The mission of the SPARTAN science satellite to study solar phenomena was called off today after an attempt to activate its attitude control system failed following its release from Columbia’s robot arm for two days of free-flying operations.
Mission Specialist Kalpana Chawla released SPARTAN from the robot arm on time at 3:04 p.m. Central time while the shuttle and the satellite were traveling over the Pacific Ocean. But SPARTAN failed to execute a pirouette maneuver a few minutes later, indicating a problem with its attitude control system for fine pointing toward solar targets. SPARTAN officials later said it appeared that the satellite’s attitude control system jets failed to activate, leaving the satellite without the ability to orient itself for science collection.
Chawla regrappled the SPARTAN moments later, but did not receive a firm capture indication and backed the arm away once more, apparently initiating a rotational spin of about two degrees per second on the satellite. Commander Kevin Kregel fired Columbia’s jets to try to match the rotational rate of the SPARTAN for another grapple attempt, but Flight Director Bill Reeves called off the effort shortly after 4 p.m., ordering Kregel to begin a seperation maneuver to place Columbia in a position 40 nautical miles behind the satellite. That will enable Columbia to re-rendezvous with SPARTAN, perhaps on Monday for its retrieval and berthing in the cargo bay.
NASA managers held several meetings throughout the day to discuss options for the capture of SPARTAN. The leading candidate calls for a manual retrieval of the satellite during a scheduled spacewalk Monday night by astronauts Winston Scott and Takao Doi. Options range from putting two crewmembers in foot restraints on the SPARTAN truss structure in the cargo bay to one crewmember positioned in a foot restraint at the end of the robot arm.
Mission managers will meet again Saturday morning to review retrieval options and details of a spacewalk timeline for the SPARTAN capture. Officials will also consider what other tasks planned for the scheduled spacewalk may be preserved and added to the new spacewalk scenario. A final decision on the spacewalk retrieval of SPARTAN may not be made until Sunday morning.
Unaffected by the SPARTAN activity is the scientific data being collected by the suite of experiments comprising the United States Microgravity Payload, the prime payload for the mission. Its instruments continue to operate autonomously, collecting information on the effect of weightlessness on materials and fluids.
The astronauts are scheduled to begin an eight-hour sleep period at 1:46 a.m. Central time Saturday and will be awakened at 9:46 a.m. for their fourth day in orbit. Highlights of tomorrow’s activity will include a checkout of the spacesuits Scott and Doi will wear during their spacewalk as well as other associated tools.
Columbia continues to fly in flawless fashion in an orbit 176 statute miles above the Earth.
The next STS-87 status report will be issued around 6 a.m. Saturday.
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