Third Spacewalk To Repair Station Cooling System Now Monday

A third spacewalk to restore full U.S. cooling capability at the International Space Station will be performed Monday rather than Sunday, a move meant to give flight and ground crews more time to prepare for the work.

The 150th spacewalk to be performed since station assembly began in 1998 likely will start around 6:55 a.m. Monday, with live coverage beginning at 6 a.m. here in The Flame Trench.

U.S. station flight engineer Doug Wheelock will be making his sixth career spacewalk -- and third in nine days. Crewmate Tracy Caldwell-Dyson will be making her third spacewalk -- all performed since Aug. 7. The two astronauts so far have put in 15 hours and 29 minutes of spacewalking work aimed at recovering from the July 31 failure of a U.S. coolant system pump, which was removed during today's seven-hour, 26-minute excursion outside the outpost.

A spare ammonia pump is to be put in place Monday.

NASA managers say a fourth spacewalk will be required at a future date to move the failed pump from temporary storage on the station's mobile rail cart to an external stowage platform on the station's central truss. The schedule for that outing is still to be determined.