CAPE CANAVERAL, Fla., March 24 (Reuters) - Two spacewalking astronauts ventured outside the International Space Station on Friday on the first of three outings to prepare the orbiting research laboratory for future commercial space taxis and to tackle maintenance chores, NASA TV showed. The first spacewalk will prepare the Pressurized Mating Adapter-3 (PMA-3) for installation of the second International Docking Adapter, which will accommodate commercial crew vehicle dockings, NASA said. The U.S. National Aeronautics and Space Administration is making the retrofits in the hope that private companies could begin flying astronauts to the station by the end of 2018. Kimbrough and Pesquet are also expected to lubricate part of the space station's robotic arm, inspect a radiator valve suspected of a small ammonia coolant leak, as well as replace cameras mounted to the exterior of the station's Japanese segment, which consists of the huge Kibo laboratory module, a storage room and exterior porch-like platform covered with experiments. Pesquet and Kimbrough also plan to install new computer equipment outside the space station, and will lubricate and inspect the space station's robotic arm, used to grab approaching spacecraft and move items outside the global laboratory. [Space Station's Expedition 50 Mission in Pictures]

Kimbrough, who commands the station's Expedition 50 crew, and Pesquet "will disconnect cables and electrical connections on PMA-3 to prepare for its robotic move Thursday, March 30," NASA officials said in a statement. "PMA-3 will be moved from the port side of the Tranquility module to the space-facing side of the Harmony module, where it will become home for the docking adapter, which will be delivered on a future flight of a SpaceX Dragon cargo ship," NASA officials added. While Kimbrough's two spacewalks will be the fifth and sixth of his career, Whitson will be making the eighth and ninth spacewalks of her career - more than any other female astronaut. A third spacewalk on April 6 is to include Pesquet and Whitson, who will surpass the record for spacewalks by any female astronauts.
NASA astronaut Shane Kimbrough and ESA astronaut Thomas Pesquet take a spacewalk outside of the International Space Station to prepare the vessel for new arrivals.