The Lockheed F-117 Nighthawk is a single-seat, twin-engine stealth ground-attack aircraft. The F-117 was born after combat experience in the Vietnam War when increasingly sophisticated Soviet surface-to-air missiles (SAMs) downed heavy bombers. It was a black project, an ultra-secret program for much of its life, until the late 1980s. The project began in 1975 with a model called the “Hopeless Diamond”(a wordplay on the Hope Diamond due to its appearance).