On May 1, 1960, an American Lockheed U-2 unarmed reconnaissance plane piloted by Gary Powers, was shot down by a Soviet surface-to-air missile (SAM). It happened at the height of the Cold War and although Gary Powers parachuted down safely, he was immediately arrested, tried for spying and sentenced to ten years in prison. Missions over the Soviet Union had to be abruptly terminated. Consequently, the United States (US) was left with no credible means to gather intelligence about the Soviet Union’s nuclear capability, ICBM programme and military installations. President Eisenhower therefore, sent a terse message to Lockheed: Make an aircraft that can’t be shot down and make it fast. Only one man in the US and perhaps the whole world, could have even considered such an impossible demand and that was Kelly Johnson, head of Lockheed’s “Skunk Works” team. The outcome was the SR-71 Blackbird, a long-range, highlevel, Mach 3.3 strategic reconnaissance aircraft.

There has never been an aircraft quite like the SR-71. Its first flight was on December 22, 1964 and it entered operational service in January 1966 with the United States Air Force (USAF). During its 30-year reign, it flew over regions bristling with some of the deadliest air defence systems in the world, including the USSR and North Vietnam. In fact, probably no other reconnaissance aircraft in history has had over 1,000 missiles launched against it. Yet, true to President Eisenhower’s mandate, not one SR-71 was shot down. The secret of this plane’s remarkable survivability was its extremely high speed and operating altitude. When a Blackbird pilot received a missile launch warning in the cockpit, all he had to do was accelerate and the missile would invariably be left far behind.

The SR-71 soon set records as the world’s fastest and highest-flying operational manned aircraft – a distinction it held throughout its memorable career. On July 28, 1976, an SR-71 pilot set an absolute altitude record for a manned jet of 25,929m. The same day another pilot set an absolute speed record of 3,529.6 kmph, approximately Mach 3.3. Although other SR-71 pilots claim to have exceeded the figures, these two stand as official records to this day. The Soviet Union had a formidable supersonic interceptor in the Mikoyan-Gurevich MiG-25, but its maximum speed of Mach 2.83 and service ceiling of 20,700m was no match for the SR-71.

A conventional design could not have provided the aircraft’s performance or withstood the scorching temperatures due to surface friction. The SR-71 was made with a unique material – a titanium alloy covered with a corrugated skin. It was painted dark blue, almost black, to radiate the intense heat to the atmosphere and serve as camouflage against the night sky, giving rise to its name Blackbird. It was also one of the first aircraft to have a stealthy shape that reduced its 33-metre long radar cross section (RCS) by 90 per cent and made it appear smaller than a human on enemy radar. Its high speed was thanks to its powerful engines – two Pratt & Whitney J58-1 continuous-bleed afterburning turbojets, each producing 15,400 kgf (151 kN) of thrust. The engines were operated continuously in afterburner mode for cruise at supersonic speeds. Even the JP-7 fuel they burned was unique. It had a high flash point and high thermal stability to prevent it from vaporising or exploding under the extreme heat and pressure the Blackbird was subject to. The rear seat was occupied by a Reconnaissance Systems Officer (RSO) in charge of navigation and imaging systems. The RSO had a range of high-resolution cameras and electronic intelligence-gathering devices plus electronic countermeasures to jam hostile radars.

Out of the 32 SR-71 aircraft built, as many as 12 were lost in accidents. This may seem high, but eleven of these crashes happened between 1966 and 1972 when the plane was still new and the peculiarities of such extreme flight were imperfectly understood. The delicate controls needed immense concentration and care because even a slight deviation from the recommended angle of attack, especially at high speeds, could render the aircraft unstable. During the rest of its service life, just one Blackbird was lost in April 1989. Only one crew member was killed, the rest managing to abandon their stricken aircraft safely.

Ultimately it was the high operating cost of the SR-71 that led to its premature retirement in 1999. Other factors were the improved performance of US reconnaissance satellites and the Blackbird’s increasing vulnerability to the upgraded SAMs. According to USAF test pilot Terry Pappas, of all the planes he flew, the SR-71 was “at the pinnacle. When you walk up and look at it for the first time, it’s kind of hard to believe they built something like that.”