The rover Opportunity signalled to Nasa scientists on Saturday that it has driven onto the surface of Mars to begin a mission to explore the planet's geological history and search for signs of water.
Engineers at Nasa's Jet Propulsion Laboratory in Pasadena checked the rover's systems before pressing a computer button at 12:26 am PST (3:26 EST/0826 GMT) that sent the rover a sequence of commands.
About 90 minutes later, JPL's mission control center erupted in cheers and strains of "Going Mobile" by The Who when a signal from the rover indicated that it had begun its drive onto the martian surface.
"The vehicle should already be on the surface at this time we have probably already executed egress," mission manager James Erickson said.
The team had to wait another 90 minutes for confirmation from the orbiter Odyssey that Opportunity had safely negotiated the 10-feet (3-metre) drive forward down a reinforced cloth ramp to the planet's surface.
The six-wheeled rover was ordered to beam photos of its new position in the Meridiani Planum to the orbiter Odyssey, which was scheduled to pass overhead at about 3:20 am PST (6:20 am EST/1120 GMT).