Expedition 16 commander Peggy Whitson and flight engineer Dan Tani completed the preparations
during a Nov. 24 spacewalk in which they routed
�ammonia cooling lines and cables for power and data systems between ISS
and its hub-like Harmony connecting module. That work cleared the way for NASA’s planned Dec. 6 launch of its STS-122 mission
to deliver the European Space Agency’s (ESA) Columbus laboratory to the station
The seven-hour, four-minute spacewalk marked the third in 15 days for the station’s Expedition 16 astronauts and served as the finish line for a work marathon that began with a Nov. 9 excursion just after NASA’s shuttle Discovery left the ISS.
Discovery’s STS-120 crew delivered Harmony to the ISS, but it was up to Whitson, Tani and crewmate Yuri Malenchenko to move the node to its current perch at the front of the station’s Destiny lab. There, Harmony will serve as the hub for Columbus and the
�Japanese Kibo laboratory slated to launch in 2008.
“What we’ve accomplished in the last 15 days is the equivalent of a very ambitious shuttle assembly mission,” said ISS flight director Derek Hassmann after the spacewalk, adding that the three-member Expedition 16 crew achieved on their own what a team of up to 10 ISS and shuttle astronauts
normally would tackle.
Whitson and Tani spent the bulk of the
�spacewalk routing a
�tray of ammonia cooling system lines between Harmony and the ISS. The work installed the second half of cooling, power and data cables to completely fold Harmony into the space station’s systems.
Whitson also removed a series of launch restraints on the Harmony and finished hooking up the station’s power transfer that allows visiting shuttles to feed off the ISS power grid.
In addition to the work on Harmony, Whitson and Tani inspected the
�massive gear that turns the station’s starboard solar wings to face the sun.
found metallic grit in the gear, known as the starboard Solar Alpha Rotary Joint (SARJ), during a late October spacewalk inspection after engineers on Earth detected odd vibrations and slight power spikes from the
�wide structure. During the Nov. 24
inspection, Tani uncovered a different section of the joint and found similar contamination.
“I see the same damage I saw on the other panel,” Tani said. “In fact, I would say there are more shavings here.”
Station flight controllers have moved the starboard gear only sparingly to avoid further damage, but its counterpart on the station’s port side continues to perform flawlessly and showed no signs of contamination during a previous spacewalk inspection.
and Whitson said it appeared that one of the starboard gear’s two bearing race rings appeared to be pitted or damaged.
The starboard SARJ gear
likely will have to be repaired before the major component of Japan’s three-segment Kibo laboratory can be installed at the ISS next year, but mission managers said any attempt to fix the joint can wait until after December’s planned shuttle flight. Depending on the nature of repair required, the effort could take up to four extra spacewalks, but understanding the full extent of contamination is vital before any attempt is staged, NASA has said.
“I consider that to be, as it turns out, one of the key accomplishments of today’s spacewalk,” Hassmann said of the Expedition 16 crew’s SARJ inspection. “Basically, the damage is significant and it is widespread.”