MENG 185: CubeSat Rover

Design and fabricate a rover constrained to CubeSat dimensions (10×10×20 cm) capable of autonomously deploying extremophile samples onto a simulated planetary surface and retrieving them via an electromagnet-based pickup system. The mission context: testing whether extremophiles could survive on a newly discovered planet, as a potential path toward off-Earth agriculture. 

Each team was issued the same package of DC motors, and before any parts were designed I ran a torque check to confirm they could actually drive the vehicle. Sizing against the 2.66 kg mass limit, rolling resistance came out to 0.52 N, which required 0.0157 Nm of total wheel torque at a 3 cm wheel radius. Split across all four wheels, that is 0.0039 Nm per motor against the 0.002 Nm the supplied motors produced, roughly half of what was needed even in the most generous drive configuration. The result also exposed a coupling I had not expected: the kit motors were only viable if all four wheels were driven, but the motor shield provides four DC channels and the stepper driving our sample drop-off mechanism consumed two of them. Driving four wheels would have left no channels for the mechanism that made the rover more than a chassis. I presented the calculation and the channel conflict to the course faculty, who then lifted the restriction on sourcing our own motors. We moved to higher torque geared DC motors, committed to a two wheel rear drive layout, and made mass reduction an explicit design priority from that point forward. The final build came in at 820 g, well under the limit the analysis had been sized against. 

Won the end-of-semester design competition, judged by faculty, TAs, and NASA judges on uniqueness/creativity, complexity, functionality, and robustness. Out of 8 teams, only 4 rovers achieved locomotion, and ours was one of just two to demonstrate a second mechanical function (sample deployment/retrieval) in addition to driving.