A Rover That Tumbles Over Small, Rocky Worlds

A mechanical “hedgehog,” sitting on a comet.

NASA is developing a new kind of rover, which can boldly move on terrains not navigable by conventional rovers.  

Dubbed the “hedgehog,” it looks like a spiked cube and is built to hop and tumble on knobby worlds, such as asteroids and comets, which have very little gravity,

Probes like the SUV-size Curiosity, which have sets of wheels, work well on planets. But on smaller astronomical objects, they’re at risk of floating away or tripping over rugged boulders.