When scientists at NASA's Jet Propulsion Lab (JPL) ventured out into the Mojave dessert to test an inflatable rover, they had no idea that an accident with the device would provide a solution to a problem they needed to solve. The problem was how to propel and maneuver a rover on the surface of Mars. The shoulder-high tires on the rover test vehicle that JPL scientist Jack Jones and technician Tim Conners rolled out onto the Mojave Desert that windy day resembled large beach balls. While conducting experiments of how the rover might maneuver on the rocky surface of Mars, one of the wheels broke off and blew away. "It went a quarter of a mile in nothing flat," says Conners. He had to jump in an all-terrain recreational vehicle to chase down the wheel. "It soared," according to Jones, which gave him the beginning of a solution to his problem. "If we make these things big enough, nothing will stop them." The ball he envisions sending to Mars could have a diameter of twenty feet. The radar and electronic devices that the Rover carries are now placed inside the ball, suspended from the center of a spoke-like structure that extends to the giant ball's perimeter. There was still one problem—how to stop the ball or "throw anchor." The solution is partial deflation—lowering the devices contained within the ball down to the surface of the red planet, so tests and experiments can be conducted. When ready to move on to the next site, the ball re-inflates itself and waits for the next Martian wind to take it away. "This is preliminary work," cautions Jones, who thinks the idea might hold promise for the exploration of Mars, Pluto, Neptune, Jupiter, and other worlds with atmospheric winds. Although the ball seems to be at the mercy of the wind for now, Jones is working on a way to steer it. For more information, go to www.nasa.gov.