Historically, planetary and lunar
rovers have been wheeled-driven. While this is usually seen as an advantage –due to the flight experience– in some cases, the unavoidable presence of
gears and mobile parts can be a significant hazard
the mission. The abrasive lunar regolith has been the origin of substantial problems with the Apollo rovers.
Here we propose a completely different scheme: a spherical rover in which all the moving parts are protected from the environment by an external spherical shell
CitacióGutierrez, J.; Tristancho, J. Spherical Rover for lunar and planetary exploration. A: European Lunar Symposium. "European Lunar Symposium: April 19-20, 2012: Berlin". Berlin: 2013, p. 38.