Professional Development Short Course On:
Space Systems Fundamentals
Instructor:
Dr. Mike Gruntman
ATI Course Schedule:
http://www.ATIcourses.com/schedule.htm
ATI's Space Systems Fundamentals:
http://www.aticourses.com/space_systems_fundamentals.htm
Space Systems Fundamentals
NEW!
May 18-21, 2009
Albuquerque, New Mexico
June 22-25, 2009
Beltsville, Maryland
$1590
Summary
This four-day course provides an overview of the
fundamentals of concepts and technologies of modern
spacecraft systems design. Satellite system and
mission design is an essentially interdisciplinary sport
that combines engineering, science, and external
phenomena. We will concentrate on scientific and
engineering foundations of spacecraft systems and
interactions among various subsystems. Examples
show how to quantitatively estimate various mission
elements (such as velocity increments) and conditions
(equilibrium temperature) and how to size major
spacecraft subsystems (propellant, antennas,
transmitters, solar arrays, batteries). Real examples
are used to permit an understanding of the systems
selection and trade-off issues in the design process.
The fundamentals of subsystem technologies provide
an indispensable basis for system engineering. The
basic nomenclature, vocabulary, and concepts will
make it possible to converse with understanding with
subsystem specialists.
The course is designed for engineers and managers
who are involved in planning, designing, building,
launching, and operating space systems and
spacecraft subsystems and components. The
extensive set of course notes provide a concise
reference for understanding, designing, and operating
modern spacecraft. The course will appeal to engineers
and managers of diverse background and varying
levels of experience.
Instructor
Dr. Mike Gruntman is Professor of Astronautics at
the University of Southern California. He is a specialist
in astronautics, space technology, sensors, and space
physics. Gruntman participates in several theoretical
and experimental programs in space science and
space technology, including space missions. He
authored and co-authored more 200 publications in
various areas of astronautics, space physics, and
instrumentation.
What You Will Learn
• Common space mission and spacecraft bus
configurations, requirements, and constraints.
• Common orbits.
• Fundamentals of spacecraft subsystems and their
interactions.
• How to calculate velocity increments for typical
orbital maneuvers.
• How to calculate required amount of propellant.
• How to design communications link..
• How to size solar arrays and batteries.
• How to determine spacecraft temperature.
60 – Vol. 97
(9:00am - 4:30pm)
"Register 3 or More & Receive $10000 each
Off The Course Tuition."
Course Outline
1. Space Missions And Applications. Science,
exploration, commercial, national security. Customers.
2. Space Environment And Spacecraft
Interaction. Universe, galaxy, solar system.
Coordinate systems. Time. Solar cycle. Plasma.
Geomagnetic field. Atmosphere, ionosphere,
magnetosphere. Atmospheric drag. Atomic oxygen.
Radiation belts and shielding.
3. Orbital Mechanics And Mission Design. Motion
in gravitational field. Elliptic orbit. Classical orbit
elements. Two-line element format. Hohmann transfer.
Delta-V requirements. Launch sites. Launch to
geostationary orbit. Orbit perturbations. Key orbits:
geostationary, sun-synchronous, Molniya.
4. Space Mission Geometry. Satellite horizon,
ground track, swath. Repeating orbits.
5. Spacecraft And Mission Design Overview.
Mission design basics. Life cycle of the mission.
Reviews. Requirements. Technology readiness levels.
Systems engineering.
6. Mission Support. Ground stations. Deep
Space Network (DSN). STDN. SGLS. Space Laser
Ranging (SLR). TDRSS.
7. Attitude Determination And Control.
Spacecraft attitude. Angular momentum. Environmental
disturbance torques. Attitude sensors. Attitude control
techniques (configurations). Spin axis precession.
Reaction wheel analysis.
8. Spacecraft
Propulsion.
Propulsion
requirements. Fundamentals of propulsion: thrust,
specific impulse, total impulse. Rocket dynamics:
rocket equation. Staging. Nozzles. Liquid propulsion
systems. Solid propulsion systems. Thrust vector
control. Electric propulsion.
9. Launch Systems. Launch issues. Atlas and
Delta launch families. Acoustic environment. Launch
system example: Delta II.
10. Space Communications. Communications
basics. Electromagnetic waves. Decibel language.
Antennas. Antenna gain. TWTA and SSA. Noise. Bit
rate. Communication link design. Modulation
techniques. Bit error rate.
11. Spacecraft Power Systems. Spacecraft power
system elements. Orbital effects. Photovoltaic systems
(solar cells and arrays). Radioisotope thermal
generators (RTG). Batteries. Sizing power systems.
12. Thermal Control. Environmental loads.
Blackbody concept. Planck and Stefan-Boltzmann
laws. Passive thermal control. Coatings. Active thermal
control. Heat pipes.
Register online at www.ATIcourses.com or call ATI at 888.501.2100 or 410.956.8805
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Space Systems Fundamentals
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Section 03 –
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Section 04 –
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Section 05 –
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Section 06 –
Space Systems Fundamentals, 2009 (01)
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Fundamentals
Day 1
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Part 02
Universe, Galaxy, Solar System
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Part 07
Orbital Mechanics III
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Part 08
Space Mission Geometry
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Part 09
Operations. Reliability.
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Space Mission Overview.
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Space Environment II
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Part 05
Orbital Mechanics I
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Part 06
Orbital Mechanics II
Part 11
ADC I
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Part 12
ADC II
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Day 2
Part 01
Organization and Scope of the
Course. Space Missions and
pp
Applications.
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ADC III
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Part 14
Propulsion I
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Part 15
Propulsion II
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Propulsion III
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Communications I
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Communications II
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Electric Power I
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Electric Power II
Part 17
Launch Systems I
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Thermal Control l
Part 18
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Thermal Control II
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Space Systems Fundamentals – Part 01. Course. Space Missions.
American economy, infrastructure,
f
and
national security depend on satellites
more than those of any other nation.
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United States
Two main government programs
• Civilian
• National security space
– Military
– Intelligence
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Contribution of national security space to
space technology roughly equals
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publicly visible civilian space program.
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Government-regulated
• Commercial space
Commitment to space
Only France (and the old Soviet Union in
the past) approaches the U.S. space
expenditures in terms of the fraction of
the gross domestic product (GDP). Most
other industrialized countries (Europe
and Japan) spend in space, as fraction
of GDP, four to six times less than the
United States.
Worldwide space industry revenues
reached $180B in 2005, according to a
new report from Space Foundation …
$110B in commercial activity and $70B in
government-funded civil and military
space spending.
Aviation Week &Space Technology, p.16, 20 Nov 2006
Space Systems Fundamentals, 2009 (01)
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Inertial Systems
of Coordinates
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Radiation belts
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During
magnetospheric
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disturbances,, strong
precipitation of these
ions to lower altitudes
may occur in polar
regions which
produces
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Anisotropy of
energetic particle
velocities is often
described through the
pitch-angle
distribution
• Trapped ions gyrate around magnetic field lines while
It is usually assumed
moving back and forth from one polar region to another
that spacecraft
(between the “mirror” points).
bombarded by
energetic particles
Example: 1-MeV electrons at 4 RE
from all directions
gyroradius – 6.3
6 3 km
gyroperiod – 0.22
0 22 ms
(isotropically)
mirror period – 0.27 sec
drift period – 3.7 min
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Space Systems Fundamentals – Part 03. Space Environment I
© 2006–2009 by Mike Gruntman
Space Systems Fundamentals, 2009 (01)
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Space Systems Fundamentals – Part 04. Space Environment II
Monthly Number of Cataloged Objects
in Earth Orbit by Object Type
Space Debris
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Orbital Debris
Quarterly
News (NASA),
v. 13, issue 1,
p. 12, January
2009
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Summary of all objects in Earth orbit officially cataloged by the U.S. Space Surveillance Network.
“Fragmentation
Fragmentation debris
debris” includes satellite breakup debris and anomalous event debris,
debris while “mission
missionrelated debris” includes all objects dispensed, separated, or released as part of the planned mission.
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Space Systems Fundamentals, 2009 (01)
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Classical Orbital Elements
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Space Systems Fundamentals – Part 05. Orbital Mechanics I
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© 2006–2009 by Mike Gruntman
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Space Systems Fundamentals – Part 06. Orbital Mechanics II
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20/24
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Space Systems Fundamentals – Part 07. Orbital Mechanics III
D i d by
Devised
b the
th USSR tto provide
id
features of a geosynchronous orbit
•
g of northern latitudes
with better coverage
•
USSR was largely a Northern country:
¾ latitude of Moscow =
mid-Labrador, Hudson Bay
¾ latitude of Leningrad =
southern tip of Greenland
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global coverage from an orbit without the
large orbital plane change during launch
¾ Tyuratam (Baikonur) – 45°54’ N
¾ Plesetsk – 62°48’ N
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⇒
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© 2006–2009 by Mike Gruntman
Space Systems Fundamentals, 2009 (01)
13/22
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Example: Sun
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Synchronous Satellite – One Day’s Orbits n
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Mike Gruntman
Space Systems Fundamentals – Part 08. Space Mission Geometry
Circular orbit: altitude = 1248.0 km
Inclination = 100.65 deg
Orbital period = 6627 sec = 1h 50min 27sec
AT
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13.0 orbits per day
Figures: AGI’s STK
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© 2006–2009 by Mike Gruntman
Space Systems Fundamentals, 2009 (01)
17/20
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T ki and
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Mike Gruntman
•
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Relay satellites in
geosynchronous orbit
Eliminates the need for
worldwide network
the first TDRS was
launched
au c ed in 1983
983
operational satellites
are separated by 135°
of longitude
ground terminal at
g
White Sands
initially provided 80%
coverage of satellite
orbits
expanded to 100% with
the addition of the third
location (satellite) and
ground terminal in
G
Guam
AT
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Space Systems Fundamentals – Part 09. Operations. Reliability
•
S
© 2006–2009 by Mike Gruntman
Space Systems Fundamentals, 2009 (01)
12/20
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Mike Gruntman
Technology Readiness Levels – TRLs
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TRL 9
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demonstration (ground or flight)
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TRL 7
System prototype demonstration
in a space environment
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TRL 6
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System/subsystem model or
prototype demonstration in a
relevant environment (ground or
space)
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© 2006–2009 by Mike Gruntman
TRL 5
Component and/or breadboard
validation in relevant environment
TRL 4
Component and/or breadboard
validation in laboratory environment
TRL 3
Analytical and experiment critical
function and characteristic proof-ofconcept
TRL 2
Technology concept and/or
li ti fformulated
l t d
application
TRL 1
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p
reported
F
s
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through successful mission
operations
TRL 8
M
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Space Systems Fundamentals – Part 10. Mission Overview. System Engineering
y
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Space Systems Fundamentals, 2009 (01)
14/20
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Earth Horizon Sensors – Scanning Sensors n
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Space Systems Fundamentals – Part 11. Spacecraft ADC I
Scanning Sensors
• employ a spinning mirror or
prism
i
tto focus
f
a narrow pencilil off
light onto sensing element
• sensing element is usually a
bolometer
• electronics
l t i iin th
the sensor d
detect
t t
when the infrared (IR) signal
from the Earth is first received or
finally lost during each sweep of
the scan cone
• horizon sensor detects not the
first contact with land or ocean,
but the point in the atmosphere
at which the 16 μ radiation
reaches a certain intensity
• from the time between the arrival
of signal (AOS) and loss of
signal (LOS) the Earth width is
d t
determined
i d
AT
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Mike Gruntman
M
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© 2006–2009 by Mike Gruntman
Simple narrow field-of-view fixed
head sensor types (called pippers or
horizon crossing indicators) are used
on spinning spacecraft
Space Systems Fundamentals, 2009 (01)
21/28
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Mike Gruntman
m
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•
cylindrical solar
array
•
spinning sensors
(sun, earth, star, RF)
•
despun platform
•
speed and
precession control
•
wobble and nutation
(d
(dampers)
)
•
despin control
example:
F
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Dual Spin
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Space Systems Fundamentals – Part 12. Spacecraft ADC II
E
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DSCS II, TIROS,
HS396
S
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© 2006–2009 by Mike Gruntman
Space Systems Fundamentals, 2009 (01)
10/18
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Mike Gruntman
•
•
•
•
•
AT
I
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24 satellites in six orbit planes
4 satellites in each orbit
12-hour period 26,561.75 km
circular orbits
inclination: 55°
55
longitude crossing at the equator
kept fixed to within ±2° by the
GPS Control Segment
perturbations:
¾ atmospheric drag is
insignificant
¾ lunar and solar gravitational
pull can be significant
¾ solar radiation pressure can
be significant
precisely timed GPS signals are
transmitted at two L
L-band
band
frequencies: 1.57542 GHz and
1.2276 GHz
frequencies are selected to
minimize interference with radio
astronomy bands
•
S
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Space Systems Fundamentals – Part 13. Spacecraft ADC III
© 2006–2009 by Mike Gruntman
GPS Space
p
Segment
g
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Figures
courtesy
Crosslink
GPS IIA
Space Systems Fundamentals, 2009 (01)
GPS IIR
18/20
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Mike Gruntman
Space Systems Fundamentals – Part 14. Spacecraft Propulsion I
Rocket
Equation
m
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ΔU = u lnRE
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© 2006–2009 by Mike Gruntman
m
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s
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Assume
• no gravity
• no drag
•
•
•
•
•
m
= constant
FTH = constant
tB is the
burnout time
U is the rocket
speed
d
ΔU = ueq lnR
ueq = ge ISP
Space Systems Fundamentals, 2009 (01)
15/18
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Mike Gruntman
t
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Space Systems Fundamentals – Part 15. Spacecraft Propulsion II
Regenerative Cooling – RL10
•
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•
•
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Pratt & Whitney developed
RL10 in 1959
initially liquid H2 is heated to a
temperature sufficiently higher
above the critical temperature
that it can be used to expand
as a gas through the turbine
that drives the liquid H2 and
O2 pumps.
capable
bl off self-starting
lf
i iin
space (using pressure in
hydrogen tanks)
pressure is high
¾ no boiling takes place
gaseous H2 is an excellent
coolant
¾ high thermal conductivity
© 2006–2009 by Mike Gruntman
m
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RL-10A
Figure courtesy
Pratt & Whitney, A United Technologies Company
Space Systems Fundamentals, 2009 (01)
11/22
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Mike Gruntman
Space Systems Fundamentals – Part 16. Spacecraft Propulsion III
m
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A j t
Arcjet
•
obtains the necessary
energy content
t t by
b
electric discharge to
heat the working fluid
p p
propellant
heated in
discharge and
expanded in a
conventional nozzle
•
ISP in the range
1000–3000 s
•
much higher thrust than
provided by
electrostatic ion
thrusters
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© 2006–2009 by Mike Gruntman
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the smaller molecular mass the better
•
because of H2 dissociation, He looks promising
Space Systems Fundamentals, 2009 (01)
18/20
Delta
Family
Delta launch vehicle
family. Figure courtesy
Th Boeing
The
B i Company
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Space Systems Fundamentals – Part 17. Launch Systems I
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© 2006–2009 by Mike Gruntman
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Space Systems Fundamentals, 2009 (01)
13/22
s
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Delta II Launch
Typical Delta II
7925/7925H
profile –
mission p
GTO missions (ER
launch site).
Figure courtesy The Boeing Company
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Space Systems Fundamentals – Part 18. Launch Systems II
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© 2006–2009 by Mike Gruntman
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Space Systems Fundamentals, 2009 (01)
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Space Systems Fundamentals – Part 19. Spacecraft Communications I
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Antenna
and
dG
Gain
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λ
D
(radians) ≈ 70 ×
D
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antenna gain varies with the angle, usually being maximum along the physical
“boresight”
•
3-dB beamwidth is defined as the angle between the points where gain has
dropped to half its maximum
•
high-gain
high
gain antenna must have narrow beamwidth
•
in a perfectly efficient antenna, the product of gain times the vertical
and horizontal beamwidths (θv,θh), expressed in degrees, would equal
the total number N0 of square degrees in a sphere
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⎛ π ⎞
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θ3−dB ≅ 1.22 ×
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⇒
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= 41, 253
1 sq. deg
⇒
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M
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© 2006–2009 by Mike Gruntman
Space Systems Fundamentals, 2009 (01)
Gθ2
iss co
constant
sa
Directive
gain
41, 253
θv θh
Power
gain
13/24
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Space Systems Fundamentals – Part 20. Spacecraft Communications II
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Space Systems Fundamentals, 2009 (01)
12/24
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Space Systems Fundamentals – Part 21. Electric Power Systems I
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Geostationary
t ti
Orbit
O bit
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Mike Gruntman
Typical Sun tracking: solar panels rotate about
the axis normal to the orbital (equatorial) plane
m
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eclipses
¾ the longest eclipses,
eclipses of about
72 minutes, occur at
equinoxes
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¾ two “seasons” ((45 days
y
each) centered around vernal
(March 21) and autumnal
(September 21) equinoxes
© 2006–2009 by Mike Gruntman
Power out put of 1-m2 panel
for ε0 = 20% and ξ = 4%/yr
y
Space Systems Fundamentals, 2009 (01)
10/22
Depth of Discharge (DOD)
•
•
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Mike Gruntman
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Space Systems Fundamentals – Part 22. Electric Power Systems II
for LEO
m
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relatively large
number
b off llowdepth
discharges
for GEO
E
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relatively small
number of deep
p
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S
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© 2006–2009 by Mike Gruntman
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Space Systems Fundamentals, 2009 (01)
t
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13/20
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Main Environmental Thermal Loads
e
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Mike Gruntman
Space Systems Fundamentals – Part 23. Thermal Control I
environmental heating
on orbit
¾ direct sunlight
¾ sunlight reflected
off the Earth
(especially for LEO)
¾ infrared (IR) energy
emitted from the
Earth (especially for
LEO)
•
free molecular heating
during launch or in
exceptionally lowaltitude orbits
S
-
AT
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•
E
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•
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M
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Overall thermal control of a satellite is usually achieved by balancing
¾ energy emitted by the spacecraft (as infrared radiation)
¾ energy
gy dissipated
p
byy internal electrical components
p
¾ energy absorbed from the environment
© 2006–2009 by Mike Gruntman
Space Systems Fundamentals, 2009 (01)
5/22
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at the evaporator end, the
pipe
p has a wickedheat p
reservoir end heated by
the same environment
that heats the evaporator
•
wick in the reservoir not
connected to the wick in
the evaporator
•
wick in the reservoir dry
d i normall operation
during
ti
•
when the pipe is
reversed, liquid is tied up
in the reservoir to cause
the pipe to dry out
•
S
t
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Li id T
Liquid-Trap
Diode
Di d e
m
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Space Systems Fundamentals – Part 24. Thermal Control II
•
AT
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Mike Gruntman
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shutoff is neither
instantaneous nor
complete
M
A
© 2006–2009 by Mike Gruntman
Space Systems Fundamentals, 2009 (01)
14/22
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