US astronauts have completed the first of three planned spacewalks from the shuttle Atlantis a day after the craft docked with the International Space Station.

Astronauts Garrett Reisman and Stephen Bowen finished the seven-hour, 25-minute spacewalk at 3:19 pm (local time) after installing a second space-to-ground communications antenna and a spare parts platform on Dexter, the two-armed robotic device on the orbiting ISS.