Astronauts make third space foray to fix ISS cooling pump

Flight Engineers Tracy Caldwell Dyson (left) and Doug Wheelock work to set up the ammonia spare pump module after it was installed on the S1 Truss. Credit: NASA TV

by Staff Writers
Washington (AFP) Aug 16, 2010
Astronauts from the International Space Station on Monday wrapped up a third and final spacewalk to replace a busted cooling unit on the orbiting outpost, NASA said.

Spacewalkers Doug Wheelock and Tracy Caldwell Dyson began installing a replacement ammonia pump module on the ISS at 6:20 am (1020 GMT) Monday and finished at 1:40 pm (1740 GMT) -- a seven hour, 20 minute space foray, according to the US space agency.

Flight Engineer Shannon Walker assisted the effort from inside the ISS by operating the station's robotic arm and space officials reported no detectable ammonia leaks.

The cooling unit's nearly 800-pound (360 kilo) ammonia pump failed unexpectedly on July 31 and was removed from the 100-billion dollar orbiting station during a spacewalk last Wednesday.

The pump is critical to keep the station from overheating. The six-member crew has relied on a single backup since the malfunctioning pump failed during a power surge.

The incident set off alarms on the station, although officials have said that the crew of three Russians and three Americans were never seriously in danger.

A first spacewalk to begin repairs on the malfunctioning cooling system took place on August 7 and lasted eight hours, three minutes, with a follow-up second spacewalk on August 11.

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