Update, 2 p.m. ET: The astronauts have finished their repairs, reports NBC News.
U.S. astronauts Rick Mastracchio and Michael Hopkins are making a rare Christmas Eve spacewalk to fix vital cooling systems on the International Space Station.
Both astronauts are spending 6.5 hours floating in space—which NASA TV is streaming live from 7:10 a.m. EST—for their second spacewalk in four days.
It is the second time in NASA history–and the first time in 14 years–astronauts have conducted a Christmas Eve spacewalk.
One of the space station’s two external cooling lines shutdown on Dec.11, reports the AP. Mastracchio and Hopkins removed a faulty ammonia pump on Saturday, which they will be attempting to replace on Tuesday says Space.com.