Nuts and bolts of space mission

Space walk deemed a success despite work problems

September 14, 2006|By John Johnson Jr. | John Johnson Jr.,LOS ANGELES TIMES

How many astronauts does it take to unscrew a bolt?

"Apparently, it takes three. Two outside and one inside," Pam Melroy, of mission control at Johnson Space Center in Houston, said yesterday.

Melroy's jest was at the expense of astronauts from the space shuttle Atlantis, who were trying without much success to continue installing a new set of solar arrays during a spacewalk outside the International Space Station.

After grunting and groaning in their bulky spacesuits, Steve MacLean and Dan Burbank, with astronaut Joe Tanner advising from inside the space station, had to return to a toolbox for a new wrench to pry loose the recalcitrant bolt.

The bolt, which held the solar arrays in place during Atlantis' launch Saturday, was one of two unexpected difficulties to crop up during the second of three scheduled space walks by the Atlantis crew. Another bolt disappeared into space, the second time in two days of space walking construction work that a bolt has drifted away from the work site.

The bolts are small, and mission managers said neither would pose a threat to the space station or Atlantis.

Astronaut training stresses the need to take care of tools during space walks. Several thousand pieces of space junk already orbit Earth, some large enough to pose a danger to the space station in a collision.

The problems aside, yesterday's spacewalk was termed a success by NASA. The principal task of the more than seven-hour spacewalk was to put into operation a large joint that allows the solar arrays to swivel as the space station circles Earth, keeping the sun constantly in line with the power-generating solar cells.

After the astronauts loosened six launch restraints, four thermal covers, and 16 launch locks, mission controllers successfully rotated the joint 5 degrees, then 180 degrees.

"We had numerous battles with the hardware," said John McCullough, lead space station flight director. "But that's the reason we have people working out there." He added: "It's almost like giving birth today, the fighting that we had to go through and the labor pains. I hate to use the analogy because it's nothing like that."

But in the end, everything worked out. "What a great day," he said.

Overnight, the solar arrays will be unfurled to their full length of 240 feet. When put into operation, the arrays will double the amount of power produced by the space station.

Atlantis is the first construction mission to the half-built space station in about four years. Besides the solar arrays, Atlantis carried a truss that was added to the port side of the station.

While playing down the seriousness of the lost bolts, NASA officials said engineers are studying the events to determine whether they need to change any procedures to prevent further losses during future spacewalks.

Astronauts Tanner and Heidemarie Stefanyshyn-Piper, who conducted the first spacewalk of the 11-day mission Tuesday, planned to finish the installation job during the third and final spacewalk today.

John Johnson Jr. writes for the Los Angeles Times. The Associated Press contributed to this article.

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