In forty-five years of spaceflight and exploration, there have only been six rovers: three Apollo mission lunar rovers, two Russian Lunokhods, and one Sojourner rover on Mars. Under current conditions, the need has been for small robotic vehicles rather than a vehicle to transport humans.

Original Use and Purpose

The primary purpose of the Apollo lunar rovers was to transport the astronauts, saving their energy and oxygen supplies for collecting rock samples to bring back to Earth. These rovers were built by the Boeing Company and NASA's Marshall Space Flight Center. Rovers were sent on Apollo 15, 16, and 17. Each one weighed about 204 kilograms (450 pounds) and could carry about 454 kilograms (1,000 pounds). The frames were made of aluminum alloy tubing, and the chassis was hinged in the middle so that the rover could be folded up and fit in the lunar module. There were two foldable aluminum seats with...