By Marcia Dunn

Cape Canaveral, Florida - Space shuttle Atlantis' astronauts are about to step out on the first spacewalk of their mission.

Michael Foreman and Dr Robert Satcher Jr will float outside on Thursday morning to hook up a spare antenna and cables on the International Space Station. They also will tackle some other chores.

It will be the first spacewalk for Satcher. He became the first orthopaedic surgeon in space, with Atlantis' liftoff earlier this week.

Three spacewalks are planned during the shuttle's week-long visit, which began with a smooth docking on Wednesday.

Already, the astronauts have unloaded several tons of pumps, tanks and other big spare parts. All this gear should keep the space station operating well past next year's shuttle retirement. - Sapa-AP