PUBLISHED: 08:25 EST, 21 December 2013 | UPDATED: 07:19 EST, 23 December 2013 Astronauts removed an old space station pump today, sailing through the first of a series of urgent repair spacewalks to revive a crippled cooling line. The two Americans on the crew, Rick Mastracchio and Michael Hopkins, successfully pulled out the ammonia pump with a bad valve -- well ahead of schedule. That task had been planned for the next spacewalk on Monday. 'An early Christmas,'observed Mission Control as Mastracchio tugged the refrigerator-size pump away from its nesting spot. SCROLL DOWN FOR VIDEO
@highlight
Two American crew members named Rick Mastrachhio and Michael Hopkins made an urgent repair to the cooling system
@highlight
'Potentially serious fault' saw half of station's system shut down last week
@highlight
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 on Christmas Day as originally anticipated
The two astronauts who tackled the job three years ago were in @placeholder, offering guidance.