Skycrane success for NASA

NASA's Mars rover Curiosity has landed on the Red Planet. The one-tonne rover, suspended on nylon ropes from a "skycrane", touched down on 6 August.

It was the end of a 36-week flight and the beginning of a two-year mission to investigate whether the Gale Crater ever offered conditions favourable for microbial life. The Mars Science Laboratory (MSL) spacecraft that carried Curiosity "succeeded in every step of the most complex landing ever attempted on Mars, including the final severing of the bridle cords and flyaway manoeuvre of the rocket backpack," according to NASA.

To land the car-sized rover, the air bag method used on previous Mars rovers was unsuitable. Mission engineers at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, designed the "sky crane" method for the final several seconds of the flight. A backpack with retro-rockets controlling descent lowered the rover on three nylon cords just before touchdown.

During a critical period lasting only about seven minutes, the MSL spacecraft carrying Curiosity had to decelerate from more than 13,000 mph (5,900 metres per second) to allow the rover to land on the surface at about 1.7 mph (0.75 metres per second). "The Seven Minutes of Terror has turned into the Seven Minutes of Triumph," said NASA Associate Administrator for Science John Grunsfeld.

The rover will use a drill and scoop at the end of its robotic arm to gather soil and powdered samples of rock interiors, then sieve and parcel out these samples into analytical laboratory instruments inside the rover.

"Today, the wheels of Curiosity have begun to blaze the trail for human footprints on Mars. Curiosity, the most sophisticated rover ever built, is now on the surface of the Red Planet, where it will seek to answer age-old questions about whether life ever existed on Mars - or if the planet can sustain life in the future," said Charles Bolden, NASA Administrator.