CAPE CANAVERAL, Fla., Dec 15 (Astronauts aboard
the International Space Station are preparing for possible
spacewalks this week to repair the outpost's failed cooling
system, NASA said on Sunday.
One of two ammonia cooling systems on the U.S. side of the
station shut down on Wednesday after a problem developed with a
valve inside a pump located outside the $100 billion laboratory.
The shutdown forced astronauts to turn off non-essential
equipment, suspending some of the station's science experiments.
The six-member crew was not in any danger.
The station, a permanently staffed research laboratory owned
by 15 countries, flies about 250 miles (about 400 km) above
NASA engineers on Sunday continued to assess options for
fixing the valve, said agency spokesman Josh Byerly with the
Johnson Space Center in Houston.
Meanwhile, space station flight engineers Rick Mastracchio
and Michael Hopkins began preparing their spacesuits in case
spacewalks were needed to replace the faulty pump, NASA said in
a statement posted on its website on Saturday.
"It's a serious problem, obviously it's something we have to
fix," Mastracchio said during an inflight interview on Friday.
"It's not something I'm worried about, though," he added.
Astronauts were called upon in 2010 to replace the pump that
is now experiencing problems. That work required three
"The biggest challenge on this spacewalk, in my opinion, is
the large fluid connectors that are connected to the pump
module. But of course, we have a lot of tools if we have
problems with those to fix that," Mastracchio said.
NASA on Saturday also decided to delay by at least one day
the launch of an Orbital Sciences Corp Antares rocket
from Wallops Island, Virginia, on its first cargo run to the
Orbital Sciences is one of two firms hired by NASA to fly
cargo to the station following the retirement of the space
shuttles in 2011.
Orbital Sciences completed a successful test flight to the
station in September and had been preparing to launch its first
operational mission on Wednesday. That flight, the first of nine
under a $1.9 billion NASA contract, will now occur no sooner
than Thursday, NASA said.
Ongoing efforts to troubleshoot the station's failed cooling
system could further delay the launch of Orbital Sciences'
Cygnus cargo ship to as late as Dec. 21, before NASA would
reschedule the mission for January, the agency said.
(Editing by Vicki Allen)