Douglas IsbellHeadquarters, Washington, DC(Phone: 202/358-1753)
John BluckAmes Research Center, Moffett Field, CA(Phone: 650/604-5026)
Anne WatzmanCarnegie Mellon University, Pittsburgh, PA(Phone: 412/268-3830)
A hardy traveler named "Nomad" recently set a record by traveling farther than any remotely controlled robot has before over rough territory. The robot's four wheels logged more than 133 miles (215 kilometers) across Chile's rugged Atacama Desert from June 15 to July 31, during a field experiment designed to prepare for future missions to Antarctica, the Moon and Mars.
Scientists from NASA's Ames Research Center, Moffett Field, CA, and Carnegie Mellon University's Robotics Institute in Pittsburgh performed experiments with Nomad for 45 days, conducting both technology demonstrations and scientific activities. Nomad often worked on its own to avoid obstacles and, in a clear foreshadowing of the future duties of similar robots, it recognized meteorites planted in the desert as a test and may even have found a fossil.
"The Atacama trek is a quantum leap for the planetary robotics culture, where the historical standard of travel has been yards, not miles," said principal investigator Dr. William L. "Red" Whittaker of Carnegie Mellon. "Although the 'straight-line' distance on a map was only about 13 miles, Nomad had to weave through very difficult terrain, and it made numerous sidetrips for science and to test the meteorite sensors. It is a pioneer laying a trail toward future planetary robots, who will be challenged for thousands of miles and years of operations, in bold missions like searching for signs of life."
The 1,600-pound robot, developed at Carnegie Mellon and funded by NASA, validated the use of color stereo video cameras with human-eye resolution for geology. A separate panospheric camera returned more than a million video panoramas from the Atacama, a cold, arid region located above 7,000 feet.
"During different phases of testing, we configured the robot to simulate wide-area exploration of the Moon, the search for past life on Mars and for the gathering of meteorite samples in the Antarctic," said Dave Lavery, telerobotics program manager at NASA Headquarters, Washington, DC. "Nomad met or exceeded all of our objectives for this project."
"We want to give planetary scientists experience using mobile robots, so that they can develop the skills necessary for performing remotely guided investigations," added Dr. David Wettergreen, Nomad project leader at Ames.
Nomad is about the size of a small car. To maneuver through rough terrain, the robot has four-wheel drive and four-wheel steering with a chassis that expands to improve stability and travel over various terrain conditions. Four aluminum wheels with cleats provide traction in soft sand. For this terrestrial experiment, power was supplied by a gasoline generator that enabled the robot to travel at speeds up to about one mile per hour.
"Nomad drove itself through about 12 miles (20 kilometers) of the 133 miles it traveled," said Dr. Mark Maimone, Nomad software and navigation lead at Carnegie Mellon. "Autonomous driving is critical for planetary exploration because the communications delay between Earth and planets can be many minutes. With autonomous driving, a robot can explore a much greater distance because it doesn't have to wait for a person to decide a safe route. The rover is able to see obstacles and recognize them on its own," he said.
Nomad's unique onboard panospheric camera provided live 360-degree, video-based still images of the robot's surroundings. "Experimentation with the panospheric camera validated the use of immersive imagery for remote driving," Maimone said.
The camera takes a 360-degree picture -- one frame per second -- and did so throughout the mission. The high-resolution video camera focuses up into a hemispheric mirror similar to a store security mirror. The video view includes all of the ground up to the horizon in the circle surrounding Nomad.
"The camera is a new technology, and it gave members of the public as well as scientists a new way to drive with peripheral, or side vision," he explained. "We sent the Nomad pictures to a theater at the Carnegie Science Center in Pittsburgh that has a 200-degree, semi-circular screen. Fifty people at a time pushed a button to vote on whether the robot should look to the left, center or right."
On June 25, NASA scientists were driving the robot remotely from their laboratory at Ames, more than 5,455 miles (8,780 kilometers) away, when the scientists in California found a rock that appeared to contain algae fossils.
Using the rover's cameras, scientists noticed a light-colored, three-inch diameter rock with a darker, intricately shaped marking in a rock outcrop in the Chilean desert. The rock was retrieved by Chilean scientists and was brought to Ames for scientific analysis.
"The rock is sedimentary and was formed in an ancient sea bed. However, the consensus is that this rock does not contain fossilized algae," said Dr. Nathalie Cabrol, the expedition's NASA science team leader. The science team was excited to learn that the outcrop was an undiscovered geologic deposit from the Jurassic Period.
"This experience is one of the most important of the science tests," Cabrol said. "I am not sure that we can get much closer to what may happen with the research of interesting rocks on Mars and the related search for life in the coming Mars exploration program. We are most likely to face this exact situation of selecting a rock because it looks interesting to us. Once in the lab, we were unable to tell conclusively if there had been life in the rock at one time or not."
"The first-level interpretation from the rover camera was close enough, fossil or not," she added. "The team was able to reconstruct the geology of the site, often matching or at least getting very close to the conclusions of the back-up field team."
The total cost of developing Nomad and conducting the desert trek is $1.6 million. The project is funded by NASA with in-kind support from corporate sponsors and educational foundations.
NASA and Carnegie Mellon are formulating plans to use Nomad to look for meteorites in Antarctica in 1998 and 1999.
Further information about the Atacama desert trek, images and data are available from the Ames Intelligent Mechanisms Group at URL:
Carnegie Mellon's Robotic's Institute also has a website at URL:
Materials provided by National Aeronautics And Space Administration. Note: Content may be edited for style and length.
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