Two astronauts from the US space shuttle Atlantis have made their first spacewalk as part of their mission to the International Space Station.Mike Foreman and Robert Satcher ventured out to attach vital cables and an extra antenna to the ISS. They were also due to perform several other tasks with work predicted to last about six hours. Atlantis blasted off from the Kennedy Space Center earlier this week for the 11-day mission. The shuttle’s six man crew will carry out two other walks before the craft’s return. That will also see a seventh crew member, Nicole Stott, come back to earth after spending almost three months in space. It is the fifth shuttle mission this year and the last for 2009 ahead of the space shuttle fleet’s eventual retirement in 2010.