The lunar truck provides an idea of what the transportation possibilities may be when astronauts start exploring the moon. This vehicle, being built at NASA's Johnson Space Center, Houston, would have active suspension, a six-wheel drive with independent steering for each wheel, no doors, no windows and no seats.
On this rover, all 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.
Though astronauts will not have trouble finding a parking space on the moon, the feature, called crab steering, has advantages for a vehicle designed to drive into the craters of the moon. If a slope is too steep to drive down safely, the vehicle could drive sideways instead - no backing up or three-point turns required.
The all-wheels, all-ways steering also could come in handy when unloading and docking payloads or plugging into a habitat for recharging.
Introducing crab steering drove the concept in several other ways. If the rover's wheels turn to drive in a different direction, 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.
"If you have a payload on the back or are plugging into something, it could be really important to keep your eyes directly on it," said Rob Ambrose, assistant chief of the Automation, Robotics and Simulation Division at Johnson.
The vehicle also can be the ultimate low-rider. It can lower its belly to the ground, making it easier for astronauts in spacesuits to climb on and off. Individual wheels or sections can be raised and lowered to keep the vehicle level when driving on uneven ground.
Some, all, or none of these features may be selected for the design of a rover that eventually goes to the moon. "This rover concept changed the whole paradigm," said Diane Hope, program element manager for NASA's Exploration Technology Development Program. "It's not something I would have expected. It provides an alternative approach," she added.