More Replanning
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Posted
by Frank Morring, Jr. at
10/31/2007 10:31 AM CDT
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Mission managers have decided to repair the solar array damaged as it was deployed on Tuesday, pushing back an already-replanned spacewalk on Thursday to allow more time to prepare for an array-repair sortie as early as Friday.
Early word to the flight crew also left open the possibility that the fourth extravehicular activity (EVA) of the STS-120/10A International Space Station assembly mission might be deferred until Saturday.
The combined crews of the space shuttle Discovery and the ISS are discussing options with mission managers for completing their hardscrabble mission, which has serious power-production problems at both ends of the main station truss.
Plans to devote the next extravehicular activity (EVA) to an inspection of a fouled rotary joint on the starboard-side truss were literally scrapped. A timeline for pulling all the covers off the starboard solar alpha rotary joint (SARJ) for photography and taking samples of the metal filings in its gear teeth had been drafted and distributed when NASA officials announced the change.
On board the station, spacewalker Scott Parazynski could be seen preparing tools with Kapton tape insulation needed to avoid electric shock when working on the solar arrays. ISS Program Manager Mike Suffredini said Oct. 30 the top priority of the mission remains getting the relocated P6 truss/array combination up and running on the port end of the truss, and his view apparently prevailed in management discussions.
The array ripped as it was being unfurled Oct. 30, following a faultless three-day robotic activity with the shuttle and station robot arms to move the P6 unit from its temporary position on top of the station to its final location at the port end of the truss. Although the array ripped when it was about 90 feet out, and the solar-cell blanket was generating almost full power, the array structure isn't sound unless it is extended to its full 110-foot length.
That limits the ability of the port-side SARJ to rotate it so the most sunlight can fall on its solar cells, and also raises structural issues surrounding thruster firings and shuttle, Soyuz and Progress dockings. Engineers and planners were working to design an EVA to repair the damage, holding open the possibility that the next spacewalk might have to wait until Saturday to allow more time for planning and preparation.
