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The race to put humans back on the moon is traveling through the Mon Valley.

Scarab, a platform for lunar rover technology being developed at Carnegie Mellon University, is being tested at Lafarge North America's Duquesne slag plant off of Buttermilk Hollow Road in West Mifflin.

Equipped with machinery capable of drilling into materials as hard as granite, then pulverizing the samples and analyzing their chemical content, Scarab is a "skid-steer" vehicle that operates much like a skid-loader, says David Wettergreen, research scientist in Carnegie Mellon's Field Robotics Center.

The rover is being developed with funding from NASA's Exploration Technology Development Program. Later this month, it departs for two weeks of testing on the sides of Mauna Kea, a dormant volcano that makes up the majority of Hawaii's "Big Island."

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The mission of a Scarab-like robot would be to travel to the moon's poles in search of ice. That ice could be harvested for water that would support life on a permanent lunar base, which could then serve as a launching pad for missions to other planets.

Little firsthand information is known about the moon's poles. NASA's six manned lunar missions between 1969 and 1972 never strayed far from the moon's equator.

Practically speaking, such a trip by a robot like Scarab probably five to 10 years away from reality, Wettergreen says.

Rather than having a complicated steering mechanism, Scarab steers by stopping and starting one or more of its four wheels.

"It simplifies the design, because we only need four drive motors," Wettergreen says. It can also crawl along the ground like an inchworm.

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But there's really nothing simple about the way Scarab crawls across the moon-like terrain of the slag pile. Actually, it's rather elegant. Instead of springs, Scarab's wheels are anchored by long, pivoting arms that allow it to tackle steep slopes (up to a 30 percent grade), uneven terrain, or raise itself nearly two feet above the ground.

(One thing Scarab doesn't do is scamper --- it's top speed is five centimeters per second. That's about 1/10 mph.)

The wheels are able to lean or pivot as necessary to help Scarab climb hills that would stymie vehicles with more conventional suspensions.

Scarab's suspension also helps stabilize the Canadian-built drill at the rover's center. That drill will enable Scarab to take core samples from up to three feet below the surface. The material removed by the drill is then pulverized and heated to more than 1,600 degrees Fahrenheit; the gases released are analyzed by a chromatograph to determine the chemical composition of the rock.

Researchers tried a variety of methods for supporting the robot during drilling operation --- including outriggers --- but returned to standard skid-loader tires for field tests, Wettergreen says.

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However, regular pneumatic tires wouldn't work at the moon's poles, where temperatures will be a brisk 40 degrees Kelvin (about 387 degrees below zero Fahrenheit). Conventional tires would be shattered by the cold.

For that possible journey, Michelin has developed an airless tire called the "tweel." They're made of standard tread that's supported by spokes instead of inflated sidewalls. The spokes are made from the same fabric as spacesuits, Wettergreen says.

The Scarab team expects to be testing the "tweels" on the Lafarge slag pile before heading to Hawaii, he said.

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Although Wettergreen used a joystick to manually steer Scarab during a press conference on Tuesday, the robot's on-board navigation system is designed to allow it to drive itself over the moon's surface, finding the best routes and choosing locations to stop and drill for samples. A laser scanner gives it a 3-D view of the terrain.

Scarab's power requirements are a surprisingly low 100 to 120 watts. On Earth, that's supplied by lithium-ion batteries, but Wettergreen says that if Scarab was deployed on a moon mission, it would probably get a Stirling engine powered by a radioactive isotope.

Stirling engines convert heat directly into motion; with the right isotope, Scarab could be powered for 10 years, barring wear-and-tear on components or some other mechanical failure.

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The tests in West Mifflin are taking place on a man-made mountain created from slag --- rock that's the byproduct of melting iron ore in blast furnaces --- that was for decades dumped by the Mon Valley's steel mills.

Lafarge grinds the slag into aggregates that are used in poured concrete, railroad ballast, road paving material, and other products.

Wettergreen says the punishing surface is a good substitute for the types of conditions that lunar rovers would face, and praises Lafarge for allowing Carnegie Mellon researchers to test Scarab and other robots on its West Mifflin slag piles.

Lafarge workers have even helped create obstacles and trails for the robots to tackle, he says.

It's a low-tech environment in the Mon-Yough area that's helping to propel science for years to come.

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Disclaimer: The writer is employed by Carnegie Mellon University, but no remuneration or influence was placed upon Tube City Online to publish this story, and opinions expressed at Tube City Online are not those of Carnegie Mellon University, its staff, or affiliates.

Photo by Wade H. Massie.