The US robotic probe that landed on Mars 10 days ago has rolled off its pad and on to the Martian surface.
The Spirit rover rolled three metres down on to the red soil of Mars; widely considered one of the riskiest steps in the US Space Agency's mission.
If all goes well, it will take part in joint experiments with US and European orbital spacecraft.
It can now embark on its mission of exploration to find evidence of water, past and present, in the Martian soil.
Confirmation of the successful manoeuvre off its landing pad was given at 1000 GMT.
"Mars is now our sand box and we are ready to learn," Charles Elachi, director of the US space agency's (Nasa) Jet Propulsion Laboratory, told a news conference in Pasadena, California.
"For centuries, people have been looking up and wondering what's up there (Mars). Now we know what's up there."
But Nasa waited for images taken by the onboard cameras before they could be sure the rover was safely on the soil.
There was loud cheering at mission control when the images were flashed up on computer screens.
Images taken from Spirit's rear "hazcam" camera showed the landing pad 81 centimetres (32 inches) behind the rover and parallel tracks in the Martian soil.
Pictures from the front of the rover show "Sleepy Hollow", a mysterious depression near where Spirit touched down.
"A couple of days ago I said 'we are a rover'. Today I say: 'we are a rover...on Mars' - in our native environment," said Chris Lewicki, flight director for Spirit.
"We have cut the umbilical cord and the baby free, as of today," said mission scientist Joel Krajewski.
As the robot rover rolled down on the Martian surface, it encountered a 10-centimetre (3.9-inch) drop.
It will now halt for three or four days to test the soil and rocks immediately around it to prepare for travelling across the surface.
In response to an observation that the soil disturbed by the tracks in the picture from the rear camera looked "cakey", lead mechanical engineer Kevin Burke told journalists: "It's very different to what we experienced in test."
With America now contemplating a manned mission to Mars, the rover is tasked with examining Martian rocks and dust for evidence of the past presence of water.
Spirit is now free to roam the Gusev Crater - a crater the size of Wales - which may once have been a lake.
Its ultimate destination is a nearby hollow carved by a meteorite hitting the planet.
Scientists believe it is a good place to look for deposits which could have contained water, a key ingredient for life.