U.S. astronauts aboard the International Space Station have successfully completed the last in a series of spacewalks meant to prepare the station for docking of U.S. space "taxis" now under development, NASA says.
Station commander Barry "Butch" Wilmore and flight engineer Terry Virts finished installing cables, antennas and navigation aides on the station's exterior to prepare parking spots for crew capsules being developed by Boeing and SpaceX, the space agency announced.
The space walk, the last of three to prepare the berthing slips for the intended U.S. spacecraft, was expected to take seven hours but Wilmore and Virts were back inside the ISS in five and a half hours, after installing 400 feet of cabling along with reflectors and antennas that approaching spaceships will use to navigate and dock with the orbiting laboratory.
The antennas were part of a system dubbed Common Communications for Visiting Vehicles, or C2V2.
In the coming years it is expected that Boeing's Crew Transportation System (CST)-100 and the SpaceX Crew Dragon will use the newly created berthing slips to transport new crews to the ISS.
The new berthing slips will be outfitted with docking port adapters expected to arrive at the ISS later this year.
One will be put on an existing slip previously used by NASA space shuttles until the fleet's retirement in 2011, with the second installed on an adjacent station node.
Since the shuttles were retired, the U.S. has had to depend on Russia to take U.S. astronauts to the ISS aboard Soyuz spacecraft, but NASA says it hopes to be putting American crewmembers on SpaceX and Boeing craft in 2017.
During 187 spacewalks for assembly and maintenance during the ISS's history, crew members have spent more than 1,100 hours in space.
The just-completed space walk was the third for Virts, who has spent 19 hours outside the space station, and the fourth for Wilmore, who's been in space outside the station for a total of 25 hours and 36 minutes, NASA said.
