ISS Astronauts Celebrate Holidays in Orbit

NASA astronaut Rick Mastracchio performs a spacewalk outside the International Space Station on Dec. 22, 2013, the first of two spacewalks to replace an ammonia coolant pump in one of two cooling loops on the orbiting lab.

Credit: NASA

Six space travelers living in orbit definitely aren't home for Christmas today, but that doesn't mean they won't get into the holiday spirit on the International Space Station.

The space station's six-man Expedition 38 crew includes two Americans, three Russians and one Japanese astronaut.

This year, Christmas falls between two spacewalks — a Christmas Eve spacewalk to fix the outpost's cooling system and a Dec. 27 excursion by Russian cosmonauts — so it is likely a welcome rest in an otherwise busy week.

"Hey folks, MERRY CHRISTMAS!" NASA astronaut Rick Mastracchio wrote in a Twitter post Sunday (Dec. 22), adding that he would write more after finishing the station's "home improvement project" to replace a cooling system pump.

He and NASA astronaut Mike Hopkins finished that work in a spacewalk on Tuesday.