SR-71 Blackbird

The Lockheed SR-71 "Blackbird" was a strategic reconnaissance aircraft built for long-range, high-altitude, and supersonic flight at over Mach 3. It was retired from service. The aircraft was nicknamed "Blackbird" and "Habu". Lockheed's Skunk Works division developed it in the 1960s as a secret "black project". Engineer Clarence "Kelly" Johnson led the design, which was based on the earlier Lockheed A-12. The A-12 had pioneered stealth features with a reduced radar cross-section, but the SR-71 was longer and heavier to carry extra fuel and a two-person crew seated one behind the other. The public first saw the SR-71 in July 1964, and it began service with the United States Air Force in January 1966.

During missions, the SR-71 flew at Mach 3.2 and 85,000 feet (26,000 meters). These speeds and altitudes let it evade or outrun threats. If a surface-to-air missile launch was detected, the standard response was to accelerate and outpace the missile. Its reconnaissance equipment included signals-intelligence sensors, side-looking airborne radar, and a camera. Because of lengthy preparations, an SR-71 could only fly about once per week on average. A total of 32 were built; 12 were lost in accidents, and none were shot down by enemy action.

Starting in 1968, reconnaissance missions flew from Kadena Air Base in Okinawa, first over North Vietnam and Laos during the Vietnam War, and later over North Korea. From 1976, missions launched from RAF Mildenhall in the UK, flying along the Soviet Union's Baltic and Barents Sea coastlines. Other missions covered Cuba, Nicaragua, Libya, and probed nuclear weapons sites in Israel and South Africa. Unlike earlier CIA-operated aircraft, SR-71 missions were flown openly with USAF markings, and they never overflew the Warsaw Pact or China.

In 1974, the SR-71 set a record for the fastest flight between London and New York: 1 hour, 54 minutes, and 56 seconds. In 1976, it became the fastest airbreathing manned aircraft, beating the record held by its predecessor, the Lockheed YF-12. As of 2026, the Blackbird still holds both world records.

The USAF retired the SR-71 in 1989, largely for political reasons, though a few were briefly reactivated before a second retirement in 1998. NASA was the final operator, using the aircraft as a research platform until 1999. After retirement, its role was taken over by reconnaissance satellites and unmanned aerial vehicles (UAVs). As of 2018, Lockheed Martin was developing a proposed UAV successor called the SR-72, but as of 2026, it remains a concept.

Development of the SR-71 began with Lockheed's earlier reconnaissance aircraft, the slower U-2, built for the CIA. In late 1957, the CIA asked Lockheed to build an undetectable spy plane. The project, named Archangel, was led by Kelly Johnson at Lockheed's Skunk Works in Burbank, California. Work started in the second quarter of 1958, aiming to fly higher and faster than the U-2. Over ten months, 11 designs were drafted; the "A-10" was the front-runner, but its shape made it vulnerable to radar. After a March 1959 meeting with the CIA, the design was altered to cut radar cross-section by 90%. On 11 February 1960, the CIA approved a $96 million contract for Skunk Works to build a dozen A-12 spy planes. Three months later, the downing of Francis Gary Powers's U-2 in May 1960 highlighted the need for less vulnerable aircraft.

The A-12 first flew at Groom Lake (Area 51), Nevada, on 25 April 1962. Thirteen were built, plus five more in two variants: three YF-12 interceptor prototypes and two M-21 drone carriers. The aircraft was meant to use the Pratt & Whitney J58 engine, but development delays meant it initially flew with the lower-thrust Pratt & Whitney J75. J58s were retrofitted as they became available and became the standard engine for all subsequent aircraft in the series (A-12, YF-12, M-21), as well as the SR-71. The A-12 flew missions over Vietnam and North Korea before retiring in 1968. The program was canceled on 28 December 1966, due to budget concerns and the upcoming SR-71, a derivative of the A-12.

The SR-71 designation continued the pre-1962 bomber series; the last aircraft in that series was the XB-70 Valkyrie. A bomber variant of the Blackbird was briefly given the B-71 designator, which was kept when the type changed to SR-71. During later testing, the B-70 was proposed for a reconnaissance/strike role with an "RS-70" designation. When the A-12's performance proved much greater, the USAF ordered a variant in December 1962, originally named R-12 by Lockheed. This USAF version was longer and heavier than the A-12, with a longer fuselage for more fuel, a two-person crew in tandem cockpits, and reshaped fuselage chines. Its reconnaissance equipment included signals intelligence sensors, side-looking airborne radar, and a photo camera. The CIA's A-12 was a better photo-reconnaissance platform than the USAF's R-12: it flew higher and faster, and with only a pilot, it had room for a better camera and more instruments. The A-12 flew covert missions, while the SR-71 flew overt missions with USAF markings and pilots carrying Geneva Conventions Identification Cards. During the 1964 campaign, Republican presidential nominee Barry Goldwater repeatedly criticized...