Spacewalking on 100-foot extension works all right, astronauts say

Discovery shuttle astronauts Saturday gave generally good reviews to a new spacewalking technique that could be used to repair potential space shuttle heat damage: Working at the end of a wobbling 100-foot (30-meter) extension pole and robotic arm.

They confided that it did feel strange at times. British-born astronaut Piers Sellers said he was "like a bug on the end of a fishing rod here."

In what was scheduled to be a 6.5-hour spacewalk, the first of three planned orbital excursions, Sellers and Michael Fossum said they could do most of the mock tasks called upon them with only moderate difficulty and an occasional audible grunt.

The astronauts had traveled to the international space station, where they dropped off German astronaut Thomas Reiter, who was to become the third member of the station's crew.

That is what NASA wanted to hear, especially after a still-unresolved problem with a shuttle heat shield. The technique was developed to make sure there is never a repeat of the Columbia disaster, which killed seven astronauts in 2003. Foam from the shuttle's external tank struck Columbia's wing during launch, creating a breach that allowed fiery gases to penetrate the shuttle during the return flight to Earth.

Last year, emergency spacewalking repairs were needed because of heat shield damage to Discovery.

Fossum and Sellers may get a chance to use the boom for a real repair on their third spacewalk, now scheduled for next Wednesday. NASA managers on Saturday were still evaluating whether a piece of fabric filler protruding from the thermal tiles on Discovery's belly needs to be removed by the spacewalkers. If it is, Fossum and Sellers may have to go back on the boom and yank out the filler.

NASA were concerned that astronauts could not work well from a 50-foot (15-meter) extension boom that is attached to the similar-sized shuttle robotic arm. The agency's top spacewalk officer said working that way could be like painting a house from the top of a rickety ladder.

But as Fossum and Sellers were finishing up, NASA officials said they found less sway and oscillating than expected.

Fossum said one drill technique was "beyond my ability" and "too much motion to handle" from the boom. Aside from that one mock-drilling, using a numerical rating scale for the wobbles they experienced and the force they needed to compensate, the worst Fossum reported was a 5 on a 1-10 worsening difficulty scale. That translates to doable but with "moderately objectionable deficiencies."

"I think we got all we needed there," Discovery pilot Mark Kelly told the spacewalkers, telling them to end their tests and start clean up.

The spacewalkers marveled at the view from 210 miles (340 kilometers) above Earth.

"It's beautiful," Fossum said. "The thin glow of the moonlit Earth below."

With both astronauts attached to the end of the boom, which was attached to the 50-foot (15-meter) shuttle arm, Sellers noted: "It's very crowded at the end of this boom," reports AP.