Astronauts Rick Mastracchio and Michael Hopkins are installing a new ammonia cooling pump.
Two space station astronauts have floated outside on Christmas Eve in hopes of wrapping up urgent cooling system repairs.
Astronauts removed an old space station pump Saturday, sailing through the first of a series of urgent repair spacewalks to revive a crippled cooling line.
The spacewalking astronaut who came close to drowning in a flooded helmet searched for clues in his spacesuit Wednesday, in hopes of understanding the unprecedented water leak.
Two astronauts on the International Space Station are preparing for a possible impromptu spacewalk to work on a leaking coolant line.