It sounds like a crazy idea but Elon Musk, PayPal creator and founder of SpaceX, is determined to build a reusable space launch system that could cheaply carry people to Mars. In this animation, you can see how his proposed rockets would work, using thrusters to cushion re-entry and fire back to Earth. The reusable design should allow for economical testing before the maiden launch.
The scheme builds on the company's previous innovations. Last year, SpaceX launched its Falcon rocket, the first of a new generation that can carry heavy loads, as well as its reusable Dragon capsule that can be fitted for cargo or crew. A previous mission also attempted to launch a recoverable rocket but it failed to parachute back to the ground.