Astronauts from the space shuttle Atlantis began their first of three scheduled spacewalks Thursday morning.
Michael Foreman and Robert Satcher Jr. are slated to hook up a spare antenna and some cables on the outside of the International Space Station.
The astronauts will also do some maintenance and lubrication of the station's robotic arms, Canadarm2 and the Japanese Kibo arm.
This is the first spacewalk for Satcher, billed as the first orthopedic surgeon in space. It is the fourth spacewalk for the veteran Foreman.
After Atlantis docked with the space station Wednesday, astronauts unloaded several tonnes of pumps, tanks and other big spare parts for the ISS.
There are only five more shuttle launches scheduled before the vehicles are decommissioned, so NASA is trying to get as much gear up to the station as possible on these final flights.