CAPE CANAVERAL, Florida (Reuters) - A spacewalking NASA astronaut pitched two large pieces of obsolete equipment off the International Space Station and into orbit on Monday.
A 1,400-pound (630-kg), refrigerator-sized reservoir that contains ammonia was cast overboard during a spacewalk by station flight engineer Clay Anderson and his commander, Russian cosmonaut Fyodor Yurchikhin. Anderson also tossed away a 212-pound (96 kg) camera mounting.
NASA normally frowns on littering in space, but found itself with no better option than to discard the ammonia tank, which was no longer needed for cooling, and the obsolete video equipment.
With just 14 missions to the space station remaining before the space shuttles are retired in 2010, engineers could not make room in a shuttle cargo bay to transport the gear back to Earth.
So Anderson, who was making his first spacewalk, positioned himself at the end of the station’s outstretched robotic arm, leaned back and heaved the junk overboard.
“Nice work,” said astronaut Chris Cassidy from NASA’s Mission Control Center in Houston.
Television cameras anchored outside the station showed the huge white tank tumbling away from the station as it flew over the Atlantic Ocean.
NASA is concerned the free-flying debris might strike the station and as a precaution, planned to raise its orbit by 4.5 miles later in the day to give the space junk wide berth.
Both items will be tracked by radar until they tumble from space and burn up in Earth’s atmosphere. The video mounting is expected to completely disintegrate, but pieces of the ammonia tank as large as 39 pounds (17.5 kg) could survive and strike Earth.
NASA expects any debris to land in the ocean but calculated a 1:5,000 chance that it could injure or kill a person. The ammonia tank is expected to remain in orbit for at least 300 days and the agency will issue warnings if it becomes a threat during re-entry.
Dressed in U.S. spacesuits, Yurchikhin and Anderson left the station shortly after 6:30 a.m. (1030 GMT) to begin a planned 6.5-hour outing. Flight directors later extended the outing to up to eight hours so the men could tackle some extra jobs.
The third station crew member, Oleg Kotov, remained aboard the orbital complex to operate the station’s robot arm, the first Russian cosmonaut to do so.
In addition to discarding the old gear, the spacewalkers cleaned debris off a docking port so the complex will be ready for new laboratories built by Europe and Japan, and replaced a faulty electronics switch in the mobile transporter that moves the station’s robot arm to various work locations along the station’s exterior support beams.
The $100 billion outpost, a project of 16 nations, is a little more than half-finished. Additional work on the station is planned next month during a seven- to 10-day servicing call by the space shuttle Endeavour crew, which includes teacher-astronaut Barbara Morgan.