Expedition 38 Flight Engineers Rick Mastracchio and Mike Hopkins wrapped up a 5-hour, 28-minute spacewalk outside the International Space Station at 12:29 p.m. EST Saturday, completing the first in a series of excursions aimed at replacing a degraded ammonia pump module associated with one of the station’s two external cooling loops that keeps both internal and external equipment cool.
A second spacewalk to install a replacement pump module, originally planned for Monday, is now scheduled for Tuesday.
During Saturday’s spacewalk, the two astronauts focused on removing a degraded pump module from Loop A of the station’s external Active Thermal Control System. That pump module encountered a problem Dec. 11 when an internal valve stuck in an incorrect position, causing temperatures in the station’s cooling lines to drop.
Mastracchio now holds 43 hours and 58 minutes of spacewalking time during seven spacewalks, and Hopkins now holds 5 hours and 28 minutes during one spacewalk.
Saturday’s spacewalk was the 175th in support of space station assembly and maintenance.