American astronauts Mike Hopkins and Rick Mastracchio started their second spacewalk early Tuesday morning to make critical repairs to the International Space Station, NASA said.
The pair’s Christmas Eve spacewalk was meant to replace a faulty pump that helps cool equipment inside and outside the space station.
“The spacewalk officially began at 6:53 a.m. EST and is scheduled to run about 6 hours and 30 minutes,” NASA wrote on its website.
Half of the space station’s cooling system malfunctioned earlier this month, forcing the crew to turn off all nonessential equipment.
On Saturday, Hopkins and Mastracchio performed their first spacewalk and removed a failed pump module, according to NASA.
Officials said the two astronauts completed the task ahead of schedule.
If things go as planned Tuesday, NASA officials said a third scheduled spacewalk would not be needed.
Hopkins, a Missouri native, is a colonel in the U.S. Air Force, NASA said.
Mastracchio, born in Connecticut, is an engineer.