431-XXX-XXXXXX
Revision (Add Level i.e., -, A, B, etc.)
Effective Date: To be added upon Release
Expiration Date: To be added upon Release
DRAFT
Lunar Reconnaissance Orbiter Project
Pointing and Alignment Specification
March 15, 2006
Goddard Space Flight Center
Greenbelt, Maryland
National Aeronautics and
Space Administration
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Title of LRO Document
431-XXX-XXXXXX
Revision Release Status (i.e. DRAFT)
CM FOREWORD
This document is a Lunar Reconnaissance Orbiter (LRO) Project Configuration Management
(CM)-controlled document. Changes to this document require prior approval of the applicable
Configuration Control Board (CCB) Chairperson or designee. Proposed changes shall be
submitted to the LRO CM Office (CMO), along with supportive material justifying the proposed
change. Changes to this document will be made by complete revision.
Questions or comments concerning this document should be addressed to:
LRO Configuration Management Office
Mail Stop 431
Goddard Space Flight Center
Greenbelt, Maryland 20771
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TABLE OF CONTENTS
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Page
1.0
2.0
3.0
4.0
5.0
Introduction .................................................................................................................... 1-1
1.1
Scope .................................................................................................................... 1-1
1.2
Applicable Documents ......................................................................................... 1-1
1.3
Units ..................................................................................................................... 1-1
Coordinate System ......................................................................................................... 2-1
Pointing and Alignment Budget Component Definitions ........................................... 3-1
3.1
Targeting and Mapping Errors ............................................................................. 3-1
3.1.1 Surface Error ............................................................................................ 3-1
3.1.2 Timing Error ............................................................................................ 3-2
3.1.3 Orbit Determination Error........................................................................ 3-2
3.1.4 Ephemeris Error ....................................................................................... 3-2
3.2
Spacecraft Error ................................................................................................... 3-2
3.2.1 Attitude Control System Error ................................................................. 3-2
3.2.2 Jitter.......................................................................................................... 3-2
3.2.3 Thermal Distortion ................................................................................... 3-2
3.2.4 Static Bias ................................................................................................ 3-2
3.3
Instrument Errors ................................................................................................. 3-3
3.4
Budget Combination ............................................................................................ 3-3
3.4.1 Pointing Accuracy.................................................................................... 3-3
3.4.2 Pointing Knowledge................................................................................. 3-4
3.4.3 Pointing Stability ..................................................................................... 3-5
CRaTER Pointing and Alignment Allocations ........................................................... 4-1
4.1
CRaTER Pointing Accuracy ................................................................................ 4-1
4.2
CRaTER Pointing Knowledge ............................................................................. 4-2
4.3
CRaTER Pointing Stability .................................................................................. 4-2
4.3.1 PSD of Distribution at CRaTER Feet with Diviner ................................. 4-2
4.3.2 PSD of Distribution at CRaTER Feet without Diviner ............................ 4-2
4.4
Other Pointing and Alignment Requirements ...................................................... 4-3
4.4.1 Alignment to Spacecraft Reference ......................................................... 4-3
4.4.2 Co-Alignment .......................................................................................... 4-3
Diviner Pointing and Alignment Allocations ............................................................... 5-1
5.1
Diviner Pointing Accuracy .................................................................................. 5-1
ii
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5.2
5.3
5.4
6.0
7.0
8.0
9.0
10.0
Diviner Pointing Knowledge ............................................................................... 5-2
Diviner Pointing Stability .................................................................................... 5-2
Other Pointing and Alignment Requirements ...................................................... 5-2
5.4.1 Alignment to Spacecraft Reference ......................................................... 5-2
5.4.2 Co-Alignment .......................................................................................... 5-2
LAMP Pointing and Alignment Allocations ................................................................ 6-1
6.1
LAMP Pointing Accuracy.................................................................................... 6-1
6.2
LAMP Pointing Knowledge ................................................................................ 6-1
6.3
LAMP Pointing Stability ..................................................................................... 6-2
6.3.1 PSD of Disturbances at LAMP Feet with Diviner ................................... 6-2
6.3.2 PSD of Disturbances at LAMP Feet without Diviner .............................. 6-2
6.4
Other Pointing and Alignment Requirements ...................................................... 6-2
6.4.1 Alignment to Spacecraft Reference ......................................................... 6-2
6.4.2 Co-Alignment .......................................................................................... 6-2
LEND Pointing and Alignment Allocations ................................................................ 7-1
7.1
LEND Pointing Accuracy .................................................................................... 7-1
7.2
LEND Pointing Knowledge ................................................................................. 7-2
7.3
LEND Pointing Stability ...................................................................................... 7-2
7.3.1 PSD of Disturbances at LEND Feet with Diviner ................................... 7-2
7.3.2 PSD of Disturbances at LEND Feet without Diviner .............................. 7-2
7.4
Other Pointing and Alignment Requirements ...................................................... 7-2
7.4.1 Alignment to Spacecraft Reference ......................................................... 7-2
7.4.2 Co-Alignment .......................................................................................... 7-3
LOLA Pointing and Alignment Allocations ................................................................ 8-1
8.1
lOLA Pointing Accuracy ..................................................................................... 8-1
8.2
lOLA pointing knowledge ................................................................................... 8-1
8.3
lOLA Pointing Stability ....................................................................................... 8-2
8.3.1 PSD of Disturbances at LOLA Feet with Diviner ................................... 8-2
8.3.2 PSD of Disturbances at LOLA Feet without Diviner .............................. 8-2
8.4
Other Pointing and Alignment Requirements ...................................................... 8-2
8.4.1 Alignment to Spacecraft Reference ......................................................... 8-2
8.4.2 Co-Alignment .......................................................................................... 8-2
lROC-NAC Pointing and Alignment Allocations ....................................................... 9-1
9.1
LROC-NAC Pointing Accuracy .......................................................................... 9-1
9.2
LROC-NAC Pointing Knowledge ....................................................................... 9-1
9.3
LROC-NAC Pointing Stability and Jitter ............................................................ 9-2
9.3.1 PSD of Disturbances at LROC-NAC Feet with Diviner ......................... 9-2
9.3.2 PSD of Disturbances at LROC-NAC Feet without Diviner .................... 9-2
9.4
Other Pointing and Alignment Requirements ...................................................... 9-2
9.4.1 Alignment to Spacecraft Reference ......................................................... 9-2
9.4.2 Co-Alignment .......................................................................................... 9-2
LROC-WAC Pointing and Alignment Allocations ................................................... 10-1
10.1 LROC-WAC Pointing Accuracy ....................................................................... 10-1
iii
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10.2
10.3
LROC-WAC Pointing Knowledge .................................................................... 10-1
LROC-WAC Pointing Stability ......................................................................... 10-2
10.3.1 PSD of Disturbances at LROC-WAC Feet with Diviner....................... 10-2
10.3.2 PSD of Disturbances at LROC-WAC Feet without Diviner ................. 10-2
10.4 Other Pointing and Alignment Requirements .................................................... 10-2
10.4.1 Alignment to Spacecraft Reference ....................................................... 10-2
10.4.2 Co-Alignment ........................................................................................ 10-2
11.0 Mini-RF Pointing and Alignment Allocations........................................................... 11-1
11.1 Mini-RF Pointing Accuracy............................................................................... 11-1
11.2 Mini-RF Pointing Knowledge............................................................................ 11-2
11.3 Mini-RF Pointing Stability ................................................................................ 11-2
11.3.1 PSD of Disturbances at Mini-RF Feet with Diviner .............................. 11-2
11.3.2 PSD of Disturbances at Mini-RF Feet without Diviner ......................... 11-2
11.4 Other Pointing and Alignment Requirements .................................................... 11-3
11.4.1 Alignment to Spacecraft Reference ....................................................... 11-3
11.4.2 Co-Alignment ........................................................................................ 11-3
12.0 High Gain Antenna Pointing Budget ......................................................................... 12-1
13.0 Solar Array Pointing Budget ...................................................................................... 13-1
Appendix A. Abbreviations and Acronyms ................................................................................1
iv
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LIST OF FIGURES
Figure
Page
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Figure 2-1. LRO Coordingate System ........................................................................................ 2-1
Figure 3-1. Sample Figure Title Format ..................................................................................... 3-1
Figure 3-2. Pointing Accuracy .................................................................................................... 3-3
Figure 3-3. Contributions to Pointing Accuracy ......................................................................... 3-4
Figure 3-4. Contributions to Pointing Knowledge ...................................................................... 3-4
Figure 3-5. Pointing Stability...................................................................................................... 3-5
LIST OF TABLES
Table
Page
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Table 4-1. CRaTER Pointing Accuracy...................................................................................... 4-1
Table 4-2. CRaTER Pointing Knowledge .................................................................................. 4-2
Table 5-1. Diviner Pointing Accuracy ........................................................................................ 5-1
Table 5-2. Diviner Pointing Knowledge ..................................................................................... 5-2
Table 6-1. LAMP pointing accuracy .......................................................................................... 6-1
Table 6-2. LAMP Pointing Knowledge ...................................................................................... 6-2
Table 7-1. LEND Pointing Accuracy.......................................................................................... 7-1
Table 7-2. LEND Pointing Knowledge ...................................................................................... 7-2
Table 8-1. LOLA Pointing Accuracy.......................................................................................... 8-1
v
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Table 8-2. LOLA Pointing Knowledge ...................................................................................... 8-2
Table 9-1. LROC-NAC Pointing Accuracy ................................................................................ 9-1
Table 9-2. LROC-NAC Pointing Knowledge ............................................................................. 9-2
Table 9-3. NAC Co-Alignment................................................................................................... 9-3
Table 10-1. LROC-WAC Pointing Accuracy ........................................................................... 10-1
Table 10-2. LROC-WAC Pointing Knowledge ........................................................................ 10-2
Table 11-1. Mini-RF Pointing Accuracy .................................................................................. 11-1
Table 11-2. Mini-RF Pointing Knowledge ............................................................................... 11-2
Table 12-1. LRO High Gain Antenna Pointing Budget ............................................................ 12-1
Table 13-1. LRO Solar Array Pointing Accuracy Budget ........................................................ 13-1
vi
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1.0
INTRODUCTION
The Lunar Reconnaissance Orbiter is the first mission of the Robotic Lunar Exploration
Program. The LRO mission is focused on obtaining new data that will facilitate returning
humans safely to the moon. This mission will launch late in 2008 and will take measurements of
the moon for at least one year.
The LRO spacecraft is made up of several modules. The propulsion module interfaces to the
launch vehicle and houses the propulsion system. The avionics module houses most of the
electronics equipment to run the spacecraft. At the top of the spacecraft is the instrument module
where LRO’s six instruments are located. LRO also has two deployable components, a solar
array and a high gain antenna.
LRO has seven instruments to perform its exploration measurements. They are Cosmic Ray
Telescope for the Effects of Radiation (CRaTER), Diviner Lunar Radiometer Experiment
(DLRE), Lyman-Alpha Mapping Project (LAMP), Lunar Exploration Neutron Detector (LEND),
Lunar Orbiter Laser Altimeter (LOLA), the Lunar Reconnaissance Orbiter Camera (LROC), and
the Mini-RF.
1.1
SCOPE
The purpose of this document is to define the pointing requirements and allocations for each of
the LRO Instruments, the Solar Array and the High Gain Antenna.
1.2
APPLICABLE DOCUMENTS
LRO Mission Requirements Document, 431-RQMT-00004
LRO Integration and Test Plan, 431-PLAN-000100
LRO LRO GN&C ACS Specifications Document 431-SPEC-000162
LRO Alignment Plan
1.3
UNITS
All pointing budgets shall be shown in both arc-seconds and micro-radians. All budgets are 3
sigma worst case allocations.
1-1
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2.0
COORDINATE SYSTEM
The reference coordinate system for the LRO is show in figure 2.1. The origin for this
coordinate system is at a center of the spacecraft/Launch Vehicle interface. The X axis is
pointed in the main thrust direction of the orbiter. The Z axis is pointed in the nadir, instrument
aperture, direction and the Y axis completes the right handed coordinate system. All allocations
are requirements are defined in this coordinate
system.
X
Y
Z
Figure 2-1. LRO Coordingate System
2-1
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3.0
POINTING AND ALIGNMENT BUDGET COMPONENT DEFINITIONS
This Pointing and alignment errors can be broken down into three major types of errors,
target/mapping errors, spacecraft errors and instrument errors. Figure 3-1, shows how the
various components of the pointing and alignment budget work together.
Spacecraft
Instrument
LROC LOLA
LAMP
LEND CRaTER Diviner Mini-RF
Item 1
Item 1
Item 1
Item 1
Item 1
Item 1
Item 1
É
É
É
É
É
É
É
Item n
Item n
Item n
Item n
Item n
Item n
Item n
Optical Bench
Thermal
S/C Structure
Thermal
Mechanical
Mechanical
ACS
Target
GCI
ACS
Orbit Determination
Timing Error
Surface Error
Surface
Figure 3-1. Sample Figure Title Format
3.1
TARGETING AND MAPPING ERRORS
Targeting error is the error in predicting where a particular location on the moon will be. This
represents the on-orbit knowledge of where the spacecraft is relative to the moon. Targeting
error includes definitive orbit determination error, ephemeris propagation error, timing error and
surface error. Mapping error is the error in knowledge of where a particular location on the
moon was. This represents the post processed knowledge of where the spacecraft was relative to
the moon. Mapping error includes definitive orbit determination error, and timing error.
3.1.1 Surface Error
Surface error represents the difference between the true latitude and longitude location of a
particular target and its estimated latitude and longitude on the moon. Because surface error is
target dependant and it cannot be changed by any engineering parameters, it shall not be
considered as part of the LRO pointing and alignment budget. If surface error is important to a
particular observation, the Principal Investigator should take it into consideration.
3-1
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3.1.2 Timing Error
Timing error is the error in knowledge of where the spacecraft is in its ground track due to clock
errors. The error is the clock error times the ground speed of the spacecraft.
3.1.3 Orbit Determination Error
Orbit determination represents the difference between the true orbit of the spacecraft in GCI and
its estimated location in GCI. This calculation is made on the ground and is developed from
spacecraft tracking data.
3.1.4 Ephemeris Error
Ephemeris error represents the difference between the true location of the spacecraft in GCI and
its predicted location in GCI. This calculation is made on the ground and uploaded to the
spacecraft.
3.2
SPACECRAFT ERROR
Spacecraft error is the difference between the GCI reference frame and the instrument mounting
feet.
3.2.1 Attitude Control System Error
Attitude Control System (ACS) error is the error between GCI and the spacecraft main reference
frame. ACS error has two components, ACS knowledge error and ACS control error.
3.2.2 Jitter
Jitter is the difference between the spacecraft main reference frame and the instrument mounting
feet. This error is caused by vibration of the spacecraft. For the purpose of this document jitter
shall be any disturbance to the spacecraft above the ACS control bandwidth.
3.2.3 Thermal Distortion
Thermal distortion is the difference between the spacecraft main reference frame and the
instrument mounting feet. Thermal distortion is caused by thermal gradients on the spacecraft
structure. Thermal distortion occurs on an orbital frequency.
3.2.4 Static Bias
Static bias is the difference between the spacecraft main reference frame and the instrument
mounting feet. Static bias does not change once the spacecraft is on orbit. Sources of static bias
include 1 g release, launch shift and alignment. For instruments that have the ability to calibrate
the location of their bore sight while on orbit, static bias becomes calibration error
3-2
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3.3
INSTRUMENT ERRORS
Instrument error is the pointing error between the instrument mounting feet and the instrument
bore sight. These errors are dependant on a particular instrument, and it is the responsibility of
the instrument development team to define these.
3.4
BUDGET COMBINATION
3.4.1 Pointing Accuracy
Pointing accuracy is defined as the difference between truth and the desired target. Figure 3-2
illustrates this concept. Several items contribute to pointing control accuracy including ACS
knowledge and controller error, jitter, thermal distortion, static bias and instrument errors. These
errors shall be summed together. Figure 3-3 shows have the components of pointing accuracy go
together.
Target
Estimate
Accuracy
Knowledge
True
Figure 3-2. Pointing Accuracy
3-3
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Accuracy
GCI to
Instrument mount
Jitter
ACS
ACS
Knowledge
Thermal Distortion
sum
Static Bias
Instrument
ACS Controller
Figure 3-3. Contributions to Pointing Accuracy
3.4.2 Pointing Knowledge
Pointing Knowledge is the difference between the estimated pointing and the true pointing.
Pointing knowledge is illustrated in Figure 3-1. ACS knowledge, spacecraft jitter, thermal
distortion, static bias and instrument errors are summed to obtain the pointing knowledge
allocation. Figure 3-3 shows the contributions to pointing knowledge.
Knowledge
GCI to
Instrument mount
ACS
Knowledge
Jitter
Thermal
Distortion
Static Bias
Figure 3-4. Contributions to Pointing Knowledge
3-4
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Instrument
3.4.3 Pointing Stability
Pointing Stability is a pointing error time profile. Within the required attitude control and
knowledge accuracies, pointing varies as a function of time. Figure 3-5 illustrates the concept of
pointing stability.
Pointing Error Time Profile
(Note tim e ave rage co-plotte d w ith e rror signal)
Attitude
Angle
Instantane ous
Know le dge Error
M axim um e xcurs ion
during obs e rvations
( < 0.1 arc-sec for cross-axis, 3sigma)
Individual Im aging
obse rvation
pe riod (1 to 9 hours )
t1
t2
Time
Figure 3-5. Pointing Stability
3-5
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4.0
CRATER POINTING AND ALIGNMENT ALLOCATIONS
The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) will characterize the global
lunar radiation environment and its biological impacts. The CRaTER instrument requires only
that its nadir field of view look completely at the lunar surface.
CRaTER will not have an alignment cube or fudicial to add in its alignment to the spacecraft
reference. It also does not have anyway to calibrate out any static errors in its alignment while
on orbit.
4.1
CRATER POINTING ACCURACY
The CRaTER instrument needs a pointing accuracy of 35 degrees. The angle formed by the
lunar surface to LRO will be approximately 150 degrees. The CRaTER nadir field of view will
be no more than 80 degrees. A pointing accuracy of 35 degrees insures that the CRaTER nadir
field of view is always facing the lunar surface.
The LRO Allocations for CRaTER result in a pointing accuracy of approximately 6 degrees with
5 degrees allocated to the CRaTER instrument. Table 4-1 shows the allocations for the CRaTER
pointing accuracy.
Table 4-1. CRaTER Pointing Accuracy
Rx
30
15
ArcSec
Ry
30
15
Rx
145
73
microradian
Ry
145
73
Rz
30
15
Rz
145
73
50
50
50
242
242
242
ACS
ACS Knowledge
ACS Controller
Jitter
Jitter
Thermal
Thermal
Distortion
500
500
500
2423
2423
2423
1-g Release
Launch Shift
Alignment
100
30
300
100
30
300
100
30
300
485
145
1454
485
145
1454
485
145
1454
318
318
318
1539
1539
1539
913
18000
18928
913
18000
18928
913
18000
18928
4422
87222
91717
4422
87222
91717
4422
87222
91717
Static Bias
Static Bias
RSS
Spacecraft
Total
Instrument
Total
4-1
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4.2
CRATER POINTING KNOWLEDGE
CRaTER will examine the possibility of directionality of the primary radiation. This could be
due to alignment of solar energetic particles with the local magnetic field or obscuration of
incident particles by favorable Earth geometry. A pointing knowledge of 10 degrees or better
insures that this is possible.
The LRO Allocations for CRaTER result in a pointing knowledge of approximately 5 degrees
with exactly 5 degree pointing knowledge allocated to the CRaTER instrument. Table 4-2 shows
the allocations for the CRaTER pointing accuracy.
Table 4-2. CRaTER Pointing Knowledge
ACS
ACS Knowledge
30
Arcsec
Ry
30
30
Rx
145
microradian
Ry
145
Jitter
Jitter
50
50
50
242
242
242
Thermal
Thermal
Distortion
500
500
500
2423
2423
2423
100
30
300
318
100
30
300
318
100
30
300
318
485
145
1454
1539
485
145
1454
1539
485
145
1454
1539
898
18000
18898
898
18000
18898
898
18000
18898
4350
87222
91572
4350
87222
91572
4350
87222
91572
Rx
Static Bias
1-g Release
Launch Shift
Alignment
Static Bias RSS
Spacecraft
Total
Instrument
Total
4.3
Rz
CRATER POINTING STABILITY
The CRaTER instrument does not have any pointing stability requirements.
4.3.1 PSD of Distribution at CRaTER Feet with Diviner
TBD
4.3.2 PSD of Distribution at CRaTER Feet without Diviner
TBD
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Rz
145
4.4
OTHER POINTING AND ALIGNMENT REQUIREMENTS
4.4.1 Alignment to Spacecraft Reference
CRaTER shall be aligned to the spacecraft reference to within 300 arc-seconds (1454 microradians) per axis.
4.4.2 Co-Alignment
CRaTER does not need to be or knowledge of alignment with any other instruments.
4-3
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5.0
DIVINER POINTING AND ALIGNMENT ALLOCATIONS
The Diviner Lunar Radiometer Experiment is a multi-channel solar reflectance and infrared filter
radiometer. Diviner will map the surface temperatures of the moon. Diviner operates
continuously while LRO is in measurement mode. The driving requirement for Diviner is the
post-processed knowledge of where the data was taken. Diviner will not be targeting specific
sites on the moon.
The Diviner instrument has the ability to calibrate out static biases between its detector and the
spacecraft star tracker. This will reduce static bias down to 124 arc-seconds (600 micro-radians).
Diviner will have an optical cube for alignment reference.
5.1
DIVINER POINTING ACCURACY
The Diviner instrument requires a pointing accuracy of 1238 arc-seconds (6000 micro-radians).
(Not including the Diviner instrument?) Table 5-1 shows the current allocations for Diviner
pointing accuracy.
Table 5-1. Diviner Pointing Accuracy
30
15
Rz
30
15
Rx
145
73
microradian
Ry
145
73
50
50
50
242
242
242
Thermal
Distortion
500
500
500
2423
2423
2423
1-g Release
Launch Shift
Alignment
100
30
300
100
30
300
100
30
300
485
145
1454
485
145
1454
485
145
1454
318
318
318
1539
1539
1539
913
913
913
913
913
913
4422
0
4422
4422
0
4422
4422
0
4422
ACS
ACS Knowledge
ACS Controller
Jitter
Jitter
Thermal
Static Bias
Static Bias
RSS
Spacecraft
total
Instrument
Total
Rx
30
15
ArcSec
Ry
5-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
Rz
145
73
5.2
DIVINER POINTING KNOWLEDGE
The Diviner instrument requires a pointing knowledge of 619 arc-seconds (3000 micro-radians).
(Not including the Diviner instrument?) Table 5-2 shows the pointing knowledge allocations for
Diviner.
Table 5-2. Diviner Pointing Knowledge
Rx
30
ArcSec
Ry
30
Rx
145
microradian
Ry
145
Rz
30
Rz
145
50
50
50
242
242
242
ACS
ACS Knowledge
Jitter
Jitter
Thermal
Thermal
Distortion
500
500
500
2423
2423
2423
1-g Release
Launch Shift
Alignment
100
30
300
100
30
300
100
30
300
485
145
1454
485
145
1454
485
145
1454
318
318
318
1539
1539
1539
898
898
898
898
898
898
4554
0
4554
4554
0
4554
4554
0
4554
Static Bias
Static Bias
RSS
Spacecraft
total
Instrument
Total
5.3
DIVINER POINTING STABILITY
The Diviner instrument has a pointing stability requirement of 1.5 milli-radians over 0.128
seconds.
5.4
OTHER POINTING AND ALIGNMENT REQUIREMENTS
5.4.1 Alignment to Spacecraft Reference
Diviner shall be aligned to the spacecraft reference to within 300 arc-seconds (1454 microradians) per axis.
5.4.2 Co-Alignment
LRO shall be aligned to the spacecraft reference to within 300 arc-seconds (1454 micro-radians)
per axis
5-2
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
6.0
LAMP POINTING AND ALIGNMENT ALLOCATIONS
The Lyman-Alpha Mapping Project (LAMP) instrument will observe the lunar surface in the far
ultraviolet spectrum. LAMP will search for surface ices and frosts in the pole regions and
provide spectral images of the permanently shadowed regions illuminated only by starlight and
the interplanetary medium hydrogen Lyman-alpha sky glow. LAMP will operate continuously
on the dark side of the moon. It will not take data on the illuminated side of the moon. Post
processed knowledge of where the LAMP data was taken is the driving requirement. LAMP will
not be targeting specific locations on the moon.
LAMP has the ability to calibrate static biases out of its alignment while on orbit by looking at
UV bright stars.
The LAMP instrument will have an alignment cube.
6.1
LAMP POINTING ACCURACY
LAMP requires a pointing accuracy of +/- 0.15 degrees three sigma. This is 540 arc-sec or 2618
micro radians. Table 6-1 shows the allocations for LAMP pointing accuracy.
Table 6-1. LAMP pointing accuracy
Rx
30
15
ArcSec
Ry
30
15
Rz
30
15
Rx
145
73
microradian
Ry
145
73
Rz
145
73
ACS
ACS Knowledge
ACS Controller
Jitter
Jitter
10
10
10
48
48
48
Thermal
Thermal
Distortion
50
50
50
242
242
242
Static Bias
Calibration Error
30
30
30
145
145
145
135
30
165
135
30
165
135
30
165
654
145
799
654
145
799
654
145
799
Spacecraft
Total
Instrument
Total
6.2
LAMP POINTING KNOWLEDGE
LAMP requires pointing knowledge to a fifth of a pixel at the three sigma level, or +/-0.06
degrees. (216 arc-sec or 1047 micro radians) The allocations shown for LAMP pointing
knowledge are shown in Table 6-2.
6-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
Table 6-2. LAMP Pointing Knowledge
Rx
30
15
ArcSec
Ry
30
15
Rz
30
15
Rx
145
73
microradian
Ry
145
73
Rz
145
73
ACS
ACS Knowledge
Jitter
Jitter
10
10
10
48
48
48
Thermal
Thermal
Distortion
50
50
50
242
242
242
Static Bias
Calibration Error
30
30
30
145
145
145
135
30
150
135
30
150
135
30
150
654
145
727
654
145
727
654
145
727
Spacecraft
Total
Instrument
Total
6.3
LAMP POINTING STABILITY
The LRO spacecraft shall provide the LAMP instrument of a pointing stability of +/- 0.05
degrees three sigma in 1.0 seconds.
6.3.1 PSD of Disturbances at LAMP Feet with Diviner
TBD
6.3.2 PSD of Disturbances at LAMP Feet without Diviner
TBD
6.4
OTHER POINTING AND ALIGNMENT REQUIREMENTS
6.4.1 Alignment to Spacecraft Reference
LAMP shall be aligned to the spacecraft reference to within 300 arc-seconds (1454 microradians) per axis.
6.4.2 Co-Alignment
LRO shall measure the alignment between the LAMP optical reference cube and the LROCNACs’ optical alignment cubes.
6-2
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
7.0
LEND POINTING AND ALIGNMENT ALLOCATIONS
The Lunar Exploration Neutron Detector (LEND) will provide high spatial resolution maps of
neutron emission at the lunar surface. LEND measurements will be used to create high
resolution Hydrogen distribution maps, characterize surface distribution and column density of
possible near-surface water ice deposits, and create a global model of the neutron component of
space radiation from thermal energies up to 15 MeV.
Pointing knowledge is more important to LEND measurements than pointing accuracy although
towards the end of the LRO mission LEND may want to target specific sites on the Lunar
surface.
The LEND instrument does not have anyway to calibrate out static biases between the LEND
detectors and the LRO star trackers while on-orbit.
7.1
LEND POINTING ACCURACY
The LEND instrument requires a pointing accuracy of 0.1 degrees or 360 arc-seconds. The
LEND pointing allocations are shown in Table 7-1.
Table 7-1. LEND Pointing Accuracy
ACS
ACS Knowledge
ACS Controller
Jitter
Jitter
Thermal
Thermal
Distortion
Static Bias
1-g Release
Launch Shift
Alignment
Static Bias
RSS
Spacecraft
Total
Instrument
Total
Rx
30
15
ArcSec
Ry
30
15
Rx
145
73
microradian
Ry
145
73
Rz
30
15
Rz
145
73
20
20
20
97
97
97
100
100
100
485
485
485
75
10
30
75
10
30
75
10
30
363
48
145
363
48
145
363
48
145
81
81
81
394
394
394
246
100
346
246
100
346
246
100
346
1194
485
1679
1194
485
1679
1194
485
1679
7-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
7.2
LEND POINTING KNOWLEDGE
The desired pointing knowledge for LEND is also 0.1 degrees (360 arc-seconds). This desired
pointing knowledge can be met by the allocations shown in Table 7-2.
Table 7-2. LEND Pointing Knowledge
ACS
ACS Knowledge
Jitter
Jitter
Thermal
Thermal Distortion
Static Bias
1-g Release
Launch Shift
Alignment
Static Bias
RSS
Spacecraft
total
Instrument
Total
7.3
Rx
30
ArcSec
Ry
30
Rx
145
microradian
Ry
145
Rz
30
Rz
145
20
20
20
97
97
97
100
100
100
485
485
485
75
10
30
75
10
30
75
10
30
363
48
145
363
48
145
363
48
145
81
81
81
394
394
394
231
100
331
231
100
331
231
100
331
1121
485
1606
1121
485
1606
1121
485
1606
LEND POINTING STABILITY
LEND does not have any specific stability requirements.
7.3.1 PSD of Disturbances at LEND Feet with Diviner
TBD
7.3.2 PSD of Disturbances at LEND Feet without Diviner
TBD
7.4
OTHER POINTING AND ALIGNMENT REQUIREMENTS
7.4.1 Alignment to Spacecraft Reference
The Doppler filter should be pointed to the direction of flight to an accuracy of 3 degrees. This
results in a requirement for pointing about the Z axis to be within 3 degrees.
7-2
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
LEND shall be aligned to the spacecraft reference to within 300 arc-seconds (1454 microradians) per axis.
The pointing accuracy for the LEND instrument is 251 arc-seconds and the alignment to the
spacecraft reference is 300 arc-seconds. This means that if the Doppler filter is aligned with the
LEND reference to within 10,249 arc-seconds (2.8 degrees), the pointing accuracy requirement
for the Doppler filter will be met.
7.4.2 Co-Alignment
LEND does not require alignment knowledge to any other instrument.
7-3
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
8.0
LOLA POINTING AND ALIGNMENT ALLOCATIONS
The Lunar Orbiter Laser Altimeter (LOLA) will produce global geodetic lunar topography,
characterize polar region illumination, image permanently shadowed regions, assess meter scale
features for landing site selection, and identify near-surface water ice. The LOLA instrument
pulses a single laser through a diffractive optical element to produce five beams that will
illuminate the lunar surface. For each beam, LOLA measures the time of flight (range), pulse
spreading (surface roughness) and transmit/return energy (surface reflectance). LOLA will
produce topographic maps of the moon.
LOLA runs continuously while LRO is in measurement mode. LOLA will not target specific
sites on the moon. The driving requirement for LOLA is post-processed pointing knowledge.
LOLA will have an optical cube for alignment reference.
8.1
LOLA POINTING ACCURACY
LOLA requires a pointing accuracy of 1 degree/ 3600 arc-seconds. The allocations for LOLA
pointing accuracy meet this requirement and are shown in Table 8-1.
Table 8-1. LOLA Pointing Accuracy
Rx
30
15
ArcSec
Ry
30
15
Rz
30
15
Rx
145
73
microradian
Ry
145
73
Rz
145
73
ACS
ACS Knowledge
ACS Controller
Jitter
Jitter
10
10
10
48
48
48
Thermal
Thermal
Distortion
50
50
50
242
242
242
Static Bias
Calibration Error
22
22
22
105
105
105
127
31
158
127
31
158
127
31
158
614
150
764
614
150
764
614
150
764
Spacecraft
Total
Instrument
Total
8.2
LOLA POINTING KNOWLEDGE
LOLA have a pointing knowledge requirement of TBD. The allocations for LOLA pointing
knowledge are shown in Table 8-2.
8-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
Table 8-2. LOLA Pointing Knowledge
Rx
30
ArcSec
Ry
30
Jitter
10
Thermal
Thermal
Distortion
Static Bias
Calibration Error
ACS
ACS Knowledge
Jitter
Spacecraft
Total
Instrument
Total
8.3
30
Rx
145
microradian
Ry
145
10
10
48
48
48
50
50
50
242
242
242
22
22
22
105
105
105
112
31
143
112
31
143
112
31
143
541
150
691
541
150
691
541
150
691
Rz
Rz
145
LOLA POINTING STABILITY
LOLA does not require any special stability because the laser time of flight is extremely short.
8.3.1 PSD of Disturbances at LOLA Feet with Diviner
TBD
8.3.2 PSD of Disturbances at LOLA Feet without Diviner
TBD
8.4
OTHER POINTING AND ALIGNMENT REQUIREMENTS
8.4.1 Alignment to Spacecraft Reference
LOLA shall be aligned to the spacecraft reference to within 300 arc-seconds (1454 microradians) per axis.
8.4.2 Co-Alignment
LRO shall place the LOLA field of view within one of the fields of view of the LROC-NAC’s.
The LOLA team would like to have the LOLA field of view placed within the overlap area
between the LROC-NAC’s. LRO shall measure the alignment between the LOLA alignment
cube and both of the LROC-NACs alignment cube.
8-2
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
9.0
LROC-NAC POINTING AND ALIGNMENT ALLOCATIONS
The Lunar Reconnaissance Orbiter Camera (LROC) takes images of the lunar surface to help
with landing site certification and polar illumination. LROC Narrow Angle Cameras (NACs)
will take imagines of approximately meter scale to identify hazards near landing sites.
LROC has two NACs. The NACs a limited number of images on the illuminates side of the
moon. The LROC NACs need to target specific sites on the Lunar surface. Pointing accuracy is
the most important alignment requirement for the NACs. Pointing knowledge is also important
for the LROC NACs as it affects the quality of the uncontrolled polar mosaics.
The LROC NACs will each have an alignment cube for alignment reference.
9.1
LROC-NAC POINTING ACCURACY
The requirement for LROC-NAC pointing accuracy is TBD. LROC-NAC pointing accuracy
allocations are shown in Table 9-1.
Table 9-1. LROC-NAC Pointing Accuracy
Rx
30
15
ArcSec
Ry
30
15
Rz
30
15
Rx
145
73
microradian
Ry
145
73
Rz
145
73
ACS
ACS Knowledge
ACS Controller
Jitter
Jitter
10
10
10
48
48
48
Thermal
Thermal
Distortion
50
50
50
242
242
242
Static Bias
Calibration Error
5
5
5
24
24
24
110
21
131
110
21
131
110
21
131
533
100
633
533
100
633
533
100
633
Spacecraft
Total
Instrument
Total
9.2
LROC-NAC POINTING KNOWLEDGE
The requirement for LROC-NAC pointing knowledge is TBD. LROC-NAC pointing knowledge
allocations are shown in Table 9-2.
9-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
Table 9-2. LROC-NAC Pointing Knowledge
Rx
30
ArcSec
Ry
30
Rz
30
Rx
145
microradian
Ry
145
Rz
145
ACS
ACS Knowledge
Jitter
Jitter
10
10
10
48
48
48
Thermal
Thermal
Distortion
50
50
50
242
242
242
Static Bias
Calibration Error
5
5
5
24
24
24
95
21
116
95
21
116
95
21
116
460
100
560
460
100
560
460
100
560
Spacecraft
Total
Instrument
Total
9.3
LROC-NAC POINTING STABILITY AND JITTER
The LROC-NACs have a pointing stability requirement of 5 micro-radians peak-to-peak in 0.3
milliseconds.
9.3.1 PSD of Disturbances at LROC-NAC Feet with Diviner
TBD
9.3.2 PSD of Disturbances at LROC-NAC Feet without Diviner
TBD
9.4
OTHER POINTING AND ALIGNMENT REQUIREMENTS
9.4.1 Alignment to Spacecraft Reference
LROC-NAC shall be aligned to the spacecraft reference to within TBD arc-seconds (1454 microradians) per axis.
9.4.2 Co-Alignment
LROC-NAC’s do not need to be aligned with any other instruments on LRO. The LROC-NACs
need to be aligned with each other to within +/-2.5 milli-radians. This requirement can be easily
met with the allocations shown in Table 9-3.
9-2
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
Table 9-3. NAC Co-Alignment
Jitter
Jitter
Thermal
Thermal Distortion
Static Bias
Rx
cross track
15
Arc-Sec
Ry
long
track
15
75
Alignment
Accuracy
1-g Release
Launch shift
Static Bias
RSS
Instrument
Total
microradian
Rx
cross
track
73
Ry
long track
73
75
363
363
150
106
15
150
106
15
727
514
73
727
514
73
184
184
893
893
29
29
142
142
304
304
1471
1471
9-3
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
10.0
LROC-WAC POINTING AND ALIGNMENT ALLOCATIONS
The Lunar Reconnaissance Orbiter Camera (LROC) takes images of the lunar surface to help
with landing site certification and polar illumination. The LROC-WAC will acquire synoptic
100m/pixel images of the poles during most orbits throughout the year to identify permanently
shadowed and near permanently illuminated regions.
The LROC-WAC will not have an alignment cube and it will not perform any on-orbit
calibrations to remove static bias.
10.1
LROC-WAC POINTING ACCURACY
The LROC-WAC has a pointing accuracy requirement of TBD. Table 10-1 shows the pointing
accuracy allocations for the LROC-WAC.
Table 10-1. LROC-WAC Pointing Accuracy
30
15
Rx
145
73
microradian
Ry
145
73
10
10
48
48
48
50
50
50
242
242
242
75
10
300
309
75
10
300
309
75
10
300
309
363
48
1454
1499
363
48
1454
1499
363
48
1454
1499
604
604
604
2929
2929
2929
604
604
604
2929
2929
2929
ACS
ACS Knowledge
ACS Controller
30
15
Arc-Sec
Ry
30
15
Jitter
Jitter
10
Thermal
Thermal
Distortion
Rx
Static Bias
1-g Release
Launch Shift
Alignment
Static Bias RSS
Spacecraft
Total
Instrument
Total
10.2
Rz
Rz
145
73
LROC-WAC POINTING KNOWLEDGE
The LROC-WAC has a pointing knowledge requirement of TBD. Table 10-2 shows the pointing
knowledge allocations for the LROC-WAC.
10-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
Table 10-2. LROC-WAC Pointing Knowledge
30
Rx
145
microradian
Ry
145
50
50
242
242
242
200
200
200
969
969
969
75
10
300
75
10
300
75
10
300
363
48
1454
363
48
1454
363
48
1454
309
309
309
1499
1499
1499
589
589
589
2856
2856
2856
589
589
589
2856
2856
2856
ACS
ACS Knowledge
30
Arc-Sec
Ry
30
Jitter
Jitter
50
Thermal
Thermal
Distortion
1-g Release
Launch Shift
Alignment
Rx
Static Bias
Static Bias
RSS
Spacecraft
Total
Instrument
Total
10.3
Rz
Rz
145
LROC-WAC POINTING STABILITY
The pointing stability requirements for the LROC-WAC will be met if the pointing stability
requirements for the LROC-NACs are met.
10.3.1 PSD of Disturbances at LROC-WAC Feet with Diviner
TBD
10.3.2 PSD of Disturbances at LROC-WAC Feet without Diviner
TBD
10.4
OTHER POINTING AND ALIGNMENT REQUIREMENTS
10.4.1 Alignment to Spacecraft Reference
LROC-WAC shall be aligned to the spacecraft reference to within 300 arc-seconds (1454 microradians) per axis.
10.4.2 Co-Alignment
The LROC-WAC does not need to be aligned with any other instruments on LRO.
10-2
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
11.0
MINI-RF POINTING AND ALIGNMENT ALLOCATIONS
The Mini-RF is a technology demonstration. It does not have an alignment cube?
11.1
MINI-RF POINTING ACCURACY
The pointing accuracy allocations for the mini-RF are shown in Table 11-1.
Table 11-1. Mini-RF Pointing Accuracy
Rx
30
15
ArcSec
Ry
30
15
Rx
145
73
microradian
Ry
145
73
Rz
30
15
Rz
145
73
50
50
50
242
242
242
ACS
ACS Knowledge
ACS Controller
Jitter
Jitter
Thermal
Thermal
Distortion
500
500
500
2423
2423
2423
1-g Release
Launch Shift
Alignment
100
30
300
100
30
300
100
30
300
485
145
1454
485
145
1454
485
145
1454
318
318
318
1539
1539
1539
913
913
913
4422
4422
4422
913
913
913
4422
4422
4422
Static Bias
Static Bias
RSS
Spacecraft
Total
Instrument
Total
11-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
11.2
MINI-RF POINTING KNOWLEDGE
The pointing knowledge requirements for the Mini-RF are shown in Table 11-3.
Table 11-2. Mini-RF Pointing Knowledge
Rx
30
ArcSec
Ry
30
Rx
145
microradian
Ry
145
Rz
30
Rz
145
50
50
50
242
242
242
ACS
ACS Knowledge
Jitter
Jitter
Thermal
Thermal
Distortion
500
500
500
2423
2423
2423
1-g Release
Launch Shift
Alignment
100
30
300
100
30
300
100
30
300
485
145
1454
485
145
1454
485
145
1454
318
318
318
1539
1539
1539
898
898
898
4350
4350
4350
898
898
898
4350
4350
4350
Static Bias
Static Bias
RSS
Spacecraft
Total
Instrument
Total
11.3
MINI-RF POINTING STABILITY
The Mini-RF does not have any pointing stability requirements.
11.3.1 PSD of Disturbances at Mini-RF Feet with Diviner
TBD
11.3.2 PSD of Disturbances at Mini-RF Feet without Diviner
TBD
11-2
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
11.4
OTHER POINTING AND ALIGNMENT REQUIREMENTS
11.4.1 Alignment to Spacecraft Reference
Mini-RF shall be aligned to the spacecraft reference to within 300 arc-seconds (1454 microradians) per axis.
11.4.2 Co-Alignment
The Mini-RF does not need to be aligned with any other instruments on LRO.
11-3
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
12.0
HIGH GAIN ANTENNA POINTING BUDGET
The high gain has a pointing accuracy requirement of 0.30 deg. 3.
LRO High Gain Antenna System
POINTING ERROR BUDGET
Bias
Random (asec)
Random/
Gnd-to-
1
Table 12-1.
LRO
High Gain
Budget
Known
Very LowAntenna PointingSubsystem
Parameter (3σ values)
ACS/GN&C Knowledge/Command
Errors
ACS pointing knowledge
(asec)
2
Orbit (asec)
Ephemeris accuracy
Freq.
Low Freq.
72
Algorithm accuracy
Hardware Alignment Errors
High Freq. Requirement
3
A/T
30
ACS
A
36
ACS
A
36
ACS
A
Antenna boresight error
540
36
Comm
HGADS I/F to S/C Ref error
1800
72
HGAS/Mech
A/T4
T
Boom to HGADS I/F error5
Gimbal to boom axis co-alignment error
Gimbal to Gimbal-HGA I/f alignment error
1800
72
HGAS/Mech
T
468
468
72
72
T
T
504
504
72
72
HGAS
Comm/Gimb
al
Comm/Gimb
al
Gimbal
0
HGADS
A
7200
360
1800
HGAS
HGADS
A8
T
1969
Gimbal
T
0
0
0
Comm
Comm
A
A
7200
36
36
Mech
Mech
A
A
144
HGAS/ACS
ACS (RW) induced boom dynamics
Other S/C induced dynamics
72
72
ACS
ACS
A/T4
A
A
Gimbal tracking error
288
Gimbal
A
HGAS
A
Gimbal
Comm
A
A/T
Total Uncompensated
error (asec)
9533
HGA to Gimbal-HGA I/f alignment error
Gimbal interaxial orthogonality
Launch/Deployment/Gravity Release
Errors
HGADS launch shift6
HGADS/gimbal gravity release7
HGADS Deployment error
Gimbal actuator interface launch shifts
6
Antenna launch shift
Antenna gravity release
HGADS to S/C reference launch shift6
HGADS to S/C reference gravity release
Dynamic Pointing Errors
Gimbal/boom dynamic interaction
Thermal Distortion
S/C ref through Boom to El bracket
108
72
Gimbal, El bracket to antenna
Antenna
Column Totals (sum bias, RSS random),
sum all for total on orbit error (asec)
Column Totals (RSS), total on orbit error
(after compensation and on-orbit
calibration)9,10,11 (asec)
72
36
6192
2693
144
144
102
204
343
Hardware RSS Launch, RSS Ephem RSS Gimbal,
RSS
Alignment Deploy, 1g Acc, S/C ref Antenna
Dynamic
Errors +
through
Pointing
Thermal
Boom to El
Errors, ACS
Distortion
Bracket
Errors
deg ->
0.00
197
102
204
343
Total Error
Post
Calibration
(deg)
T
T
2.65
0.23
(1) Bias errors assumed measurable/predictable,
removable by compensation.
(7) 1-g error of <2-deg predicted/compensated by analysis to this error.
(2) Measure and corrected after on-orbit deployment
(3) A/T - verification by analysis or test/inspection.
(8) +/- 1-g testing unlikely, analysis only.
(9) Calibration done right after ephemeris upload.
(4) If possible, test to verify dynamic interactions.
(10) Multiple calibrations averaged to remove thermal distortion bias.
(5) Deployment repeatability kept under "HGADS
Deployment error"
(11) Random/ground to orbit column total is analytical calibration residual error.
(6) Pinned interface.
12-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
13.0
SOLAR ARRAY POINTING BUDGET
The solar array has a pointing accuracy requirement of 5.0 deg 3.
Table 13-1. LRO Solar Array Pointing Accuracy Budget
ACS/GN&C Knowledge/Command
Errors
Bias Errors
(deg) (sum)
ACS/GN&C Knowledge/Command
Errors
0.05
Hardware Alignment
0.50
Launch/Deployment/Gravity Release
3.00
Random Errors
(deg) (rss)
Dynamic Pointing Errors
0.10
0.10
Thermal Distortion
0.10
Total Error
3.65
0.14
13-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.
3.79 deg
Appendix A. Abbreviations and Acronyms
Abbreviation/
Acronym
DEFINITION
A-1
CHECK WITH LRO DATABASE AT:
https://lunarngin.gsfc.nasa.gov
TO VERIFY THAT THIS IS THE CORRECT VERSION PRIOR TO USE.