Engineers at U.S. space agency NASA went back to the drawing board to create a new "concept car" for the moon. The result: a six-wheeled, truck-style vehicle — dubbed "Chariot" — that someday might rove around the lunar surface more like a crab than a car.

Developed at Johnson Space Center in Houston, Tex., the conceptual Chariot design has no windows and no seats, and it features independent steering for each of the six wheels, so astronauts can drive sideways, diagonally or whichever direction best suits their mission. And the driver's seat rotates 360 degrees with the wheels, enabling a pilot to pivot without repositioning his body to suit the direction of the truck.

As an added bonus, it comes in gold.

The team was given one year to design and build the ultimate concept lunar rover.

According to a statement from NASA:

The vehicle provides an idea of what the transportation possibilities may be when astronauts start exploring the moon. Other than a few basic requirements, the primary instruction given to the designers was to throw away assumptions made on NASA's previous rovers and come up with new ideas.

"To be honest with you, it was scary when we started," said Lucien Junkin, a Johnson robotics engineer and the design lead for the prototype rover. "They tasked us last October to build the next-generation rover and challenge the conventional wisdom."

"The idea is that, in the future, NASA can put this side-by-side with alternate designs and start to pick their features," Junkin continued.

Credit: NASA

Mars rovers Spirit and Opportunity, still cruising the Red Planet, have already proved the value of a couple of extra wheels. When one of the six wheels became inoperable, the rovers had no problem rolling on using the remaining five.

The number of wheels decided, the next question was how they should turn.

Unlike on a car — where the front wheels turn a few inches in either direction and both wheels point in the same direction — the rover's six wheels can pivot individually in any direction, regardless of where any other wheel points. (To parallel park, a driver could pull up next to the parking place, turn all the wheels to the right and slide right in ... not that finding a parking space on the moon is difficult.)

"If a slope is too steep to drive down safely, the vehicle could drive sideways instead — no backing up or three-point turns required," according to NASA. "The all-wheels, all-ways steering also could come in handy when unloading and docking payloads or plugging into a habitat for recharging."

The features, collectively known as "crab steering," are perfectly advantageous to a vehicle designed to drive over the moon's uneven surface.

Moreover, if the rover's wheels can rotate in different directions simultaneously and be individually raised or lowered, the driver needs to be able to do the same. The driver stands at the steering mechanism because sitting in a spacesuit is not comfortable or practical. The astronaut's perch — steering mechanism, driver and all — can pivot 360 degrees.

With the lunar truck's unique suspension system, the base of the vehicle can be raised and lowered until it rests completely on the ground, making getting in and out simpler for an astronaut in a bulky spacesuit.

Though future moon vehicles will be modeled on the Chariot's breakthrough innovations, this one is firmly earthbound. Some, all or none of these features may be selected to be in the design of a rover that eventually goes to the moon. NASA's lunar architects currently envision pressurized rovers that would travel in pairs, two astronauts in each rover. The new prototype vehicle is meant to provide ideas as those future designs are developed.

"This rover concept changed the whole paradigm," said Diane Hope, a program element manager at NASA's Exploration Technology Development Program. "It's not something I would have expected."