The flaw can be so subtle you can’t see it with the naked eye. But that’s all it might take. A layer just too-thin enough that an enemy radar will reflect off it and reveal the aircraft hidden beneath.

Unless our radar sees it first.

Contrary to many a layman’s belief, the F-117 stealth fighter is not comletely invisible to radar. It’s what experts call “low-observable.” Due to its shape and a special radar-absorbent coating, the aircraft is all-but-undetectable by radar. Maintainers at Holloman Air Force Base, N.M., home of the stealths, keep the Nighthawk stealthy with constant upkeep on that coating. And a new radar system there tells them exactly where to add an extra touch of “invisible ink.”

With the Diagnostic Imaging Radar, Holloman maintainers take photos of stealth birds that reveal not only if the aircraft will show up on radar scopes, but also what — a certain seam or particular panel — the radar sees.

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