Lockheed Have Blue was the code name for Lockheed's proof of concept demonstrator for a stealth bomber. Have Blue was designed by Lockheed's Skunk Works division, and tested at Groom Lake, Nevada. The Have Blue was the first fixed-wing aircraft whose external shape was defined by radar engineering rather than by aerospace engineering. The aircraft's faceted shape was designed to deflect electromagnetic waves in directions other than that of the originating radar emitter, greatly reducing its radar cross-section. To design the aircraft, the Skunk Works' design team leveraged the mathematics published by Soviet physicist and mathematician Petr Ufimtsev regarding the reflection of electromagnetic waves. A stealth engineer at Lockheed, Denys Overholser, had read the publication and realized that Ufimtsev had created the mathematical theory and tools to do finite analysis of radar reflection. The eventual design characteristically featured faceted surfaces to deflect radar waves away from a radar receiver. It had highly-swept wings and inward-canted vertical stabilizers, which led to it being nicknamed "the Hopeless Diamond"—a pun on the Hope Diamond. The first operational aircraft made its maiden flight on 1 December 1977. Two flyable vehicles were constructed. Both were lost due to mechanical problems. Nevertheless, Have Blue was deemed a success, paving the way for the first operational stealth aircraft, Senior Trend, or Lockheed F-117A Nighthawk. Background In the 1970s, it became increasingly apparent to U.S. planners that, in a military confrontation with Warsaw Pact forces, NATO aircraft would quickly suffer heavy losses. This came as a result of sophisticated Soviet defense networks, which used surveillance radars, radar-guided surface-to-air missiles (SAM), and anti-aircraft artillery (AAA) to seek and eliminate enemy aircraft. Consequently, the Defense Advanced Research Projects Agency (DARPA) started a study on low-observability aircraft, seeking to design and produce an operational stealth aircraft. Five companies were initially invited, three of which bowed out early. The remaining two were later joined by Lockheed. Design and development Origins The Lockheed Have Blue was born out of a requirement to evade radar detection. During the Vietnam War, radar-guided SAMs and AAA posed a significant threat to US aircraft. For this reason, strike aircraft during the war often required support aircraft to perform combat air patrols and suppression of enemy air defenses (SEAD). The 1973 Yom Kippur War again highlighted the vulnerability of aircraft to SAMs – the Israeli Air Force lost 109 aircraft in 18 days. During the Cold War, the