Orbital GEOStar Hosted Payloads - Manual (Page 2)

Orbital Sciences Corporation
45101 Warp Drive • Dulles, Virginia 20166 • www.orbital.com
©2014 Orbital Sciences Corporation FS001_08_2998
GEOStar
™
Hosted Payloads
Specifications
Core Features
Payload Mass Capability: < 150 kg (negotiable based on size of
primary payload)
Avail. Payload Vol.: Up to 165 x 63 x 101 cm (negotiable)
Orbit: Geosynchronous
Launch Vehicle:
Ariane, Soyuz, Land Launch, Proton, and
similar
Typical Mission Life:
1-4 years
Program Schedule: 24 months from ATP to launch
Structure
Construction of
Payload Platform:
Composite/aluminum facesheets over
aluminum honeycomb core
Thermal Control: Passive; payload may elect its own active
control
Power Subsystem Available
Payload Power:
500 W-1,000 W BOL (negotiable)
Bus Voltage: +36 VDC (nominal)
Attitude Control Subsystem
Stability Mode: 3-axis; zero momentum
Pointing Control: 0.01 ° granularity in maintaining pointing
Pointing Knowledge: <0.03 ° During nominal operations
(standard Earth sensor/Sun sensor suite)
Rate/Stability: Provided upon request; dependent upon
time increment
Command and Data Handling Subsystem
Payload Interface: Independent via Orbital's HPI Modem
interface or as Remote Terminal on 1553
bus (dependent upon data rate)
Radiation Tolerance: 100 Krad for Spacecraft (15 years at
GEO) HPI Modem at 20 Krad (1 to 4
years at GEO)
RF Uplink: Up to 2 Mbps (based on ground station
parameters)
Data Downlink: Up to 75 Mbps (based on ground station
parameters)
Hosted Payload Accommodation
Depending on the design of the host spacecraft, a wide variety of
hosted payload configurations can be supported. The payload is
mounted on the nadir-facing deck providing excellent field of view
for Earth-viewing instruments and for thermal radiators. Non-
Earth-staring payloads can be accommodated on the nadir deck
as well by canting the boresight of the instrument at an angle.
Deep-space viewing instruments may also be mounted on the
zenith end of the spacecraft using a modified antenna support
bracket.
The payload panel structure consists of aluminum face-sheets
over an aluminum honeycomb core with embedded heat pipes
and conductors, providing stability and thermal control. Increased
platform stability for specific missions can be achieved by using
a mission-specific platform with quasi-kinematic mounts. A
combination of an inertial reference unit, earth sensor assembly,
and sun sensors are used to offer accurate attitude knowledge
needed to meet 0.1 degree pointing accuracy or better. Downlink
data rates of up to 75 Mbps can be provided (based on ground
station parameters). No solid state recorder is needed because,
during nominal operation, the spacecraft continually transmits
data to a known location on Earth with a pre-specified minimum
effective isotropic radiated potential.
Hosted Earth Imager
Payload (Example)
A close-up view of the notional
instrument and associated
Hosted Payload
Electronics
An Earth-staring remote
sensing hosted payload
on the nadir deck of a
GEOStar-2 bus
More Information
Mr. Guy Savage
Program Director
(703) 948-8484, [email protected]