This portion of NASA's Mars Science Laboratory, called the descent stage, does its main work during the final few minutes before touchdown on Mars.
The descent stage will provide rocket-powered deceleration for a phase of the arrival at Mars after the phases using the heat shield and parachute. When it nears the surface, the descent stage will lower the rover on a bridle the rest of the way to the ground.
The Mars Science Laboratory spacecraft is being assembled and tested for launch in 2011.
This image was taken at NASA's Jet Propulsion Laboratory, Pasadena, Calif., which manages the Mars Science Laboratory Mission for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology.