At 2230 GMT on Friday, a Nasa commentator announced that the $450 million Mars Reconnaissance Orbiter spacecraft was "in orbit around Mars".

The success of the complex procedure was met with loud cheers by mission controllers at Nasa's jet propulsion laboratory in California, and means Orbiter can now proceed with its mission to scour the planet for evidence of life and locations where astronauts may be able to land in future.

The unmanned craft achieved a perfect orbit around a planet that has defeated most of the probes sent there. If it had failed to achieve orbit it would have flown off into space like the Japanese Nozomi orbiter in 1998.

'Near-perfect' manoeuvre

"It's almost like dodging a bullet," said Dan McCleese, the Jet Propulsion Laboratory's chief Mars scientist. "It's going to take a few trips around the planet to know for sure, but from what we can see so far it's a near-perfect entry into orbit."

The Orbiter left Earth in August on its 306 million-mile journey and will spend the next six months using the drag of Mars' atmosphere to reel itself in from an elongated 35-hour loop to a nearly circular two-hour orbit.

It will then begin its primary scientific mission.

"There's nothing intrinsically more difficult than other planets"

Rob Lock, Orbiter lead mission planner

To ease into orbit around Mars, the ship was required to turn its main thrusters forward and fire them for 27 minutes, effectively slamming on the brakes while cruising at more than 11,000 mph.

The orbit insertion burn began on schedule at 1.24pm PST and about an hour later the ship, which lost contact with Nasa when it went behind Mars, regained contact with Earth and signalled that it was on course.

Tricky planet

The most technologically advanced spacecraft so far to be sent to another planet, Nasa's orbiter is equipped to send back 10 times as much data as all previous probes put together.

But missions to Mars have proven notoriously difficult, with two of the last four attempts by Nasa to put a spacecraft in orbit around the planet ending in failure.

"Mars is just for some reason harder to get a mission to than other places in the solar system," lead mission planner Rob Lock said. "I might even use the word 'unluckier' because there's nothing intrinsically more difficult than other planets."

The Mars Reconnaissance Orbiter programme was expected to cost a total of about $720 million, including $450 million for the spacecraft and its on-board instruments, $90 million for the launch and $180 million for mission operations, science processing and support.