NASA Astronauts Make Rare Christmas Eve Spacewalk 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. Watch the live stream below. Space.com