WASHINGTON: Astronauts from the US space shuttle Atlantis were to venture into open space on a third and final spacewalk of their mission aimed at maintaining and installing more high-tech equipment on the International Space Station. Mission specialists Randy Bresnik and Robert Satcher spent the night in the Quest airlock of the shuttle as part of the overnight “campout” procedure that helps purge nitrogen from their bloodstreams, preventing decompression sickness once they move out into the vacuum of space. After a 0728 GMT wake-up call today, both were declared by NASA “ready” for the walk that is slated to begin at 1218 GMT. Spacewalk veteran Mike Foreman will assist the pair in their activities and coordinate communications between them and Mission Control in Houston, Texas, according to the US space agency NASA. The second spacewalk on Saturday, executed by Bresnik and Foreman, was shortened by about 30 minutes due to false depressurization and smoke alarms, but the duo completed all their scheduled tasks in six hours and eight minutes, according to NASA. They installed a cargo attachment system on the space-facing side of the station’s Starboard 3 truss and set up a wireless video system to transmit images to the station and relay them to Earth.