STS-109 Crew Replaces Power Control Unit
Diode Box Assembly, Install Diode Box Controller Cross Strap Harness Diode Box Assembly and Reaction Wheel Assembly-1 (PCU) with the Advanced Camera for Surveys, Install Electronics Support Module and Perform Power Control Unit Cleanup Tasks and Multi-Object Spectrometer (NICMOS) Cryogenic Cooler and NICMOS Cooling System Radiator |
The STS-109 crew successfully replaced the Hubble Space Telescope’s Power Control Unit during the mission’s third space walk this morning. Mission Specialists John Grunsfeld and Rick Linnehan began their excursion outside Space Shuttle Columbia at 2:28 a.m. CST (0828 GMT) and wrapped it up at 9:16 a.m. CST (1516 GMT).
The start of the space walk was delayed about two hours due to a water leak in Grunsfeld’s spacesuit. After analyzing the situation, the flight control team decided to have Grunsfeld put on another suit and to press ahead with space walk’s objectives.
In order for Grunsfeld and Linnehan to replace the unit, Hubble was powered down for the first time in its history at 3:37 a.m. CST (0937 GMT). It was successfully turned back on at 8:02 a.m. CST (1402 GMT) after the installation of the new Power Control Unit.
Mission Specialist Nancy Currie operated the shuttle’s robot arm, and Mission Specialists Jim Newman and Mike Massimino coordinated the space walk. Newman and Massimino are scheduled to perform the mission’s fourth space walk Thursday morning.
