As research platforms, the aircraft could cruise at Mach 3 for more than one hour. The SR-71 was developed as a black project from the Lockheed A-12 reconnaissance aircraft during the 1960s by Lockheed's Skunk Works division. The aircraft flew at an altitude of over 80,000 feet (24,000 m) and at speeds over 2,190 miles per hour (3,520 km/h). [85] The rest of the crew members ejected safely or evacuated their aircraft on the ground. The system's digital computer ephemeris contained data on a list of stars used for celestial navigation: the list first included 56 stars and was later expanded to 61. [N 5][47][48], The air inlets allowed the SR-71 to cruise at over Mach3.2, with the air slowing down to subsonic speed as it entered the engine. It was a slow craft and visible on radar, but it compensated for these deficiencies with its high-altitude capability. The SR-71 Blackbird is a supersonic reconnaissance aircraft. Soviet overflights ceased and the U-2 continued flying missions over places with less sophisticated air defense systems. Two SR-71s were lost during these missions, one in 1970 and the second aircraft in 1972, both due to mechanical malfunctions. No. The SR-71 was designed for flight at over Mach3 with a flight crew of two in tandem cockpits, with the pilot in the forward cockpit and the reconnaissance systems officer operating the surveillance systems and equipment from the rear cockpit, and directing navigation on the mission flight path. Book Synopsis. As the fastest jet aircraft in the world, the SR-71 has an impressive collection of records and history of service. [26], In 1988, Congress was convinced to allocate $160,000 to keep six SR-71s and a trainer model in flyable storage that could become flightworthy within 60 days. More than a decade after their retirement the Blackbirds remain the world's fastest and highest-flying production aircraft ever built. President Eisenhower had approved the use of bombers and balloons in the early 1950s for intelligence gathering, but these craft were vulnerable to antiaircraft artillery and fighter-interceptors. Flights often lasted more than six hours and covered more than 11,265 kilometers (7,000 square miles). US Air Force supersonic aircraft, 19641998, "SR-71" redirects here. The shape of the SR-71 was based on that of the A-12, which was one of the first aircraft to be designed with a reduced radar cross-section. Water bottles had long straws which crewmembers guided into an opening in the helmet by looking in a mirror. Locals nicknamed the SR-71 Habu, after a poisonous pit viper found on the neighboring Ryukyu Islands. Thankfully, this possibility seemed less and less likely, and the SR-71 was also capable of conventional intelligence gathering. Unofficially, SR-71 pilot Brian Shul states in his book The Untouchables that he flew in excess of Mach 3.5 on 15 April 1986 over Libya to evade a missile. [11][127][128][129] Several aircraft have exceeded this altitude in zoom climbs, but not in sustained flight. At take-off, the afterburner provided 26% of the thrust. With your help, we can continue to preserve and safeguard the worlds most comprehensive collection of artifacts representing the great achievements of flight and space exploration. These SR-71 photos were photographed by civilians or members/veterans of the US. [11] That same day SR-71 serial number 61-7958 set an absolute speed record of 1,905.81 knots (2,193.2mph; 3,529.6km/h), approximately Mach3.3. [8] As of 2023[update] the SR-71 holds the world record it set in 1976 as the fastest air-breathing manned aircraft, previously held by the related Lockheed YF-12. The aircraft flew at more than 2200 mph (Mach 3+ or more than three times the speed of sound) and at altitudes over 85,000 feet. Landis and Jenkins 2005, pp. Also, with the allocation requiring yearly reaffirmation by Congress, long-term planning for the SR-71 was difficult. They had a second cockpit for an instructor pilot. [22], In 1968, Secretary of Defense Robert McNamara canceled the F-12 interceptor program. SR-71 Blackbird. Maximum speed limit was Mach 3.2, but could be raised to Mach 3.3 if the engine compressor inlet temperature did not exceed 801F (427C). [26] At sustained speeds of more than Mach 3.2, the plane was faster than the Soviet Union's fastest interceptor, the Mikoyan-Gurevich MiG-25, which also could not reach the SR-71's altitude. Kansas City, Missouri, to Washington, D.C., distance 942 miles (1,516km), average speed 2,176 miles per hour (3,502km/h), and an elapsed time of 25 minutes 59 seconds. [33] Research was conducted on a liquid hydrogen powerplant, but the tanks for storing cryogenic hydrogen were not of a suitable size or shape. The squadron finally closed in mid-1990, and the aircraft were distributed to static display locations, with a number kept in reserve storage.[26]. [28] During its service life, no SR-71 was ever shot down. The U-2 was able to cruise at heights of more than 21,336 meters (70,000 feet), out of the reach of contemporary Soviet surface-to-air missiles and interceptors. The modified A-12s were re-designated M-21s, and were designed to take off with the D-21 and then launch the drone at speeds high enough to ignite the drones ramjet motor. The reactivation met much resistance: the USAF had not budgeted for the aircraft, and UAV developers worried that their programs would suffer if money was shifted to support the SR-71s. On 28 July 1976, SR-71 serial number 61-7962, piloted by then Captain Robert Helt, broke the world record: an "absolute altitude record" of 85,069 feet (25,929 m). Furthermore, an emergency ejection at Mach3.2 would subject crews to temperatures of about 450F (230C); thus, during a high-altitude ejection scenario, an onboard oxygen supply would keep the suit pressurized during the descent. During aerial reconnaissance missions, the SR-71 operated at high speeds and altitudes (Mach 3.2 and 85,000 feet, 25,900 meters), allowing it to outrace or entirely avoid threats. 61-7956, flies its 1,000th sortie, 21 April 1989: SR-71, AF Ser. Proper alignment was achieved as the airframe heated up, with thermal expansion of several inches. [56], The SR-71 was powered by two Pratt & Whitney J58 (company designation JT11D-20) axial-flow turbojet engines. Marshall, Elliot, The Blackbird's Wake, Air and Space, October/November 1990, p. 35. Imagery gathered included supply depots, harbor installations, industrial complexes, and prisoner-of-war camps. Graham noted that in the 1970s and early 1980s, SR-71 squadron and wing commanders were often promoted into higher positions as general officers within the USAF structure and the Pentagon. SR-71 Blackbird - Absolute Speed Record - Manned Aircraft It was located above and behind the student cockpit. The highest altitude recorded on an SR-71 Blackbird is 25,929 meters. [42] Drawing on early studies in radar stealth technology, which indicated that a shape with flattened, tapering sides would reflect most energy away from a radar beam's place of origin, engineers added chines and canted the vertical control surfaces inward. Major sections of the skin of the inboard wings were corrugated, not smooth. Merlin, Peter W. "The Truth is Out There SR-71 Serials and Designations". [26], The SR-71, while much more capable than the Lockheed U-2 in terms of range, speed, and survivability, suffered the lack of a data link, which the U-2 had been upgraded to carry. [11][129][130] SR-71 pilot Brian Shul states in his book The Untouchables that he flew in excess of Mach3.5 on 15 April 1986 over Libya to evade a missile.[95]. [27] Finished aircraft were painted a dark blue, almost black, to increase the emission of internal heat and to act as camouflage against the night sky. Pic of the Day: SR-71 Blackbird, A Profile in Speed | SOFREP Filmed with Digital Combat Simulator New Videos Every Day Subscribe Turn On Noti. How the MiG-31 repelled the SR-71 Blackbird from Soviet skies Congressional conferees stated the "experience with the SR-71 serves as a reminder of the pitfalls of failing to keep existing systems up-to-date and capable in the hope of acquiring other capabilities. The SR-71 also holds the "speed over a recognized course" record for flying from New York to Londondistance 3,461.53 miles (5,570.79km), 1,806.964 miles per hour (2,908.027km/h), and an elapsed time of 1 hour 54 minutes and 56.4 secondsset on 1 September 1974, while flown by USAF pilot James V. Sullivan and Noel F. Widdifield, reconnaissance systems officer (RSO). [15], The SR-71 designation is a continuation of the pre-1962 bomber series; the last aircraft built using the series was the XB-70 Valkyrie. Beginning in 1980, the analog inlet control system was replaced by a digital system, which reduced unstart instances. Tweet in Share Print Number of views (3286) Tweet Print Number of views (3119) Tags: Aircraft Records SR-71 Record List PDF Blackbird Facts - NASA [49] Its "blue light" source star tracker, which could see stars during both day and night, would continuously track a variety of stars as the aircraft's changing position brought them into view. Lockheed found that washing welded titanium requires distilled water, as the chlorine present in tap water is corrosive; cadmium-plated tools could not be used, as they also caused corrosion. Lockheed SR-71 Blackbird | National Air and Space Museum On 6 March 1990, Lt. Col. Raymond E. Yeilding and Lt. Col. Joseph T. Vida piloted SR-71 S/N 61-7972 on its final Senior Crown flight and set four new speed records in the process: These four speed records were accepted by the National Aeronautic Association (NAA), the recognized body for aviation records in the United States. How Swedish Viggen Fighter Jet Caught SR-71 Blackbird Spy Plane [4][5] Eleven of these accidents happened between 1966 and 1972. The SR-71's record setting speed and high-altitude flights helped it keep enemies at bay. The Legendary YF-12: The Fighter That Should Have Changed Everything [81] Initially, the TEOCs could not match the resolution of the A-12's larger camera, but rapid improvements in both the camera and film improved this performance. [137] Unmanned aerial vehicles (UAVs) are also used for aerial reconnaissance in the 21st century, being able to overfly hostile territory without putting human pilots at risk, as well as being smaller and harder to detect than manned aircraft. 61-7980/NASA 844). Itek KA-102A 3648in (9101,220mm) camera. The 1st Strategic Reconnaissance Squadron (1 SRS) kept its pilots and aircraft operational and active, and flew some operational reconnaissance missions through the end of 1989 and into 1990, due to uncertainty over the timing of the final termination of funding for the program. [111] The most common site for the lock-on was the thin stretch of international airspace between land and Gotland that the SR-71s used on their return flights. In 1976, the Lockheed SR-71 Blackbird broke the worlds record for sustained altitude in horizontal flight at 25,929 meters (85,069 feet). Aerodynamicists initially opposed the concept, disparagingly referring to the aircraft as a Mach 3 variant of the 1920s-era Ford Trimotor, which was known for its corrugated aluminum skin. SR-71 Online - SR-71 Blackbird - SR-71 Online - An Online Aircraft Museum Its initial purpose would have been to conduct post-nuclear strike reconnaissance; that is, looking over the enemys situation after a nuclear exchange. On that same day, the aircraft set the Speed Over a Closed Course record of 2,193.167 mph. The Lockheed SR-71 Blackbird was a two-seat twin-engine long-range supersonic strategic reconnaissance aircraft produced by Lockheed Corporation. The addition of chines also allowed the removal of the planned canard foreplanes. Aircraft VOL.11, NO. From 80,000 feet, an SR-71 could survey 100,000 square miles of Earth's . Mach3.2 was the design point for the aircraft, its most efficient speed. Some of this compressor flow (20% at cruise) was removed after the fourth compressor stage and went straight to the afterburner through six bypass tubes. 3,500lb (1,588kg) of mission equipment, Aircraft of comparable role, configuration, and era. [63], Originally, the Blackbird's J58 engines were started with the assistance of two Buick Wildcat V8 internal combustion engines, externally mounted on a vehicle referred to as an AG330 "start cart". SR-71 Blackbird spotted breaking the sound barrier at high altitude. The specialized tooling used to manufacture both the YF-12 and the SR-71 was also ordered destroyed. From the operator's perspective, what I need is something that will not give me just a spot in time but will give me a track of what is happening. It was built by Lockheed's "Skunk Works" in the 1960s for the United States Air Force (USAF). [19], During the 1964 campaign, Republican presidential nominee Barry Goldwater repeatedly criticized President Lyndon B. Johnson and his administration for falling behind the Soviet Union in developing new weapons. Mission equipment for the reconnaissance role included signals intelligence sensors, side looking airborne radar, and a camera;[2] the SR-71 was both longer and heavier than the A-12, allowing it to hold more fuel as well as a two-seat cockpit. The TEB produced a characteristic green flame, which could often be seen during engine ignition. A second round of armed JA-37s from ngelholm replaced the first pair and completed the escort to Danish airspace. They cost $2,300 and would generally require replacing within 20 missions. Blackbird aircraft have been setting records since day one. [100][101] Over the course of its reconnaissance missions during the Vietnam War, the North Vietnamese fired approximately 800 SAMs at SR-71s, none of which managed to score a hit. Crickmore, Paul F. "Blackbirds in the Cold War". In 1976, the SR-71 Blackbird flew at a sustained altitude of 85,069 feet with top speeds of 2,193 MPH, setting records of top speed and altitude that haven't been beaten to this day. Merely accelerating would typically be enough for an SR-71 to evade a SAM;[3] changes by the pilots in the SR-71's speed, altitude, and heading were also often enough to spoil any radar lock on the plane by SAM sites or enemy fighters. When the A-12's performance potential was clearly found to be much greater, the USAF ordered a variant of the A-12 in December 1962,[17] which was originally named R-12 by Lockheed. [33] The heat would have caused a smooth skin to split or curl, whereas the corrugated skin could expand vertically and horizontally and had increased longitudinal strength. This lack of immediate real-time capability was used as one of the justifications to close down the program. 98, 100101. In the following years, Blackbird crews provided important intelligence about the 1973 Yom Kippur War, the Israeli invasion of Lebanon and its aftermath, and pre- and post-strike imagery of the 1986 raid conducted by American air forces on Libya. On 26 April 1971, 61-7968, flown by majors Thomas B. Estes and Dewain C. Vick, flew over 15,000 miles (24,000km) in 10 hours and 30 minutes. In flight, the ANS, which sat behind the reconnaissance systems officer's (RSO's), position, tracked stars through a circular quartz glass window on the upper fuselage. View 20 Images 1 / 20. [103], While deployed at Okinawa, the SR-71s and their aircrew members gained the nickname Habu (as did the A-12s preceding them) after a pit viper indigenous to Japan, which the Okinawans thought the plane resembled. Crickmore, Paul F. "Lockheed's Blackbirds A-12, YF-12 and SR-71A". [131] This equates to an average speed of about Mach2.72, including deceleration for in-flight refueling. The CIA requested designs from aerospace manufacturers for a new aircraft that would not be as susceptible to attack. For comparison, the best commercial Concorde flight time was 2 hours 52 minutes and the Boeing 747 averages 6 hours 15 minutes. Meanwhile, the Air Force wanted a long-range interceptor aircraft that could fly long distances at triplesonic cruise speed above 21,336 (70,000 feet) to intercept enemy bombers with Hughes Falcon air-to-air missiles. By 1970, the SR-71s were averaging two sorties per week, and by 1972, they were flying nearly one sortie every day. . Originally planned as a high . As velocity decreased, so did frictional heat. Much of the needed material came from the Soviet Union. [121] Rear Admiral Thomas F. Hall addressed the question of why the SR-71 was retired, saying it was under "the belief that, given the time delay associated with mounting a mission, conducting a reconnaissance, retrieving the data, processing it, and getting it out to a field commander, that you had a problem in timelines that was not going to meet the tactical requirements on the modern battlefield. [36] The temperature of the exterior of the windscreen reached 600F (316C) during a mission. On 28 July 1976, SR-71 serial number 61-7962, piloted by then Captain Robert Helt, broke the world record: an "absolute altitude record" of 85,069 feet (25,929 m). On 29 November 2018, the four Swedish pilots involved were awarded medals from the USAF.[116][117]. The air then entered the engine compressor. During the Cold War, pilots of the Concorde were asking air traffic control to move the SR-71 out of its way so it could proceed to New York's JF as well as other destinations. [64][65], Several exotic fuels were investigated for the Blackbird. Due to the excessive cost of operating both A-12 and SR-71 programs, the SR-71 was chosen to take over Operation Black Shield at Kadena in 1968. Later start carts used Chevrolet big-block V8 engines. The mission was to do an incident preparedness check and identify an aircraft of high interest. "Department of Defense Authorization for Appropriations for Fiscal Year 1994 and The Future Years.". The remaining engine's asymmetrical thrust would cause the aircraft to yaw violently to one side. 3. The 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. One of the most impressive vehicles to come out of the Lockheed Skunk Works experimental and clandestine development team is the SR-71 Blackbird. (In order to be selected into the SR-71 program in the first place, a pilot or navigator (RSO) had to be a top-quality USAF officer, so continuing career progression for members of this elite group was not surprising.) These were called the TA-12, SR-71B, and SR-71C. Rescue parties were sent in to repair the planes before leaving. [citation needed], Flying at 80,000ft (24,000m) meant that crews could not use standard masks, which could not provide enough oxygen above 43,000ft (13,000m). Paul Crickmore, Lockheed Blackbird: Beyond The Secret Missions, 1993, p. 233. They refueled from a KC-135, accelerated. However, by the mid-1980s, these SR-71 generals all had retired, and a new generation of USAF generals mostly wanted to cut the program's budget and spend its funding on different priorities, such as the very expensive new B-2 Spirit strategic bomber program. ", "SR-71 Pilot Interview Richard Graham Veteran Tales", "SR-71 Online - SR-71 Flight Manual: Section 4, Page 4-86", "SR-71 Online - SR-71 Flight Manual: Section 4, Page 4-99", "SR-71 Online - SR-71 Flight Manual: Section 4, Page 4-123", "SR-71 Online - SR-71 Flight Manual: Section 4, Page 4-129", "SR-71 Online - SR-71 Flight Manual: Section 4, Page 4-132", "SR-71 Online - SR-71 Flight Manual: Section 4, Page 4-146", "First man to fly the world's fastest aircraft dies in Rancho Mirage", "SR-71 Pilot Interview Richard Graham, Veteran Tales interview at Frontiers of Flight Museum (at 1:02:55)", "Memorandum for the Chairman, Sanitization and Decontrol Working Group Black Shield Photography", "Bye Bye U-2: CIA Legend Allen Predicts End Of Manned Reconnaissance", "SPIONFLY, DEN KALDE KRIGEN - Spionfly landet i Bod", "TV: Krnvapenskra bunkern styrde flygplanen", "4 Swedish JA-37 Viggen pilots receives medals for SR-71 Blackbird rescue operation 1987 Part:1/2", "4 Swedish JA-37 Viggen pilots receives medals for SR-71 Blackbird rescue operation 1987 Part:2/2", "SR-71 World Record Speed and Altitude Flights", "A-12, YF-12A, & SR-71 Timeline of Events", "Spy Plane Sets Speed Record, Then Retires. [7] The SR-71 has several nicknames, including "Blackbird" and "Habu". The Blackbirds owes its success to the continuum of aircraft that came before it. [57][58] The engine was most efficient around Mach3.2,[59] the Blackbird's typical cruising speed. NASA Released Rare Footage Of The SR-71 - YouTube A closer view of the target area was given by the HYCON Technical Objective Camera (TEOC), which could be directed up to 45 left or right of the centerline. No. Titanium was in short supply in the United States, so the Skunk Works team was forced to look elsewhere for the metal. By the time the SAM site could track the SR-71, it was often too late to launch a SAM, and the SR-71 would be out of range before the SAM could catch up to it. [35] Within 20 seconds the aircraft traveled 4,500 feet (1,400m), reached 240 miles per hour (390km/h), and lifted off. Famous Vehicles Of The Air Force And Their Most Ridiculous Features Blackbird Aircraft Records [34] Because of this, and the lack of a fuel-sealing system that could handle the airframe's expansion at extreme temperatures, the aircraft leaked JP-7 fuel on the ground prior to takeoff,[35] annoying ground crews. Due to unease over political situations in the Middle East and North Korea, the U.S. Congress re-examined the SR-71 beginning in 1993. On Jul. On 1 November 2013, media outlets reported that Skunk Works has been working on an unmanned reconnaissance airplane it has named SR-72, which would fly twice as fast as the SR-71, at Mach 6. 61-7972, when the Astro-Inertial Navigation System (ANS) fails on a training mission and they accidentally fly into Mexican airspace, 5 February 1968: Lockheed ordered to destroy A-12, YF-12, and SR-71 tooling, 8 March 1968: First SR-71A (AF Ser. 28, 1976 in fact, SR-71 61-7962 set two world records for its class an absolute speed record of 2,193.167 mph and an absolute altitude record of 85,068.997 feet (although SR-71 61-7953 unofficially reached 86,700 feet in 1968). Only one aircraft even has the distinction of achieving radar lock on the legendary spy plane. The SR-71 was driven by Bill Weaver with a Lockheed flight test specialist, Jim Zwayer in the back seat and it took off from Edwards AFB at 11:20 am . Development began on a coal slurry power plant, but Johnson determined that the coal particles damaged important engine components. [26] Graham said that the last-mentioned one was only a sales pitch, not a fact, at the time in the 1990s. The funding was later cut to $72.5million. The SR-71 was in duty from 1964 until 1989 and during a reactivation from 1993 until 1998. American aerospace engineer Clarence "Kelly" Johnson was responsible for many of the aircraft's innovative concepts. The event had been classified for over 30 years, and when the report was unsealed, data from the NSA showed that multiple MiG-25s with the order to shoot down the SR-71 or force it to land, had started right after the engine failure. [84] After landing, information from the SLAR, ELINT gathering systems, and the maintenance data recorder were subjected to postflight ground analysis. NASA Armstrong Fact Sheet: SR-71 Blackbird | NASA Wide-area imaging was provided by two of Itek's Operational Objective Cameras, which provided stereo imagery across the width of the flight track, or an Itek Optical Bar Camera, which gave continuous horizon-to-horizon coverage. [53] After wind tunnel testing and computer modeling by NASA Dryden test center,[54] Lockheed installed an electronic control to detect unstart conditions and perform this reset action without pilot intervention. These same factions also forced expensive sensor upgrades to the SR-71, which did little to increase its mission capabilities, but could be used as justification for complaining about the cost of the program. Kloesel, Kurt J., Nalin A. Ratnayake and Casie M. Clark. Working through Third World countries and bogus operations, they were able to get the rutile ore shipped to the United States to build the SR-71. The SR-71 had a radar cross-section (RCS) around 110sqft (10m2). "[99], From the beginning of the Blackbird's reconnaissance missions over North Vietnam and Laos in 1968, the SR-71s averaged approximately one sortie a week for nearly two years. Lockheed Martin SR-72 - Wikipedia [21][N 3] To conceal the A-12's existence, Johnson referred only to the A-11, while revealing the existence of a high speed, high altitude reconnaissance aircraft. The SR-71 was one of several spy airplanes built to venture into enemy territory without being shot down or even detected. Much like the SR-71, the A-12 was about 30-meters (100-feet) long, had a wingspan of 17 meters (55 feet), and weighed 54,431 kilograms (120,000 pounds). Capture of the plane's shock wave within the inlet is called "starting the inlet". [124] All other Blackbirds have been moved to museums except for the two SR-71s and a few D-21 drones retained by the NASA Dryden Flight Research Center (later renamed the Armstrong Flight Research Center). The SR-71 originated in a post-World War II environment where reconnaissance was in high demand. It is the integration of strategic and tactical. In other words, it was a spy plane. [85], The cockpit could be pressurized to an altitude of 10,000 or 26,000ft (3,000 or 8,000m) during flight. The aircraft was flown to the National Museum of the United States Air Force near Dayton, Ohio in March 1990. Colonel Rich Graham, SR-71 pilot, described the acquisition process: The airplane is 92% titanium inside and out. There were two routes. ", U-2 / A-12 / YF-12A / SR-71 Blackbird & RB-57D WB-57F locations. Some secondary references use incorrect 64- series aircraft serial numbers (e.g. SR-71 Blackbird Speed and Altitude Records - wvi.com [68], Specialized KC-135Q tankers were required to refuel the SR-71. Kelly Johnson realized that the A-12 airframe might work, and designed an interceptor version of the A-12. No. Supersonic flights generally lasted no more than 90 minutes before the pilot had to find a tanker. During unstarts, afterburner extinctions were common. During one mission, SR-71 pilot Brian Shul flew faster than usual to avoid multiple interception attempts; afterward, it was discovered that this had reduced fuel consumption. SR-71 Blackbird - Absolute Altitude (Sustained Flight) - Manned Aircraft. In addition to reaching altitudes higher than 25,908 meters (85,000 feet) and cruise at speeds greater than Mach 3.2, it could survey up to 160,934 square kilometers (100,000 square miles) of territory in just one hour. The dark color led to the aircraft's nickname "Blackbird". Sepanjang perkhidmatannya selama 24 tahun dengan Tentera Udara Amerika Syarikat, pesawat SR-71 Blackbird yang boleh terbang selaju Mach 3++ kekal sebagai pesawat paling laju dan berkemampuan terbang paling tinggi pada 80,000 kaki altitude. According to Aerotime.aero, in the same altitude bracket flew the US Air Force (USAF) SR-71 Blackbird spy plane. In actuality, the YF-12 was the twin-seat version of the top-secret single-seat Lockheed A-12, and its design became the forerunner of the highly sophisticated SR-71 Blackbird strategic reconnaissance aircraft. Hall also stated they were "looking at alternative means of doing [the job of the SR-71]. Air Force and NASA. [26]:204 While the SR-71 survived attempts to retire it in 1988, partly due to the unmatched ability to provide high-quality coverage of the Kola Peninsula for the US Navy,[119][26]:194195 the decision to retire the SR-71 from active duty came in 1989, with the last missions flown in October that year. [112][113][114], On 29 June 1987, an SR-71 was on a mission around the Baltic Sea to spy on Soviet postings when one of the engines exploded.