For release: 02/06/02 (for week ending 02/06/02)
Science Ops status report #: 02-025
Space Station science back on track after power shutdown
The International Space Station crew and ground controllers quickly resumed science activities this week after a computer problem onboard had shut down power to many systems and payload racks. Space Station science experiments and payload operations are managed by the Payload Operations Center at the Marshall Center.
Photo: The EarthKAM experiment aboard the Station began Expedition Four operations this week. (University of California, San Diego)
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.”
Editor’s Note: The Payload Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Ala., manages all science research experiment operations aboard the International Space Station. The center is also home for coordination of the mission-planning work of a variety of international sources, all science payload deliveries and retrieval, and payload training and payload safety programs for the Station crew and all ground personnel.
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