The stealth technology that hides U.S. warplanes from enemy missiles is one of the nation's most sophisticated secrets — a military edge, experts say, that no other country can beat.

To reveal those secrets to foreign governments, as Maui resident Noshir Gowadia is accused of doing, is a serious crime. Those nations may not be able to build their own B-2 stealth bomber, but the classified knowledge could help them hide other kinds of airplanes or put U.S. warplanes in their cross hairs.

"With respect to anti-aircraft radar and missiles, the rule is if you can see it, you can kill it," said Edwin Smith, a professor of law and international relations at the University of Southern California.

FBI agents arrested Gowadia, 61, on Wednesday at his home in Ha'iku, Maui, on suspicion of selling classified U.S. military technology to seven foreign governments. The FBI said Gowadia, a former design engineer for Northrop who worked on the B-2 stealth bomber, had marketed himself globally as "father" of the technology that hides the bomber's propulsion system, according to court papers.

'TECHNOLOGICAL EDGE'

Stealth aircraft use their technology to hide from radar-guided and heat-seeking missiles.

"If we talk about a technological edge that is a combination of radar suppression and heat-seeking suppression, that gives us a technological edge that no one can beat at this point," Smith said. "Anyone who gives that away is giving away our core technological edge with regard to aircraft."

The reason this is potentially serious for national security is that many U.S. air-to-air missiles rely on infrared homing, locking in on a target's heat source, said physicist Dean Wilkening, director of the science program at Stanford University's Center for International Security and Cooperation.

But the severity of the security breach depends on how close to the research Gowadia actually was and what he gave away, Wilkening said. "He may call himself the father of this but it may be an exaggerated claim," Wilkening said. If his claims are true, the U.S. government "will go after this guy with everything they've got," he said.

The "why" is easier to understand than the stealth technology that keeps missiles off the trail of an airplane's red-hot exhaust.

"The reason foreign governments would like this technology is if they reverse-engineer it, they can apply this to their fighter aircraft," Wilkening said. "If you do that, our air-to-air missiles don't work very well. They can't find the target."

BASICS OF STEALTH

The technology that allegedly was sold, even if it was significant, would still not allow others to observe the B-2, and it would remain a stealthy aircraft, Wilkening said.

John Pike, director of Global-Security.org, a private defense policy group in Virginia, said the B-2 is stealthy for several reasons.

"We normally think of the stealth bomber as being nearly invisible," he said. "But it has four big jet engines and the hot stuff comes out the back end. They have gone to considerable effort to do things to reduce someone's ability to track that heat."

The surface of the plane, with its curves and lack of numerous angles, is shaped in a way that reflects a radar signal away from the plane and from the antenna that sent the signal, Pike said.

A special kind of paint also absorbs radar, although it tends to chip, which reduces its efficiency because it then allows the paint to absorb water and get soggy, he said.

The heat from the plane is limited in part by special chemicals in the exhaust that cool them, and because the engines are mounted on top of the bomber, their heat is not visible from the ground, Pike said.

And any kind of infrared suppression technology would try to keep the heat from the engines from seeping through the hull of the aircraft in much the same way heat from a car engine radiates through the hood, he said.

"What they want to avoid is a situation where someone can fire a heat-seeking missile that would fly up the tailpipe," he said. "We don't want to have the engines generate a contrail."

Reach Mike Gordon at mgordon@honoluluadvertiser.com.