Astronauts Mike Fossum and Ron Garan, who arrived at the station aboard Discovery on Monday, stepped into the void about 338 kilometers (210 miles) above Southeast Asia at 1622 GMT, in the first of three spacewalks in the mission. Their first order of the day was to disconnect a shuttle inspection boom from the station, where it had been left behind during the last mission in March to make room for the bus-sized lab inside Discovery's cargo bay. Japanese astronaut Akihiko Hoshide then used the station's robotic arm to hand over the boom to American colleague Karen Nyberg, who used the shuttle's robotic arm to return it to Discovery.