PASADENA, Jan 31: 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 that sent the rover a sequence of commands.

About 90 minutes later, JPL's mission control centre 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 three-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.

"We expect to see pictures of the lander without the rover on it and the ground in front of us," Erickson said.

Mission control "woke" Opportunity for the drive off its landing pad on its seventh martian day, or sol 7, with Bruce Springsteen's "Born to Run".-Reuters