The spiky space balls are nicknamed "hedgehogs," though they'll act more like acrobats, leaping and tumbling across the surface of moons and asteroids.
Hoppers are a favored design for future planetary explorers because they could cover much more terrain than a rover, and could easily cross canyons and other hazardous areas. With a hopper, you don't face problems like a stuck wheel, which doomed NASA’s Spirit Mars rover. MIT and Draper Labs have a prototype moon hopper vying for the Google Lunar X Prize: The Terrestrial Lunar and Reduced Gravity Simulator, or Talaris. That one uses ducted fans and compressed nitrogen to hover and hop around.