Now that Jörg's rover concept has been demonstrated in the field the design goes on focusing on critical mechanical parts. These pictures show the design of the wheel and the gearbox. There are no ball bearings and no plastic parts on it!
Jörg's rover is called WRV1: Wheeled Rover Vehicle 1. You can follow and contribute to the development of WRV1 at http://forum.xprize.frednet.com/viewtopic.php?t=204