Astronauts begin 2nd spacewalk
(AP) - Two astronauts aboard the combined space shuttle and international space station have begun the second spacewalk of this mission.
The plans for Monday's spacewalk lacked the drama of the astronauts' jaunt on Saturday, when they stood on the end of 100 feet of a sometimes-oscillating shuttle robotic arm connected to an extension boom. They were testing its sturdiness for making repairs to the space shuttle, reports Trend.
Their more mundane tasks this time involved installing a spare external pump compartment to the station's cooling system and replacing a severed cable that provides power, video and data to the space station's rail car.
The spacewalk, arriving at the middle of space shuttle Discovery's 13-day mission, was expected to last under seven hours. The last spacewalk of the mission is scheduled for Wednesday.
Replacing the cable on the rail car, or mobile transporter, is crucial for the continuation of construction of the space station. The cable was accidentally severed last December by a cable cutter. During Saturday's spacewalk, the astronauts immobilized a cable cutter on a duplicate cable leading to the transporter. The rail car could be put back into use as early as September when space shuttle Atlantis visits the space station with construction parts.
In what may be an awkward maneuver, astronaut Piers Sellers will hold the old 330-pound cable reel in one hand and the new one in the other.
"The most challenging thing tomorrow is going to be just the choreography, going back and forth in the payload bay," astronaut Mike Fossum said Sunday. "It's quite a ballet."
Discovery's four other astronauts will help with the spacewalk by operating the station's robotic arm and giving directions from inside the orbiting space lab. The space station's three crew members on Monday planned to pack up materials and trash that need to be taken back to Earth.
The shuttle's crew awoke Monday to a recording of Coldplay's "Clocks," which was requested by Sellers' family.
The shuttle's astronauts got welcome news Sunday when NASA managers cleared Discovery's thermal protective skin as safe to return to Earth next Monday. Hundreds of images of Discovery were taken during liftoff, in-flight to the space station and before docking with the complex to make sure the shuttle doesn't have any damage like the kind that doomed Columbia's seven astronauts in 2003.
Flying foam off Columbia's external tank struck the shuttle's wings during liftoff and allowed fiery gases to penetrate it. During last week's launch, Discovery's tank performed well and no pieces of foam fell off the tank in excess of what was allowed, flight controllers told the astronauts in the morning electronic message.
The controllers also offered more details on why NASA managers had cleared as safe three items that previously had concerned them.
A gap filler hanging out by about an inch from Discovery's belly was expected to be forced down to a third of an inch during re-entry into Earth's atmosphere, posing no problems.
Two thermal blanket patches thought to be slightly damaged were cleared because tests on the ground showed that it would take far more force to dislodge them than they will experience during re-entry. Even if they became dislodged, they wouldn't damage the shuttle.