[sdcantrell56]

Using a vacuum to create downforce, as long as nothing other than rover wheels are touching the ground should not be illegal or against the spirit of the rules. This would be an innovative solution as you would not be adding anything extra between the physical interaction of the ground and the robot, and as such would not be adding traction. Also the Cof is remaining the same no matter how much downward force is applied, the only thing changing is the normal force which is not friction.