December 20, 2013
Expedition 38 Crew To Conduct Spacewalk Saturday To Fix Faulty Pump
redOrbit Staff & Wire Reports - Your Universe Online
The first of three spacewalks required to fix issues with one of the International Space Station’s (ISS) external coolant systems is scheduled to begin shortly after 7am EDT Saturday morning, NASA officials have confirmed.
American crew members Rick Mastracchio and Mike Hopkins and Japanese astronaut Koichi Wakata spent Thursday reviewing extra-vehicular activity (EVA) procedures and finalizing preparations for the mission, the US space agency said. Mastracchio and Hopkins will leave the station to replace a faulty pump module in the cooling system, while Wakata will operate the facility’s robotic arm to maneuver the spacewalkers at the worksite.
The astronauts will set up their worksite on the S1 truss during Saturday’s spacewalk, which is set to begin at 7:10am EDT and is expected to last approximately 6.5 hours. A second spacewalk, currently scheduled for Monday, will involve the removal and replacement of the malfunctioning pump module with a spare. If necessary, a third spacewalk to finalize the installation process would take place on December 25.
“It’s a serious problem, obviously it’s something we have to fix. It’s not something I’m worried about, though,” Mastracchio told Reuters during an inflight interview conducted Friday. “The biggest challenge on this spacewalk, in my opinion, is the large fluid connectors that are connected to the pump module. But of course, we have a lot of tools if we have problems with those to fix that.”
On December 11, the ISS crew was forced to disable some of the station’s non-critical systems after the pump module on one of the external cooling loops went into automatic shutdown after reaching pre-determined temperature limits. Those loops operate by circulating ammonia outside of the orbiting laboratory in order to help keep both internal and external equipment from overheating, NASA officials explained at the time.
At first, it was unclear whether or not the issue was software-related or a hardware problem, but engineers ultimately determined that a spacewalk was necessary to fix the failing coolant system. The Expedition 38 crew spent much of this past Sunday prepping their spacesuits for the EVA mission, due to issues with a valve in the unit.
While some experiments had to be temporarily suspended, NASA maintained throughout that the ISS astronauts were never in any danger. A similar incident that occurred back in May also required a pair of astronauts to take part in a spacewalk to fix the problem, the space agency told The Guardian on December 12.
Shortly after the conclusion of Saturday’s spacewalk, mission controllers will conduct a post-EVA briefing at Houston’s Johnson Space Center to discuss the day’s events, the space agency said. NASA Television coverage of the event is scheduled to kick-off approximately one hour before the scheduled EVA start time.
“In the Russian side of the space station, Commander Oleg Kotov and Sergey Ryazanskiy are preparing for a Dec. 27 pre-planned spacewalk,” NASA added. “The duo will install a foot restraint; install medium and high resolution cameras; jettison gear from a pair of external experiments; and install a new experiment as well as a payload boom on the Zvezda service module.”