NASA Rolls Out Lunar Hot Rod

Jan. 31, 2008 — -- When this hot rod rolls out on the street, traffic stops and people stare.

People aren't quite sure what to make of the bright-white vehicle with gold rims and gold trim that is a cross between an off-road vehicle and someone's fantasy hot rod.

This vehicle is dubbed the Chariot by the design team at the Johnson Space Center. This team was given one year to design and build this ultimate concept lunar rover.

Lucien Junkin, a 17-year veteran of the NASA robotics program, is the chief engineer for the project, and he could hardly wait to get started on designing a new lunar rover. "We built this vehicle in 12 months. Our mandate was building a truck that could go to the moon. When we return to the moon, we will need a utility vehicle, a lunar truck if you will."

NASA is planning to return to the moon by 2020 and is well along the design process with a new capsule called Orion, which looks remarkably similar to the original Apollo, which carried the first U.S. astronauts to the moon. The plan is to build a colony on the moon, so clearly the astronauts will need transportation to explore.

Junkin's Chariot doesn't bear much resemblance to the first-generation lunar rovers. "It challenges all the conventional wisdom of astronauts sitting as they drive. Our crew members will stand up, and we can carry more than two astronauts. The Chariot can move in a crablike motion from side to side as well as forward and reverse. It has six wheels instead of four wheels."

Harrison Schmitt and Gene Cernan were the last two astronauts to visit the moon during Apollo 17 in December 1972. Schmitt was the last person to drive a lunar rover. The new team asked him for advice before it started building the rover.

Schmitt told designers a lower step on the rover would make it much easier for the astronauts to get on board.

"The spacesuits were bulky and not that flexible. My own weight plus the total weight of the suit and life support system totaled about 370 earth pounds, even though the weight on the moon was only about 61 pounds," he told ABC News.

But he added, "We were happy with our rover, it performed very well. … What we used on the moon with Apollo 15, 16 and 17 was a four-wheel vehicle with independent drive on each wheel, front and rear wheel steering, which you could use independently."

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."