Under a contract from NASA, in the late 1980's and early 1990's the Universities Space Research Association (USRA) operated the NASA/USRA University Advanced Design Program. Several participants in the Advanced Design Program chose as their project a pressurized rover for Moon or Mars exploration. The Virginia Polytechnic design was 7 m long, with a 3-m-diameter cylindrical main vehicle, and a trailer which housed the power and heat rejection systems. Total mass was 6.2 metric tons. The pressure shell consisted of a layered carbon-fiber/foam composite. Wheels were each attached to a double Ackerman-arm aluminum suspension, which allowed each wheel 1 m of vertical motion. In conjunction with a 0.75 m ground clearance, the suspension aided the rover in negotiating the uneven lunar terrain. The trailer contained a radioisotope thermoelectric generator providing 6.7 kW. A secondary backup energy storage system for short-term high-power needs was provided by a battery.
Six 1.5 m diameter wheels were mounted to the main body and two 1.5 m diameter wheels on the trailer. The wheels were constructed of composites and flexed to increase traction and shock absorption.15 N-m torque brushless electric motors were mounted with harmonic drive units inside each of the wheels. The vehicle was steered by electrically varying the speeds of the wheels on either side of the rover. The trailer could be detached to facilitate docking of the main body with the lunar base via an airlock located in the rear of the PLR. The airlock was also used for EVA operation during missions. This rover had a nominal speed of 10 km/hr and a top speed of 18 km/hr. It was capable of towing 3 metric tons of payload, in addition to the RTG trailer. It could support a nominal crew of four for 14 days, and a crew of six in an emergency with no range requirement. Operational radius was 500 km.
Crew Size: 4. Electric System: 6.70 average kW.
Gross mass: 6,200 kg (13,600 lb).
Height: 7.00 m (22.90 ft).
Diameter: 3.00 m (9.80 ft).