On August 5, 2012, the rover Curiosity will land on Mars using a completely different landing scheme than before. Prior to this landing, parachutes and balloons were used to soften the landings of the Mars Rovers.
This time, a parachute will be used to slow the entry pod down to 200mph, then a rocket propelled transporter to bring it to a hover over the surface. Since the rockets would create a huge dust cloud, it will hover far enough above the surface to prevent dust. The robotic system will then lower the Curiosity on a cable until it rests on the surface. As soon as the rover touches the surface, the cable will disengage and the transporter will rocket away to a safe distance and land.
It takes 14 minutes for radio transmissions to reach Earth from Mars. NASA will know when the Curiosity enters the atmosphere, and that it’ll take seven minutes to reach the surface. The Curiosity will have been on the surface for a full seven minutes before we know if it arrived safely. They’re calling it “Seven Minutes of Terror”
This movie clip is an excellent preview of what we can expect in August, 2012.