TRW Inc. has started the assembly, integration and test (A,I&T) of the Space-Based Infrared System-Low (SBIRS-Low) Flight Demonstration System (FDS) satellites.
Over the next several months, the avionics, propulsion and
electrical subsystems will be integrated into the two FDS spacecraft
buses. Much of the process will be completed by early next year, when
the sensor payload built by Raytheon Systems Co. is delivered and
mated with the spacecraft.
The FDS spacecraft are scheduled for launch in late 1999 aboard a
single Delta II launch vehicle. TRW will operate the satellites for
one year after launch and has total system program responsibility
(TSPR) for providing the Air Force with spacecraft test data,
satellite health and mission status information.
“Integrating and testing the spacecraft software represents one
of the largest challenges we face,” said Jim Burnett, TRW’s SBIRS-Low
program manager. “SBIRS-Low spacecraft are very complex,
software-intensive spacecraft. They are capable of processing large
amounts of mission data in space that older programs must process on
the ground.”
To improve the quality and reduce the risk associated with the
software integration process, TRW has built an electrical engineering
model test bed. Consisting of all the spacecraft avionics/electronics
and some actual flight units, the test bed is currently being used to
validate and verify all spacecraft functions. The test bed is
colocated with the spacecraft and will be used during A,I&T to resolve
anomalies.
TRW is building a ground station at its Redondo Beach facility
that will also be used during A,I&T as a software validation and risk
reduction tool. Data will be sent between the ground station and the
spacecraft via a high-speed telephone line, enabling engineers to
debug the ground station database and software while at the same time
gaining experience in understanding how the FDS spacecraft will
operate on orbit.
The ground station hardware and software will be transitioned to
serve as the operational command and control segment of FDS.
SBIRS-Low is the low Earth component of the SBIRS system, the
next-generation surveillance system. It will consist of a
constellation of advanced spaceborne sensors geared to track the
threats of the 21st century — and will provide continuous
observations of ballistic missiles in the boost, midcourse and
re-entry phases of attack.
A TRW/Raytheon team is designing, building and launching two
SBIRS-Low FDS spacecraft and the infrared sensor payload under
contract to the Air Force Space & Missile Systems Center.
Concurrently with spacecraft A,I&T, Raytheon is developing,
integrating and testing a total of six infrared payload sensors and
associated mission data processing hardware and software at its
facilities in El Segundo, Calif. Four sensors will be integrated into
the spacecraft next year; the other two are considered “pathfinders,”
or extremely high-fidelity engineering prototypes.
The sensor payload includes a scanning short wavelength infrared
target acquisition sensor and a staring multispectral infrared
tracking sensor. The acquisition sensor provides high-resolution
horizon-to-horizon coverage, plus coverage a few degrees above the
horizon, to search for, detect and track missiles in the boost phase.
The track sensor can receive a handover from the acquisition
sensor and continue to track the missile with greater precision
through midcourse and re-entry.
FDS will demonstrate all key operational SBIRS-Low’s
capabilities, including the ability to:
- detect and track theater and strategic ballistic missiles in boost, midcourse and re-entry;
- autonomously hand over acquisition sensor tracks to tracking sensor;
- hand over track sensor target data to a second satellite via crosslinks;
- show flexibility of the system design for additional missions such as space surveillance, theater missile defense, technical intelligence and battlespace characterization; and
- exhibit overall feasibility of a low Earth orbit infrared missile tracking system as part of the SBIRS architecture.
