The Death of Stealth

Lockheed F-117A Nighthawks

Being a stealth pilot is one of the most labor-intensive and time-constrained types of flying that I know.
We have very strict timing constraints: to be where you are supposed to be all the time, exactly on time, and that has to be monitored by the pilot.
For example, during a bomb competition in training in the US, I dropped a weapon that landed 0.02 seconds from the desired time, and finished third!

- Lieutenant Colonel Miles Pound USAF

Lockheed F-117A Nighthawks, the world's first operational aircraft fully to exploit stealth technology

Intended primarily to penetrate dense enemy environments at night, and attack high-value targets with great accuracy, the F-117A was designed to overcome seven signatures that could otherwise give away its position to an enemy, namely radar, infra-red, visual, contrails, engine smoke, acoustic and electromagnetic emissions, thereby remaining virtually "invisible" and undetectable. The most obvious feature is its almost "lifting body" facetted airframe, comprising many angled skin plates intended to reflect an incoming radar beam away from its source, assisted by radar-absorbing edges and coatings. The possibility of infra-red detection is reduced by the use of non-afterburning engines and efflux cooling, above-wing air intakes and shielded exhaust nozzles of "platypus" slot type that hasten contrail dispersal. In 1996 some 53 F-117As remained in USAF service.

Source: The World's Strangest Aircraft: A Collection of Weird and Wonderful Flying Machines by Michael Taylor

New "Passive" Radar, under Development by Russia and China, Could Threaten Stealth Aircraft

by John McWethy

China, Russia, and several European and US companies are working on a new type of radar that could be used to make America's premier stealth aircraft far more detectable, intelligence sources.

The cutting-edge work threatens to make today's most advanced stealth planes obsolete - the $40 billion fleet of B-2 bombers that saw its first action just two years ago in the air war over Kosovo and the older $6 billion fleet of F-117s.

"In the end you may have to redesign your stealth aircraft or think about adding jamming or other countermeasures," says Dan Goure, a former Pentagon official who is a senior fellow at the Lexington Institute in Arlington, Virginia. hat could cost billions of dollars. And the new radar also could put US pilots in non-stealth aircraft at risk.

In highly classified intelligence assessments, analysts worry that Iraq - with help from China - could be laying the groundwork for building such a system. That would pose a new and deadly threat to US and British pilots who patrol Iraq's "no-fly zones" and are regularly fired upon.

"Passive" Radar Is Stealthy

1) Mobile phone masts normally are honeycombed across large areas, transmitting and receiving signals to provide a continuous service for users. They, and radio and television transmitters, produce a screen of radiation that can be distorted by moving aircraft.
2) Special receivers, scattered over an area, are used to receive radio frequency waves already in the atmosphere.
3) The receivers are linked to a high-performance computer that can process all the signal data and provide a graphical depiction of the aircraft location.
4) A global positioning satellite might be used to help pinpoint the location of the aircraft for targeting.
5) A US F-117 stealth aircraft is shaped so it is difficult to detect when traditional radar signals strike it head on. With the passive system, signals are transmitted from many fixed points near the ground. It's asserted they might bounce off the aircraft's fairly flat underbelly, making the plane easier to detect.

Of immediate concern is that this so-called passive radar can also track all types of aircraft without the pilots knowing they are being watched or targeted. With conventional radar, pilots know when they are being tracked and can take appropriate action. Conventional radar sends out its own high-frequency signal that a pilot can detect. The new radar simply listens to low-frequency radio waves that are already in the atmosphere in great profusion, from power sources such as transmitters used for television, FM radio and cell phones.

"And because there are quite a large number of transmitters that they can use for that purpose, it's quite effective," says Professor Hugh Griffiths of University College London.

Spread of High-Performance Computers

The breakthrough that is making this possible is the use of new high-speed computers to sort through the clutter of signals, picking out those radio waves that are bouncing off moving objects in the air.

"If you have not only the ability to do this kind of detection passively, but also to communicate the data to your military units, the way we use air power is going to have to change," says Goure. "We are simply not going to own the skies in the same way. "We have the potential in fact for a revolution in air defense and the reason it is such a revolution is because of what's changed in computing power," he says. "Not only computing power, but access to computing power and software by almost any nation in the world."

It hasn't happened yet, but intelligence sources say the race is on. And what is likely to guarantee widespread use of passive radar is cost. It is expected to be much less expensive than today's high-frequency systems. Air Force officials say they are watching these developments closely and insist they are already anticipating ways to deal with them.

Source: ABC News 14 June 2001; small photo credit Staff Sergeant Andy Dunaway/US Air Force

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