CAPE CANAVERAL, Fla. April 23 Two U.S.
astronauts floated outside the International Space Station on
Wednesday to replace a failed computer that serves as a backup
to critical control systems, including the outpost's solar panel
Flight engineers Rick Mastracchio and Steve Swanson left the
station's Quest airlock just after 10 a.m. EDT (1400 GMT) for
what was expected to be a 2-1/2-hour spacewalk. They carried
with them a spare computer to be installed in the central
section of the station's exterior power truss.
"It looks like a great day to take a walk in space,"
Canadian astronaut Jeremy Hansen radioed to the crew from NASA's
Mission Control in Houston.
NASA scheduled the abbreviated outing - most U.S. spacewalks
last more than six hours - after the computer failed on April
The device, which is about the size of a small microwave
oven, is one of two that control several critical systems
outside the station, including rotating the solar panel wings to
track the sun and positioning a mobile base for the station's
Replacing the computer is "pretty straightforward,"
astronaut and former space station crewmember Chris Cassidy said
in an interview last week on NASA Television.
"We anticipate it to go quickly, but as with anything in
space operations ... you never know what's going to be thrown at
you," Cassidy said.
Except for emergency repairs, such as the computer
replacement, NASA spacewalks remain suspended while engineers
continue to assess the spacesuit failure last year that caused
the helmet worn by Italian astronaut Luca Parmitano to fill with
water, nearly drowning him.
The leak was later traced to a blocked filter. NASA flew new
parts to the station for astronauts to make spacesuit repairs.
Before two emergency spacewalks in December to fix the station's
cooling system, astronauts also outfitted their helmets with
absorbent pads and snorkels for breathing if the leak
Those spacewalks were completed with no problems.
Mastracchio, who is making his ninth spacewalk, and Swanson, on
his fifth, also included the snorkels and pads in their helmets
for Wednesday's outing.
A new spacesuit was among the cargo aboard the Space
Exploration Technologies' Dragon capsule that reached the
station on Sunday.
NASA expects to resume routine spacewalks for maintenance
and less-pressing repairs in July.
The station, a $100 billion project of 15 nations, is a
permanently staffed research laboratory that flies about 260
miles (420 km) above Earth.
(Reporting by Irene Klotz; Editing by Jonathan Oatis)