Astronauts Battle Stubborn Cable, Power Outage in Spacewalk
Astronauts Garrett Reisman and Stephen Bowen stepped out of the space station's Quest airlock to begin the first spacewalk of their STS-132 shuttle mission on Monday, May 17, 2010.
Credit: NASA TV

This story was updated at 6:32 p.m. EDT.

A pair of spacewalking astronauts battled a stubborn cable and a brief power outage while working outside the International Space Station Monday, ultimately falling behind in work to install a spare communication antenna and other gear for the orbiting lab.

The partial power failure ? which posed no danger to the space station or spacewalkers ? occurred early in the day's work as Atlantis shuttle astronauts Garrett Reisman and Stephen Bowen worked to attach a 6-foot (1.8-meter) antenna dish to the top of the orbiting lab. Their planned six-and-a-half hour spacewalk ended up stretching to seven-and-a-half hours, with the astronauts capping off the excursion at 3:19 p.m. EDT (1919 GMT).

"[We] ran into some snags along the way," lead space station flight director Emily Nelson said at a Monday briefing. "I think we got through all of those and had a highly successful day."

Early on, a little after 10:00 a.m. EDT (1400 GMT), a power unit on one of the space station's three command and control computers failed, temporarily stalling the spacewalk because it was responsible for powering two robotic arm video camera views needed for the spacewalk.

Astronauts onboard the station quickly re-routed power to the system, and the spacewalkers got back to work.

"At that point it wasn't a big problem because we had gotten a little bit ahead because the crew was doing so well," said Lisa Shore, lead spacewalk officer.

Later, the two spacewalkers hit snags again, this time with the new antenna itself. First, they found a persistent gap between the huge antenna dish and its 8-foot (2.4-meter) high mast. Then an umbilical cable refused to connect home.

When Reisman tried to force the cable in place, he saw metal shavings float off into space.

"I think we're just wearing down whatever's blocking it there," Reisman said.

The spacewalkers suspected that the heating environment of space had led to some of their equipment expanding. They kept one piece in the shade and exposed the other to sunlight and managed to get the cable attached.

"Yep, it's all good," Riesman said.

"Woohoo!" the spacewalkers cheers.

Mission Control, however, told Bowen to stop work that would finish the antenna installation to give them more time to study the unexpected events. Instead, he lashed it in place and went on to other tasks. Mission controllers are looking into the issue further to decide when to send spacewalkers back to complete the installation. When that happens, it shouldn't be a major task; Shore estimated it might take one crewmember between 30 and 45 minutes of work to finish hooking up the antenna.

The antenna is a vital spare for the station's communications system and is responsible for providing backup telephone, e-mail, video and other two-way communication services between the station and its Mission Control centers on Earth.

Reisman and Bowen also worked to install a spare parts deck on the station's Canadian-built Dextre maintenance robot.

Overall, mission managers said they were happy with how the spacewalk went.

"We've had a few glitches here and there but they're not significant in the grand scheme of the things we're trying to accomplish," said LeRoy Cain, STS-132 mission management team co-chair.

For much of the spacewalk, Reisman rode on the space station's outstretched robotic arm between a cargo pallet and the top of the orbiting laboratory. The ride offered some amazing views on the trips back and forth.

"That's awesome," Reisman said when he first stepped out into space. "Nice sunny day out here."

Later, Bowen got some down time to enjoy the views of Earth from space while he was waiting for Reisman to arrive at their work site.

"I don't know what else I can do," Bowen said.

"You should enjoy being in outer space on a spacewalk with a camera and a view," advised spacewalk choreographer and mission pilot Tony Antonelli.

"I guess I could do that," replied Bowen. "Where are we?"

"The top of South America," Antonelli replied.

Today's spacewalk is the first of three planned for the shuttle's 12-day mission, which is slated to be the last flight of Atlantis and also includes the delivery of a new Russian room for the station.

Atlantis arrived at the space station Sunday after a two-day orbital chase that began with a Friday launch from Florida. [Atlantis shuttle launch photos.]

Atlantis' mission is the shuttle's final planned spaceflight after 32 missions since it entered service in 1985. Only two more shuttle flights are scheduled (on Discovery and Endeavour, respectively), before NASA retires the orbiter fleet later this year.

However, Atlantis will not be mothballed immediately since it must also be ready to serve as a rescue ship for the final planned shuttle mission on Endeavour, which is slated to launch no earlier than Nov. 27, NASA shuttle officials have said.

SPACE.com is providing complete coverage of Atlantis' STS-132 mission to the International Space Station with Senior Writer Clara Moskowitz and Managing Editor Tariq Malik based in New York. Click here for shuttle mission updates and a link to NASA TV.