<p>Outside the cockpit, another revolution was going on, not with aircraft but with ordnance. The Paveway series of precision-guided bombs and munitions, named for the acronym PAVE (precision avionics vectoring equipment) was being improved, while newer weapons were being developed. The USAF pushed ahead with the cruise missile and eventually fielded the AGM-109 Tomahawk that enabled a B-52 or smaller warplane to stand off at increased distance and strike accurately. Intelligence confirmed that the Soviets, too, were fielding a new generation of jet fighters and of precision weapons, but there was one area where the Soviets were unwilling to invest. It was to become known as stealth.
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<p>The Air Force took over a 1974 DARPA (Defense Advanced Research Projects Agency) study into making fighters less detectable by radar. The effort was so secret, it became SAR (Special Access Required), what would later be called a 'black' programme.
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<p>In 1975, the USAF invited Lockheed and Northrop to develop and test an aircraft known as the Experimental Survivable Testbed (XST). Research at Lockheed's 'Skunk Works' led to an aircraft in which individual surfaces and edges were orientated to reflect incoming radar energy into narrow beams aimed away from the radar detector. In addition to this 'faceting' shape, the external surface of the aircraft then being designed was to be covered with radar-absorbent material (RAM). Lockheed built two Have Blue sub-scale demonstrators to prove the concept of a fighter with, as they were now called, VLO (very low observable) characteristics. In total secrecy, the first Have Blue flew at the USAF's confidential Groom Lake, Nevada facility on 1 December 1977. In the decade to come, the unorthodox test plane evolved into a 'black' stealthy fighter known as Senior Trend and later designated F-117.
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<p>In 1980, presidential candidates Jimmy Carter and Ronald Reagan accused each other of risking security by talking about stealth. Neither man, however, revealed the flight tests taking place in the western American desert.
