This artist's concept shows the sky crane maneuver during the descent of NASA's Curiosity rover to the Martian surface. The entry, descent, and landing (EDL) phase of the Mars Science Laboratory mission begins when the spacecraft reaches the Martian atmosphere, about 81 miles (131 kilometers) above the surface of the Gale crater landing area, and ends with the rover Curiosity safe and sound on the surface of Mars. Instead of the familiar airbag landing systems of past Mars missions, Mars Science Laboratory will use a guided entry and a sky crane touchdown system to land the massive rover.