Aerospace engineers at MIT are testing a new concept for a hovering rover that levitates by harnessing the moon’s natural charge. Because they lack an atmosphere, the moon and other airless bodies such as asteroids can build up an electric field through direct exposure to the sun and surrounding plasma. On the moon, this surface charge is strong enough to levitate dust more than 1 meter above the ground, much the way static electricity can cause a person’s hair to stand on end. Engineers at NASA and elsewhere have recently…