We have been working hard on the rocker-bogie suspension system for the Spirit II, our Mars Rover. In this picture, the front wheel will be attached on the left side. The two back wheels will be attached on the right side. The two back wheels will be connected together by a tube that pivots on its center. The entire thing pivots on a central shaft (connected at the junction second from the left) that goes through the counter-rotating differential to an identical chassis frame on the other side of the robot. We are building the chassis frame out of .625 aluminum tube, tube connectors, and aluminum plate. It takes a bit of imagination at this point to visualize how this is going to become a Mars Rover, but it’s coming along. If it all actually works, we’ll be amazed.