How Dante Walks
Dante is a frame-walking, eight legged vehicle. The vehicle has two frames, each of which has four legs attached. The frames are separated by a track which along which the frames may slide relative to each other. In most cases, at least one frame has all four of its legs touching the ground.
Starting from the case where all eight legs are in contact with the ground, one frame will first lift its legs off the ground. That frame will then slide forward. When the moving frame has gone as far as it can, it plants its legs on the ground and distributes the forces on the legs so that the other frame can lift its legs off the ground and slide forward. The result is that Dante can slowly move ahead by moving one frame at a time while the other frame remains planted on the ground.
To help support the vertical component of its weight, a tether is attached to the upper frame and is spooled out as the upper frame moves forward.
Here's an mpeg of Dante walking out at CMU (307K).