U-2

single-seat, U.S. high-altitude jet reconnaissance and research aircraft. A prototype flew in 1955. On May 1, 1960, a U-2 was shot down over the Soviet Union (see U-2 Affair), and in 1962 a U-2 took photographs that confirmed the presence of Soviet missiles in Cuba. The U-2 had a top speed of 494 miles (795 km) per hour and a service ceiling of approximately 70,000 feet (21,000 m). The U-2 was replaced in U.S. service in the mid-1960s by the SR-71 Blackbird, a two-jet aircraft constructed mainly of titanium, capable of flying at even higher altitudes than the U-2 and at speeds exceeding 2,000 miles per hour (3,200 kilometres per hour). It could survey 100,000 square miles (260,000 square km) of the Earth's surface in one hour. Artificial satellites now accomplish most observations formerly undertaken by the U-2 and SR-71.