![tm112_s.gif](https://webarchive.library.unt.edu/eot2008/20080916055046im_/http://stardust.jpl.nasa.gov/images/mission/tm112_s.gif)
Key Spacecraft Characteristics |
SpaceProbe
Deep Space Bus |
Advanced
Lightweight Composites |
Silicon Solar
Cell Arrays |
No RTGs.
No RHUs |
Fixed High-gain
Antenna, x-Band Telecommunication |
Body-mounted
Science (no scan platforms) |
Simple Hydrazine
Monopropellant Propulsion |
Streamlined,
Low-cost Sample Return Capsule (SRC) |
The STARDUST mission spacecraft is derived from
the SpaceProbe deep space bus developed by Lockheed
Martin Astronautics.
![sc0297bs.jpg](https://webarchive.library.unt.edu/eot2008/20080916055046im_/http://stardust.jpl.nasa.gov/images/mission/sc0297bs.jpg) |
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STARDUST
encounter with Wild 2 |
|
This new lightweight spacecraft incorporates
components, virtually all of which are either
currently operating in space or are flight qualified
and manifested to fly on upcoming missions.
The total weight of the spacecraft including the
propellant needed for deep space maneuvers is
380 kilograms. The overall length of the main
bus is 1.7 meters, about the size of an average
office desk.
The STARDUST spacecraft encountered
comet Wild 2 early in 2004 and collected samples
of cometary dust and volatiles while flying through
the coma at a distance of approximately 250 km
on the sunlit side of the nucleus. It will then
return the samples to Earth for analysis in 2006.
Comet and interstellar particles are collected
in ultra low density silica aerogel. More than
1,000 square centimeters of collection area is
provided for each type of particle (cometary and
interstellar). The CIDA instrument is a time-of-flight
mass spectrometer that determines the composition
of individual dust grains which collide with a
silver impact plate. The Navigation camera is
used for targeting the flyby of the Wild 2 nucleus,
but also provides high-resolution science images
of the comet. The DFM instrument, mounted on the
front of the Whipple shield, monitors the flux
and size distribution of particles in the environment.
Sample Return Capsule
|
Blunt Body
Entry Vehicle |
Clamshell
Mechanism to Open the Capsule |
Parachute
and Mortar Unit |
The Sample
Return Capsule (SRC) is a 60-degree
blunt body reentry capsule for landing the returned
sample on Earth. The capsule is encased in PICA
and SLA-561 ablator materials to protect the samples
stowed in its interior from the heat of reentry.
A parachute slows its descent to the Earth's surface
to prevent damage to the precious scientific cargo
of comet samples.
Propulsion |
Monoprop
Propulsion System |
Because it is on a low-energy trajectory for its
flyby of comet Wild 2 and return to Earth, aided
by a gravity-assisted boost maneuver as it flies
by the Earth for the first time, the Stardust
spacecraft needs only a relatively modest propulsion
system. This is provided by ultra pure hydrazine
(N2H4) monopropellant.
Attitude Control |
3-Axis Stabilized
|
Eight
1-lb Thrusters, Plus Eight 0.2-lb Thrusters
|
Thrusters
are mounted in four clusters of 4 thrusters
each. |
Star Camera
+ IMU, Analog Sun Sensors Backup |
The Stardust spacecraft is 3-axis stabilized in
all mission phases, following separation from
the launch vehicle. The primary attitude determination
is via the star camera and the inertial measurement
unit (IMU), and is backed up by analog sun sensors.
The IMUs are needed only during trajectory correction
maneuvers, and during the flythrough of the cometary
coma when stars may be difficult to detect. Otherwise,
the vehicle can be operated in an all-stellar
mode.
Command & Data Handling
|
RAD6000 Processor
|
128 MBytes
Data Storage |
The RAD6000 is a central processing 32-bit unit
embedded in the spacecraft's Command and Data
Handling (C&DH) subsystem and provides computing
capability for all spacecraft subsystems, including
the payload elements. Electronic cards are provided
to interface instruments and subsystems to the
C&DH subsystem. 128 Mbytes of data storage
is provided on the processor card, although the
spacecraft uses approximately 20% of this for
its own internal programs. The rest of the space
in the memory is used for science programs and
data storage for sending back to Earth 600 megabits
(Mb) of images taken by the navigation camera,
100 Mb by the Comet Interstellar Dust Analyzer
(CIDA) instrument, and 16 Mb by the Dust Flux
Monitor (DFM).
Telecommunications |
Cassini Deep
Space Transponders |
15
Watt Radio Frequency Solid State Amplifiers
|
One 0.6 meter
High Gain Antenna (Transmit/Receive) |
One Medium
Gain Antenna (Transmit Only) |
Three Low
Gain Antennas (Receive Only) |
Primary communication between the Earth and the
orbiter is by use of the Deep Space Network (DSN)
X-band (up/down) link and the orbiter’s
deep space transponder developed for the Cassini
spacecraft, a 15 Watt RF solid state amplifier,
and a 0.6 meter (2 ft) diameter fixed high gain
parabolic antenna.
Power |
2 Solar Array
Panels of Special Silicon Solar Cells |
Nickel-Hydrogen
CPV Batteries |
Two non-gimbaled solar arrays are deployed immediately
after launch. They provide 6.6 square meters (71
sq. ft.) of solar energy to power the Stardust
spacecraft, even when it is nearly three times
farther from the sun than is the Earth. One nickel-hydrogen
(NiH2) 16 amp-hour battery using common pressure
vessel (CPV) cell pairs provides power during
eclipses and for peak power operations. The electrical
power control electronics are derived primarily
from the Small Spacecraft Technology Initiative
(SSTI) spacecraft development.
Thermal Control |
Passive:
Louvers, MLI, Paints, Dedicated Radiators |
Thermostatically
and Computer Controlled Heaters |
The thermal control subsystem uses passive methods
and louvers to control the temperature of the
batteries and the solid state power amplifiers.
Passive coatings as well as multi-layer insulation
blankets are used to control other temperatures.
Where needed, radiators are used to take the excess
heat out of the spacecraft components to keep
them at their proper operating temperature.
Structure |
Composite
structure, using Facesheets over Honeycomb
|
The Stardust spacecraft structure is in the form
of a rectangular box, with approximate dimensions
of 1.6 meters long by a square cross-section of
0.66 meters on each side. Panels use graphite
fibers with polycyanate as facesheets and aluminum
honeycomb as the core.
Redundancy |
Software
Fault Protection |
Critical
Items Cross-Strapped |
Virtually all spacecraft subsystem components
are redundant with critical items cross-strapped.
The battery includes an extra pair of cells. A
software fault protection system is used to protect
the spacecraft from reasonable, credible faults
but also has resiliency built into it so many
faults not anticipated can be accommodated without
taking the spacecraft down.
Whipple Shield |
Multiple
Separated Layers |
Bumper and
Catcher Shields |
Nextel Blankets
|
The Whipple shield shadows the spacecraft to
protect it during the high speed encounter with
particles in the cometary coma. Bumper shields
are composite panels which disrupt particles as
they impact. Nextel blankets of ceramic cloth
further dissipate and spread the particle debris.
Three blankets are used in the main body shield,
and two are used in the solar array shields. The
composite Catcher absorbs all of the debris for
primary particles up to 1 cm in diameter for the
shield protecting the spacecraft main body.
Last updated November
26, 2003 |
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