The IMPASS from Virginia Tech is a robot that relies on two sets of spoked wheels for mobility. What makes the sets of wheels notable is that they are created from six separate spokes which adjust in length to the terrain. The adjustment in length of the spokes ensures that the wheel will always be in touch with the ground. The idea for the IMPASS is similar to something from an Aurthur C Clark novel, it was also mentioned in Snowcrash by Neal Stephenson. In Snowcrash, the idea takes the form of 'Smart Wheels' which are attached to skateboards. The spokes function very much the same as shocks on a car or bicycle.
I think that the Virginia Tech design for IMPASS could be improved and made for use in space. The difference of course, is that Virginia Tech is not developing these wheels for use in a zero-g environment (or at least they are not testing them in zero-g). I would make the spokes longer, de-computerize the hydraulics, and increase the size of the pad at the end of the spoke. If the wheels were attached to a 4-wheeled vehicle they would be able to bounce along the ground without bouncing, so to speak. Each time a spoke hits the ground, a simple spring loaded shock absorber would depress the spoke to the correct length. Rocks and holes could be easily navigated. Because of the constant contact and push, I think that the wheel system would see great advantages in a zero-g environment especially when compared to regular wheels or tracks.
But then again, maybe they already thought of all that and there is some reason they have done what they did?