Mission Control Center
A Canadian “handshake in space” occurred at 4:02 p.m Central time today, as the Canadian-built space station robotic arm – operated by Expedition Two crew member Susan Helms – transferred its launch cradle over to Endeavour’s robotic arm, with Canadian Space Agency astronaut Chris Hadfield at the controls. The exchange of the pallet from station arm to shuttle arm marked the first ever robotic-to-robotic transfer in space.
The successful exchange of the pallet was the last remaining major objective of the mission to be accomplished and could pave the way for Endeavour to undock from the station Sunday morning, if computers on board can be placed in a stable configuration overnight. Mission managers had established three specific criteria to be met prior to Endeavour’s undocking. The criteria were to reberth the cradle pallet in the shuttle’s payload bay, complete final transfer activities and place the station’s command and control (C&C) computers in a stable configuration.
With the pallet securely in Endeavour’s payload bay and all final transfer items in place, the one remaining item is to ensure the computer system is in a stable configuration prior to Endeavour’s departure. Overnight, flight controllers will uplink a series of commands designed to restore the two computers to full capability. C&C three is in an acceptable condition, although it is known to have a bad hard drive. Helms and crew mate Jim Voss will perform repair work on that computer at a later date.
A final decision whether to undock Endeavour – and delay the docking of the Soyuz replacement vehicle – is expected late tonight or early Sunday morning.
After spending much of this morning refining procedures to minimize inputs to the station’s primary command and control computer, which developed problems accessing its hard drive, Space Station Flight Director Mark Ferring gave the Expedition Two crew a “go” to begin with arm operations at 1:27 p.m. With Helms working at the robotic work station, first motion of the station arm occurred at 3:01 p.m. Through a series of carefully choreographed commands, the station arm was maneuvered into its handoff position. Hadfield then slowly moved Endeavour’s 50-foot long robot arm into position to latch onto the cradle, which was securely attached to the station arm at 3:43 p.m. At 4:02 p.m., as the two spacecraft flew over British Columbia, the pallet changed hands.
Both arms then began backing away – with the station arm now under command of Voss, according to plan. Hadfield then stowed the pallet in Endeavour’s payload bay at 4:51 p.m.
Earlier in the day, Voss informed flight controllers that Endeavour crew members were helping with maintenance activities on the station’s treadmill, called TVIS, installing new hardware to allow the Expedition crew to once again use it for exercise. The treadmill’s walking surface had degraded and the crew had been told not to use it until repairs were made. Voss reports repairs are now about 50 per cent complete.
After enjoying a meal together, both crews were scheduled to go to sleep shortly after 7 p.m. Both crews will enjoy an extra hour of sleep, waking up just before 4 a.m.
Due to a compressed schedule tomorrow, the in-flight crew news conference, originally scheduled for 6:15 a.m. Sunday, has been canceled.
If a decision is made to undock tomorrow, the astronauts and cosmonauts will exchange final farewells about 9:30 a.m. and then begin closing the hatches between the two spacecraft. Undocking would occur at 12:34 p.m. central. Pilot Jeff Ashby would then slowly back Endeavour away to a distance of approximately 450 feet, where he will begin a three-quarter circle flyaround of the station before commanding a final separation burn signaling Endeavour’s final departure from the station. With an undocking Sunday, the mission is scheduled to conclude with a landing at the Kennedy Space Center at 8:04 a.m. Central time Tuesday.
The next mission status report will be issued following crew wake on Sunday, or sooner as events warrant.
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