Washington - Two astronauts from the Discovery space shuttle on Saturday began a second spacewalk to perform maintenance work on the International Space Station, reported NASA, the US space agency.

US astronauts Steve Swanson and Joseph Acaba will swap out batteries, fasten an antenna and install equipment for external storage, reported NASA.

The spacewalk is expected to last six and a half hours.

On Friday, the Discovery crew completed installation of the station's final pair of solar panels, which will expand the satellite's power supply.

Discovery is scheduled to end its 13-day mission on March 28. One more spacewalk is scheduled for Monday. (dpa)