James Dean, Florida Today
Spacewalkers accomplished more than expected Saturday outside the International Space Station but wrapped up their work early, after one reported feeling cold.
Rick Mastracchio and Mike Hopkins breezed through the removal and stowage of a failed ammonia coolant pump module, a job that was scheduled to be finished during a second spacewalk Monday.
But given the opportunity to do more, Mastracchio radioed that he would prefer to call it a day.
He didn't explain exactly why, but earlier had complained of being "very, very cold," particularly his toes.
Mastracchio turned on spacesuit heaters and did not mention discomfort again until mission controllers suggested doing additional get-ahead tasks.
While temperatures apparently had an effect Saturday, neither spacewalker experienced any trouble with water leaking into their helmets, a problem that aborted the previous U.S. spacewalk this past summer and prompted new safety equipment and procedures.
Saturday's excursion began at 7:01 a.m. EST and lasted five hours and 28 minutes, about an hour shorter than planned.
If a spare pump module is installed Monday, as expected, it might not be necessary to perform a third spacewalk on Christmas Day.
Saturday's spacewalk was the seventh for Mastracchio and first for Hopkins. It was the 175th supporting assembly and maintenance of the ISS, whose construction began 15 years ago.