Dec. 1, 2006

Katherine Trinidad
Headquarters, Washington

James Hartsfield
Johnson Space Center, Houston


HOUSTON - The International Space Station crew have been preparing for
the planned arrival next week of the Space Shuttle Discovery on a
complex mission to rewire the station’s electrical system.

Shuttle Discovery is due to launch at 8:35 p.m. CST Thursday, Dec. 7
on mission STS-116. In addition to work that will bring power online
at the station from solar arrays delivered to the complex in
September, Discovery also will bring a new crew member to the

Expedition 14 Commander Mike Lopez-Alegria and flight engineers
Mikhail Tyurin and Thomas Reiter reviewed the STS-116 mission plans
this week. They prepared the station’s Quest airlock, spacesuits and
tools for three spacewalk planned for the shuttle mission. The crew
packed equipment that will return to Earth aboard the shuttle,
including Reiter’s personal items since he will get a ride home
aboard Discovery. STS-116 astronaut Sunita Williams will replace him
as an Expedition 14 flight engineer.

Flight controllers worked on two problems aboard the station this
week, neither of which is expected to affect Discovery’s launch or

An attempted reboost of the space station’s altitude was cut short
Wednesday. Russian flight controllers suspect that sensitive software
detected a slight shift in the orientation of the station as the
thrusters were fired. The change in orientation is believed to be
normal, but it is new for the station due to the changes in its mass
and balance resulting from the addition of the new solar arrays and
truss segment in September.

The Progress cargo craft’s thrusters fired for 3 minutes, 16 seconds
before automatically shutting off. They had planned to fire for 18
minutes, 22 seconds. Russian controllers plan to complete the reboost
Monday with a 21-minute firing of the Progress thrusters and a
software adjustment. The reboost next Monday, planned for around 3:35
p.m. CST, will optimize Discovery’s rendezvous with the station.

Flight controllers are analyzing a problem that occurred during
testing of a new software package used to detect and solve problems
with the station’s giant Solar Alpha Rotary Joint. The joint is used
to rotate the new solar arrays, allowing them to track the sun. The
new software is designed to automatically realign the teeth of the
joint’s gears should they become misaligned, rather than requiring
controllers to send commands for the realignment.

However, while running through a test of the software on Tuesday, a
remote power controller, or station circuit breaker, opened. The
circuit breaker was successfully reset on Thursday. Extensive
analysis and troubleshooting appears to indicate there is no problem
with any equipment aboard the station. Work continues, however, to
refine the new software.

Unless events warrant, the next station update will be included in
status reports for the STS-116 mission beginning on Thursday, Dec. 7
after Discovery’s launch. For more about the crew’s activities and
station sighting opportunities, visit: