Washington, May 18 - Two astronauts grappled with an unruly cable and struggled with an antenna Monday during the first spacewalk of shuttle Atlantis' final scheduled mission.
Astronauts Steve Bowen and Garrett Reisman had to pause mid-walk because a power outage shut down the external video cameras needed for the spacewalk.
In the end, they spent 45 minutes beyond their planned six and a half hours outside the International Space Station, and were having such fun that they asked for still more work. But managers at the US space agency NASA nixed the idea.
"You guys may not be tired, but I'm done," a ground controller in Houston replied.
The pair installed a new space-to-ground antenna, but there were still some finishing touches that remained at the site.
Bowen started the work of exchanging six 1,000-kg batteries by loosening the bolts that hold them in place. On Wednesday, during the second spacewalk, Bowen and astronaut Michael Good will swap the old ones for new batteries that were delivered by Atlantis.
The old batteries will be returned to Earth with Atlantis.
Bowen and Reisman installed a new tool platform for the Dextre external robot.
In separate activity outside the space station, the shuttle's robotic arm got the Russian Mini Research Module-1 - called Rassvet, or Dawn - ready for scheduled installation Tuesday.
Rassvet, the shuttle flight's primary cargo, will provide the station crew with more workspace and update docking facilities for Russia's Soyuz crew vehicles and Progress transport vehicles, which will be the only means of transport into space when the NASA shuttles are retired later this year.
Reisman and Bowen were in high spirits, typical of their seven-member crew who donned tuxedoes before takeoff for a photo. Their spacewalk chatter went beyond the normal techno-speak of spacewalks.
"That is so unfair," said one of them as the other got to ride a robot arm.
When a tool went missing, ground control said: "That's OK, you can pay me for it later".
Atlantis blasted off Friday from Cape Canaveral, Florida, on its farewell mission after 25 years of service. The entire shuttle fleet is scheduled to be retired after two remaining flights: one each by Endeavour and Discovery.
Atlantis will be prepared again for flight, though, until the final two flights are finished, being kept in reserve in case an emergency rescue is needed.
US President Barack Obama has proposed to scrap plans to return to the moon on a new, yet to be built spacecraft. Instead, Obama hopes to develop a commercial spaceflight industry to shuttle astronauts into orbit and allow NASA to focus on more distant manned missions.