Autonomous Robot Finds Meteorites
Laurel M. Sheppard
PITTSBURGH -- A four-wheeled robot named Nomad recently made history in Antarctica by autonomously searching for and classifying meteorites. The expedition was a collaboration between researchers at Carnegie Mellon University's Robotics Institute and the National Science Foundation's Antarctic Search for Meteorites program. Two previous expeditions tested the robot's navigational capabilities under polar conditions in the Chilean section of Antarctica and Chile's Atacama Desert.
Nomad used two types of cameras. A high-resolution Sony XC-003 CCD camera was mounted on a pan/tilt unit on the sensor mast. This camera offers 640 x 480-pixel resolution, 24-bit color and a horizontal resolution of 570 lines. It identified the size, color and texture of rocks to facilitate classification.
A custom-built panoramic camera comprising a Sony EVI370D imaging device and a convex optical mirror was mounted atop Nomad to image a 360° area. Panoramic images were used during the second expedition to track objects for landmark-based navigation. In the most recent expedition, the equipment allowed middle-school students to follow the mission online.
The Nomad used high-resolution and panoramic cameras in conjunction with a reflection spectrometer to autonomously search for and classify meteorites in Antarctica earlier this year.
An S2000 reflection spectrometer from Ocean Optics Inc. of Dunedin, Fla., determined the chemistry of a rock sample. A manipulator arm with a small camera on its wrist allowed the robot to visually position the spectrometer 1 to 2 cm from the sample. The spectrometer, sensitive from 300 to 1100 nm, projected incandescent light from a small tungsten-halogen bulb through a reflection probe onto the surface of a target. The probe collected the light and transmitted it via optical fibers to the spectrometer for evaluation.
This expedition, Nomad's third trip to a location resembling another planet, concluded the current project. Several hundred images and spectra were taken of rocks, and, of the six meteorite samples removed from the field, five were classified correctly. However, noise from reflected ice can be a problem.
"We are looking for additional funding to develop a truly autonomous 'turnkey' system that, for instance, could survive a whole year of searching without human intervention," said Michael Wagner, a research programmer at the university. The robotic technology could serve as a prototype for scientific missions to Mars and the moon.
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