spacewalk eva
December 21, 2013

ISS Cooling System Repairs Ahead Of Schedule Following First Spacewalk

redOrbit Staff & Wire Reports - Your Universe Online

Saturday’s extra-vehicular activity (EVA) procedure, the first in a series required to correct issues with a cooling system located outside the International Space Station (ISS) proved to be more successful than NASA had initially anticipated.

During the spacewalk, Expedition 38 crew members Rick Mastracchio and Mike Hopkins intended to set up their worksite on the S1 truss and disconnect a 780-pound degraded pump module from Loop A of the station’s external Active Thermal Control System. They were assisted by robotics operator Koichi Wakata.

Roughly three hours into the spacewalk, which officially began at 7:01am EDT, Mastracchio and Hopkins had successfully disconnected the four fluid lines to the degraded ammonia pump. At that time, they were well ahead of schedule, so the decision was made to begin working on tasks originally scheduled for Monday’s second EVA.

During their extended mission, the astronauts were able to remove the old pump “well ahead of schedule,” Associated Press (AP) Aerospace Writer Marcia Dunn reported Saturday afternoon. “If Mastracchio and Hopkins keep up the quick work, two spacewalks may be enough to complete the installation of a spare pump and a third spacewalk will not be needed on Christmas Day as originally anticipated.”

The spacewalk lasted a total of five hours, 28 minutes and concluded at 12:29pm EDT, according to NASA TV. It was the seventh for Mastracchio, who was serving as the lead spacewalker (EV1), and the first for Hopkins (EV2). Prior to Saturday’s EVA, they consulted Douglas Wheelock and Tracy Caldwell-Dyson, former ISS crew members who had replaced this same the ammonia pump during a series of spacewalks which took place in August 2010.

While some experiments on the orbiting laboratory facility had to be temporarily suspended, and the scheduled December 18 launch of the Cygnus resupply spacecraft was delayed, NASA officials maintain the malfunction poses no threat to the safety of the ISS crew.

According to Kenneth Chang of the New York Times, the spacesuits worn by Mastracchio and Hopkins during the EVA had been equipped with makeshift snorkels and absorbent pads. These safety precautions were taken in response to a July incident in which Italian astronaut Luca Parmitano nearly drowned when his helmet began filling with water during a spacewalk.

“Engineers found that contamination had clogged one of the suit’s filters, causing water from the suit’s cooling system to back up. Those parts have been replaced, and tests have indicated no lingering problems. Officials admit to some uneasiness, however, because the source and cause of the contamination remain unknown,” Chang said, adding the agency had planned to send replacement spacesuits to the ISS prior to the cooling system malfunction.