In a few years, a robotic airplane may soar through the thin atmosphere of Mars, snapping images as it maneuvers effortlessly over the rusty terrain. Sarita Thakoor of the Jet Propulsion Laboratory and Steven Zornetzer of NASA Ames Research Center, along with colleagues at the Australian National University and the University of California at Berkeley, are refining a prototype of an autonomous micro-flyer (below) with a 34-inch wingspan. The delta-shaped plane on the micro-flyer is guided by an artificial vision system inspired by dragonflies and bees.
Eight photodiodes detect changes in light levels and pick up the horizon line, mimicking the function of a dragonfly's simple eyes. The location and angle of the horizon line contain enough information for the plane to maintain level flight. Meanwhile, three cameras send data to a microprocessor that measures speed and distance the way bees do: Objects that are close appear to move more quickly than those that are far away. "The two sets of inputs are fused to determine the commands that control the flyer," says Thakoor. The robot controlled its own flight last fall, but the camera-image processing was done on the ground. Trials this winter will test a version that performs all the work onboard. In 2004 the flying machine will collect images and sensor readings of a Mars-like environment on Earth, where Zornetzer expects it will prove how valuable it would be on the Red Planet. "A micro-flyer has a view you cannot get on an orbiter or on the surface," he says.
Photograph courtesy of NASA/JPL.