Curiosity's Descent Stage
Curiosity will next be integrated with its descent stage, seen here, which will take it to the Martian surface. The rover will use a bold, new landing system. Like Viking, Pathfinder and the Mars Exploration Rovers that came before it, Mars Science Laboratory will be slowed by a large parachute. As the spacecraft loses speed, rockets will fire, controlling the spacecraft's descent until the rover separates from its final delivery system, the sky crane. Like a large crane on Earth, the sky crane touchdown system will lower the rover to a "soft landing" — wheels down-on the surface of Mars, ready to begin its mission.
Once mated to its descent stage, the Mars Science Laboratory will be placed inside its aeroshell that will protect Curiosity during its deep space cruise to Mars. The hatchway opening in the aeroshell will allow engineers access a few days before launch to install the rover's power source, a radioisotope power system that generates electricity from the heat of plutonium's radioactive decay. This power source gives the mission an operating lifespan on Mars' surface of at least a full Martian year (687 Earth days, or 1.9 Earth years).