ISS Science Operations Weekly Status Report 6 Feb 2002
The Space Station crew and ground controllers quickly resumed science activities
this week after a computer problem onboard shut down power to many systems and
payload racks.
“I was pleasantly surprised by how little time it took us to recover payload
operations,”Payload Operations Director Tim Horvath said. “It took less than
six hours to get back power to sensitive payloads and we were back to nominal
operations within 24 hours. We got great support from the crew and the Mission
Control team in Houston.”
On Monday, an accidental computer shutdown interrupted the Space Station’s
attitude control, which allows the solar arrays to track the sun and generate
power. As a precautionary measure, all payloads and many on-board systems shut
down, and the crew shut down other systems.
Power was restored in about six hours, and the crew and the Payload Operations
Center in Huntsville began reactivating experiments and their supporting
computers and other hardware.
EXPRESS Rack 4, designated the Station’s continuously powered rack,
was brought back to life, and power was restored to the Bio Technology Refrigerator
and the Protein Crystal Growth Single Thermal Enclosure System payloads
in the rack. These were the most power sensitive experiments because the biological
samples being processed or stored inside them must remain at a constant temperature.
The temperature rise during the power outage was less than expected, and the
science team is hopeful that the stress on those samples will be minimal.
The Payload Operations Center restored operations with the Ku band receiver
Monday night. The antenna is the main communications link for command and data
traffic to and from science experiments aboard the Station.
The crew finished filter maintenance on the Microgravity Acceleration Measurement
System on Monday before the computer problem, and it was reactivated Tuesday
and is recording vibration data. On Tuesday, the crew and ground controllers
powered up the Space Acceleration Measurement System computer and sensor
heads, as well as EXPRESS Racks 1 and 2. With Rack 2 reactivated, the control
team reactivated the Experiments on Physics of Colloids in Space to begin
a scheduled 72-hour run.
The Earth Knowledge Acquired by Middle School Students (EarthKAM) camera,
located in a window of the Russian Service Module, was activated Tuesday to
begin its Expedition Four photography program. The EarthKAM team reported to
Flight Engineer Daniel Bursch that 50 images had been downlinked, including
several coastal views of the Persian Gulf. A total of 25 schools, including
those in Japan and Germany, are participating in the program, including 12 currently
active in gathering photo data.
The Education Payload Operation 4 program, scheduled for Monday and
Tuesday, is being re-planned for later in the mission with no expected impact.
This science activity requires to crew to set up and videotape some simple experiments
examining the differences between weight and mass, inertial balance, and fluids
behavior in the Station’s microgravity environment.
Geographical targets for the Crew Earth Observation program
this week include reefs and atolls on the Malaysian coast, Tropical
Cyclone Francesca in the Indian Ocean, smog over industrialized Southeastern
Africa, vegetation colors and agricultural patterns in the Argentina
and Paraguay, Patagonian glaciers, Bombay, India, the Mekong River Delta
in Southeast Asia, and fires and dust storms in the Sahel region of
Northwest Africa.
Looking ahead, a Human Research Facility workstation test is scheduled
for Wednesday and a test of the Ultrasound life science gear is set for
Thursday and Friday. Crew familiarization and checkout activities with the
Zeolite Crystal Growth furnace are scheduled for Friday.
Also planned for Friday is activation of one of the growth cylinders in the
Protein Crystal Growth Single Thermal Enclosure System Unit 7, which
is identical to the PCG-STES Unit 10 experiment already operating.
“The temperature in the Bio Technology Refrigerator didn’t rise as much as
we expected, so we hope any loss to our biological samples will be less than
anticipated when this event occurred,”said John Uri, lead increment scientist
for Expedition Four. “Overall, this was a great team effort to minimize the
impact on science, and we’re now back on track.”
