NASA Road-Tests New Moon Rover
by Brittany Sauser | Submitted Thursday Sep 17, 2009 [05:58 AM]
NASA’s new Lunar Electric Rover was successfully field tested in Arizona this week.
Credit: Brittany Sauser
If NASA astronauts return to the moon in the next decade, they'll get to cruise the lunar surface in style.
The space agency's current plan is to send humans back to the moon by 2020, and this includes using a new exploration vehicle called Lunar Electric Rover (LER). About the size of a small pickup truck, LER has 12 pivoting wheels that enable the rover to move in any direction and turn on a dime; it features a tilting cockpit for close-up views of the terrain; and it runs on batteries and fuel cells.
This week NASA completed field tests of the rover in Black Point Lava Flow, AZ, as part of an annual event called the Desert Research and Technology Studies (D-RATS). The desert landscape--a rugged terrain of sand dunes that is subject to sandstorms and violent temperature swings--is ideal for simulating lunar exploration.
NASA began developing LER in 2007. It is now as "close to [fully] operational as possible,"says Michael Gernhardt, an astronaut and manager of the Environmental Physiology Laboratory at NASA's Johnson Space Center (JSC) in Houston.
The new rover is pressurized so that astronauts can safely explore much more of the moon's surface. During the Apollo program, exploration was limited by the distance astronauts could walk in their spacesuits in case their rover broke down--approximately 9.7 kilometers. LER has a range of about 241 kilometers because astronauts could safely reside inside until rescued by another rover--NASA plans to have at least two on the surface simultaneously.
The new rover weighs four tons, has a 20-horsepower engine, and can traverse 30-degree slopes and climb over meter-sized boulders. "It's a beast," says Rob Ambrose, a human robotics engineer at JSC, who works on LER.
LER's 12 wheels are driven by two electric motors and can pivot 360 degrees, allowing the vehicle to travel in a sideways, crablike motion. "If things get complicated, it has a way to wiggle its way out, and it can lift its legs up and down to stay out of trouble," Ambrose says.
LER is a plug-in electric vehicle that uses battery technologies similar to those in a consumer or commercial electric vehicle. Currently it uses a lithium-ion battery with 125 watt-hours per kilogram, but the working rover will need a battery with 200 watt-hours per kilogram. Inside the vehicle is an exercise bike that the astronauts can use to charge the batteries.
The Arizona field tests were important for both the rover and the astronauts. The testing "gives us the opportunity to flesh out the requirements we would actually need for exploration, the mission scenarios such as science activities, and the mission control timelines," says Joe Kosmos, mission manager of D-RATS.
NASA conducted a mock 14-day mission during which two crew members lived inside the rover and left it, wearing spacesuits, only to perform simulated moonwalks. In addition to evaluating the rover's performance, Kosmos says the focus was to assess the conditions for astronauts. The D-RATS researchers also tested how different communication scenarios--continuous, limited, and non-real time--affected the crew's productivity.
So-called "suitports" allow astronauts to slip in and out of their spacesuits without having to ever bring them inside the vehicle, leaving the cabin free of dust and contaminants. A hatch inside the rear of the cabin opens, and the suit's life-support system or pack serves as a doorway so that an astronaut can crawl out of the suit and into the rover. This also means that astronauts can suit up in less than 10 minutes, a remarkable feat compared to the six hours needed for the procedure at the International Space Station.
LER's cabin, which doubles as a storm shelter during solar or dust events, can also be removed. The astronauts can then use the rover's base, called Chariot, for exploration or for carrying large payloads. Chariot can be driven by the astronauts or remotely operated.
During the simulated mission, the rover covered a total of 142 kilometers and conducted a mock rescue of "lost" crew members, using new navigation software to find the missing astronauts in less than an hour. LER docked with a second rover, called Athlete--a remotely operated heavy-lifting vehicle. A third rover, called K-10, was used to explore the test site a few months earlier, scouting the area, mapping it, gathering data, and planning tasks for LER.
"We successfully completed the 14-day mission and demonstrated that two crew members can be maintained in the lunar electric vehicle over that period of time," says Kosmos.
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