The initial studies we did considered a six wheled rover as the best approach for a moon rover. That was due to the fact that a 6 wheel drive vehicle is excellent for off road conditions and to cruise unknown and difficult terrains. Our initial rover had 6 wheels in a rocker bogie configuration. The 6 wheels had traction and 4 of them (the ones at the front and rear) had steering capabilities. The configuration was very similar to the rovers sent by NASA to Mars. In order to get a piggyback launch opportunity, we conducted a reasearch to have the smallest possible footprint, by folding wheels, solar panels, cameras and antennas. At this point it was clear that the vehicle should reduce its complexity. Having 6 wheels enhanced the off-road capabilities but at a high penalty on cost, weight and complexity. Some models were constructed with excellent traction results but very high complexity and cost.

Due to the fact that our strategy is to develop a low cost mission, a different approach had to be taken. We reduced the number of wheels from 6 to 4. Also a big effort was made to compact the rover in order to avoid the need to fold elements. We simplyfied the mechanical designs.

The outcome of this process of simplification is a 4 wheel rover which is much simpler and robust. This simplicity defines directly the cost of the vehicle and also the ever important variable: the weight. At the moment several versions of 4 wheeled rovers have been constructed and are being tested and refined by our engineers.