The SR-71 came from a project designed for the CIA by Kelly Johnson at the Lockheed Skunk Works. As the project evolved, Lockheed designated the aircraft A-1 to A-12 as configuration changes occurred.

The first flight, by an A-12 known as “Article 121”, took place at Groom Lake, Nevada, on April 25, 1962 equipped with the less powerful Pratt & Whitney J75 engines due to protracted development of the intended Pratt & Whitney J58. The J58s later became the standard power plant for all subsequent aircraft in the series (A-12, YF-12, M-21) as well as the follow-on SR-71 aircraft.

Although the predecessor A-12 first flew in 1962, the first flight of an SR-71 took place on 22 December 1964, at Air Force Plant 42 in Palmdale, California. The first SR-71 to enter service was delivered to the 4200th (later, 9th) Strategic Reconnaissance Wing at Beale Air Force Base, California, in January 1966. On 21 March 1968, Major (later General) Jerome F. O’Malley and Major Edward D. Payne flew the first operational SR-71 sortie in SR-71 serial number 61-7976 from Kadena AB, Okinawa. The United States Air Force Strategic Air Command had SR-71 Blackbirds in service from 1966 through 1991.

A total of 32 SR-71 aircraft were built: 29 as SR-71As for operational missions and two as SR-71B trainers. The 32nd airframe was fabricated in 1969 as a hybrid trainer designated the SR-71C by mating the back half of an YF-12 wrecked in a 1966 landing accident with a fully-functional SR-71 forward section of a static test specimen. Only one crew member, Jim Zwayer, a Lockheed flight-test reconnaissance and navigation systems specialist, was killed in a flight accident. The rest of the crew members ejected safely or evacuated their aircraft on the ground.

Dimensions

Wingspan

55 ft 7 in (16.94 m)

Length

107 ft 5 in (32.74 m)

Height

18 ft 6 in (5.64 m)

Wing area

1,800 ft2 (170 m2)

Empty weight

67,500 lb (30 600 kg)

Loaded weight

170,000 lb (77 000 kg)

Max takeoff weight

172,000 lb (78 000 kg)

Performance

Speed

Mach 3.2+ (2,200+ mph, 3530+ km/h) at 80,000 ft (24,000 m);

Combat Range:

2,900 nmi (5400 km);

Ferry Range:

3,200 nmi (5,925 km);

Service ceiling:

85,000 ft (25,900m, 16 mi);

Rate of climb:

11,810 ft/min (60 m/s);

Payload:

3,500 lb (1,600 kg) of sensors

Powerplant

Two Pratt & Whitney J58-1 continuous-bleed afterburning turbojets, 32,500 lbf (145 kN) each

Armament

None. The SR-71 was an unarmed reconnaissance aircraft. Its speed of Mach 3.2+ and operational altitude of 80,000 ft+ were its primary defense.