Nasa's Phoenix Mars lander touched down on the Red Planet early this morning, in a mission that may yield evidence of primitive life amid the permafrost.
Mission controllers faced a tense wait as the £212m probe plummeted through the thin Martian atmosphere and used a heat shield, parachutes and jet thrusters to slow its descent from an entry speed of 13,000mph to just 5mph on landing, in what was dubbed "seven minutes of terror".
The craft, the first mission to Mars for four years, touched down at 12.53am, ending a 420m-mile, 10-month journey since it was launched from Cape Canaveral in Florida. The touchdown, the first soft landing by a spacecraft on legs on Mars for more than 30 years, was greeted with shouts and applause back at mission control.
Speaking ahead of the landing, Peter Smith, the mission's lead investigator from the University of Arizona, Tucson said: "If we get the signal all the way to the surface we'll be very happy and there's going to be tremendous cheers."
Using a robotic arm, the rover will pierce the topsoil of the Martian northern polar region, and for the first time take ice and mineral samples from beneath the surface to see if the planet could sustain life.
Water is known to exist on Mars as vapour in the atmosphere and as ice below the surface, but there is currently no water on the planet's surface. However previous Nasa explorations have revealed canyons and shallow lakes, suggesting water flowed billions of years ago.
Scientists believe that bacterial spores could lie dormant in cold, dry and airless conditions for millions of years, potentially reactivating when conditions change.
The first images were expected to take two hours to be beamed back to earth.
A British team from Imperial College London contributed to the mission, providing 10 tiny silicon discs, etched with a pattern of pits and pins designed to hold on to grains of soil and act as slides for the two onboard microscopes.
Speaking before the touchdown, team leader Dr Tom Pike, who previously worked at Nasa's Jet Propulsion Laboratory, said: "As we dig we're going to see what's been laid down by a series of arctic winters. We're not looking for the signatures of life at this stage, we're looking to see if the paper is there to write the signature on. What Phoenix could show is the potential for life, and that's a very interesting result on its own."
The success of the Phoenix landing is a major boost to Nasa's longterm Mars exploration programme, which aims to establish if life has ever existed on the planet and detail the geology and climate, ahead of a pioneering human exploration.
Nasa has not had a successful powered landing since the twin Viking landers in 1976. The last time the space agency tried was in 1999 when the Mars Polar Lander, angling for the south pole, crashed after prematurely cutting off its engines. The Mars rover missions used parachutes and airbags for their landings.
Backstory
There have been 40 attempts to reach Mars but two-thirds of them have ended in failure, the majority losing contact en route, burning up on entry or being dashed to pieces on attempting to land. Soviet missions Marsnik 1 and Marsnik 2, designed to fly past the planet, fell to Earth shortly after being launched in 1960. Two years later the Soviet Sputnik 22 probe exploded, and the first successful flyby was not until 1964 when the US Mariner 4 returned pictures of the dusty red landscape. The first successful landing took place in 1976 when US twin Viking landers touched down, took soil samples and tested them for signs of life. A Russian mission ended in failure when the launch vehicle blew up in 1996. Japan's single attempt to reach Mars failed in 1998 because of problems with its propulsion system. In 1999 Nasa lost three missions. In 2003 the European Space Agency's Beagle 2 probe disappeared before landing.
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