A Spy On the Wall

In the old days, the U.S. government got a lot of publicity when it did really cool stuff, like landing on the moon. Thirty years later, it's a little tougher to attract such notice without providing something truly huge, or truly scandalous, to the public.

Or maybe just truly . . . weird. Consider the "Micromechanical Flying Insect" being promoted by the Office of Naval Research and the Defense Advanced Research Project Agency, after an early assist by the National Science Foundation.

Also known affectionately as "Robofly," it is exactly what it sounds like: a 100-milligram flying robot with a two-centimeter wingspan -- about the size of an engorged blowfly. It will cost about $4.3 million through 2004. Look for it on your kitchen ceiling in perhaps five years.

Although the feds are interested in basic research, they also see great possibilities in this thing. As Naval Research program officer Teresa McMullen put it recently, Robo-fly would be great for "clandestine reconnaissance and surveillance" -- thus bringing new meaning to the phrase "fly on the wall." Or perhaps spy on the wall.

"It will be difficult to detect, particularly in urban environments," McMullen said. "It will be highly maneuverable, and able to go around corners and hover."

Just the thing for spying on terrorists, kidnappers or wayward spouses.

The Robofly researchers must do two things first, though: (1) figure out how bugs fly; (2) make one. The discipline is called biomimetics -- "using the physical principles of biological systems to design robots," said McMullen, who oversees the bug-building.

The first breakthrough came in May when how-bugs-fly researcher Michael H. Dickinson, of the University of California at Berkeley, began collecting data from a six-foot-tall drum of high viscosity mineral oil in which he had suspended a pair of 10-inch imitation insect wings fitted with sensors.

Dickinson explained that the forces generated by the movement of insect wings are so varied and complicated that "there is not a computer on the planet" capable of modeling them. So, low-tech was the only way to go -- large wings set in oil to imitate the thick feel that air has on a tiny flying creature. "It's just been a geyser of information," said Dickinson.

Researchers knew that insects benefited from a pheno-menon called "delayed stall," in which air forms a "swirly hurricane" above a fast-flapping wing, sucking the insect upward, Dickinson said. But Dickinson's experiment also showed insects getting additional lift from "rotational circulation," the same sort of spin that makes baseballs curve, and "wake recapture," the ability to gain a surf-like boost from air that's filling the hole behind the flying insect.

All of these effects, Dickinson said, arise because insect wings flap at a fast rate and air is heavy relative to their body weight. This enables bugs to hover, carry twice their weight and flit about simply by tipping their bodies, much the same way a helicopter travels.

This is all new and "a big deal," Dickinson said. Berkeley bug-building researcher Ron Fearing is getting ready to put the new principles to work.

"We have a design, and are fabricating the components," Fearing said. He plans to use "thin films" a "few microns thick" to build most of the tiny beast.

"How we direct [steer] it is several years down the road," Fearing said, but not nearly as difficult to figure out "as getting the thing to hover and fly stably." This, he hopes, will occur in three years.

"Rather than having a head and ugly legs," the final product "will look less alien" than a blowfly, Fearing said. Still, an artist's depiction on Fearing's Web site (robotics.eecs.berkeley.edu/~ronf/mfi.html) looks like a cross between a dragonfly and the original Wright brothers' Flyer. If one landed on your arm, the first impulses would be to gag, cringe -- and swat. Think twice before doing that, though; that would be one expensive dead bug.

Guy Gugliotta is a reporter on The Post's National Staff. Al Kamen is on vacation and will be back In the Loop September 19.