DSCS-III Shutdown
New Experience For 3rd SOPS
(13 July 2005) The 3rd Space
Operations Squadron satellite operators and engineers here "turned off the
lights" on Defense Satellite Communications System Satellite A-2, the first
satellite of its kind to be completely deactivated.
Space systems operators boosted the satellite out of geosynchronous orbit when
its fuel tanks were almost empty.
Once boosted to super-synchronous
orbits, satellites may be used as test platforms for software upgrades or shut
down. For Satellite A-2, shutdown was the only option, said Lt. Col. Keith
Hinson, 3rd SOPS commander.
DSCS engineers prepared by running
simulations and verifying commands that would be sent to the satellite.
However, some variables differed between the simulator and the real thing.
Each satellite handles a bit differently, said Colonel Hinson. "No two
satellites are the same. You can't just plug it into a diagnostic and say,
'This is how we expect it to work.'"
The shutdown process started at
about 4 a.m. as operators depleted the satellite's residual fuel. Cheyenne
Mountain Air Force Station, Colo., worked with 3rd SOPS to get a final orbit
projection. Engineers also collaborated with the 22nd SOPS to get Air Force
Satellite Control Network range time for the shutdown.
The process hit
a snag around 8:45 a.m. Engineers attempted to force the satellite into an
inert survival mode, however, the system aboard the satellite that normally
triggers survival mode failed to activate. The team took the setback in stride
and searched for a possible error in their process while they waited for the
backup failsafe to kick in. "It's a dead satellite, but we'd like it to be
perfect," said Colonel Hinson. The backup kicked in 80 minutes later,
completing the satellite's shutdown.
"The satellite's in a completely
safe configuration," said Captain Becker, DSCS engineering chief. "All in all,
it was a complete success."
Before its shutdown, A-2 functioned as
part of the DSCS constellation for 16 years - six years beyond its design life.
Ageing satellites are no longer useful once they run out of fuel to keep them
pointed at the earth's surface, said Colonel Hinson. However, upgrades in
software control systems and new techniques for manoeuvring satellites have
allowed them to conserve fuel and live longer.
"These guys are
incredible," he said. "There's no one else who can do this."
The
engineers and operators will have plenty of opportunity to do it again in the
future. More satellite shutdowns scheduled in the months to come. As the
military moves toward a new generation of communications systems, other
DSCS-III satellites will come to rest alongside Satellite A-2 in the silence of
space.
(source: Air Force Space Command)