Astronauts Partially Furl ISS Solar Array in Spacewalk
STS-117 spacewalkers Patrick Forrester (left, partially obscured) and Steven Swanson helped partially stow a starboard-reaching solar array on the International Space Station's P6 truss on June 13, 2007.
CREDIT: NASA TV.
HOUSTON -- Two spacewalking astronauts partially furled an old solar wing outside the International Space Station (ISS) Wednesday, then faced down tough bolts and crossed wires to help prime the outpost?s newest arrays to track the Sun.
Atlantis shuttle astronauts Patrick Forrester and Steven Swanson began their seven-hour, 15-minute spacewalk poking, prodding and fluffing the nearly seven-year-old solar array partway back into its storage boxes before moving on to other tasks.
?We were able to get to about just-not-halfway retracted,? said Kelly Beck, NASA?s lead ISS flight director for the STS-117 mission.
The remaining portion of the 115-foot (35-meter) solar array, which reaches starboard from the station?s tower-like Port 6 (P6) truss, will be retracted during a later extravehicular activity (EVA) by Atlantis? STS-117 crew.
?Pat and Steve left them in a nice [configuration] for EVA attempts later on,? said Atlantis? STS-117 commander Rick Sturckow.
Forrester and Swanson used a set of improvised tools - including a so-called ?hockey stick? named for its shape - wrapped in translucent orange Kapton tape to free stuck grommets, snip off loose spring leaders and feather the P6 solar panels so that they would retract properly.
?Now this is a view to remember right here,? said Forrester, who handled the tools while perched at the end of the station?s robotic arm.
Mission managers have already set aside more time later in the STS-117 crew?s mission to complete the solar array retraction, with additional efforts set for Thursday and during a Friday spacewalk.
?It was always the plan to give us several days to retract the arrays,? said Mike Suffredini, NASA?s ISS program manager, after the spacewalk.
During Wednesday?s EVA, shuttle managers also decide to add an anticipated Atlantis heat shield blanket repair to the docket of the STS-117 crew?s Friday spacewalk. A corner of the blanket pulled free of its position on Atlantis? left aft-mounted Orbital Maneuvering System (OMS) during the shuttle?s June 8 launch.
Forrester and Swanson began their spacewalk from the station?s Quest airlock at 2:28 p.m. EDT (1828 GMT), about 20 minutes later than planned, due to communication difficulties between themselves and crewmates aboard Atlantis helping to choreograph their work. The spacewalk also ran longer than the initially planned 6.5 hours, leaving the astronauts a bit low on some spacesuit supplies by the excursion?s end.
Near-ready to rotate
By the end of today?s spacewalk, astronauts and flight controllers reeled in the P6 solar array enough to allow the station?s new starboard solar wings to rotate and track the Sun, but spacewalkers found an apparent wiring mix-up with two gears to drive that rotation.
Forrester encountered the wiring error as he installed a Drive Lock Assembly gear to drive a 2,500-pound (1,133-kilogram) Solar Alpha Rotary Joint (SARJ) to rotate the station?s new Starboard 4 truss and its two solar wings like a Ferris wheel to track the Sun. The gear is one of two that drive the SARJ?s rotation.
?It looks like the wires were crossed,? NASA astronaut Megan McArthur, serving as spacecraft communicator in Mission Control here at the Johnson Space Center, told the spacewalkers after some tests by flight controllers found commands meant for one gear were going to its counterpart.
The hardware was later installed successfully, though more work on a later spacewalk will be required to repeat the fix on the second SARJ gear.
To keep the SARJ from rotating, Forrester and Swanson left a one of a series of launch locks in place to secure it. They also loosened the torque on a series of launch restraint bolts that will now be removed on a later spacewalk. The locks and restraints secured the SARJ and S3/S4 truss inside Atlantis? payload bay during its June 8 liftoff and are no longer needed.
Wednesday?s EVA marked the second of four planned for the STS-117 mission, the 85th dedicated to space station construction or maintenance, and the 57th originate from the ISS itself.
The spacewalk also marked the first career EVA for Swanson and the third for Forrester.
?Thanks to the help from you and the ground,? Forrester told his crewmates. ?That was wonderful.?
NASA is broadcasting the space shuttle Atlantis' STS-117 mission live on NASA TV. Click here for mission updates and SPACE.com's video feed.
- VIDEO: A Look at STS-117?s Second Spacewalk
- SPACE.com Video Interplayer: Space Station Power Up with STS-117
- STS-117 Power Play: Atlantis Shuttle Crew to Deliver ISS Solar Wings
- Complete Shuttle Mission Coverage
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