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Astronauts complete final spacewalk to prepare for commercial craft

Paul Sutherland, Feature writer
Mar 2, 2015, 5:01 UTC

Sen—Two NASA astronauts successfully completed their third and final spacewalk in eight days outside the International Space Station today, Sunday March 1, to prepare it for the arrival of commercial space vehicles.

The 5h 38m EVA, by Expedition 42 Commander Barry “Butch” Wilmore and Flight Commander Terry Virts, went ahead despite earlier concerns about water floating inside Virts’ spacesuit following the previous spacewalk on Wednesday, February 25.

Experts who analysed the situation concluded that the “leak” was due to a small amount of residual water in a cooling unit condensing during repressurisation, and the suit had a history of this. It only happened following a spacewalk and there was no danger during the EVAs themselves.

The first two excursions lasted 13.5 hours, during which Wilmore and Virts deployed cables, lubricated the station’s robotic arm and prepared its Tranquility module for the relocation and arrival of modules in the future.

Today’s EVA was designed to set up a number of antennas and other communications equipment to help future crews arriving on commercial spacecraft from the U.S. to rendezvous with the orbiting outpost. Beginning at 6.52 am EST (11.52 UTC) when they switched their suits to battery power, it included laying 400 ft of cable along the space station’s truss.

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Spacewalker Terry Virts is seen working outside the Quest airlock. Image credit: NASA TV

After only one hour outside, Virts and Wilmore were ahead of scheduled, having each installed a boom with two antennas for what is called the Common Communications for Visiting Vehicles (C2V2) system. Virts worked on the port side and Wilmore on the starboard side of the ISS.

They next worked together to connect the C2V2 to satnav (GPS) and antenna systems on the space station before working on the run of cable. Regular checks showed that their spacesuits were working well without any leaks.

The EVA had been expected to last 6 hours, 45 minutes. But more than an hour ahead of schedule, and with all tasks successfully completed, plus an additional one to retrieve a bag of equipment, the spacewalk ended when Wilmore and Virts were back in the ISS and the Quest airlock had been repressurised.

The spacewalk was Virts’ third and the fourth for Wilmore. And it brought the total time that crews have spent outside the ISS doing assembly and maintenance to 1,171 hours and 29 minutes during 187 EVAs.

Following his return to the safety of the ISS, Virts made a short speech to mark the fact that this year is the 50th anniversary of the first spacewalks.