Astronauts Overcome False Alarms, Sail Through Saturday Spacewalk, Make Space Station Upgrades

Though short on sleep, a dozen astronauts aboard the International Space Station breezed through a six hour spacewalk and tackled a range of other tasks on Saturday, each of them intended to prepare the outpost for future science experiments and operations well beyond the approaching retirement of the NASA's space shuttle.

The overnight rest period for astronauts from the shuttle Atlantis as well as those assigned to the station was interrupted for a second night in a row by a series of false depressurization and fire alarms.

Though unsure of the precise cause, NASA's Mission Control believed the problems were linked to Russia's new Poisk docking module, which was launched and attached to the space stationed earlier this month. The incidents both nights began with an alarm from Poisk falsely signaling a major air leak. That alarm in turn triggered false fire alarms in the station's European segments and American airlock.

"We're well rested," quipped one of the station's Russian cosmonauts in an exchange with his Mission Control. "I guess four hours of sleep is enough, sometimes."

NASA's Mission Control accelerated efforts to restore life support systems interrupted by the false alarms late Friday and abbreviated Saturday's spacewalk by Americans Mike Foreman and Randy Bresnik. That hardly mattered. The two men finished all of their tasks two hours early and eagerly took on extra chores.

"We're working hard to prevent that from happening again," NASA's Mission Control assured the shuttle and station crews following the latest series of false alarms. The astronauts aboard the two spacecraft joined forces for a week-long work session as Atlantis docked with the station on Wednesday.

Foreman and Bresnik displayed no signs of weariness.

"You guys are shaking and backing," fellow astronaut Robert Satcher, who choreographed the outing from inside the space station, told the two men as they floated outside the station's long solar power truss.

Early Saturday, the astronauts used a pair of robots arms to hoist a pallet securing more than six tons of spare parts from the shuttle's cargo bay and relocating it to an attachment point on the outside of the truss.

A similar pallet was transferred late Wednesday. The pallets hold spare gyroscopes, thermal control system components and robot arm gear, most of them pieces of hardware that are too large for anything other than NASA's shuttle to launch.

The shuttle fleet is facing retirement by early 2011. Though the space station is scheduled to be de-commissioned by 2016, the Obama Administration and Congress are considering an extension of operations through 2020, making the early positioning of the spare parts all the more critical.

Saturday's spacewalk was the second of three planned by the Atlantis astronauts.
Foreman and Bresnik installed U. S. Coast Guard and amateur radio antennas to the space station's European segment and mounted a video network for use by astronauts on future spacewalks.

They relocated another device that monitors the electrical environment around the outpost. A build up of static charges could lead to dangerous arcing.

They also deployed an external experiment platform upon which astronauts plan to mount the Alpha Magnetic Spectrometer, an international physics experiment. The AMS, which awaits a late July shuttle launching, was developed to detect anti-matter and cosmic radiation.

Saturday's outing was Bresnik's first spacewalk, and Foreman's fifth.

As it began, Bresnik awaited word on the birth of a daughter. His wife, Rebecca, was induced to begin labor on Friday.

A 42-year-old Marine lieutenant colonel, Bresnik termed the conflict between the shuttle flight and the birth unfortunate. But he noted the couple was only facing what others in the military confront regularly when they are stationed around the world.

The Atlantis crew intends to depart the station on Wednesday and return to Earth two days later with a landing at NASA's Kennedy Space Center in Florida.