Spacesuit Problem Delays Second ISS Spacewalk to Tuesday

International Space Station (ISS) astronauts Rick Mastracchio and Mike Hopkins had a successful spacewalk today, but the next in the series to fix a coolant loop problem has been delayed by one day to Tuesday, December 24.  The delay will allow time to resize a backup spacesuit for Mastracchio because the one he wore today had a “configuration issue.”

The spacewalk proceeded very well, with tasks accomplished ahead of schedule.  The crew is changing out a coolant loop pump assembly because a flow control value was not correctly regulating the temperature of ammonia used as a coolant.   After about four and a half hours, Mastracchio, a veteran of six spacewalks, and Hopkins, a spacewalk rookie, had disconnected the large, cumbersome troublesome pump assembly and gotten it secured in a new location on the outside of the ISS.

Ground personnel told Mastracchio that they had a list of other tasks they would like the crew to perform as “get ahead” items and asked for his input.  He replied that his vote was to end the spacewalk at that point.  Earlier he had complained that his feet were cold and ground personnel asked about his temperature, suggesting that might be the reason for his decision to call an early end to the scheduled 6.5 hour spacewalk.   Mastracchio replied that there were “a couple of things” involved in his decision and ground personnel soon agreed that it was time to call it a day.   The spacewalkers returned to the airlock and the spacewalk ended after 5 hours and 28 minutes.

What happened after that is not clear.  A NASA statement said only that during “repressurization of the station’s airlock following the spacewaik, a spacesuit configuration issue put the suit Mastracchio was wearing in question for the next excursion  – specifically whether water entered into the suit’s sublimator inside the airlock.”   

The extra day will give the crew time to get a backup spacesuit ready to replace the one Mastracchio used today.

NASA stressed that today’s problem “is not related to the spacesuit water leak” that happened in July when European astronaut Luca Parmitano’s helmet filled with water.  At a press conference on Wednesday, NASA officials cautioned that they could not “rule out water in the helmet again” but said they had developed new procedures and added two pieces of hardware to the suits to deal with such an eventuality.   That did not happen today, however, the agency said:  “Both Mastracchio and Hopkins reported dry conditions repeatedly” during today’s spacewalk.  It was Hopkins, not Mastracchio, who was wearing the spacesuit that malfunctioned during Parmitano’s spacewalk.

NASA scheduled three spacewalks to fix the coolant loop problem, but the tasks were accomplished so readily today that only two may be needed.