A New Landing System
Previous landers and rovers have used various landing techniques to touch down gently on the Martian surface. The first landers like Viking used a solid rocket to slow the descent. The current rovers used both rockets and air bags to cushion the landing, bouncing the rovers along the surface.
Curiosity will land with rockets, but in its own unique way, hanging from a descent stage by cables.
The descent will begin like all have, first with entry into the Martian atmosphere protected by a heat shield. Then the heat shield will be jettisoned and a parachute deployed at about six miles to further slow the descent.
About a mile above the Martian surface, the parachute is jettisoned and the eight rocket motors on the descent stage ignited. At this point the rover is still snugly held against the descent stage, called by NASA the ‘rocket backpack.’
About 66 feet above the surface, the cables begin to spool out and four of the rocket engines shut down. Curiosity is now hanging from the ‘backpack’ much in the same way the giant Skycrane helicopter carries a load. When the wheels touch the surface, the cables automatically release, and the backpack veers away to crash into the surface.
Curiosity is on Mars ready to look for signs of life.