In a car commercial, it would sound odd: active
suspension, six-wheel drive with independent steering for each wheel, no
doors, no windows, no seats and the only color it comes in is gold.
NASA is testing many technologies needed for research on the moon. Two examples are a lunar truck for astronauts and a rover equipped with a drill designed to dig into the moon's soil.
The concept for a future lunar truck was built at NASA's Johnson Space Center, Houston. 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."
One of the first standards to go was the traditional expectation that a
vehicle should have four wheels. Mars rovers Spirit and Opportunity, still
cruising around 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 the remaining five.
With the number of wheels decided, the next question was just how those wheels
should turn. On a car, the front wheels turn a few inches in either direction,
and both wheels point in the same direction. 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.
Introducing crab steering drove the concept in a few 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.
"The Apollo astronauts couldn't back up at all because they couldn't see where
they were going in reverse," said Rob Ambrose, assistant chief of the
Automation, Robotics and Simulation Division at Johnson. "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."
The vehicle also can be the ultimate lowrider. 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 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, program
element manager for NASA's Exploration Technology Development Program at
NASA's Langley Research Center in Hampton, Va., which sponsored the vehicle's
development. "It's not something I would have expected. It provides an
alternative approach."
Source & Credit of the pictures:
NASA
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