The second of four spacewalks scheduled for mission STS-117 was completed this evening, although all tasks weren’t accomplished. While the action was taking place above, NASA decided exactly when and how to fix damage to shuttle Atlantis.
Carpenter Newton reporting for Digital Journal –– It wasn’t picture perfect, but it was close. Astronauts Steven Swanson and Patrick Forrester fell just short of accomplishing all goals on today’s spacewalk after a crossed wire prevented activation of the space station’s Solar Alpha Rotary Joint (SARJ). However, partially folding a tricky solar array went much better than expected.
NASA began retraction of the inactive solar array this morning before the spacewalkers exited the station. The 31.5 bay mast was brought in one half bay, “wiggled” by flight controllers, then brought in three more bays.
The spacewalk officially got under way at 2:28 p.m. EDT, when Forrester and Swanson switched their spacesuits to internal battery power. Swanson, on his first spacewalk, was told by fellow Mission Specialist James Reilly, “Welcome to EVA [extravehicular activity], Swanny.”
The first task of the walk was to help with the folding of the solar array. On the previous shuttle mission, STS-116 Discovery, astronauts had significant trouble getting a similar array to fold. NASA compares the arrays to road maps left unfolded in hot sun for many years -- once they need to be refolded, they need coaxing to fold properly. The coaxing comes in the form of several homemade tools spacewalkers can use to push grommets and guide wires on the arrays in order to line them up properly. The tools, fashioned last December by Robert Curbeam and Sunita Williams, are wrapped in insulating Kapton tape to prevent electric shock.
In this beautiful photo released today by NASA, Astronaut James Reilly participates in the Monday spacewalk with the Earth’s horizon in background.
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Swanson and Forrester, along with help from crew members in the ISS and Mission Control, ended up folding the array 13 bays before having to move on to other tasks. The remainder of the array will be folded during the third spacewalk, scheduled for Friday. NASA needed the old array folded at least 12.5 bays so the newer solar arrays installed during a spacewalk on Monday could rotate and track the sun.
The spacewalking duo then went to the Starboard 3/4 truss segments to remove launch locks and bolts from the SARJ and to brace the joint for more strength.
After four braces were installed to further support the SARJ, Forrester encountered difficulty engaging a drive lock assembly designed to rotate the joint. NASA determined a wiring problem to be the complication and halted work on releasing torque on launch restraints on the SARJ until the problem can be worked on the ground. This means that only one of two drive lock assemblies are currently working on the SARJ. The second will have to be repaired in a future spacewalk.
Forrester and Swanson reentered the space station after running low on consumables at 9:44 p.m. EDT, making the length of the spacewalk 7 hours, 16 minutes and bringing total EVA time for STS-117 to 13 hours, 31 minutes.
NASA Says Repair to Shuttle Will Happen Friday During Third Spacewalk
While today’s spacewalk was taking place, NASA announced James Reilly and Danny Olivas will fix the damaged thermal blanket on Atlantis during a scheduled spacewalk on Friday.
The blanket came loose during last Friday’s launch of the shuttle and the fix will be to protect Atlantis’ Orbital Maneuvering System from the extreme heat of reentry.
The move comes as a surprise after officials said waiting until the fourth spacewalk on Sunday to apply the fix would give engineers more time to work the problem. However, it appears as though NASA has already decided on a proper fix: One of the spacewalkers will be anchored to the shuttle’s robotic arm and will push the blanket back in place, then use a double row of stainless steel surgical staples to secure it. Astronauts at Johnson Space Center said they were “highly confident” the method would fix the damage.
Russian Computer Problem Could Further Extend Shuttle Mission
Three computers in the Russian section of the ISS suffered problems on Tuesday and remained out of action today. The computers adjust the station’s attitude and are critical to ISS operations.
Russian engineers are diagnosing the problem and have several theories as to why all three computers are failing to boot up, but will not be able to troubleshoot the problem until Thursday.
At tonight’s Mission Status Briefing, NASA officials said that if the computers aren’t fixed soon, it could cause the shuttle to stay an extra day. Currently, attitude aboard the ISS is being controlled by gyroscopes in the U.S. segment. Those gyroscopes are being backed up by Atlantis’ thrusters.
According to the space agency, it is feasible for the shuttle to stay an extra day, but any longer would tap too far into consumable oxygen.
In a worst case scenario, should the computer system not be fixed, the International Space Station could be unmanned.
