A while back, NASA was running experiments with big inflatable balls, when one of them broke loose and started rolling away. As the rocket scientists watched it boing away easily across the uneven, rugged terrain, they realized that an inflatable ball was a superb locomotive design.

Thus was born the “Tumbleweed” — a new style of Mars rover. It would land on the surface of the planet, inflate, and then skitter around the planet, propelled by nothing other than the howling Martian winds. They just finished testing a prototype Tumbleweed up in the Arctic, and as Astrobiology Magazine reports, it set astonishing land-speed records:

Tumbleweed managed an average speed of 1.3 kilometers per hour (0.8 mph) over the course of the deployment. Such speeds are unattainable in conventional, mechanical rovers—such as Spirit and Opportunity, currently operating on the surface of Mars—which average little more than 0.05 kilometers per hour (0.03 mph) on flat, dry ground.

Behar said the rover’s design is especially well suited for polar missions that use instrument packages to look for water beneath the surface of an ice sheet, a task that cannot be done accurately from orbit.

I also love the idea of a probe whose direction cannot be controlled. Astrophiles and NASA engineers already tend to anthropomorphize the Mars rovers — we talk about them being “sick,” being “confused,” or whatever. (As you may already have heard, someone even started a totally hilarious blog written from the viewpoint of the Mars rover.) The Tumbleweed would take this to a new level, since, being autonomous and controlled only by the wind, it would essentially behave much more like a sentient being. You’d have NASA scientists huddled around the screen like guys around the TV for Monday night football, wondering with bated breath what’s going to happen next: Where’s the rover going to go? Who knows? I bet you’d even have off-track salons taking wagers on where the probe will drift.

(Thanks to Slashdot for this one!)