Endeavour crew starts spacewalk
Houston, Aug. 15 (AP): Two astronauts began a spacewalk today to prepare a solar array on the international space station for relocation as NASA engineers' concerns over the shuttle Endeavour's heat shield eased.
NASA was finishing up tests to determine whether it would have to devote a fourth spacewalk to repairing a gouge in the belly of the shuttle. Yesterday, officials said they were cautiously optimistic that would not be necessary.
A sliver of the wound penetrates through a pair of one-inch (2.5-centimetre)-deep thermal tiles, exposing a thin felt fabric that is the final barrier before the shuttle's aluminum frame.
But thermal analyses have so far shown Endeavour could safely return to Earth as it is, said John Shannon, chairman of the mission management team.
The six-hour spacewalk was astronaut Rick Mastracchio's third in five days. He and astronaut Clay Anderson, who has been living on the space station since June, were to prepare one of the solar arrays for relocation to another spot on the orbiting outpost during a later mission.
The Endeavour crew is halfway through their two-week mission to the international space station. The astronauts have completed most of their main goals, including attaching a new truss segment to the space station and replacing a gyroscope that helps control the station's orientation.
Any repairs to Endeavour would be conducted during the shuttle's fourth spacewalk, scheduled for Friday. If more time is needed to prepare, NASA could bump the spacewalk to Saturday and keep the shuttle at the station longer.
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