An urgent spacewalk was performed on the International Space Station for much needed repairs to a critical system. The repairs started when NASA’s Rick Mastracchio removed a faulty coolant pump far ahead of schedule.
Removing the pump enabled him and partner Mike Hopkins to install a spare on a second spacewalk on the International Space Station, which is now planned for Tuesday. They will not have to go outside a third time as planned. However, given the opportunity to get further ahead Saturday, Mastracchio said he’d prefer to “call it a day” on his seventh career spacewalk.
He had earlier reported feeling “very, very cold,” first in his fingers and then his toes, which he could barely move with his feet fastened to the end of the station’s 58-foot robotic arm.
“Because I’m just floating here on the arm, I’ve got very, very good air flow in my boots, but my toes are quite cold,” he said.
Mastracchio turned on spacesuit heaters, but apparently needed to return inside the station to thaw out.
He plans to switch to a different spacesuit for the next excursion, which had been planned Monday but will take an extra day to get ready.
Despite ending an hour earlier than planned, Saturday’s five-hour, 28-minute spacewalk accomplished more than expected.
Masstracchio and Hopkins, who was on his first spacewalk, successfully slid a refrigerator-sized pump module from a station girder and stowed it away.
Timelines had called for preparing the 780-pound box for removal but completing that work on a second spacewwalk.
“Early Christmas,” astronaut Doug Wheelock radioed from Houston after Mastracchio released a last bolt.
A valve inside the pump module failed on Dec. 11, limiting its ability to regulate temperatures in one of the two external coolant loops that dissipate heat generated by station systems.
Non-essential systems were shut down in the U.S. portion of the complex, putting science research on hold and leaving the station more vulnerable to a failure of the second loop.
NASA delayed the launch of a resupply mission and scheduled up to three spacewalks to replace the pump module with the bad valve.
Mastracchio got things off to a fast start, accomplishing with surprising ease what was expected to be the day’s toughest task.