Researchers at the Jet Propulsion Laboratory (JPL) have hit upon an idea for exploring the Red Planet that seems to be equal parts fun and serious science: it’s a lightweight, two-story tall beach ball called “the tumbleweed rover.” Equipped with scientific instruments and propelled by nothing more than the thin Martian breeze, the tumbleweed could potentially explore vast tracts of planetary terrain. The wind blowing across the face of the Red Planet would be the only engine needed to move such a ball from place to place, says Jack Jones of JPL’s Inflatable Rover Program.