Range and speed will be improved with the new rove, Schmitt said. In 1972, they drove a total of 35 kilometers at a top speed of six knots.
"We set up a mission rule about how far we would be from the lunar module, with a certain amount of consumables in the back pack in case we broke down and had to walk back, but we never did break down," he said.
That's something Junkin and his design team kept in mind with their rover.
"With one vehicle, its range is driven by the walk-back distance. If it breaks down, a suited astronaut has to be able to walk back to the base. So you can go out for four hours. To expand that distance you need to have two trucks, so you can off-load the equipment and take the other truck home. We figure about 25 kilometers exploration distance in one day. A fully suited astronaut on Earth weighs 500 pounds; this vehicle will carry 2,000 pounds," he said.
The Chariot will get a top speed of 15 mph. Astronaut John Young set a speed record of 8 mph when he went to the moon. Any faster than that, says Schmitt, and you would bounce all over the place with the moon's one-sixth gravity.
The Chariot was also influenced by the design of the sturdy little Mars Rovers, Spirit and Opportunity, which are still going four years later.
"We learned from the Mars rovers that six wheels are better than four. If one wheel fails you can lift it up still keep going on the other five. When you are on the moon it's not going to be as easy to change a spare tire," Junkin said. "We will have to do that from time to time but it is nice to have redundancy so you don't have to pull off to the side of the road and do maintenance."
During the Apollo 17 mission, Schmitt wrote in his journal from the southeastern edge of Mare Serenitatis in the Valley of Taurus-Littrow.
"For 75 hours, Gene Cernan and I lived and worked in the valley, performing extensive geological studies of the volcanic rocks that partially fill the valley," he said.
"In our explorations of the valley, we drove the Rover about 35 kilometers, collected and documented over 110 kilograms of moon rocks and soils, and took over 2,400 photographs."
What extras would Schmitt add to the rover? No cup holder but possibly a ski rack. "In one-sixth gravity you spend some time off the surface. It was like skiing. An astronaut using the skiing technique in a good suit could go that fast and keep up with the rover. Cross-country skiing will be the recreation of choice on the moon."