Astronauts have conducted their last spacewalk before coming back down to Earth in a pioneering flight on a SpaceX craft.
Nasa's Bob Behnken and Chris Cassidy left the space station to perform a range of maintanence jobs, including routing cables and hooking up a tool storage chest.
It was the tenth spacewalk for both the astronauts, and the fourth since they arrived at the station around a month ago.
It is also the last time they will leave the space station before they head off back to Earth, on board a pioneering SpaceX craft.
That carried the two astronauts up to space last month, conducting the first test of the crewed craft as well as representing the first time humans had been sent into space from the US in almost a decade.
In less than two weeks, Behnken and Doug Hurley, who monitored the spacewalk from inside, will depart the orbiting complex in the same SpaceX Dragon crew capsule in which they arrived.
SpaceX is aiming for a splashdown off the Florida coast in August — the first splashdown for astronauts in 45 years.
Weather permitting, the Dragon capsule will parachute into the Gulf of Mexico off the Florida Panhandle.
NASA Administrator Jim Bridenstine said once Tuesday's spacewalk is finished, the astronauts are "going to be focused like a laser on coming home."
Bridenstine said the SpaceX test flight has gone exceedingly well so far. "And I'm knocking on wood because it is not over until Bob and Doug are home," he said at a Space Foundation panel discussion on Monday.
The first-stage booster used to launch Behnken and Hurley on May 30 blasted off for a second time Monday from Cape Canaveral. It landed on a floating platform in the Atlantic after hoisting a satellite for South Korea's military, to be used again for another flight.
Additional reporting by agencies
