CAPE CANAVERAL — Astronauts removed an old pump at the International Space Station on Saturday, sailing through the first of a series of urgent spacewalks to repair a crippled cooling line.
The two Americans on the crew, Rick Mastracchio and Michael Hopkins, successfully pulled out the ammonia pump that has a bad valve — well ahead of schedule. That task had been planned for the next spacewalk, originally scheduled for Monday but now delayed until Tuesday, Christmas Eve, because of the need for a suit swap.
"An early Christmas," observed Mission Control as Mastracchio tugged the refrigerator-size pump away from its nesting spot.
NASA's plan initially called for the pump to be disconnected in the first spacewalk, pulled out on the second spacewalk and a fresh spare put in, and then all the hookups of the new pump completed in the third outing.
If Mastracchio and Hopkins keep up the quick work, two spacewalks may be enough to complete the installation of a spare pump and a third spacewalk will not be needed as originally anticipated.
Several hours after Saturday's spacewalk ended, Mission Control bumped the second spacewalk to Tuesday to give Mastracchio enough time to prepare a spare suit. His original suit was compromised when he inadvertently turned on a water switch in the air lock at the end of Saturday's excursion.
NASA officials said Saturday night that it's unclear whether a third spacewalk will be needed and when it might occur. A third spacewalk had been slated for Christmas Day before the latest turn of events. NASA requires a day off between spacewalks for astronaut rest.
The space station breakdown 10 days earlier left one of two identical cooling loops too cold and forced the astronauts to turn off all nonessential equipment inside the orbiting lab, bringing scientific research to a near-halt and leaving the station in a vulnerable state.
Mastracchio, a seven-time spacewalker, and Hopkins, making his first, wore extra safety gear as they worked outside. NASA wanted to prevent a recurrence of the helmet flooding that nearly drowned an Italian astronaut last summer, so Saturday's spacewalkers had snorkels in their suits and water-absorbent pads in their helmets.
To everyone's relief, the spacewalkers remained dry while outside.