Astronauts at the International Space Station have ventured outside to perform a challenging cable installation on their orbiting platform.

Spacewalkers Terry Virts and Butch Wilmore have 400 feet of cable to install as well as two sets of antennas.

According to NASA, during the spacewalk, Virts and Wilmore will deploy the 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."

Sunday's spacewalk is the last of three "extravehicular" jaunts outside the ISS "to continue upgrading the station for the arrival of private space taxis carrying astronauts in 2017," writes.

The Associated Press says that "a pair of docking ports will fly up later this year, followed by the capsules themselves, with astronauts aboard."

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