Three spacewalks in eight days

Credit: NASA

Two astronauts conducted three spacewalks in eight days to prepare the outpost for module relocations and future commercial vehicles.

On Feb. 21, 2015, Barry Wilmore and Terry Virts put on space suits and left the Quest airlock for the first Extravehicular Activity of Expedition 42. Their goal was to reroute power and data cables from the stations forward docking port called Pressurized Mating Adapter Two. PMA-2 was the docking port that hosted the space shuttles during most of the construction period of the space station and hasn't been used since the space shuttle Atlantis undocked in July of 2011.

These cable reroutes are part of a bigger plan to add an International Docking Adapter to both PMA-2, and PMA-3. Later this year, astronauts will relocate the Leonardo Permanent Logistics Module. The PMM will be moved from its current location, below the Unity node, to the forward port of the Tranquility node. Additionally, PMA-3, currently at the port side of Tranquility, will be moved to the Nadir, or top part of Harmony.

In this graphic, the PMM, left picture, is moved from its original location, blue, to its new location.
while PMA-3 is moved from its original location to its new location. Credit: NASA

This module relocation allows for two visiting vehicles to be berthed, and two to be docked on the United States side of the space station at the same. But before commercial vehicles can dock to ISS, two IDAs must be attached to the PMAs.

IDA locations. Credit: NASA

SpaceX is currently scheduled to deliver IDA-1 in June of this year. It will be attached to the front of PMA-2 by two astronauts on a spacewalk. IDA-2 will be sent up early next year.

At the end of the second spacewalk, during depressurization of the Quest airlock, Terry Virts noticed water buildup in his suit. This brought back memories of a couple years ago, when Luca Parmitano noticed water in his spacesuit while actually on the spacewalk. 

So much water collected inside his helmet that water started blocking his vision as it flowed around to his face. There was a real risk of drowning. In the end, he made it back into ISS to take off his helmet. That suit has since been returned to earth for inspection.

Engineers ruled that Virts water buildup was far less than what had occurred with Parmitano: only 15 milliliters of liquid was collected. NASA concluded that the water condensed inside his suit when repressurization began and there was no risk to his life. NASA said water condensation was somewhat rare, but not unheard of for their spacesuits.

Despite the water, NASA gave the "go" for the third EVA on March 1, 2015 to finish up work started in the first two EVAs and to install a new communications system for future commercial vehicles. ISS is now set up for moving modules to pave the way for commercial crew.