Efforts to establish control of the Wide-Field Infrared Explorer (WIRE) spacecraft are continuing. The spacecraft continues to spin, but the rate of spin has stabilized at about 60 revolutions per minute. Last night, controllers sent commands to the spacecraft to see if the telescope could be gently moved in order to reduce solar input. However, imparting even the extremely light magnetic countering force on the rotating spacecraft caused the spacecraft¿s solar arrays to begin oscillating and the maneuver was stopped.
"We are still hopeful that we can take advantage of the fact that WIRE¿s rotation rate has finally stabilized, but our efforts last night proved we have to develop a different scheme," said Jim Watzin, Small Explorer Project Manager. "We are totally focused on gaining full control of WIRE and we won¿t do anything to jeopardize other systems."
Watzin said the WIRE team is devising a new plan which will involve building a software program that would use the spacecraft¿s onboard attitude control system to "de-spin" the spacecraft." Watzin said it would take several days to develop this software package.
WIRE was launched March 4 at 9:57 p.m. EST on from Vandenberg Air Force Base, Calif. Ground controllers determined that WIRE was spinning instead of maintaining a stable position in orbit and was warmer than expected. The spacecraft carries frozen hydrogen to cool its instrument. Controllers believe the hydrogen is venting as it warms up, causing the spacecraft to spin. Spacecraft controllers do not know what specifically caused the situation.
The WIRE team is communicating with the spacecraft. "The subsystems are in good shape," said Watzin. "The solar arrays are generating power and the battery is fully charged. We have plenty of power to effect a recovery."
