A £1.6 billion one-ton robot rover the size of a small car landed safely on Mars today after one of the most daring and difficult interplanetary operations attempted.
The six-wheeled rover Curiosity was lowered to the Martian surface on three nylon tethers suspended from a hovering "sky crane" kept airborne with retro rockets.
An expected signal confirming that the robot had landed was received on Earth at 6.31am UK time.
There were scenes of wild jubilation at Nasa's Jet Propulsion Laboratory in California when the message came through to mission control: "Touchdown confirmed."
Curiosity can now start its 98 week mission - the length of one Martian year - exploring a Martian crater that billions of years ago may have been filled with water.
The nuclear powered rover is bristling with sophisticated technology designed to discover if Mars may have supported life.
Roughly the size of a Mini Cooper, Curiosity is twice as long and five times as heavy as the twin rovers Spirit and Opportunity which landed on Mars in 2004.
The robot was just too heavy to have its landing cushioned by bouncing air bags - the method used for the previous rovers.
Instead scientists came up with the dramatic "sky crane" solution.
After entering the Martian atmosphere at 13,200mph, the capsule containing the rover was first slowed by friction and then a supersonic parachute.
Closer to the ground, the descent stage carrying Curiosity was released, firing retro rockets positioned around its rim. Above the landing site in Gale Crater, near the Martian equator, the rover was dropped to the surface on 25ft tethers.
The purpose of this was to prevent damage from sand and debris kicked up by the retro rockets. Finally, the descent stage broke away to crash at a safe distance.
An Atlas V rocket carrying Curiosity blasted off from Cape Canaveral, Florida, last November. The journey to Mars crossed 352 million miles of space and took nine months.
The landing marks the start of the Mars Science Laboratory (MSL) mission during which Curiosity will act as a mobile geologist, gathering and analysing samples from the Martian surface.
The rover has a robot arm fitted with a multi-tool "hand" for scooping up soil and drilling into rock.
It also carries its own laser gun which can be used to "zap" rocks more than 6m away. The laser will vaporise tiny amounts of material in a flash of light that can be analysed to reveal chemical data.
As well as a stereo camera fitted to a mast for panoramic shots, Curiosity has a magnifying imager that can reveal details smaller than the width of a human hair.
Samples will be analysed using a state-of-the-art on-board laboratory.
Speaking after the landing, Dr John Bridges, from the University of Leicester, one of two British scientists leading teams on the mission, said: "The science community has been given a very valuable chance to move forward our understanding of how Mars has evolved. How long did wet conditions last and were there standing bodies of water on Mars?
"I hope the effective combination in MSL of science objectives and space engineering will point the way towards more exploration of the solar system and technological innovations."
Professor Sanjeev Gupta, from Imperial College London, who is also in the US leading a rover team, said: "Now that the MSL has landed we can get to grips with some remarkable science. The area the rover will be exploring, with its large areas of exposed rock and variety of landforms, will take us on a journey through geological time.”
Curiosity's target was Gale Crater, near the Martian equator, where there is geological evidence of past water. The rover landed close to Mount Sharp, a 3.4-mile (5.5km) high peak in the centre of the crater with clay deposits around its base.
Proof that Curiosity was on Mars came in the form of thumbnail images showing the planet's rock-strewn surface and one of the rover's wheels.
The images were relayed to Earth by the orbiting Nasa spacecraft Mars Odyssey. Bridges, wrote in a live blog from mission control: "It's down - landed!
"The first images are already being sent back via Odyssey. They are Hazcam images, showing a shadow cast by Curiosity on the Gale surface. Lots of very happy and excited people in this room! What an opportunity we have now to explore this fascinating planet."
- Find out more about Curiosity and its mission on Mars www.nasa.gov
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