For several reasons, a different landing system was chosen for Mars Science Laboratory compared to previous Mars landers and rovers. Curi...
For several reasons, a different landing system was chosen for Mars Science Laboratory compared to previous Mars landers and rovers. Curiosity was considered too heavy to use the airbag landing system as used on the Mars Pathfinder
and Mars Exploration
. A legged lander approach would have caused several design problems. It would have needed to have engines high enough above the ground when landing not to form a dust cloud that could damage the rover's instruments. This would have required long landing legs that would need to have significant width to keep the center of gravity low. A legged lander would have also required ramps so the rover could drive down to the surface, which would have incurred extra risk to the mission on the chance rocks or tilt would prevent Curiosity from being able to drive off the lander successfully. Faced with these challenges, the MSL engineers came up with a novel alternative solution: the sky crane. The sky crane system lowered the rover with a 7.6 m (25 ft) tether to a soft landing—wheels down—on the surface of Mars. This system consists of a bridle lowering the rover on three nylon tethers and an electrical cable carrying information and power between the descent stage and rover. As the support and data cables unreeled, the rover's six motorized wheels snapped into position. At roughly 7.5 m (25 ft) below the descent stage the sky crane system slowed to a halt and the rover touched down. After the rover touched down, it waited 2 seconds to confirm that it was on solid ground by detecting the weight on the wheels and fired several pyros
(small explosive devices) activating cable cutters on the bridle and umbilical cords to free itself from the descent stage. The descent stage flew away to a crash landing 650 m (2,100 ft) away. The sky crane powered descent landing system had never been used in missions before.[86]
