International Space Station managers met Friday morning and gave approval to proceed with U.S. EVA 31 on Sunday, March 1 as planned. The Mission Management Team reviewed the status of spacewalk preparations as well as an analysis of the minor seepage of water into the helmet of Expedition 42 Flight Engineer Terry Virts of NASA following the last spacewalk on Feb. 25 after he was back in the crew lock section of the Quest airlock and the repressurization of the airlock had begun.
Spacewalk specialists reported that Virts’ suit — serial number 3005 — has a history of what is called “sublimator water carryover”, a small amount of residual water in the sublimator cooling component that can condense once the environment around the suit is repressurized following its exposure to vacuum during a spacewalk, resulting in a tiny amount of water pushing into the helmet.
A high degree of confidence was expressed that the suit’s systems are all in good shape and approval was given to proceed with the third spacewalk in this series of EVAs.
During Sunday’s spacewalk, Virts and Expedition 42 Commander Barry Wilmore will deploy 400 feet of cable along the truss of the station and install antennas as part of the new Common Communications for Visiting Vehicles (C2V2) system that will provide rendezvous and navigational data to visiting vehicles approaching the station, including the new U.S. commercial crew vehicles.
It will be the 187th spacewalk in support of station assembly and maintenance, the fourth for Wilmore in his career and the third for Virts.
Swapping designations for this final scheduled spacewalk for Expedition 42, Virts will be designated extravehicular crew member 1 (EV1) on Sunday and will wear the suit with the red stripes. Wilmore will be extravehicular crew member 2 (EV2) with no stripes on his suit.
NASA Television coverage on Sunday will begin at 5 a.m. Central time. The spacewalk will begin around 6:10 a.m. Central time and is expected to last about 6 hours, 45 minutes.