A helicopter can be a sneaky beast. Just ask the Iraqis. In the first attack of Operation Desert Storm, U. S. Army Apache helicopters knocked out Iraqi air defenses, opening a hole for U. S. warplanes to stream through. The choppers crept in, eluding radar by flying only a few feet off the desert floor.
To prevent similar tricks from ever being played on U. S. forces, the Pentagon is developing high-tech mines to force enemy helicopters away from the ground and into radar range. The "thwop-thwop" of the rotors on an incoming helicopter would set off a mine's acoustic sensor, triggering a shotgun-like shower of projectiles aimed to take down any chopper within a 100-yard radius. The bucket-shaped mines, designed to stand on spidery legs, can be switched off remotely so friendly craft can fly by.
Texas Instruments, Ferranti International, and Textron Inc. are experimenting with separate versions. A fancy Textron model would include an infrared sensor to help explosives find their targets. The mines could be available by the mid-'90s, costing at least several thousand dollars apiece.