Chopper Probes Helicopters offer a novel idea for exploring Mars ^%ombine world-class \ J programs in rotarywing aircraft research, aerial robotics and spacecraft controls with Tech's fabled capacity for practical application, and you'll get a novel idea for exploring the Martian landscape. Dr. Robert G. Loewy, chair of the School of Aerospace Engineering at Georgia Tech, proposes that a helicopter be used for the exploration of Mars. This past August, he presented his idea at a workshop on Mars exploration at the Jet Propulsion Laboratory in California. His plan, he hastens to say, is only sketchy at this point, "really based on preliminary calculations that graduate student Andrew Baker and I did. Although we've probably carried these analyses further than most people, considerably more work must be done before we'll know whether our concept is practical." The preliminary work describes a machine that is deployed from a spacecraft entering the Martian atmosphere and auto-rotates to the planet's surface. After a period in which solar panels charge its batteries, the Mars helicopter switches into its powered-flight mode and begins to explore the area in hop-scotch fashion. "A helicopter offers a major advantage over other so-called aerial-exploration alternatives, since its rotors
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GEORGIA TECH • Fall 1998
allow it to lower gently and have its instruments examine the surface and go somewhere else if it's unsuitable," explains Loewy, who has also made sketches of the machine. "A drone airplane would be restricted to one flight since it's not likely to survive a landing or takeoff from unprepared surfaces," Loewy says. "Empowered balloons are attractive alternatives, but have to go where the winds on Mars take them." Even the most sophisticated robotic vehicle deployed to date, the Mars rover, is limited to surface exploration of only very small areas. With all its conceptual benefits, building a Mars helicopter entails daunting technological challenges. The Martian atmosphere has only 1 percent of the density of Earth's atmosphere. Although Mars' gravity is slightly less than 40 percent of Earth's, the device would have to be stingy in its consumption of power, since the only reasonable source of electricity would be solar, and sunshine may not always be bright on Mars. "One requirement for all of these vehicles is they must fold up and fit inside the rocket which carries them from Earth to Mars, then deploy and get into flight configuration," Loewy says. "That means the vehicles—whatever it is—is somewhat complicated, and when a vehicle gets complicated, making it light in weight and reliable in operation becomes more difficult." GT
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