Astronauts from the U.S. space agency have begun the first of a series of three spacewalks to repair a faulty cooling pump on the International Space Station.
Two astronauts stepped out of the ISS Saturday, just after 12 UTC. NASA says the two will spend nearly seven hours working outside the orbiting spacecraft where they will disconnect the faulty ammonia pump.
A second spacewalk is scheduled for Monday before they finish their work on Wednesday. The malfunctioning pump shut down the space station's cooling system several days ago.
The station has been using a backup system for cooling both internal and external equipment since the pump failure. The problem has forced the astronauts to turn off all non-essential equipment, including some science experiments.
NASA says the two U.S. astronauts have attached snorkels to their spacesuits to use for breathing in case of a helmet water leak.
A helmet worn by an Italian astronaut filled with water in July, causing him to nearly drown. Spacewalks have been suspended since then.