 Year Integration of the ISEE Orbit/AOG versus Cowell Figure 5-22. U] GTOS COMPARE PROGRAM KEPLERIAN ELEMENTHISTORIES SATELLITE ISEEAB 1000000 I.---------.---------.---------.-------- -.---------.--- ------.---------.---------.---------.---------.- I 45.000 . I I I I I ++ 42.500 I *+ +*+++ + +4++ +4, I I **+ * I + + + I ++*+ +* + + 40.000 I I + 4+ * ++4 4 +++ * * + * * 35.500 . I++ I+ I I I I * 0 I I I* I+ I+ I I I 27.500. 25.000 27.500 20.000 0. 500.0 1000. 1500.- 2000. 2500. TIME FROM YYMMODHHMISS 720307 0 3000. 3500. 4000. 4500. 5000. IN DYS (+) = Cowell (*) =AOG 268 U] Figure 5-23. Comparison of the Mean and Osculating Longitude of Ascending Node Histories for the 8 Year Integration of the ISEE Orbit/ AOG versus Cowell GTOS COMPARE PROGRAM KEPLERIAN ELEMENT HISTORIES I.------------------.---------.---------.--------50.00 .+ 35.00 I ++ I I I . SATELLITE . ---------------------------------------------. ISEEAS 1000000 I II I I +++ ++, I I I I 20.00 T I I I 4, 5.000 I I I I -10.00 I I .1 I -25.00 I I I I .4 -40.00 I I I -I -55.00 I I I I 4,, -70.00 I I I I 4,, 4,,, -85.00 . +++ I I I I -100.0. I.---------------------------.---------.---------.---------.---------.---------.---------.---------.---I 0. 500.0 1000. 1500. 2000. 2500. 3000. 3500. 4000. 4500. 5000. TIME FROMYYMMO0 HHIISS 720307 0 IN DYS (+) = Cowell (*) = AOG 269 Figure 5-24. Comparison of the Mean and Osculating Argument of Perifocus Histories for the 8 Year Integration of the ISEE Orbit/AOG versus Cowell 0 0 GTDS COMPARE PROGRAM KEPLERIAN ELEMENTHISTORIES I.- SATELLITE ---------------------------- --------------------------- ISEEAS 1000000 ------------------ -----------------. 200.00 I I I I I I I I I 180.00 I I I I 4.4 .4. I I I I 44, 0 .4. I I I I .4 *4 .4 I I I I 4. 60.000 4000 *4 I I I I I I I 10.000 I I I I I + I+ I I I I *4 4.4 I I I I ++ ++ ++4 I I I I 0. 0. 500.0 #b 1000. 1500. 2000. 2500. 3000. TIME FROM YYMMD HHIISS IN DYS 7203.7 0- +)=Cowell (*) = AOG 270 3,V0. 4000. 4500. 5000. 0 averaged long perturbation term models. predictions to This be made allows with a very efficient realistic force field. A the AOG execute comparison of is given in integration that the execution in integration times between Cowell Table 5-7. approximately over the eight 1/30 the year span. comparison is time includes also The even more the comparison plots described above. 271 AOG is time of It the should favorable, creation observed of the to Cowell be since and noted the AOG ephemeris 01 Table 5-7. Comparison of Cowell and AOG Execution Times for the Eight Year ISEE Integration Orbit Generator Step Size Execution Time Cowell 200 steps/rev., 300 seconds time regularized 31536000 seconds AOG a 9.95 seconds (1 year) Notes 1) 2) 3) 4) The Cowell integrator is based on the 12th order Adams-Bashforth Predictor / Adams-Moulton Corrector Algorithm The AOG uses a 4th order Runge-Kutta integration algorithm 0 The execution time for the Cowell integration contains overhead associated with file creation. The execution time for the AOG contains overhead assciated with file creation and 0 includes the ephemeris comparison step. S 0 0 272 5.3.3 VELA Test Case The evolution and stability of the high altitude VELA orbit are almost exclusively determined by the action of the sun and the perturbations semi-major moon. can axis At induce that are this short on altitude periodic the order lunar and variations of 100 118230.0 km Epoch = 8 April 1970 0.003 Oh.0,0m.0,0s.0 32.520 0.00 Period = 4.68 days 47.00 0.00 Radius of Perigee = 117875.31 km Radius of Apogee = 118584.69 km .Lunar Parallax Factor, Solar Parallax Factor, 273 (a/a')y ~ 0.3075 (a/a')s ~ 0.0008 in the kilometers. The initial orbital elements are shown in Table 5-8. Table 5-8. Epoch Osculating Elements for the VELA Test Case solar 0 The initial mean elements for the AOG prediction were The 5-9. Table in given argument days. Both periods still the third body. in the long in SPG are in the SPG has resonance the with circulates critical which PCE a period 167 days, while the second multiple of the of approximately AOG the included frequencies argument of The critical priori resonance of the VELA orbit with the reflect the shallow 6:1 moon. a correction in used models perturbation The algorithm. The differential squares least the to days. the as used were elements sixty over procedure PCE satellite osculating input a from obtained are far too short to be only retains However, it since comparison period a to the the produces the fit double resonance terms with span of included for be modelled periods the PCE. in the terms averaged should 83 around of are that Failure to model the effect can cause a noticeable bias in the computed mean elements at epoch. The mean elements the PCE are found in Table 5-10. 274 determined from Table 5-9. PCE Perturbation Models Table 5-9. PCE Perturbation Models for the VELA Test Case 1) AOG + SPG Perturbation Model: MOON SUN N = 4 N M* = 4 = 4 R*.= 8 R* -4 < t < 4 -4 7 s 7 4 NOTE: AOG r etains = 8 M* = 4 -4 < t < 4 -12 ~ t 7 12 only the do uble averaged th ird body terms maximum power of the parallax factor, N (3/a') M* 2 upper bound on the satellite Hansen coefficient d'Alembert characteristic R* 2 upper bound on the third body Hansen coefficient d'Alembert characteristic 2) Cowell Perturbing Acceleration: point mass sun point mass moon Table 5-10. Epoch Mean Elements for the VELA Test Case Equinoctial Keplerian a = 118095.5461 km a = 118095.5461 e = 0.0020558154 h = 0.0017593771 i = 32.48414636* k = 0.0010634702 = 359.9590416* p = -0.000208255 W = 58.889744020 q = 0.2913232484 M = 348.2477284* 7 = 47.096514020 275 km 0 to used were 5-10 Table in elements mean The The initialize a ten year AOG prediction of the VELA orbit. numerical integration truncation parameters characteristic the AOG prediction are and are PCE the in used those d'Alembert The upper bound on the Table 5-11. in compiled for R* M*, than different slightly N, The year. one of size step a used for the satellite Hansen coefficient has been increased to accomodate some growth in the satellite orbital is not inconsistent with the model used in third body model the since PCE the orbit VELA Cowell compare fit would file was created PCE. slow Cowell was 2700 5-25 is trajectory ten the through year 5-30 for and the by the set equinoctial the of over as represented while the mean output of the AOG is denoted by symbol (+), (*)., Figure determined Figures in elements The inclination. plots The models same the integration step size comparison are provided integration five The using both. by achieved be same the epoch eccentricity of small very the Ephemeris seconds. the at the in used those new The span. prediction year ten the over eccentricty the 5-25 mean shows the that semi-major axis. PCE has The effectively other averaged element histories show a similar ability to track the mean of the Cowell generated elements. the k element at the end of conditions error. 276 ten The slight divergence in years may be an initial Table 5-11. AOG Perturbation Model for the Ten Year VELA Integration SUN MOON N = 4 M* = 4 N = 8 M* = 6 R* = 4 R* = 8 N NOTE: AOG retains only the double averaged third body terms. maximum power of the parallax factor, (a/a') M* 3upper bound on the satellite Hansen coefficient d'Alembert characteristic R* upper bound on the third body Hansen coefficient d'Alembert characteristic Table 5-12 compares the execution times of the Cowell The use of the first order third body and AOG predictions. theory for a with a ten one year year run by step has reduced at a least factor the of execution 50. time Again, it should be noted that the AOG run time includes the ephemeris comparison step so that the efficiency theory is even better than indicated. 277 of the third body 0 0 Comparison of the Mean and Osculating SemiMajor Axis Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell Figure 5-25. 0 GTDS COMPAREPROGRAM SATELLITE EQUINOCTIAL ELEMENTHISTORIES .------ ------- --------- ---- I. --------------------------- 1000000 VELA 'I ----------------------------- 118250.0 118215.0 118180.0 I + . . I I I I I I I I +. 118145A 0 I+ I+ + 118110.0 +. ++ ++ + I I I I + .+ I I I I I + IM*M 118075.0 . I . + +. + + 118040.0 I I I I ++ I I 4 + + I 'I 117970.0 I+ I I . I I I I 117935.0 I I I I I 117900.0 11790 0 I I I I +4+ + I 118005.0 0 I I I I I+ I . --0. --500.0 1000. 1500. 2500. 2000. .--------------------4000. 3500. 3000. 4500. 0 is 1I---5000. TIM FROMYYMMODHH1MMSSIN DYS 700408 0 0 (+) (*) = = Cowell AOG is 278 Figure 5-26. Comparison of the Mean and Osculating h Element Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell GTDS COMPARE PROGRAM 1.300E-2 E 4INOCTIAL ELEMENT HISTORIES w--." SATELLITE VELA I I I I I I I 1.ZSOE-2 I I I I I + 4.4.4. 4. 1.00OE-2 4. + 4. +4. + 4. *4.4.4.4.4.4.4.4. + + 4.**4. 4.4.4.4. 4. 4. + + 4. 4. 4*4. 4. 4., 4.4. 4. 4. *+ + I+* I + - 4.4. 4.4.4. 4* 7.500E-3 5.000E-3 1000000 ------- *4 + * +*++ I+ + I I + I -2.SOOE-3 + +* ++ . 0. I. -5.000E-3 + + I *+ I -5.00E3.I~ I ~ 4. *4.4 ++ ** ****** ~~ ~~ 44. 44 4 4.44.+ +*.* +... I I -I I a -7.500E-3 I I I I I I I I -1.000E-z 0. 500.0 1000. 1500. 2000. 2500. 3000. TIME FROMYYMMODHHMMSS IN DYS 700408 0 (+) (*) 279 = = Cowell AOG 3500. 4000. 4500. 5000. Comparison of the Mean and Osculating k Element Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell Figure 5-27. 0 0 GTDS COMPARE PROGRAM SATELLITE EQUINOCTIAL ELEMENTHISTORIES 1000000 VELA 01 1.500E-2 I I I I 1.300E-2 *1 I I I I I 1.100E-2 4.4.4.4.4.4.4.4. 4. 4.4. 4.4. 4. 4. 4.4.4. 4. 9.OOOE-3 4. + 4. 4.4.4.4 +*. 4 4.4. 4. 4. I I I I 4.4.4. 4.4.4. 4. I I I I 4. 4.4.4. 4.4. 4. *.4. 4.4. 7.000E-3 I I I I 4.4.4. k 4.4. 4. 5.000E-3 4. .+* 4 +. *.44 +* 4+ +. 3.000E-3 .+ I 4 4+.+4. +.44. I+ II+ 1.000E-3 *++ + I* . + + + ++ + *. 4 I I *.4 + 4.4*.+ + + +. 4++. +.4. 4 .4+. -3.000E-3 -1.000E-3 .4 . . 4 4. .. + I+ I +.4. 0 4., -5.000E-3 I.- 0. ----.-------.-1000. 500.0 .. .----------.------1500. 2000. 2500. TIM FRO" YY1OD 700408 3000. .---3500. .----.-----. 4000. 4500. 5000. HHMMSS IN OYS 0 0 ()=Cowell (*) = AOG 280. Figure 5-28. Comparison of the Mean and Osculating p Element Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell GTDS COMPARE EGUINOCTIAL EtEMENTHISTORIES I----------.0. PROGRAM SATELLITE . -------------------- VELA -------------------------------. .++ I I I ++~ . I I I I I I I I *++4 ++. I -1.5000E-2 1000000 ++ +* ++ + -3. 0000E-2. 4, 4. -4.5000E-2 -6.0000E-2 I . . -7.5000E-2 . ++ 4., 4.* 4., r) -9.0000OE-2Z 4., -1.0500E-1 . -1. 2000E-1 . ++, ++, -1.3500E-1 -1.5000E-1 I-----------------.---0. 500.0 1000. -------------. -------------------------.---------------------------. 1500. 2000. 2500. 3000. 3500. 4000. 4500. TIME FROMYYMMDD 700408 HHMM3S IN OYS 0 ()=Cowell (*) 281 = AOG I 5000. 0 Figure 5-29. Comparison of the Mean and Osculating q Element Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell 0 0 GT6S COMPARE PROGRAM EQUINOCTIAL ELEMENT HISTORIES I. -- - SATELLITE ------------------------------ --.---------.------ --- ---------------------------. VELA 1000000 -------- 3.0000E-1. I ++++*+++++++4+++++++* I+++ I I I I I +4 +++ 0] 2.4000E-1 2.2000E-1 I. 2.0000E-1. I- CT 1.8000E-1 I I I I 1.6000E-1 1.40OOE-1 I I I I I I I I I I I I I I I I I I I I I I I I 1.2000E-1 1.OOOOE-1 0. 500.0 1000. 1500. 2500. 2000. 3000. TIME FROMYYMtOD0 HHMMSS 700408 0 3500. 4000. 4500. 5000. IN DYS 0 (*) = = Cowell AOG 282 09 Figure 5-30. Comparison of the Mean and Osculating Inclination Histories for the 10 Year Integration of the VELA Orbit/AOG versus Cowell GTDS COMPAREPROGRAM SATELLITE KEPLERIAN ELEMENTHISTORIES I.---------------------. I I 32.500 +++++++.4.* + 1000000 VELA ------------------------------------------------------ I I I I + * ++++4.* ++++.4+*+ +4 .*+ I I I I *4. 31.500. I I I I 4.4. 30.500 . 29.500 . ++ I I I I ++ I I I I 28.500 I I I I 4. 27.500 26.500 25.500 24.500 I I I I I I I 23.500 0. 500.0 --------------------.--------.---.-.-1000. 2500. 2000. 1500. --------------- ------3000. TIME FROMYYMMODHHMMSS IN OYS 700408 0 +)=Cowell (*) = AOG 283 3500. 4000. 4500. . 5000. 0 Table 5-12. Comparison of Cowell and AOG Execution Times for the Ten Year VELA Integration Orbit Generator Step Size Execution Time Cowell 2700 seconds, fixed step 482 seconds AOG 31536000 sec. 9.63 seconds 0 (1 year) 0 Notes 1) 2) 3) 4) The Cowell integrator is based on the 12th order Adams-Bashforth Predictor / Adams-Moulton Corrector algorithm. The AOG uses a 4th order Runge-Kutta integration algorithm. The execution time for the Cowell integration contains overhead associated with file creation The execution time for the AOG contains 0 overhead associated with file creation and includes the ephemeris comparison step. 0 284 U1 5.3.4 STRATSAT Test Case The STRATSAT orbit is discussed in this thesis. presented in Table During this 5-13. period, to very large values. to predict its epoch case. The ability of demanding test case Extremely strong to decay within the lunar ten years eccentricity grows rapidly is evolves radically with respect to demonstrated the third body by the theory STRATSAT 5-13. Epoch osculating Elements for the STRATSAT Test Case a= 2 11868.8 km Epoch = 21 March 1985 oh.0,0m.0,0s.0 e= 0 .001 i = 90.0* = 180.00 ) = M = Period = 11.23 days 0.00 0.00 Radius of Perigee = 211656.93 km Radius of Apogee = 212080.67 km Lunar Parallax Factor, 285 test to converge for high values of the parallax factor is also demonstrated. Table of The capability of the third body AOG an orbit which conditions most The initial orbital elements are perturbations cause the orbit epoch. the (a/a')k ~ 0.55 0 The initial mean elements for the AOG prediction were osculating satellite The quantities. given PCE a from obtained in Table procedure elements The sixty frequencies The a priori included are PCE the in used days. the as used were models perturbation 5-14. over in the SPG reflect the shalluw 5:2 resonance of the STRATSAT orbit with the The moon. critical of argument period of approximately 233 days, while the second of the critical which retains the However, prevent circulates with multiple a period of about These periods are too short to be included in the 116 days. AOG argument a has resonance the a only resonance bias in elements determined the the double should be mean modelled elements at in epoch. from the PCE are given in 286 lunar averaged the terms. SPG The to mean Table 5-15. 9 Table 5-14. PCE Perturbation Models for the STRATSAT Test Case 1) AOG + SPG Perturbation Model: MOON N = 12 M* = 6 R* = 8 -4 < t < -10 7 s 7 4 NOTE: AOG retains only the double averaged third body terms 10 N maximum power of the parallax M* upper bound on the satellite Hansen coefficient d'Alembert characteristic R* E upper bound on the third 2) Cowell Perturbing Acceleration: 287 (/a') body Hansen coefficient d'Alembert characteristic point mass moon factor, 0 Table 5-15. Epoch Mean Elements for the STRATSAT Test Case 0 Equinoctial Keplerian a = 211134.9014 a = 211134.9014 km km e = 0.0044788188 h = -0.0022599939 i = 90.11755585* k = 0.0038668133 = 180.0375365* p = -0.000656481 = 149.6579277* q = -1.002053629. X = 178.67126280 M = 208.97579860 The initialize mean an elements year eight Table in The numerical year. The truncation parameters found in Table N, 5-16. R* M*, The size for to STRATSAT the of a step used used were 5-15 prediction AOG integration orbit. prediction are 0 of one the maximum power AOG of the parallax factor has been conservatively chosen to ensure the on the satellite characteristic to The upper bound accuracy of the eight year prediction. accomodate has been allowed the orbital eccentricity. anticipated 288 d'Alembert coefficient Hansen to assume growth its of maximum value the satellite Table 5-16. AOG Perturbation Model for the Eight Year STRATSAT Integration MOON N = 15 M* = 15 R* = 8 NOTE: AOG retains only the double averaged third body terms. N maximum power of the parallax factor, (a/a') M* upper bound on the satellite Hansen coefficient d'Alembert characteristic R* on the third body Hansen coefficient d'Alembert characteristic 2 upper bound 289 0 used 150 time 5-31 eccentricity, through Figure accurately eccentricity of radius 0.8 that of the per plots of the 5-32. Cowell over the revolution for are the shown perigee attention should in Figure follow from an integration inclination The Special eccentricity plot to comparison and 5-33. 5-34. steps regularized Ephemeris satellite. axis, was created file The Cowell compare be is in Figures plotted focused The AOG (*) integration eight year semi-major the on is observed (+) up prediction to thesis can be reliably used to monitor the an span. The plots indicate that the third body theory developed this in in evolution and stability of rapidly evolving orbits. Table and Cowell 5-17 compares predictions. the execution times The execution time of of the the AOG AOG for an eight year run is seen to be at least a factor of 14 less than that of the corresponding Cowell integration. 290 09 Figure 5-31. Comparison of the Mean and Osculating SemiMajor Axis Histories for the 8 Year Integration of the STRATSAT Orbit/AOG versus Cowell COMPARE PROGRAM OTDS KEPLERIAN ELEMENTHISTORIES 213450. SATELLITE STRATSAT 1000000 . I I I I + 213020. 212590. I I 212160. 44 I+ 211730. 4 I 211300. ++, +I . 210440. +4 4 + + + 4 +++ 4 4 +4 + I I I + 4 + 210870. + + + I I + . + +++ ++ 4 + + 4 +4 4 4 4 + + + + + + . 4 + 4,+ +4 ++ I + + 210010. 4 + I I I I 209580. I I I I I I I I 209150. 0. 500.0 1000. 1500. 2000. 2300. TIM FROM YYMMD0 850321 (+) (*} 291 = = 3000. HN'NSS 0 IN DYS Cowell AOG 3500. 4000. 4500. 5000. 0 Figure 5-32. 0 Comparison of the Mean and Osculating Eccentricity Histories for the 8 Year Integration of the STRATSAT Orbit/AOG versus Cowell 0 GTDS COMPARE PROGRAM KEPLERIAN ELEMENTHISTORIES I I.----.-----.---------------- ~~~~~------------------------------------------------*--------- 8.0000E-1 SATELLITE STRATSAT 1000000 ---------- ----------- :---------.I -- --------- ---- -- . I + 4 I I 4+* I* 7.2000E-1 I I I I 6.4000E-1 I I I I 4* 5.6000E-1 E C C E N T R I C I T y 0 I I I I 4.8000E-1 I I I +* +4* 4.0000E-1 I I I I ++ -I 3.2000E-1 . I I I I 44 44* 2.4000E-1 . I I I I 1.6000E-1 . I I I I 4,, 4, 8.0000E-2 I + I+++++++* I I I I 4,,,,, 4*44 k,,,, 4 0. I.---. - 0. 500.0 -------------- 1000. ---- --- -- 1500. - 2500. 2000. --- -- 3000. 3500. - - - 4000. 4500. - 5000. TIME FROM YYMMD HH?01SS IN DYS 850321 0 (+) (*) = = Cowell AOG 0 292 41 Figure 5-33. Comparison of the Mean and Osculating Inclination Histories for the 8 Year Integration of the STRATSAT Orbit/AOG versus Cowell GTDS COMPARE PROGRAM KEPLERIAN ELEMENT HISTORIES SATELLITE I.--------------------.---------.-- -------.------------------.- STRATSAT 1000000 -----------------------------------.I 120.00 I I I I I I I 116.00 I I I I 4* I 112.00 I I I I 108.00 10 00. I I I I 4* . 4, 100.00 4* *4* r 44* 44* 96.000 44* 444**4 92.000 . ++ ++++4 88.000 84.000 80.000 I. .0. ~ ~~~~~ .----.----.------.- 500.0 1000. 1500. ----. 2000. 2500. TIME FROM YYMMDD 850321 HHM55S IN DYS 0 (+) = Cowell ( *) = AOG 293 -----.---------.---------.---------.- 3000. 3500. 4000. 4500. 5000. Figure 5-34. 0 Comparison of the Mean and Osculating Radius of Perifocus Histories for the 8 Year Integration of the STRATSAT Orbit/AOG versus Cowell GTDS COMPAREPROGRAM SATELLITE HISTORIES OF PERIFOCAL RADIUS 2.1170E+5 I +I STRATSAT 1000000 I ---------------------------------------------. - I.---------.------------------.-----------------. ++++ 1.9482E+5 I I I I 4* 1.779'.E45 I I I I 4* 4, ** 1.6106E+S 44* I I I I 4* 44* 1.4418E+5 4* I I I I 4* 4, 1.2730E45 4* I I I I 4* 1.1042E.5 I I I I 4* 4* 93540. I I I I * 4* 76660. I I I I I * 44* 59780. * I I I I 4* 4 4 4E900. I.--------------0. 500.0 ---. 1000. - 1500. ----- - ----. 2000. 2500. - -. ------ 3000. ---------.---------. --------. 3500. 4000. 4500. 5000. TIME FROMYYMMODHH1MtSS IN DYS 850321 0 (+) = Cowell (*) = AOG 01 294 01 Table 5-17. Comparison of Cowell and AOG Execution Times for the Eight Year STRATSAT Integration Orbit Generator Cowell Step Size Execution Time 150 steps/rev., 170 seconds time AOG regularized 31536000 seconds (1 year) 12.44 seconds Notes 1) 2) 3) 4) The Cowell integrator is based on the 12th order Adams-Bashforth Predictor / Adams-Moulton Corrector algorithm. The AOG uses a 4th order Runge-Kutta integration algorithm. The execution time for the Cowell integration contains overhead associated with file creation. The execution time for the AOG contains overhead associated with file creation and includes the ephemeris comparison step. 295 Lunar Resonance Test Case 5.3.5 0 This test case the examines 5:2 are given resonance with in Table 5-18. the moon. The the third The initial orbital body AOG to accomodate resonance terms. elements of capability The orbit is in a near argument crisical of the resonance has a period of approximately 1340 days, while the second multiple period of 670 of the critical argument circulates a= 2 09831.6 km for the 0 Epoch = 21 March 1985 Oh.0,0m.0,0s.0 e= 0 .001 90.0" = 90.0* 3 a days. Table 5-18. Epoch Osculating Elements Lunar Resonance Test Case i= with Period = 11.07 days = 0.0* M = 0.00 Radius of Perigee = 209621.76 km Radius of Apogee = 210041.43 km Lunar Parallax Factor, (a/a')k = 0.546 296 0 The initial mean elements for the AOG prediction were obtained from satellite PCE. a PCE elements over were The perturbation included these terms used as model days. the used The a priori in the PCE osculating input is the to given in were the not AOG. also Care was modelled taken in the to ensure SPG. that The mean elements determined from the PCE are given in Table 5-20. Table 5-19. PCE Perturbation Models for the Lunar Resonance Test Case 1) AOG + SPG Perturbation Model: MOON NOTE: AOG retains the double averaged terms and the resonant terms corresponding to the index N = 12 M* = 6 R* = 8 -4 < t < 4 -10 7 s 7 N M* 10 pairs (t=2,s=-5), (t=-2,s=5), (t=4,s=-10), and (t=-4,s=10). These index pairs are deleted from the SPG. maximum power of the parallax factor, 2 (a/a') upper bound on the satellite Hansen coefficient d'Alembert characteristic R* 2 in Resonant terms with periods of 670 days or over Table 5-19. were sixty upper bound on the third body Hansen coefficient d'Alembert characteristic 2) Cowell Perturbing Acceleration: point mass moon 297 6 6 the Epoch Mean Elements for Table 5-20. Lunar Resonance Test Case Equinoctial Keplerian = km = 209702.4301 209702.4301 km e = 0.0049611077 h = 0.0023951282 i = 90.09639511* k = -0.0043446461 3 = 90.045887870 p = = 61.08692413* q = -0.0008022429 I M = 298.16803290 1.001683508 = 89.3008449* 0 The Table in elements mean were 5-20 used to initialize a five year AOG prediction of the lunar resonance the averaged equations of motion used a step size of 115 days. The AOG test model is in shown Hansen satellite numerical The orbit. been increased five year to Table 5-21. coefficient allow prediction for The on the characteristic has growth over the compare file was upper d'Alembert eccentricity The span. of integration Cowell bound generated from an integration that used 150 time regularized steps per revolution of the satellite. Ephemeris comparison 298 0 plots are for the provided histories (*) semi-major axis, in Figures are in general eccentricity 5-35 through agreement and inclination 5-37. with the motion observed in the Cowell generated histories The AOG long term (+). Table 5-22 compares the execution times of the Cowell and AOG predictions. five year run is seen The execution to be at least time of the AOG for the a factor of 3.5 less than that of the corresponding Cowell integration. Table 5-21. AOG Perturbation Model for the Five Year Lunar Resonance Integration MOON NOTE: AOG retains the double averaged terms and the resonant terms N = 12 M* = 12 corresponding to the index pairs (t=2,s=-5), (t=-2,s=5), (t=4,s=-10), R* = and 8 N 2 M* 2 upper bound (t=-4,s=10). maximum power of the parallax factor, (a/a') on the satellite Hansen coefficient d'Alembert characteristic R* 2 upper bound on the third body Hansen coefficient d'Alembert characteristic 299 0 Comparison of the Mean and Osculating SemiMajor Axis Histories for the 5 Year Integration of the Lunar Resonance Test Orbit/AOG versus Cowell Figure 5-35. 61 0 GTDS COMPAREPROGRAM KEPLERIAN ELEMENTHISTORIES 210650. . 210170. + + I I I+ I* 209690. .* + I+* 4 + **+ I* . 4. * *+++4. *+4 209210. + * + . + .++ + *. 4.4+ + 4+ * 208730. I * *- .+ 4. I I I I 209210. 4. 4. *. * I I I I + 4. + + + 4.* +. + 4. + 4. ~.4. + 4. *. . I I 207770. 4. 4. I, I 208290. 4. 4. 4 + +. + +. +. I I I I 4.+ *.4*+ 4.4 + +. 4.4. I + + I +. +4+ I I I I 206330. I I I I I I I I 205850. I.-- ------ ---------.---------.---------.-------- ---------- 0. 250.0 500.0 730.0 1000. 1250. TIME FROMYYMMODHHMtSS 850321 0 -------- -------------------------- - - 1500. 1750. 2000. 2250. I 2500. IN DYS (+) = Cowell (*) = AOG 0 300 Comparison of the Mean and Osculating Eccentricity Histories for the 5 Year Integration of the Lunar Resonance Test Orbit/AOG versus Cowell Figure 5-36. GTDSCOMPARE PROGRAM KEPLERIAN ELEMENTHISTORIES S.OOOOE-1 I 4.5000E-1 + +* * I .* +I +I I I 4.0000E-1 *+ * * E *++ TI**+ C TI**4+ NI 3 .5000E-1 03.OOOE-1 5 0 2 .OOOOE-1 E E *++ .* I.+ + +I+ ** ++++ 1.500E-1 TI I I * + I. I I+ 2.SOOOE-1 I *4+ +I I R **+ " - *++ + I 4 I I 4 * 44 I I ++4 + -I EI I802 40I 44 1.0O00E-1 I.- - - - - -- - - - --0+ I I I+ - - - - - - -- - -- 4- - - - . -- - - -*- - -" - - -I" " - - - I *++4 +* I 4*4** I I - I I-- - - - - 44 ------- -- ()= ()= 301 Cowell AOG -- - - - -- a Comparison of the Mean and Osculating Inclination Histories for the 5 Year Integration of the Lunar Resonance Test Orbit/AOG versus Cowell Figure 5-37. a a COMPAREPROGRAM 6TDS KEPLERIAN ELEMENTHISTORIES .----------------------------------------------------------- I. -------- ---------.-------------- 91.5000 91.1500 + + I I I I +*** +* 4 I + + + I + * N+ 4++ 4 + + + + I I I I ++ 4 + ++*N *+ + 90.4500 4+ +4+* + I + +* +* *N +++N+ ++++*NNN + + + + + 4 4++ 4 IN*N .+ + I+ I. * 4 + I I I I 4 *44 I *4 +4 + I 89.7500 61 ** * + a I I I I * I+* I *+4 90.1000 6 I I I * ** ** NNNN4 + * * 89.4000 4 * 4+ 4+ 0s 89.0500 I I I I 88.7000 4 I I I I 88.3500 I I I I I I I 88.0000 . 0. 250.0 500.0 750.0 1250. 1000. 1500. 1750. 2000. 2250. 2500. TIME FROM YYMMODHHMMSS IN DYS 850321 0 0s (+) (*) = = Cowell AOG 01 302 40 Table 5-22. Comparison of Cowell and AOG Execution Times for the Five Year Lunar Resonance Integration Orbit Generator Step Size Execution Time Cowell 150 steps/rev. time regularized 111 AOG 9936000 seconds seconds 32 seconds (115 days) Notes 1) 2) 3) 4) The Cowell integrator is based on the 12th order Adams-Bashforth Predictor / Adams-Moulton Corrector algorithm. The AOG uses a 4th order Runge-Kutta integration algorithm. The execution time for the Cowell integration contains overhead associated with file creation. The execution time for the AOG contains overhead associated with file creation and includes the ephemeris comparison step. 303 0 This test case has demonstrated the capability of the third body Table 5-22 to resonant to shows Cowell comparison incorporate integration to resonance that the efficiency is the previous terms that were of motion to AOG terms. of the AOG with respect substantially test cases. included in This the degraded in because the is averaged have periods that are still too short the double averaged terms. However, The result is equations in relation an unnecessary restriction of the integration step size. An attempt with only was the double made to perform averaged with the resonance modelled semi-major PCE should axis have plot in PCE initialization terms retained in the SPG. Figure 5-35 converged a would in the AOG and Inspection of the indicate that to a constant semi-major the axis of around 208395 kilometers, which seems well removed from the exact the resonance PCE caused value procedure by of did "overshoot" 207830 not in For correction algorithm. kilometers. This converge. the least Nevertheless, was squares an iteration of the probably differential PCE, it is possible that a correction to the mean semi-major axis was computed resonance that placed with the the orbit in moon. Since a region of nearly exact the tesseral analog short periodics are numerically ill-conditioned in the vicinity of exact of small resonance because of the presence 304 divisors, the semi-analytical for the subsequent residuals between osculating orbit generated trajectory was iteration the and Cowell the data fit the so the to approximation were span Hence, erroneous. semi-analytical the over as large to prevent convergence of the PCE. It is desirable model to all sharpest the but commensurabilities as short periodics, while retaining only the double averaged terms of averaging can benefit study of constrained initialization with respect the in be AOG, exploited. procedures to the that solution the full Accordingly, the so that are point more is required to avoid the problems encountered in this test case. 305 highly Chapter 6 Conclusions and Future Work The goal of this thesis semi-analytical third body dict term evolution the orbits long both has theory accurately and that of with been to construct can be high used altitude an efficiency a to presatellite that exceeds the capability of conventional mission analysis techniques. The averaged functions mathematical equations was of based development motion on the and of short application the periodic of the Method of Averaging to the Lagrangian form of cision satellite body disturbing essential equations. potential to the A in tial was performed in Chapter given in factor eq. (2-110). to an arbitrary The The orbital approach the to the satellite potential near-equatorial were elimination dynamical orbits. third elements for retains was the poten- the power and no assumptions elements the 2, with the final result being the geometry of the third body orbit. tial Generalized the high pre- orbital analysis body recovery representation of satellite development. third used of The 306 made on Non-singular equinocas artificial equations are parallax for potential part of a unified 'singularities near-circular was developed in and with to respect the the reference order first The potential efficient computation in a numerical program. was also expanded the satellite of longitudes into the mean to towards view a with theory. possible wherever structure analytical the the employed were functions modularize of complexity analytical Special frame of the satellite to minimize and the disturbing body so that resonance could be studied. of Substitution Planetary equations leads to a system of satellite equations of motion that depend lite and theory, the on the on based of Method the right hand sides in eq. (3-25), motion, shown average of the high respect to each of the of the are precision rapidly of linear combinations of At first quantities. formulated in The obtained equations varying terms of periodic short the mean 307 equations averaged osculating elements have been replaced mean for equations the satellite and disturbing body mean longitudes. order, satel- Averaging, the of components motion depending on rapidly varying the an averaging 3 developed Generalized undesired of removal the fast angles of two Chapter third body. the Lagrange the into potential the of multiple a by motion angles, of where with all by the corresponding recovery elements functions, output by the a averaged equations evaluation of the of motion, indefinite are obtained integrals in eqs. from the (3-32) and (3-33). Chapter 4 synthesized the results of Chapters 2 and 3 to produce mathematical expressions for th±e numerical imple- averaged the of mentation of equations series Fourier of m-daily in derivatives Section 4.3. of elements is shown for the 4.2 third the of h', j Table in for the The variazonal tesseral, The with investigated the 4-2. periodic short potential of forms respect to in detail in Of particular interest are the partial derivak' and and l. to form body potential. related quantities were satellite elements the The theory. Section of analogs partial tives motion coefficients tions were developed and body third with ' These dynamical the respect expressions system of to the mean the relate satellite third through reference evolution of the satellite orbital plane and are body the the result of having chosen a non-inertial frame to develop the potential. Section 4.4 contained a complete discussion of recur- rence relations for the computation of special functions auxiliary quantities. body theory relations on were Truncation introduced the indices of in parameters Section 4.5. for and the third Constraining the third body potential were derived on the basis of these parameters. 308 0 The of choice over the third body disturbing of structure the of elements analytical orbital the the on dependence a assumed body third compact potential body disturbing the of associated the and more the for exchange In summation. the elimination the to function inclination satellite the led potential of development the for frame inertial frame reference satellite non-inertial the orbital elements of the satellite which had to be accounted of equations the their partial only theory t are eq. s recovery advantage was in non-inertial third body frame elements and to be computed once for each evaluation of the averaged element rates of use periodic are known and have derivatives the proof respect to was with not periodic. (4-19) equations of are the that the mean the for of derivatives partial satellite order first elements p and i Hence, averaging integrals of the form in This vanish. contributions frame coordinate relative a to the relating central result A the short periodics. and the of forms analytical the in formulated potential the since averaged However, the net computational functions. favor of short the in and motion the in taken were derivatives partial when for means retained motion for in terms constraint of eq. (4-31). 309 that the that no first do residual order not secular averaged satisfy the Chapter 5 described of implementation The theory. results third first order body software third the components: the the Orbit Averaged of a numerical body averaging consisted Generator (AOG) of two and the Short Periodic Generator (SPG). The capability to construct a semi-analytical to high precision ephemerides is algorithms. sion of approximation provided combination of epoch (PCE) mean initialization elements procedure from osculating long term integrations of the averaged Long term predictions five using the the AOG and SPG This capability was used in the Precise Conver- Elements accurate by a satellite AOG and of compared test against to produce elements for equations of motion. orbits Cowell were performed integration for speed and accuracy.- 6.1 Conclusions The principal conclusion of this thesis is that the first order semi-analytical third body theory can be used to accurately predict satellite superior further (on the with to an the long efficiency conventional conclusion order of term motion of a high altitude is that one that mission analysis the large year) makes it decisively techniques. integration step permitted by the third A sizes body 310 0 are theory models compatible other- - averaged with that might be included in a general results verify perturbation analysis mission program. The of capable numerical test predicting the mean is tory over a time span that of a high very long provide a highly accurate AOG the is trajec- precision comparison to the in The SPG was also span of the initialization process. to that of representation found the third body short periodic variations. The excellent agreement of long term AOG predictions, based Cowell on the PCE-generated precision ephemeris epoch mean validates elements, both the with the and SPG AOG algorithms. The semi-analytical third body theory was shown to be successful in predicting the long term motion of high altitude satellites over a broad range in orbital geometry. theory produced very fine results for high satellite orbital eccentricity and for parallax factor. The capability to of the large values of the model resonance in the AOG was also demonstrated. 311 values The third body a Several conclusions behavior recursive processes be used speed to drawn regarding in computation well appear body In par- "stand-alone" found in investigations issue stability have recurrences in derivation along rapidly parallax MACSYMA package manipulation powers is 4.4.6, using The [31]. since the quite of since factor the their converges even when the interpolator Finally, large. of Hansen's theory the parallax symbolic resolution some by relations, the attention Furthermore, of supported recurrence little received is the required was 1855. factor and 4.4.5 Sections of sub- the third and conclusion This behaved. third non-zero of the satellite coefficients scrir'ted Hansen the for relations recurrence the the the body theory are stable for the test cases examined. ticular, the First, body software. third of the numerical can concepts are applicable to the computation of the third body short periodic coefficients, since the coefficients meet the slowly varying. requirement of being 6.2 Future Work Several suggested the by analysis, developed in areas of the present research. refinement, this investigation future thesis. and are of algorithms concerned exploration of new algorithmic approaches. 312 been are concerned with Some application Others have with the the accuracy At present, coupling an terms in of interactions and averaged the with of solar and lunar non-spherical of neglecting integration is often difficult propagation of small errors Orbit Averaged the substantially longer Generator be of taken the with over a long a on term the from conditions. initial initializing span data day fit each perturbations. distinguish the the 60 than test cases in Chapter 5. to arise from the this problem could be provided by into Insight body terms to in can perturbations these effect The of motion remains terms central order second including equations Coupling question. unresolved other importance the theory. body third order first the limits of determine to required is testing numerical Further span used that is for the This would allow greater advantageerror PCE smoothing Any properties. residual discrepancies between the resulting semi-analytical trajectory and Cowell integration could then such second terms order would become more more The effect realistically attributed to second order terms. of be important as the prediction span is lengthened. Continuing with the question of model accuracy, orbit determination long arcs of tests using actual the tracking semi-analytical data for theory high and altitude satellites would provide another stringent end-to-end test. 313 A careful through algorithmic optimization. are. possible software body third to the Improvements examination of the flow of indices in the third body theory could lead to a more completely recursive software architecture which places reliance less Z ,r coefficient in discussed for are not the computing These. 4.4.1. Section implemented in work to date the Furthermore, while software. current functions. special helpful be are easy to derive, but recurrences the would relations Recurrence of storage the on has demonstrated both accuracy and efficiency, these results have usually been various indices. indices these achieved with conservative values of the Automatic algorithms to rationally select and axis semi-major arbitrary an for would be quite valuable. eccentricity to capability The stability map parametrically regions for high altitude satellite orbits can be of immense the study of orbits for value strong lunar and in the solar perturbations STRATSAT class, where can cause rapid decay The first if initial conditions are not judiciously chosen. order third body theory can provide this capability with an efficiency test orbits that was not previously can the time that it trajectory. mission be generated in possible. averaged A great element many space in would take to integrate one high precision Having constraints, found a a mean orbit corresponding that set satisfies of the osculating 314 0 could elements not, If tions. they could be used input to priori as a be suf- might injection condi- world real to determine accurate ficiently elements These osculating periodic recovery. short analytical using computed be then a PCE which would refine the estimate of the real world orbit. the was interior satellite orbit that assuming By body. can be expression the to the orbit of body, orbit extend the applica- development The satellite the derivatives satellite in the region. translunar in to polynomial bility of the third body theory to satellites moving tial third exterior is Legendre a new which will developed body, under the assumption that the satellite of the disturbing the orbit inverse of the the disturbing and was performed (2-17), eq. for expansion between the satellite the distance given in polynomial Legendre The of of the elements with orbital into elements orbital introduces frame reference third body disturbing poten- third body the equations partial respect of to motion. The cross coupling of these partial derivatives in a second order averaging tial in is This complexity. (3-20). theory lead can to significant illustrated clearly in eqs. analytical (3-19) and Hence, the representation of the third body poten- eq. (2-111), may offer inertial substantial coordinates, advantages if an seen in attempt second order terms. 315 is made to develop Appendix A Computation and Storage of the Newcomb Operators in theory, the functions computed (4-236). non-zero using the recurrence Hansen and the relations body third coefficient body are (4-249) and disturbing in eqs. kernel Similarly, the derivatives of the kernel functions using are computed and satellite the for subscripted the of implementation software the In the Third Body Theory The (4-240). calculation the of recurrence relations recurrences initial values in eqs. the require from power the (4-250) explicit series expressions: Satellite 000 n, -m K% ti=0 - I0 X n, -m i+ - e 2i (A-i) 9,i+_ q - and 316 0 dKn, -m t (j+1) de 2 j=0 - 2j Xn,-m j+ - +1, e j++1 (A- 2) where q = (t + m) (A-3) Disturbing Body K-n-1,r s i=o X-n-1 ,r i+ . 2 ,12i (A-4) and dK-n-1 s de' 2 ,r 1 1,r x-nj+ j=0 + +q+1, j+ e ,2j 1 (A-5) 317 a where a q The series = s - (A-6) r coefficients, and are governed Xu,v, are by the recurrence the Newcori relations operators [17]: a =0 4p X p, 0 u~~v u,v+1uv+ 2(2v - u) X = 1 0 + (v p- , u) X p-2,0 (A-7) p = 0 4a X 0, a = -2(2v + u) Xu, -1 0, a-1 - (v + u) Xu, 0, o-2 (A-8) 318 0l p > 1, 4 a = 1 (p + 1) X p,1 = 2(2v - + + (v - u) u, v+ 1 p- 1 'l 2(2v + u) (v U) xu,v+2 + 2(2p u)1 2 - xu, vp ,0 1 + u,v u)Xp 1. (A- 9) p = 1, 4(1 a > 1 + a) X 1,a = 2(2v - - (v + u) u) X u,v+1 0,a 2(2v + u) u,v-2 + 2(2a - 1, a-2 -u) 2 2-u)v X 1 ,a-1 X r 0, a-1 (A-10 ) 319 6 p > 1, a > 1 0 4( p + Xurv p, a a) = + (v - Xuv+1 p-1 , a u) 2(2v - 2(2v + u) Xu v-1 + p, a-1 v+2 u,v-2 (v + u) Xp v-2 + a-2+ p--2,p, u) 1p-2,a + 2(2p + 2a - 4 - u) _ X p-i , a-i (A-11) The for conditions initial these recurrence relations are given by, 0 u,v 0 - u X1,0 =v Xu ,v 0 ,1 The Newcomb identically (A-12) 1 u (A-1 3) 72 v - operators u 2 with (A- 14) negative subscripts are zero. 320 0 0 Newcomb The relations recurrence are and in stored the block data FORTRAN compiled The by "offline" computed B). Appendix (see subprograms are operators of versions these subprograms are linked to GTDS at run time, along with the three initialize to software, body third the of rest dimensional Newcomb operator arrays. there accessed to operator Newcomb are explicitly the develop each for functions kernel body disturbing and satellite be can that arrays time, present the At value of the index n, up to and including n = 20. For operator a. given are arrays value of valid for construct kernel the satellite 20 Newcomb with coefficients Hansen to up characteristics d'Alembert n, and functions with subscripts used be can that fall to within the range, -41 < t < 41 (A-15) Likewise, for a particular value of n, the disturbing coefficients can that be fall used with to within are arrays operator Newcomb body d'Alembert characteristics functions kernel construct for valid up with to Hansen 10 and subscripts the range, -31 < s < 31 3.21 - (A-16) 0 Appendix B Software Implementation of the Third Body Theory0 The for been and orbital to the is subroutine SPANAL for which time has averaged perturbations. the independent (SPG) governs for coefficients periodic elements double constructs which Generator Periodic and mean both body of motion The for the third body Averaged Orbit ANAVR rates element for third resonant (AOG) Short GTDS subroutine executive Generator The into implemented equations averaged the the sho-t periodic corrections non-resonant GTDS for theory is the averaged perturbations. by driven computation the of GTDS short averaged analytically perturbations. B.1 Subroutine Descriptions This implement EVAL, all the of the analysis temporary modified section body third theory. the subroutines of this updates. to describes thesis The GTDS incorporate the the subroutines With the were expressly and were which exception written included in of to test GTDS as subroutine EVAL was extensively analytical ephemeris discussed in Chapter 5 and is thus included in the list of third body 322 Wherever appropriate, references to the thesis subroutines. link the software text that included to the analysis are in the subroutine descriptions. The twenty-four subroutines that follow form the core of the body third generate the right hand They software. averaging used are to sides of the averaged equations of motion for double averaged third body perturbations. 1) AAPRIM: Computes n including third 2) AVEXEC: Computes Tt,s its averaged orbit to (4-86) stores = N, where N body Legendre and and (5/a' )n up to is the maximum degree and of the polynomial expansion. the partial derivatives generator (4-91)]. and real [eqs. Computes imaginary for the (4-81) to sines and parts third of body (4-83) , eqs. cosines of tT+sX' for the third body resonance implementation. 3) BROLUN: Computes the mean equinoctial elements of the Moon in mean ecliptic of date coordinates using Brown's theory [Section 5.2]. 4) BROSOL: Sun in Computes the mean equinoctial elements of the mean ecliptic of date Newcomb's theory [Section 5.2]. 323 coordinates using a 5) CMRDMR: Computes parts of [eqs. (4-168) the 6) to DUBFAC: complex to stores the polynomials (4-171), real and Cr M (a, 0) + (4-184) eqs. derivatives with respect its partial (4-175) and (4-182) , Computes eqs. (4-188) to to imaginary j D m (a,,) (4-187) ] and a and a [eqs. to (4-195) ]. and stores double factorials required for the averaged orbit generator and the short periodic generator. 7) EPRIM: Computes disturbing [Table 2-3] . and k' with [eq. 8) body (4-92) the Sun numerical Computes orbit and eqs. rotation to partial elements frame of the coordinates derivatives elements the satellite p of h' and q to (4-96) ]. and the in using matrices body k' satellite position Moon and the (4-94) integration coordinates in to respect , h' Computes Computes EVAL: the fixed velocity reference the for components for of the system analytical ephemeris. converting coordinates and inertial mean of 1950.0 coordinates to true of date coordinates. 9) FACT: Computes and stores factorials averaged orbit generator required for the and the short periodic generator. 324, 0 10) HANSTO: Computes satellite Hansen subscript zero, 11) [eqs. functions (4-254) to to h and k of (4-256) ]. satellite the of the stores kernel derivatives functions with respect kernel to coefficient Kn,-m and form closed partial the Computes in [eqs. (4-257) (4-259)]. subscript kernel functions of Hansen coefficient disturbing body zero, [eqs. KO-n-l,r' the stores and form closed in Computes HANTDO: (4-242) to (4-244)]. Computes the partial derivatives of the disturbing body 12) kernel functions with (4-245) to (4-247) ]. Computes HKSAT: the parts of [eqs. (4-215) and (4-218) ] HPKP: of the (4-211) JACPOL: real and imaginary (k - jh) -m-t derivatives (4-277) to (4-234) ]. Computes and stores the real and imaginary parts complex to and k' Computes derivative with (k' polynomials (4-214) ] respect to h' 14) k' partial its and with respect to I and li [eqs. 13) and polynomials complex to the stores [eqs. h' to respect and - jn'h') partial its [eqs. derivatives with (4-219) to (4-226) ]. [eqs. and stores the function respect Ir-si to Section 4.4.2]. 325 Y [eqs. (4-65) A(y) to and its (4-67), a 15) MEXEC: Executive over m summation for the routine in 0 16) Executive NEXCF: over summation for the n in Hansen satellite the when used is that t,s routine coefficient kernel functions are of subscript zero. 17) Computes NOD: the nutation matrix for a rotation from S mean of date coordinates to true of date coordinates. 18) Computes OBLIQ: matrix rotation the transforms that 0 ecliptic coordinates to equatorial coordinates. 19) coordinates. precession Computes the matrix of inverse to transform date of mean to coordinates 1950.0 of mean the Computes PRECES: 0 precession the matrix. 20) REXCF: Executive -that *t,s is summation routine for the when the disturbing used over r in Hansen body coefficient kernel functions are of subscript zero. 21) THIRD: the Computes disturbing the body disturbing body eccentricity semi-major vector in 9 axis, inertial coordinates and the direction cosines of the disturbing body unit orbit normal with respect to the unit vectors of the satellite frame [Section 2.2.4]. 326 0 0 22) Computes the components of XYZPOS: the disturbing body position vector in mean ecliptic of date coordinates. 23) Computes the components of the disturbing body XYZVEL: velocity vector in mean ecliptic of date coordinates. 24) Computes ZCOEFF: and coefficient the (4-142) [eqs. Zm n,r (4-144) ]. order In averaged to generator orbit body third model or model to corrections to the mean elements, the in resonance the short following the periodic subroutines are required: 25) the Transfers ASSGN: the containing contents body third of Newcomb the common operators blocks into a single common block. 26) NEXNEW: 4 for the summation over n in when used is that 't,s routine Executive the satellite Hansen coefficient kernel functions have non-zero isubscripts. 27) REXNEW: 4 t,s Executive that is used coefficient kernel routine for the summation over r in when the disturbing body Hansen functions have non-zero subscripts. 327 a 28) SATNEW: Computes satellite Hansen non-zero subscript have by coefficient expansions [eq. derivatives of (4-249) ]. the 29) SATONE: Computes satellite Hansen one subscript (4-250) the coefficient with beginning n = to respect with are relations recurrence stores and values the of that have expansions. of the satellite h and k. explicitly The re-initialized instability to avoid 11 with functions kernel derivatives partial that ]. (4-252) initial from of partial the from the Newcomb operator functions kernel to the operator functions kernel recurrence by starting been constructed Computes Newcomb Computes satellite respect to h and k [eqs. values initial the from stores functions kernel from starting constructed been and recurrence for high values of n when the kernel function subscript is one. 30) Computes THDNEW: by recurrence and stores the disturbing body Hansen coefficient kernel functions of non-zero have been from constructed expansions [eq. derivatives of from starting subscript (4-236) ]. the disturbing with respect to h' and k' [eqs. values initial the Newcomb Computes body the kernel (4-240) and that operator partial functions (4-241) ]. 328 0 The relations recurrence names having third body and SATONE, body that is n are 'loaded under expansion. polynomial software incorporates is, recurrence THDNEW, in functions There NEWn. are the for relations 19 of the to initialize disturbing kernel body these form the having loaded under names presently are these Likewise, Newcomb operator block data subprograms, used the the The of 19 through NEWS20. NEWS2 of degree the Legendre potential subprograms, SATNEW where function kernel satellite form NEWSn, the third present in which subprograms, the initialize to used are data block operator Newcomb subprograms corresponding to NEW2 through NEW20. The subroutine which is specifically required for the third implementation resonance body the in averaged orbit generator is: 31) Computes the mean longitude THDLAM: for use in the resonant [Section 2.2.3.2]. the third body eqs. The (4-118) to averaged the body third orbit generator Computes the partial derivatives of mean p and q satellite of longitude elements (4-133) [eqs. with respect (4-116) and to the (4-117), ]. subroutines which are specifically required the third body short periodic implementation are: 329 for 32) SPTHDB: Computes coefficients and 33) (4-38), DBLANG: for eqs. Computes the third analytical short body perturbations (4-48) to (4-62) periodic [eqs. (4-37) ]. the third body mean longitude and its partial derivatives with respecL to p and q. A schematic representation of the overall subroutine structure for the third body AOG and SPG is given in Figure B-1. At present partitioned data the sets body third on the software CSDL Amdahl 470 resides V/8 which in are cataloged under the following names: Non-Resonant Software FORT (1) SKC1756.GTDS.UPDATE. LOAD (FORT) (2) SKC1756.GTDS.SP. ( 0 LOAD 0 330 0 Resonance Software FORT (3) SKC1756.GTDS.RESON. ~LOAD) FORT (4) SKC1756.GTDS.SP.RESON. I ~LOAD~ Satellite Hansen Coefficient Newcomb Operators FORT (5) SKC1756.GTDS.NEWSAT1. LOAD FORT (6) SKC1756.GTDS.NEWSAT2. LOAD Third Body Hansen Coefficient Newcomb Operators FORT (7) SKC1756.GTDS.NEWTHD1. LOAD FORT (8) SKC1756.GTDS.NEWTHD2. LOAD 331 W Table B-1 third body indicates which data sets option and are needed minimum the region for size a given that is 0 required for the resulting updated GTDS load module. Third Body Optic- Data Sets Required by Identifying no. (see text) Required Region Size 0 (1) AOG without resonance 1052K AOG+SPG without resonance (1),(2),(5),(6),, (7),(8) 4976K AOG with resonance (3),(4),(5),(6), (7),(8) 4980K AOG+SPG with resonance (3),(4),(5),(6), (7),(8) 4980K 0 Table B-1. Datasets and Region Sizes Required for the Various Third Body Options 0 332 0l 9 0 9 0 W' WAUA- SHORT PERIODIC GENERATOR AVERAGED ORBIT GENERATOR * Figure B-i. EXISTING GTDS SUBROUTINE Subroutine Interaction Diagram for the Third Body Software (page 1 of 4) L~J * Figure B-i. rl EXISTING GTDS SUBROUTINE Subroutine Interaction Diagram for the Third Body Software 0 (page 2 of 4) 0 p S 5 9 5 5 5 5 5 B D DUBFAC Figure B-i. HKSAT rCMRDMR AAPRI HPKP Subroutine Interaction Diagram for the Third Body Software FACT (page 3 of 4) LA) SATONE SATNEW HANSTO F Figure B-l. e0 ZCO EF JACPOL .Subroutine Interaction Diagram for the Third Body Software 0 (page 4 of 4) 00 0 00 0 References 1. Kozai, Y., Satellites," Geodesy "Analytical Orbital The Use of Artificial and Geodynamics Theories Satellites (Proceedings for for of the International Symposium on the Use of Geodesy and Geodynamics, Athens, May 1973), ed. G. Veis, Athens, 1974, 2. pp. 237-242. Graf, Otis F., "The Elimination of Short Intermediate Period Terms from the Problem of a Altitude Earth Satellite," Celestial Mechanics, 14, No. 3, November 1976, and High Vol. pp. 321-329. 3. Krylov, N., and N. N. Bogoliubov, Introduction to Nonlinear Mechanics, Princeton University Press, Princeton, N.J., 1947. 4. Mitropolsky, Y. A., Problems of the Asymptotic Theory of Non-Stationary Vibrations, 1965. Daniel Davey, New York, 5. Hagihara, Y., Celestial Mechanics, Vol. II, Part I, MIT Press, Cambridge, Massachusetts, 1972. 6. Musen, P., "A Discussion of Halphen's Method of Secular Perturbations and Its Application to the Determination of Long-Range Effects in the Motion of Celestial Bodies," Reviews of Geophysics, Vol. 1, No. 1, February 1963, pp. 85-122. 7. Musen, P., Effects in Nonsingular "On Determining the Secular and Critical the Motion of Satellites by Means of a Set of Vectorial Elements," Journal of Geophysical Research, 1963, pp. 6255-6260. 8. Vol. 68, No. 23, December 1, Smith, A. J., "A Discussion of Halphen's Method for Secular Perturbations and Its Application to the Determination of Long Range Effects in the Motions of Celestial Bodies, Part 2," NASA TR R-194, Goddard Space Flight Center, Greenbelt, Maryland, June 1964. 9. Baxter, B. E., "On the Determination of Mean Elements for High Altitude Orbits," Aerospace Technical Memorandum 79(4404-30)-20, The Aerospace Corporation, El Segundo, California, 9 July 1979. 337 10. Ash, M. E., "Doubly Averaged Effect of the Moon and Sun Orbit," Celestial on a High Altitude Earth Satellite Mechanics, Vol. 14, No. 2, September 1976, pp. 209-2 11. "An Intermediate Seniw, P. and W. Sridharan, R., Lincoln Orbits," Altitude High for Theory Averaged Laboratory Technical Note 1979-25, Lincoln Laboratory, Lexington, Massachusetts, 27 June 1979. 12. "The Evolution of Orbits of Artificial Lidov, M. L. Satellites of Planets Under the Action of Gravitational Planetary Space Bodies," External Perturbations of Sciences, Vol. 9, 1962, pp. 719-759. 13. "Basic Theory G. E., Cook, Development the Computing Celestial Mechanics, Vol. for of A Program for PROD, Orbits," Satellite 7, No. 3, April 1973, pp. 301-314. 14. Kaula, W. M., "A Development of the Lunar and Solar NASA Satellite," a Close for Functions Disturbing Center, Goddard Space Flight D-1126, Technical Note Greenbelt, Maryland, January 1962. 15. A CSC/TR-77/6010, Corporation, Sciences Computer Semianalytic First-Order Formulated Recursively Theory Based on the Generalized Satellite Artificial The Generalized Method of I: Vol. Averaging, of Method Averaging Applied to the Artificial Satellite Problem, Wayne D. McClain, November 1977. 16. Handbook of Mathematical Functions, eds. M. Stegun, Dover Publications, Inc., and 1. A. 1972. 17. A CSC/TR-78/6001, Corporation, Sciences Computer Semianalytic First-Order Formulated Recursively Artificial Satellite Theory Based on the Abramowitz New York, Generalized The Explicit Development Method of Averaging, Vol. II: of Motion for the Equations Averaged of the First-Order Nonspherical Gravitational and Nonresonant Third-Body Perturbations, Wayne D. McClain, May 1978. 18. "A Recursive Formulation for the Tesseral Cefola, P., Variables," Equinoctial in Function Disturbing presented to the AIAA/AAS Astrodynamics Conference, San Diego, California, 76-839. August 338 18-20, 1976, paper no. 19) Morse, P. M., Physics, Part York, 1953. 20) Courant, Physics, York, and H. Feshbach, Methods of Theoretical II, McGraw-Hill Book Company, Inc., New R., and D. Hilbert, Methods of Mathematical Inc., New Volume I, Interscience Publishers, 1953. 21) McClain, W., and M. Slutsky, "A Theory for the Short presented to Satellite," Period Motion of an Artificial the AIAA/AAS Astrodynamics Conference, Danvers, Massachusetts, August 11-13, 1980, paper no. 80-1658. 22) J., "Orbit Determination and Prediction Green, A. Processes for Low Altitude Satellites," Ph.D. dissertation, Massachusetts Institute of Technology, Cambridge, MA, December 1979. 23) McClain, W. D., A. C. Long, and L. W. Early, "Development and Evaluation of a Hybrid Averaged Orbit Generator," presented to the AIAA/AAS Astrodynamics Conference, Palo Alto, California, August 7-9, 1978, paper no. 78-1382. 24) Early, L.'W., GTDS software documentation in progress, Charles Stark Draper Laboratory, Inc., Cambridge, MA. 25) Shaver, J. S., "Formulation and Evaluation of Parallel Algorithms for the Orbit Determination Problem," Ph.D. dissertation, Massachusetts Institute of Technology, Cambridge, MA, March 1980. 25) Hansen, P. A., "Expansion of the Product of a Power of the Radius Vector with the Sine or Cosine of a Multiple of the True Anomaly in Terms of Series Containing the Sines and Cosines of the Multiples of the True, Eccentric or Mean Anomaly," Abhandlungen der Koniglichen Sachsischen Gesellschaft Tur Wissenschratt, Vol. 27) 2, No. 3, pp. German by J. C. Van der Ha. 183-281, 1855; translated Collins, S. K., and P. J. 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December MA, Technology, Cambridge, 340 0 BIOGRAPHY Sean Kevin Collins was born 21 February 1952 on the Fort Belvoir military reservation in Virginia to John M. and He attended Fort Hunt High School in Gloria 0. Collins. In June of 1974 he Alexandria, Virginia from 1966 to 1970. High Distincwith Degree of Science Bachelor received the tion. in Aerospace Engineering at the University of Virginia Having entered the graduate in Charlottesville, Virginia. of the Massachusetts Institute of Technology in school September of 1974, he was granted a Master of Science degree He in Aeronautics and Astronautics in February 1977. At present Mr. July 1980. married Susan Jane Howling in is a Draper Fellow at the Charles Stark Draper Collins Laboratory in Cambridge, Massachusetts. 341