HOUSTON (CBSDC) — Astronauts Rick Mastracchio and Michael Hopkins are hoping they get what they want this Christmas: a repaired cooling line.
They ventured out for a second spacewalk to repair a faulty system on the International Space Station.
Mission Control says that, if all goes as planned, they will finish installing a new ammonia pump 260 miles above the planet.
WATCH: Live Video of Spacewalk
The pump powers one of the two external systems that regulate heat inside the station. The six-man crew had to turn off all nonessential equipment, including experiments.
NASA had thought three spacewalks might be needed. But the astronauts made so much progress on Saturday, a third may not be necessary.
The repair work will fix the line that malfunctioned on Dec. 11.
Two of the three Russians crew members will conduct a Moscow-directed spacewalk on Friday to install cameras and fresh experiments. That was planned long before the U.S. cooling system ran into trouble.