Over Hill, over Dale...

By John Greenwald

The scene is a future battlefield. On the ground, driverless tanks advance and fire with deadly accuracy, while insect-like vehicles scurry across all but impassable terrain. Overhead, pilots guide their aircraft by talking aloud in the cockpit and aim missiles with the movement of their eyes. Higher still, orbiting jets blast satellites back to earth. All this is surveyed from computer consoles by commanders who refine their strategies and issue new orders as the fighting rages.

While the ability to wage such high-tech combat will remain a dream, or nightmare, for years to come, it is very much a gleam in the Pentagon's eye. Working largely through the Defense Advanced Research Projects Agency, a special unit devoted to exotic weaponry, military planners are developing a generation of computerized land and air systems that Buck Rogers would envy. Prototypes are being built by defense contractors around the U.S., and will be tested in coming months at sites ranging from private proving grounds to engineering laboratories.

Many of these experimental weapons, of course, may never find their way into the American arsenal. Some may prove impractical, while others may fail to win congressional funding. Only a fraction of past DARPA projects have been deployed. But the 27-year-old agency, which helped develop the cruise missile and the Stealth bomber, has had a powerful impact on strategic thinking. Among the sophisticated systems now under way:

THE HEXAPOD. A six-legged manned vehicle that resembles a cross between a giant grasshopper and an Erector Set horse. Planned for use over hilly, rocky or swampy areas that would bog down jeeps and tanks, the l0-ft.-tall Hexapod is designed to lurch along at up to 8 m.p.h. by taking 9-ft. steps. Clint Kelly III, director of DARPA's Office of Engineering Application, calls the gawky-looking device the most technologically advanced off-road vehicle ever constructed.

Powered by a modified 900-cc Kawasaki motorcyle engine, the Hexapod walks with the aid of 16 on-board computers. The data processors get their information from sensors and use it to guide the vehicle forward, backward or to the side. Scientists at Ohio State, who have spent $5 million so far developing the Hexapod, will put the machine through its first walking test this fall.

AUTONOMOUS LAND VEHICLE. A robot-like, driverless device on which work is well in progress. The 15,000-lb. behemoth "sees" through a television camera linked to a built-in computer that matches images to data in its memory and decides which way the vehicle should go. The blue-and-white ALV successfully lumbered down a Denver test track earlier this summer. Though it negotiated the narrow, half-mile course at just 3 m.p.h., that was far faster than in any previous trial.

What might a riderless conveyance do? DARPA and Martin Marietta, which built the $900,000 prototype, say it could develop into a tank, a reconnaissance vehicle or a carrier of supplies. But while the Pentagon hopes to have an ALV model that can execute complex maneuvers and travel 25 m.p.h. by the 1990s, the technical obstacles remain enormous. The machine's vision system alone will require a data processor that can handle nearly 10 billion instructions a second, or about ten times more than current supercomputers. Today's less nimble ALV confuses shadows and logs, wobbles as it approaches gates and gets mixed up at intersections. Says Martin Marietta's Lloyd Thane, a deputy project manager: "Sometimes it has a mind of its own, like any infant learning new things."

THE PILOT'S ASSOCIATE. For all the sophistication of modern aircraft, their cockpits can be a bewildering array of hundreds of gauges, switches and knobs. "The demands have far outpaced the capacity of pilots to deal with them," says Robert Kahn, chief of the DARPA information processing division. To ease the burden, the agency has launched a multimillion-dollar project to produce a jet that responds to voice and eye control.

Now under development at Ohio's Wright-Patterson Air Force Base, the experimental fighter recognizes 200 verbal commands ranging from orders to drop bombs to instructions to change radio frequencies. The jet, which will take off for the first time this summer, even talks back to the pilot to show that it understands. When fully equipped, the cockpit of the future will allow a flier to aim weapons simply by looking at a target. Laser beams will then trace his eye movements and instruct a computer where to point the craft's guns.

TRANSATMOSPHERIC VEHICLE. A more advanced aircraft, the TAV would take off horizontally like a conventional plane and then zoom through the atmosphere into space. It could climb to roughly 100 miles, about half the altitude of the most recent space shuttle flight but at least five times the height attainable by standard jets, and orbit at a speed of 17,500 m.p.h. From its lofty perch, the aircraft would serve as a surveillance platform, or an antisatellite weapon, before returning to earth and landing like a plane.

DARPA has its sights on numerous other projects. Among them: night-vision goggles that will enable helicopter pilots to fly in near total darkness; a computerized system that will provide a commander with an instantaneous picture of the battlefield and suggest possible moves he might take. But those devices, like all DARPA'S weaponry, are still little more than sophisticated tools. Once in combat, even Buck Rogers had to think for himself. --By John Greenwald. Reported by Bruce van Voorst/Washington

With reporting by Reported by Bruce van Voorst/Washington