NASA’s scheme (subscription required) for getting its next Mars rover to the surface sounds awfully complicated, but it sure will be cool if it works:
Curiosity’s size makes getting it safely onto the Martian surface tricky. Previous rovers have deployed parachutes to slow their descents, and have then crashed into the ground using airbags to cushion their impacts. Curiosity is too massive for that approach to work. Instead, NASA hopes to deposit it on Mars using a contraption it has dubbed a skycrane.
As with the other rovers, Curiosity’s mother ship will rely on heat shields and air-resistance, and then on a parachute, to slow its arrival. But at an altitude of 1.6km a specially designed descent stage bearing the rover will drop away from this vehicle. The descent stage has eight rocket motors on its corners. These will slow its fall to a relatively sedate 0.75 metres a second. When it is about 20 metres above the surface, the rover will be lowered from it on wires and deposited gently onto the Martian landscape. The cables will then be cut with explosives, the descent stage will fly off and crash land elsewhere, and Curiosity will begin its mission.