View source for Lockheed SR-71 Blackbird

{{Short description|US Air Force supersonic aircraft, 1964–1998}}
{{Redirect|SR-71}}
{{Use dmy dates|date=October 2025}}
{{Use American English|date=October 2025}}
{{Infobox aircraft
|name= SR-71 "Blackbird"
|image= File:Lockheed SR-71 Blackbird.jpg
|long_caption= An SR-71B trainer over the [[Sierra Nevada|Sierra Nevada Mountains]] of California in 1994. The raised second cockpit is for the instructor.
|alt= Dryden's SR-71B Blackbird, NASA 831, slices across the snow-covered southern Sierra Nevada Mountains of California after being refueled by a USAF tanker during a 1994 flight. The SR-71B was the trainer version of the SR-71. The dual cockpit allows the instructor to fly.
| type = [[Military strategy|Strategic]] [[reconnaissance aircraft]]
| national_origin = United States
| manufacturer = [[Lockheed Corporation]]
| design_group = Lockheed [[Skunk Works]]
| designer = [[Kelly Johnson (engineer)|Clarence "Kelly" Johnson]]
| first_flight = 22 December 1964
| introduction = January 1966
| retired = {{unbulleted list
 |USAF: 1989 (temp.), 1998 (final)
 |NASA: 1999
 }}
| number_built = 32
| status = <!-- Retired (see the retired field above this.)-->
| primary_user = [[United States Air Force]] (historical)
| more_users = [[NASA]] (historical)
| developed_from = [[Lockheed A-12]]
| variants = 
| developed_into = 
}}

The '''Lockheed SR-71''' "'''Blackbird'''" is a retired [[Range (aeronautics)|long-range]], high-altitude, [[Mach number|Mach]]&nbsp;3+ [[military strategy|strategic]] [[reconnaissance aircraft]] that was developed and manufactured by the American aerospace company [[Lockheed Corporation]].{{refn|This was prior to Lockheed's merger with [[Martin Marietta]] in 1995, after which it was known as the modern day [[Lockheed Martin]].|group=N}} Its nicknames include "[[Common blackbird|Blackbird]]" and "[[Protobothrops flavoviridis|Habu]]".{{sfn|Crickmore|1997|p=64}}

The SR-71 was developed in the 1960s as a [[black project]] by Lockheed's [[Skunk Works]] division. American aerospace engineer [[Kelly Johnson (engineer)|Clarence "Kelly" Johnson]] was responsible for many of the SR-71's innovative concepts.<ref>{{cite web |title=Creating the Blackbird |url=https://www.lockheedmartin.com/en-us/news/features/history/blackbird.html |access-date=14 March 2010 |work=[[Lockheed Martin]]}}</ref> Its shape was based on the [[Lockheed A-12]], a pioneer in [[stealth technology]] with its reduced [[radar cross section]], but the SR-71 was longer and heavier to carry more fuel and a crew of two in [[tandem]] cockpits. The SR-71 was revealed to the public in July 1964 and entered service in the [[United States Air Force]] (USAF) in January 1966.<ref>{{cite web |last=Merlin |first=Peter W. |title=Blackbird Facts |url=https://www.nasa.gov/pdf/736495main_Blackbird_FAQ.pdf |archive-url=https://web.archive.org/web/20140311221447/https://www.nasa.gov/pdf/736495main_Blackbird_FAQ.pdf |archive-date=11 March 2014 |access-date=23 June 2024 |website=[[NASA]] |page=3}}</ref>

During missions, the SR-71 operated at high speeds and altitudes (Mach&nbsp;3.2 at {{cvt|85000|ft|m|sigfig=2|sp=us|disp=or}}), allowing it to evade or outrace threats.<ref name="outran" /> If a [[surface-to-air missile]] launch was [[Missile approach warning system|detected]], the standard evasive action was to accelerate and outpace the missile.<ref name="SR71 Blackbird 2006">"SR-71 Blackbird." PBS documentary, Aired: 15 November 2006.</ref> Equipment for the plane's [[aerial reconnaissance]] missions included [[signals-intelligence]] sensors, [[side-looking airborne radar]], and a camera.<ref name="outran">{{cite web|url=https://nationalinterest.org/blog/the-sr-71-blackbird-the-super-spy-plane-outran-missiles-18142|work=[[The National Interest]]|first=Sebastien|last=Roblin |date=21 October 2016 |access-date=6 July 2022 |title=The SR-71 Blackbird: The Super Spy Plane That Outran Missiles}}</ref> On average, an SR-71 could fly just once per week because of the lengthy preparations needed. A total of 32 aircraft were built; 12 were lost in accidents, none to enemy action.<ref name="Landis_p98-101">{{harvp|Landis|Jenkins|2004|pp=98,100-101}}</ref><ref name="Pace_p126-7" />

From 1968, reconnaissance missions were flown from [[Kadena Air Base|Kadena AB]], [[Okinawa Prefecture|Okinawa]], first over [[North Vietnam]] and [[Laos]] during the [[Vietnam War]], and later over [[North Korea]]. From 1976, missions were flown from [[RAF Mildenhall]], UK, along the [[Soviet Union]]'s [[Baltic Sea|Baltic]] and [[Barents Sea]] coastlines. Missions were also flown over [[Cuba]], [[Nicaragua]], [[History of Libya under Muammar Gaddafi|Libya]], and to probe nuclear weapons installations in [[Nuclear weapons and Israel|Israel]] and [[South Africa and weapons of mass destruction|South Africa]].<ref name=":0" /> Unlike previous aircraft that were under the [[Central Intelligence Agency]], SR-71 missions were flown overtly, with USAF markings, and never overflew the [[Warsaw Pact]] or China.<ref>{{Cite web |title=SR-71 Blackbird |url=https://www.iwm.org.uk/history/sr-71-blackbird |access-date=13 October 2025 |website=Imperial War Museums |language=en}}</ref><ref name=":0" /> <!-- Wording to prevent back & forth 'were none'/'was none' changes. -->

In 1974, the SR-71 set the record for the quickest flight between London and New York at 1 hour, 54 minutes and 56 seconds.<ref>{{cite web |url=https://www.theguardian.com/world/article/2024/sep/01/transatlantic-flight-speed-of-sound-record-blackbird-sr-71 |title='It's just black sky up there': 50 years on, the transatlantic flight speed record remains unbroken |first=David |last=Barnett |work=The Guardian |location=UK |date=2 September 2024 |access-date=16 June 2025}}</ref> In 1976, it became the [[Flight airspeed record|fastest airbreathing manned aircraft]], previously held by its predecessor, the closely related [[Lockheed YF-12]].<ref name="landis_jenkins_p78">{{harvp|Landis|Jenkins|2004|p=78}}</ref><ref name="Pace_p159">{{harvp|Pace|2004|p=159}}</ref><ref name="FAI_records" /> {{As of|2025}}, the Blackbird still holds both world records.

In 1989, the USAF retired the SR-71, largely for political reasons,<ref name=":0">{{Cite news |last=Richelson |first=Jeffrey |date=9 April 1989 |title=Air Force Tries to Shoot Down Its Own Spy |url=https://www.latimes.com/archives/la-xpm-1989-04-09-op-1582-story.html |access-date=28 December 2023 |work=Los Angeles Times}}</ref> although several were briefly reactivated before their second retirement in 1998. [[NASA]] was the final operator of the Blackbird, using it as a research platform, until it was retired again in 1999.<ref>{{cite web |last=Gibbs |first=Yvonne |date=1 March 2014 |title=NASA Armstrong Fact Sheet: SR-71 Blackbird |url=https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-030-DFRC.html |url-status=dead |archive-url=https://web.archive.org/web/20161123054447/https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-030-DFRC.html |archive-date=23 November 2016 |access-date=6 July 2022 |work=[[NASA]]}}</ref> Since its retirement, the SR-71's role has been taken up by a combination of [[reconnaissance satellite]]s and [[unmanned aerial vehicle]]s (UAVs). As of 2018, Lockheed Martin was developing a proposed UAV successor, the [[Lockheed Martin SR-72|SR-72]], with plans to fly it in 2025.<ref name="US pushes hard">{{cite web|url=https://www.btimesonline.com/articles/105181/20181123/u-s-pushes-hard-build-sr-72-hypersonic-fighter.htm|title=U.S. Pushes Hard To Build SR-72 Hypersonic Fighter|first=Artie |last=Villasanta|publisher=Business Times|date=23 November 2018}}</ref>{{Update inline|date=December 2025|reason=This reference is, as of December 2025, 7 years old. As of yet, there has been no official flights, and the SR-72 is still largely considered conceptual.}}

==Development==

===Background===
{{main|Lockheed A-12}}

Lockheed's previous reconnaissance aircraft was the relatively slow [[Lockheed U-2|U-2]], designed for the [[Central Intelligence Agency]] (CIA). In late 1957, the CIA approached the defense contractor [[Lockheed Corporation|Lockheed]] to build an undetectable spy plane. The project, named Archangel, was led by [[Kelly Johnson (engineer)|Kelly Johnson]], head of Lockheed's Skunk Works unit in Burbank, California. The work on project Archangel began in the second quarter of 1958, with aim of flying higher and faster than the U-2. Of 11 successive designs drafted in a span of 10 months, "A-10" was the front-runner, although its shape made it vulnerable to radar detection. After a meeting with the CIA in March 1959, the design was modified to reduce its radar cross-section by 90%. On 11 February 1960, the CIA approved a US$96&nbsp;million (~${{Format price|{{Inflation|index=US-GDP|value=96000000|start_year=1960}}}} in {{Inflation/year|US-GDP}}) contract for Skunk Works to build a dozen [[Lockheed A-12|A-12]] spy planes. Three months later, the May [[1960 U-2 incident|1960 downing]] of [[Francis Gary Powers]]'s U-2 underscored the need for less vulnerable reconnaissance aircraft.<ref>{{harvp|Rich|Janos|1994|p=85}}</ref>

The A-12 first flew at Groom Lake ([[Area 51]]), Nevada, on 25 April 1962. Thirteen were built, plus five more of two variants: three of the [[Lockheed YF-12|YF-12]] interceptor prototype and two of the [[Lockheed M-21|M-21]] drone carrier. The aircraft was to be powered by the [[Pratt & Whitney J58]] engine, but J58 development was taking longer than scheduled, so it was initially equipped with the lower-thrust [[Pratt & Whitney J75]] to enable flight testing to begin. 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. The A-12 flew missions over Vietnam and North Korea before its retirement in 1968. The program's cancellation was announced on 28 December 1966,<ref>{{harvp|McIninch|1971|p=31}}</ref> due both to budget concerns<ref name="futile">{{cite book |last=Robarge |first=David |url=https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/books-and-monographs/a-12/a-futile-fight-for-survival.html |archive-url=https://web.archive.org/web/20071009211621/https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/books-and-monographs/a-12/a-futile-fight-for-survival.html |url-status=dead |archive-date=9 October 2007 |title=Archangel: CIA's Supersonic A-12 Reconnaissance Aircraft |chapter=A Futile Fight for Survival |publisher=CSI Publications |date=27 June 2007 |access-date=13 April 2009}}</ref> and because of the forthcoming SR-71, a derivative of the A-12.<ref>{{cite book |last1=Cefaratt |last2=Gill |title=Lockheed: The People Behind the Story|publisher=Turner Publishing Company |year=2002 |isbn=978-1-56311-847-0 |pages=78, 158}}</ref>

===Designation as SR-71===
[[File:SR71 factoryfloor SkunkWorks.jpg|thumb|SR-71 Blackbird assembly line at [[Skunk Works]]|alt=Blackbird on the assembly line at Lockheed Skunk Works]]

The SR-71 designation is a continuation of the [[1924 United States Army Air Service aircraft designation system|pre-1962 bomber series]]; the last aircraft built using the series was the [[XB-70 Valkyrie]]. However, a bomber variant of the Blackbird was briefly given the B-71 designator, which was retained when the type was changed to SR-71.<ref>{{cite web|url=http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2699 |title=Lockheed B-71 (SR-71) |date=29 October 2009 |publisher=National Museum of the United States Air Force |access-date=2 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131004214346/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2699 |archive-date=4 October 2013 }}</ref>

During the later stages of its testing, the B-70 was proposed for a reconnaissance/strike role, with an "RS-70" designation. 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,<ref name="Landis_p56">{{harvp|Landis|Jenkins|2004|pp=56-57}}</ref> which was originally named R-12 by Lockheed.{{refn|See the opening fly page in {{harvp|Crickmore|2000}}, which contains a copy of the original R-12 labeled plan view drawing of the vehicle.|group=N}} This USAF version was longer and heavier than the original A-12 because it had a longer fuselage to hold more fuel. The R-12 also had a crew of two in tandem cockpits, and reshaped fuselage [[Chine (aeronautics)|chines]]. Reconnaissance equipment included [[signals intelligence]] sensors, a [[side-looking airborne radar]], and a photo camera.<ref name="Landis_p56"/> The CIA's A-12 was a better photo-reconnaissance platform than the USAF's R-12: since the A-12 flew higher and faster, and with only a pilot, it had room to carry a better camera<ref name="futile"/> and more instruments.<ref>{{harvp|McIninch|1971|p=29}}</ref> The A-12 flew [[covert mission]]s while the SR-71 flew overt missions; the latter had USAF markings and pilots carried [[Geneva Conventions Identification Card]]s.<ref name="iwm20211103">{{Cite AV media |url=https://www.youtube.com/watch?v=Tn9U6hAlf14 |title=SR-71 Blackbird - Cold War icon |date=3 November 2021 |type=YouTube |publisher=Imperial War Museums}}</ref>

During the [[1964 United States presidential election|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. Johnson decided to counter this criticism by revealing the existence of the YF-12A USAF interceptor, which also served as cover for the still-secret A-12<ref name="oxcartstory">{{harvp|McIninch|1971|pp=14-15}}</ref> and the USAF reconnaissance model since July 1964. USAF Chief of Staff General [[Curtis LeMay]] preferred the SR (Strategic Reconnaissance) designation and wanted the RS-71 to be named SR-71. Before the July speech, LeMay lobbied to modify Johnson's speech to read "SR-71" instead of "RS-71". The media transcript given to the press at the time still had the earlier RS-71 designation in places, creating the story that the president had misread the aircraft's designation.<ref>{{harvp|Merlin|2005|pp=4-5}}</ref>{{refn|{{harvp|Crickmore|2000}}, original R-12 labeled plan view drawing|group=N}} 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.<ref>{{harvp|McIninch|1971}}</ref>

In 1968, Secretary of Defense [[Robert McNamara]] canceled the F-12 interceptor program. The specialized tooling used to manufacture both the YF-12 and the SR-71 was also ordered destroyed.<ref name=Landis_p47>{{harvp|Landis|Jenkins|2004|p=47}}</ref> Production of the SR-71 totaled 32 aircraft: 29 SR-71As, two SR-71Bs, and one SR-71C.<ref>{{harvp|Merlin|2005|p=6}}</ref>

==Design==

===Overview===
[[File:Evergreen Aviation & Space Museum Oregon12.jpg|thumb|Tandem cockpits]]
[[File:SR-71 flight instruments.triddle.jpg|thumb|Lockheed SR-71 Blackbird Cockpit]]

The SR-71 was designed for flight at over [[Mach number|Mach]]&nbsp;3 with tandem cockpits for a crew of two: a pilot; and a reconnaissance systems officer who navigated and operated the surveillance systems. It was extremely important for the pilot and RSO to work well together as a crew.{{sfn|Graham|2008|page=6}}<ref name=crown>{{cite web |url=https://fas.org/irp/program/collect/sr-71.htm |title=Senior Crown SR-71 |work=[[Federation of American Scientists]] |date=7 September 2010 |access-date=17 October 2012 |archive-url=https://web.archive.org/web/20150417003154/https://fas.org/irp/program/collect/sr-71.htm |archive-date=17 April 2015}}</ref>{{sfn|Graham|1996}} The SR-71 was designed with the smallest radar cross-section that Lockheed could achieve, an early attempt at stealth design.{{sfn|Crickmore|2009|pp=30-31}} Aircraft were painted black. This color radiated heat from the surface more effectively than the bare metal, reducing the temperature of the skin and thermal stresses on the airframe.{{sfn|Merlin|2009|p=16}} The appearance of the painted aircraft gave it the nickname "Blackbird".

===Airframe, canopy, and landing gear===
Titanium was used for 85% of the structure, with much of the rest being [[polymer]] [[composite material]]s.<ref>{{harvp|Merlin|2009}}</ref> To control costs, Lockheed used a more easily worked titanium alloy, which softened at a lower temperature.{{refn|While titanium ores are cheap and abundant, converting those ores into metallic titanium is laborious and expensive. Soviet production of metallic titanium was several times US production, so the CIA{{snd}}without Soviet knowledge{{snd}}used dummy intermediary firms to obtain Soviet-produced metallic titanium for US military use.<ref>{{cite report |url=https://www.cia.gov/readingroom/docs/CIA-RDP86T00591R000200170005-0.pdf |title=The Soviet Titanium and Its Role in the Military Buildup |publisher=Directorate of Intelligence |access-date=15 January 2025}}</ref><ref>{{harvp|Rich|Janos|1994}}</ref><ref>{{cite web |url=https://nationalinterest.org/blog/buzz/titanium-russia-was-secret-ingredient-sr-71-blackbird-207691/ |title=Titanium from Russia Was the Secret Ingredient in the SR-71 Blackbird |date=3 December 2023 |first1=Maya |last1=Carlin |work=National Interest |accessdate=27 January 2025}}</ref>|group=N}} The challenges posed led Lockheed to develop new fabrication methods, which have since been used in the manufacture of other aircraft. Lockheed found that washing welded titanium requires [[distilled water]], as the chlorine present in tap water is [[corrosion|corrosive]]; [[cadmium]]-plated tools could not be used, as they also caused corrosion.<ref>{{harvp|Rich|Janos|1994|p=213-214}}</ref> Metallurgical contamination was another problem; at one point, 80% of the delivered titanium for manufacture was rejected on these grounds.<ref>{{harvp|Rich|Janos|1994|p=203}}</ref><ref>{{harvp|McIninch|1971|p=5}}</ref>

The high temperatures generated in flight required special design and operating techniques. Major sections of the skin of the inboard wings were corrugated, not smooth.<ref>{{Cite book |last1=Linden |first1=F. Robert van der |url=https://books.google.com/books?id=8kX2DAAAQBAJ&pg=PA184 |title=Milestones of Flight: The Epic of Aviation with the National Air and Space Museum |last2=Spencer |first2=Alex M. |last3=Paone |first3=Thomas J. |date=2023-08-17 |publisher=Quarto Publishing Group USA |isbn=978-0-7603-5151-2 |language=en}}</ref>

Fuselage panels were manufactured to fit only loosely with the aircraft on the ground. Proper alignment was achieved as the airframe heated up, with [[thermal expansion]] of several inches.{{sfn|Graham|1996|p=47}} Because of this, and the lack of a fuel-sealing system that could remain leak-free with the extreme temperature cycles during flight, the aircraft leaked [[JP-7]] fuel on the ground prior to takeoff,{{sfn|Graham|1996|p=160}} annoying ground crews.{{r|iwm20211103}}

The outer windscreen of the cockpit was made of three layers of glass with cooling sections between them.{{citation needed|date=December 2024}} The ANS navigation window was made of solid [[quartz]] and was [[ultrasonic welding|fused ultrasonically]] to the titanium frame.<ref>{{cite journal |last1=Burrows |first1=William E. |title=The Real X-Jet |journal=Air & Space Magazine |date=1 March 1999 |url=https://www.airspacemag.com/military-aviation/the-real-x-jet-12377380/ |access-date=16 January 2018}}</ref> The temperature of the exterior of the windscreen could reach {{convert|600|°F|°C|abbr=on|sigfig=2}} during a mission.{{sfn|Graham|1996|p=41}}

[[File:16 19 037 SR71.jpg|thumb|Detail of SR-71A at the [[Museum of Aviation (Warner Robins)|Museum of Aviation]], [[Robins AFB]] showing red lined no-step areas. Not shown on this museum exhibit is the additional NO STEP wording on operational aircraft which showed to which side of the line the warning was applicable.]]

The Blackbird's tires, manufactured by [[Goodrich Corporation|B.F. Goodrich]], contained aluminum and were inflated with nitrogen. They cost $2,300 each and generally required replacing within 20 missions. The Blackbird landed at more than {{convert|170|kn|mph km/h|sigfig=2}} and deployed a drag parachute to reduce landing roll and brake and tire wear.<ref>Blackbird diaries, Air & Space, December 2014/January 2015, p. 46.</ref>

===Shape and threat avoidance===
[[File:Sr71 1.jpg|thumb|[[Contrail|Water vapor]] is condensed by the low-pressure vortices generated by the chines outboard of each engine inlet.]]

The SR-71 was the second operational aircraft,<ref name="cia.gov">{{cite web|url=https://www.cia.gov/news-information/featured-story-archive/2015-featured-story-archive/oxcart-vs-blackbird.html|archive-url=https://web.archive.org/web/20151208074002/https://www.cia.gov/news-information/featured-story-archive/2015-featured-story-archive/oxcart-vs-blackbird.html|url-status=dead|archive-date=8 December 2015|title=OXCART vs Blackbird: Do You Know the Difference? |website=Cia.gov}}</ref> after the [[Lockheed A-12]],<ref name="cia.gov" /> designed to be hard to spot on [[radar]]. Early studies in [[stealth technology]] indicated that a shape with flattened, tapering sides would reflect most radar energy away from a beam's place of origin, so Lockheed's engineers added [[Chine (aeronautics)|chines]] and canted the vertical control surfaces inward. Special [[radar-absorbing material]]s were incorporated into [[serration|sawtooth-shaped]] sections of the aircraft's skin. [[Cesium]]-based fuel additives were used to somewhat reduce the visibility of exhaust plumes to radar, although exhaust streams remained quite apparent. Ultimately, engineers produced an aircraft with a wing area of about {{cvt|170|sqm|sqft|order=flip}} but a radar cross-section (RCS) of around {{cvt|10|sqm|sqft|order=flip}}.{{sfn|Graham|1996|p=75}} Johnson later conceded that Soviet radar technology advanced faster than the stealth technology employed against it.<ref>Hott, Bartholomew and George E. Pollock [https://web.archive.org/web/20030216054101/http://web.ics.purdue.edu/~gpollock/The%20Advent%2C%20Evolution%2C%20and%20New%20Horizons%20of%20United%20States%20Stealth%20Aircraft.htm "The Advent, Evolution, and New Horizons of United States Stealth Aircraft."] ''archive.is''. Retrieved: 7 February 2014.</ref>

While the SR-71 carried [[Radar jamming and deception|radar countermeasures]] to evade interception efforts, its greatest protection was its combination of high altitude and very high speed, which made it invulnerable at the time. Along with its low radar cross-section, these qualities gave a very short time for an enemy [[surface-to-air missile]] (SAM) site to acquire and track the aircraft on radar. 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. If the SAM site could track the SR-71 and fire a SAM in time, the SAM would expend nearly all of the [[delta-v]] of its boost and sustainer phases just reaching the SR-71's altitude; at this point, out of thrust, it could do little more than follow its ballistic arc. Merely accelerating would typically be enough for an SR-71 to evade a SAM;<ref name="SR71 Blackbird 2006"/> 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.{{sfn|Graham|1996}} 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]],{{refn|The [[MiG-25|Foxbats]] could sustain speeds of Mach 2.83, but they also had an emergency option to reach Mach 3.2{{snd}}after which the engines would have to be repaired or replaced.<ref name=GlobalAircraftMiG-25 />|group=N}} which also could not reach the SR-71's altitude.<ref name=GlobalAircraftMiG-25>{{cite web |url=http://www.globalaircraft.org/planes/mig-25_foxbat.pl |title=MiG-25 Foxbat |website=globalaircraft.org |access-date=31 May 2011 |archive-url=https://web.archive.org/web/20141223100252/http://www.globalaircraft.org/planes/mig-25_foxbat.pl |archive-date=23 December 2014}}</ref> No SR-71 was ever shot down.<ref name="Landis_p98-101"/>

The SR-71 featured chines, a pair of sharp edges leading aft from either side of the nose along the fuselage. These were not a feature on the early A-3 design; Frank Rodgers, a doctor at the Scientific Engineering Institute, a [[Central Intelligence Agency|CIA]] [[front organization]], discovered that a cross-section of a sphere had a greatly reduced radar reflection, and adapted a cylindrical-shaped fuselage by stretching out the sides of the fuselage.<ref>Suhler 2009, p. 100.</ref> After the advisory panel provisionally selected Convair's FISH design over the A-3 on the basis of RCS, Lockheed adopted chines for its A-4 through A-6 designs.<ref>Suhler 2009, ch. 10.</ref>

Aerodynamicists discovered that the chines generated powerful [[vortex|vortices]] and created additional [[Lift (force)|lift]], leading to unexpected aerodynamic performance improvements.<ref>''AirPower'' May 2002, p. 36.</ref> For example, they allowed a reduction in the wings' [[angle of incidence (aerodynamics)|angle of incidence]], which added stability and reduced drag at high speeds, allowing more weight to be carried, such as fuel. Landing speeds were also reduced, as the chines' vortices created turbulent flow over the wings at high [[Angle of attack|angles of attack]], making it harder to [[Stall (flight)|stall]]. The chines also acted like [[leading-edge extension]]s, which increase the agility of fighters such as the [[Northrop F-5 Freedom Fighter|F-5]], [[General Dynamics F-16 Fighting Falcon|F-16]], [[McDonnell Douglas F/A-18 Hornet|F/A-18]], [[Mikoyan MiG-29|MiG-29]], and [[Sukhoi Su-27|Su-27]]. The addition of chines also allowed the removal of the planned [[Canard (aeronautics)|canard]] foreplanes.{{refn|See [[:File:Blackbird-Canards.JPG|Blackbird with Canards]] image for visual.|group=N}}<ref>Goodall 2003, p. 19.</ref><ref>''AirPower'', May 2002, p. 33.</ref>

===Propulsion system or powerplant===
====Complete powerplant====
[[File:The Blackbird Story.webm|thumb|''The Blackbird Story'' (1972) Official [[United States Department of Defense|Department of Defense]] promotional film reel.]]

The SR-71 used the same powerplant as the A-12 and [[YF-12]]. It consists of three main parts: inlet, J58 engine and its nacelle, and ejector nozzle. "Typical for any supersonic powerplant the engine cannot be considered separately from the rest of the powerplant. Rather, it may be regarded as the heat pump in the over-all system of inlet, engine, and nozzle. The net thrust available to propel the aircraft may be to a large extent controlled by the performance of the inlet and nozzle rather than by the physical potentialities of the engine alone."<ref>https://apps.dtic.mil/sti/citations/ADB183548,'Inlet-engine matching considerations', Obery and Stitt, NACA Conference on Turbojet Engines for Supersonic Propulsion, AD B183548, Section VII, Paper 2.</ref> This is illustrated for the Blackbird by the thrust contributions from each component at Mach 3+ with maximum afterburner: inlet 54%, engine 17.6%, ejector nozzle 28.4%.<ref>{{cite journal | last1=Campbell | first1=David H. | title=F-12 Series Aircraft Propulsion System Performance and Development | journal=Journal of Aircraft | date=1974 | volume=11 | issue=11 | pages=670–676 | doi=10.2514/3.60402 | url=https://arc.aiaa.org/doi/10.2514/3.60402 | url-access=subscription }}</ref>

When stationary and at low speeds the inlet caused a loss in engine thrust. This was due to the flow restriction through the inlet when stationary. Thrust was recovered with ram pressure as flight speed increased (uninstalled thrust {{cvt|34000|lb(f)|kN}}, installed at zero airspeed {{cvt|25500|lb(f)|kN}} rising through {{cvt|30000|lb(f)|kN}} at 210&nbsp;knots, unstick speed).<ref>{{cite book |url=https://www.sr-71.org/blackbird/manual/1/1-7.php |title=SR-71 Flight Manual |via=SR-71 Online |section=Section 1 |pages=1–7 |archive-date=11 August 2024 |access-date=20 September 2024 |archive-url=https://web.archive.org/web/20240811002611/https://www.sr-71.org/blackbird/manual/1/1-7.php |url-status=dead }}</ref>

At supersonic speeds not all the airflow approaching the inlet capture area entered the inlet. At supersonic speeds an intake always adapts to the engine requirements, rather than forcing air into the engine, and the unwanted air flows around the outside of the cowl, causing spillage drag. More than half the air approaching the capture area had to be spilled at low supersonic speeds and the amount reduced as the design speed was approached because the inlet airflow had been designed to match the engine demand at that speed and the chosen design point ambient temperature. At this speed the spike shock touched the cowl lip and there was minimal spillage (with its attendant drag) as shown by Campbell.<ref name="Inlet development">{{cite journal |url=https://www.jstor.org/stable/44657533 |title=F-12 Inlet Development – Fig.4 – Inlet airflow |first=David H. |last=Campbell |journal=SAE Transactions |volume=83 |year=1974 |pages=2832–2840 |publisher=SAE International|jstor=44657533 }}</ref> The inlet and engine matching was also shown by Brown,<ref>Brown, William. "J58/SR-71 Propulsion Integration, attachment to CIA-RDP90B001170R000100050008-1, Fig. 3 'Inlet and engine airflow match'".</ref> who emphasized the benefit of increased engine airflow at higher Mach numbers that came with the introduction of the bleed bypass cycle. These two authors show the disparity between inlet and engine for the Blackbird in terms of airflow and it is further explained in more general terms by Oates.<ref>"Aerothermodynamics of Aircraft Gas Turbine Engines", Oates, Air Force Aero Propulsion Laboratory, Figure 13.1.17 'Elements of Inlet Airflow Supply Determination', (a) and (b).</ref>

Engine operation was adversely affected when operating behind an unstarted inlet. In this condition the inlet behaved like a subsonic inlet design (known as a pitot type) at high supersonic speeds, with very low airflow to the engine. Fuel was automatically diverted, by the fuel derich system, from the combustor to prevent turbine over-temperature.<ref>A-12 Utility Flight Manual, 15 September 1965, changed 15 June 1968, Fuel Derich System.</ref>

All three parts were linked by the secondary airflow. The inlet needed the boundary layers removed from its spike and cowl surfaces. The one with the higher pressure recovery, the cowl shock-trap bleed, was chosen as secondary air<ref name="Inlet development"/> to ventilate and cool the outside of the engine. It was assisted from the inlet by the pumping action of the engine exhaust in the ejector nozzle, cushioning the engine exhaust as it expanded over a wide range of pressure ratios which increased with flight speed.<ref>https://www.sae.org/publications/technical-papers/content/740832/, "J58/YF-12 Ejector Nozzle Performance" pp. 1, 2.</ref>

Mach&nbsp;3.2 in a [[standard day]] atmosphere was the design point for the aircraft. However, in practice the SR-71 was more efficient at even faster speeds and colder temperatures. The specific range charts showed for a standard day temperature, and a particular weight, that Mach&nbsp;3.0 cruise used {{cvt|38000|lb/h|kg/h}} of fuel. At Mach&nbsp;3.15 the fuel flow was {{cvt|36000|lb/h|kg/h}}. Flying in colder temperatures (known as temperature deviations from the standard day) would also reduce the fuel used, e.g. with a {{cvt|-10|C|F|order=flip}} temperature the fuel flow was {{cvt|35000|lb/h|kg/h}}.<ref>{{cite book|url = https://books.google.com/books?id=6svmtOFa1JIC| pages=165, 166| title=SR-71 Revealed: The Untold Story| isbn=978-1-61060-751-3| last1=Graham| first1=Richard H.| publisher=Zenith Imprint}}</ref> During one mission, SR-71 pilot [[Brian Shul]] flew faster than usual to avoid multiple interception attempts. It was discovered after the flight that this had reduced the fuel consumption.<ref name="Shul">Shul and O'Grady 1994</ref> It is possible to match the powerplant for optimum performance at only one ambient temperature because the airflows for a supersonic inlet and engine vary differently with ambient temperature. For an inlet, the airflow varies inversely with the square root of the temperature, and for the engine, it varies with the direct inverse.<ref>https://archive.org/details/sim_journal-of-aircraft_november-december-1968_5_6/mode/2up Design and Development of an Air Intake for a Supersonic Transport Aircraft, "Effect of Ambient Temperatures", p.518</ref>

<gallery widths="270px" heights="203px" mode="packed" class="center" caption="Powerplant">
File:1 - Seattle.jpg|The inlet extends from the spike tip to the four sets of three louvers that vent the spike boundary layer bleed overboard through four spike support struts. The more-forward louvers vent the forward bypass bleed. The engine extends from there to the ejector nozzle blow-in doors (shown open) and the nozzle extends from there to the ejector flaps (shown closed).
File:SR71 J58 Engine Airflow Patterns.svg|Diagrams show operation of the air inlet, flow through the engine (primary air), nacelle flow past the engine (secondary air), and flow into the ejector nozzle (primary, secondary and tertiary air).
File:Pratt & Whitney J58 ground test.jpg|This picture of an uninstalled engine being tested illustrates the need for cooling air around the exhaust duct. The engine, when installed as part of the powerplant, has secondary cooling air at {{Convert|1200|F|C|round=50}} passing over the afterburner duct which is heated internally by combustion up to {{Convert|3200|F|C|round=50}}. The heating, followed by the primary nozzle restriction, accelerates the exhaust to sonic speed as it leaves the primary nozzle (shown). The ejector nozzle (not shown) surrounds the primary exhaust with secondary and tertiary air to cushion its expansion in the ejector nozzle.
</gallery>

====Inlet====
The engine inlets needed so-called mixed external/internal compression with internal supersonic diffusion since all-external compression used on slower aircraft caused too much drag at Blackbird speeds. Their features included a centerbody or spike, spike boundary-layer bleed slots where normal shock was located, a cowl boundary layer bleed "shock trap" entrance, streamlined bodies known as "mice", forward bypass bleed ports between the "mice", rear bypass ring, louvers on external surface for spike boundary layer overboard, and louvers on external surface for front bypass overboard. Venting this bypass overboard produced high drag: {{cvt|6000|lb(f)|kN}} at cruise with 50% door opening, compared to the total aircraft drag of {{cvt|14000|lb(f)|kN}}.<ref>https://authors.library.caltech.edu/records/6s4e6-b2j60, AE107_SR-71_Case_Study_51-120, "Drag Penalty Of Overboard Bypass At Cruise".</ref> Designer David Campbell holds a patent on the inlet's aerodynamic features and functioning,<ref>{{cite web |title=Supersonic inlet for jet engines |url=https://patents.google.com/patent/US3477455A/en |work=patents.google.com}}</ref> which are explained in the "A-12 Utility Flight Manual"<ref>A-12 Utility Flight Manual, 15 September 1965, changed 15 June 1968, Air Inlet System.</ref> and in a 2014 presentation by Lockheed Technical Fellow Emeritus Tom Anderson.<ref>{{cite web |url=https://www.enginehistory.org/members/Convention/2014/Presentations/SR-71InletDesign.pdf |title=SR-71 Inlet Design Issues And Solutions Dealing With Behaviorally Challenged Supersonic Flow Systems |last=Anderson |first=Tom |website=enginehistory.org |publisher=Aircraft Engine Historical Society |year=2014 |archive-url=https://web.archive.org/web/20210104040235/https://www.enginehistory.org/members/Convention/2014/Presentations/SR-71InletDesign.pdf |archive-date=4 January 2021 |access-date=16 June 2025}}</ref>

When an inlet was operating as an efficient supersonic compressor—a status called "started"—supersonic diffusion took place in front of the cowl and internally in a converging passage as far as a terminal shock where the passage area began to increase and subsonic diffusion takes place. An analog control system was designed to hold the terminal shock in position.

But in the early years of operation, the analog computers could not always keep up with rapidly changing inputs from the nose boom. If the duct back pressure became too great and the spike was incorrectly positioned, the shock wave become unstable and would shoot quickly forward to a stable position outside the cowl. This "inlet [[unstart]]" would often extinguish the engine's afterburner. The asymmetrical thrust from the other engine would cause the aircraft to yaw violently. [[Stability Augmentation System|SAS]], autopilot, and manual control inputs would attempt to regain controlled flight, but extreme yaw would often reduce airflow in the opposite engine and stimulate "sympathetic stalls". This generated a rapid counter-yawing, often coupled with loud "banging" noises, and a rough ride during which crews' helmets would sometimes strike their cockpit canopies.{{sfn|Crickmore|1997|pp=42-43}} One response to a single unstart was unstarting both inlets to prevent yawing, then restarting them both.<ref name="landis_jenkins_p97">{{harvp|Landis|Jenkins|2004|p=97}}</ref> After wind-tunnel testing and computer modeling by NASA Dryden test center,<ref>{{cite web |year=2004 |title=NASA Dryden Technology Facts – YF-12 Flight Research Program |url=https://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-17-DFRC.html |url-status=dead |archive-url=https://web.archive.org/web/20190912045121/https://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-17-DFRC.html |archive-date=12 September 2019 |access-date=9 March 2019 |publisher=NASA |location=US}}</ref> Lockheed installed an electronic control to detect unstart conditions and perform this reset action without pilot intervention.<ref>{{harvp|Rich|Janos|1994|p=221}}</ref>

During troubleshooting of the unstart issue, NASA discovered that the vortices from the nose chines were entering the engine and reducing engine efficiency. To fix this, the agency developed a computer to control the engine bypass doors. Beginning in 1980, the analog inlet control system was replaced by a digital system, Digital Automatic Flight and Inlet Control System (DAFICS),<ref>{{Cite web |title=SR-71 Online - SR-71 Flight Manual: Section appendix, Page A-2 |url=https://www.sr-71.org/blackbird/manual/appendix/a-2.php |access-date=21 August 2023 |website=www.sr-71.org}}</ref> which reduced unstarts.<ref name="landis_jenkins_p83">{{harvp|Landis|Jenkins|2004|p=83}}</ref>

<gallery widths="252px" heights="189px" mode="packed" class="center" caption="Inlet">
File:Lockheed SR-71A Blackbird at Evergreen Aviation & Space Museum (6586637283).jpg|Entry to the inlet. Behind is the outer wing and hinged portion of the nacelle that encloses the engine. The spike is shown in the forward position (for speeds below Mach 1.6). Just discernible behind the cowl lip are spike boundary layer bleed slots where the normal shock is located at higher speeds when the spike has moved rearwards, the cowl bleed "shock trap" ram intake, streamlined bodies ("mice") and, between the mice, the forward bypass door openings<ref>Tom Anderson. SR-71 Inlet Design Issues And Solutions Dealing With Behaviourally Challenged Supersonic Flow Systems, Lockheed Martin Corporation, presented at AEHS Convention 2014, 'Inlet Diffuser Photos'.</ref> that dump unwanted air externally through the front louvers and cause nacelle drag.<ref>https://authors.library.caltech.edu/records/6s4e6-b2j60, AE107_SR-71_Case_Study_51-120 "Drag Penalty Of Overboard Bypass At Cruise"</ref> When the landing gear is down, ambient air flows in reverse through the bypass to supplement the front inlet flow into the engine.
File:Lockheed SR-71A Blackbird at Evergreen Aviation & Space Museum (6586640345) (2).jpg|A rear view of the inlet where air enters the engine. Two features were added after flight testing highlighted the need: 1) "mice," visible as streamlined shapes, added to reduce the diffusion rate after pilots noted rumbling; and 2) rear bypass doors added to prevent unstarting the inlet during descents with low engine flow.<ref>{{cite conference |last=Anderson |first=J. Thomas |year=2013 |title=How Supersonic Inlets Work – Details of the Geometry and Operation of the SR-71 Mixed Compression Inlet |url=https://www.enginehistory.org/Convention/2014/SR-71Inlts/SR-71Inlts.shtml |conference=AEHS convention |access-date=October 26, 2024 |website=Engine History}}</ref> The ring of doors is at the extreme rear of the inlet as shown by their accompanying rear-turning scoop, extending from 7 o'clock to 5 o'clock, which directs the air through the nacelle to the ejector nozzle.<ref>{{cite web |url=https://ntrs.nasa.gov/citations/19750003899 |title=Continuous-output terminal-shock-position sensor for mixed-compression inlets evaluated in wind tunnel tests of YF-12 aircraft inlet |work=NASA Technical Reports Server |date=December 1974 |publisher=NASA |pages=Figures 7, 8 |last1=Dustin |first1=M. O. |last2=Cole |first2=G. L. |last3=Neiner |first3=G. H. }}</ref> The door actuator<ref>{{cite web |url=https://ntrs.nasa.gov/citations/19740030201 |title=Preliminary results of flight tests of the propulsion system of the YF-12 airplane at Mach numbers to 3.0 |work=NASA Technical Reports Server |date=November 1973 |publisher=NASA}}</ref>
File:Inlet shock waves at Mach 2.jpg|[[Schlieren]] flow visualization of shock waves for started and unstarted inlet at Mach 2
</gallery>

====Engine and nacelle====
{{main|Pratt & Whitney J58}}
The engine was an extensively re-designed version of the J58-P2, an existing supersonic engine which had run 700 development hours in support of proposals to power various aircraft for the US Navy. Only the compressor and turbine aerodynamics were retained. New design requirements for cruise at Mach 3.2 included:
* operating with very high ram temperature air entering the compressor, at {{Convert|800|F|C|sigfig=2}}
* a continuous turbine temperature capability {{Convert|450|F-change}} hotter than previous experience ([[Pratt & Whitney J75]])
* continuous use of maximum afterburning
* the use of new, more expensive, materials and fluids required to withstand unprecedented high temperatures

The engine was an afterburning turbojet for take-off and transonic flight (bleed bypass closed) and a low bypass augmented turbofan for supersonic acceleration (bleed bypass open). It approximated a ramjet during high speed supersonic cruise (with a pressure loss, compressor to exhaust, of 80% which was typical of a ramjet). It was a low bypass turbofan for subsonic loiter (bleed bypass open).<ref>https://authors.library.caltech.edu/records/6s4e6-b2j60, AE107_SR-71_Case_Study_321-450, p. 27.</ref><ref>A-12 Utility Flight Manual, 15 September 1965, changed 15 June 1968, 'Start Bleed And Bypass Valve Actuation', Figure 1-7</ref>

Analysis of the J58-P2 supersonic performance<ref name="roadrunnersinternationale.com">Bob Abernethy. https://www.roadrunnersinternationale.com/pw_tales.htm, 'More Never Told Tales of Pratt & Whitney'.</ref> showed the high compressor inlet temperature would have caused stalling, choking and blade breakages in the compressor as a result of operating at low corrected speeds on the compressor map. These problems were resolved by Pratt & Whitney engineer Robert Abernethy and are explained in his patent, "Recover Bleed Air Turbojet".<ref>{{cite web | url=https://patents.google.com/patent/US3344606A/en | title=Recover bleed air turbojet }}</ref> His solution was to 1) incorporate six air-bleed tubes, prominent on the outside of the engine, to transfer 20% of the compressor air to the afterburner, and 2) to modify the inlet guide vanes with a 2-position, trailing edge flap. The compressor bleed enabled the compressor to operate more efficiently and with the resulting increase in engine airflow matched the inlet design flow with an installed thrust increase of 47%.<ref name="roadrunnersinternationale.com"/><ref>William Brown. J58/SR-71 Propulsion Integration, attachment to CIA-RDP90B001170R000100050008-1, Fig. 3, 'Inlet and engine airflow match'.</ref> A continuous turbine temperature of {{Convert|2000|F|C}} was enabled with air-cooled first stage turbine vane and blades. Continuous operation of maximum afterburning was enabled by passing relatively cool air from the compressor along the inner surface of the duct and nozzle. Ceramic thermal barrier coatings were also used.

The secondary airflow through the nacelle comes from the cowl boundary layer bleed system which is oversized (flows more than boundary layer) to give a high enough pressure recovery to support the ejector pumping action. Additional air comes from the rear bypass doors and, for low speed operation with negligible inlet ram, from suck-in doors by the compressor case.

<gallery widths="220px" heights="165px" mode="packed" class="center" caption="Engine/nacelle">
File:Pratt & Whitney J58-JT11D-20K turbojet engine, 1962 - Lockheed SR-71A Blackbird, 1966 - Evergreen Aviation & Space Museum - McMinnville, Oregon - DSC01037.jpg|View of J58 engine shows some features required for flight at Mach 3.2: titanium inlet guide vanes and first stage compressor blades for lighter weight at high ram temperatures, transonic first stage compressor blades and low hub/tip ratio compressor entry, both scaled from the bigger Mach-3 J91 engine compressor, 2-position flaps on the inlet guide vanes and three of the six bypass tubes.
File:Pratt & Whitney J58 18.jpg|The afterburner was rated for continuous operation at {{cvt|3200|F|C|-2}} made possible with ceramic coatings (colored white) on duct liner and flame holders<ref>https://ntrs.nasa.gov/citations/20090018047, "History Of Thermal Barrier Coatings For Gas Turbine Engines: Emphasising NASA's Role from 1942 to 1990".</ref> and compressor bleed air cooling the duct and nozzle (above Mach 2.1 when the bleed was flowing). The nozzle is fully open, the maximum afterburning position. The main purpose of the variable nozzle area was to control engine operation which it did in conjunction with varying heat release in the afterburner.
File:Lockheed SR-71A Blackbird at Evergreen Aviation & Space Museum (6586637067).jpg|The inlet at left was depressed when the engine ran at high power settings with inadequate inlet ram (stationary and low flight speeds). The lower-than-ambient pressure in the inlet brought in extra air through the spike bleed and forward bypass louvers shown on the inlet external surface. Adequate secondary cooling air came in through the suck-in doors (shown open on the hinged nacelle).
</gallery>

====Ejector nozzle====
The nozzle had to operate efficiently over a wide range of pressure ratios: from low with no inlet ram when the aircraft was stationary, to 31 times the external pressure at {{Convert|80000|ft|m|abbr=on}}. A blow-in door ejector nozzle had been invented by Pratt & Whitney engineer Stuart Hamilton in the late 1950s<ref>Jack Connors. https://arc.aiaa.org/doi/book/10.2514/4.867293, "The Engines of Pratt & Whitney: A Technical History", ISBN 978 1 60086 711 8, p. 328.</ref> and described in his patent "Variable Area Exhaust Nozzle".<ref>"Variable Area Exhaust Nozzle", U.S. Patent 3,062,003</ref> In this description the nozzle is an integral part of the engine (as it was in the contemporary Mach 3 [[General Electric YJ93]].<ref>"Variable Geometry Exhaust Nozzles and Their Effects on Airplane Performance", SAE 680295, p. 5.</ref> For the Blackbird powerplant, the nozzle was more efficient structurally (lighter) by incorporating it as part of the airframe because it carried fin and wing loads through the ejector shroud. The nozzle used secondary air from two sources: the inlet cowl boundary layer and rear bypass from immediately in front of the compressor. It used external flow on the nacelle through the tertiary blow-in doors until the ram closed them at Mach 1.5, and secondary air alone at higher speeds.

At low flight speeds, the engine exhaust pressure at the primary nozzle exit was greater than ambient, so it tended to over-expand to lower-than-ambient pressure in the shroud, causing impingement shocks. Secondary and blow-in door air surrounding the exhaust cushioned it, preventing over-expansion. As inlet ram pressure increased with flight speed, it closed the blow-in doors, then gradually opened the nozzle flaps until they were fully open at Mach 2.4. The final nozzle area did not increase with further increase in flight speed (for complete expansion to ambient and greater internal thrust) because its external diameter, greater than nacelle diameter would cause too much drag.<ref>Design For Air Combat, Ray Whitford, {{ISBN|0 7106 0426 2}}, p. 203</ref>

<gallery widths="220px" heights="165px" mode="packed" class="center" caption="Ejector-nozzle">
File:Lockheed SR-71A Blackbird at Evergreen Aviation & Space Museum (6586638859) (2).jpg|Ejector nozzle at the rear of the powerplant. The engine nozzle (left) is the first component in the exhaust system, followed by the secondary and tertiary air flows and ejector nozzle. The tertiary doors are open. There is a fixed convergent/divergent shroud and the ejector nozzle trailing flaps are at their minimum area (closed). These nozzle and door positions correspond with full afterburner up to transonic speed, after which the doors close and flaps start to open. Secondary air from the inlet passes between the engine and nacelle and joins the blow-in door air to control the expansion of the engine exhaust through the shroud and trailing flaps.
File:SR-71A taking off with afterburner RAF Mildenhall 1983.JPEG|A similar viewing angle, unstick speed 210 knots, to the "exploded" view, and with the same operating configuration: afterburner nozzle open, blow-in doors open and trailing flaps closed due to low internal pressure with low speed low inlet ram. Note the dark con-di shroud. Air entering the blow-in doors joins secondary air from the inlet and flows over the fixed shroud surface and trailing flaps while surrounding the exhaust from the engine.
</gallery>

=== Fuel ===
[[File:Boeing KC-135Q refueling SR-71.JPEG|thumb|alt= KC-135 and SR-71 during an "in-flight" refueling|An SR-71 refueling from a [[KC-135Q Stratotanker]] during a flight in 1983.]]
[[File:A right side view of a KC-10 Extender aircraft refueling an SR-71 Blackbird aircraft in-flight during testing DF-ST-83-03355.jpg|thumb|An SR-71 refueling from a [[KC-10 Extender]]. KC-10s were added in the mid-1980s as additional tankers.{{sfn|Graham|2008|page=113}}]]

The SR-71 used [[JP-7]] fuel that was difficult to ignite. To start the engines, [[triethylborane]] (TEB), which [[pyrophoricity|ignites on contact with air]], was injected to produce temperatures high enough to ignite the JP-7. The TEB produced a characteristic green flame, which could often be seen during engine ignition.<ref name="Shul" /> The fuel was used as a heat sink for the rest of the aircraft to cool the pilot and the electronics. An electric starting system was not possible due to the limited capacity of the cooling system, so the chemical ignition system was used.<ref>{{cite tech report |url=https://www.cia.gov/readingroom/document/cia-rdp90b00170r000200280025-6 |title=J58/SR-71 Propulsion Integration Or The Great Adventure Into The Technical Unknown |first=William |last=Brown |publisher=Pratt & Whitney Aircraft Group |id=attachment RDP90B00170R000200280025-6 to CIA-RDP90B00170R000100050008-1 |via=CIA}}</ref>

On a typical mission, the SR-71 took off with a partial fuel load to reduce stress on the brakes and tires during takeoff and also ensure it could successfully take off should one engine fail.{{sfn|Graham|1996|p=46}} Within 20 seconds, the aircraft traveled {{convert|4500|ft|abbr=on}}, reached {{convert|240|mph|abbr=on}}, and lifted off. It reached {{convert|20000|ft|abbr=on}} of altitude in less than two minutes, and the typical {{convert|80000|ft|abbr=on}} [[cruising altitude]] in another 17 minutes, having used one third of its fuel.{{r|iwm20211103}} It is a common misconception that the planes refueled shortly after takeoff because the fuel tanks, which formed the outer skin of the aircraft, leaked on the ground. It was not possible to prevent leaks when the aircraft skin was cold and the tanks only sealed when the skin warmed as the aircraft speed increased. The ability of the sealant to prevent leaks was compromised by the expansion and contraction of the skin with each flight.<ref>{{cite web |last1=Boudreaux |first1=Stormy |title=The SR-71 Experience |url=https://www.youtube.com/watch?v=J5qrMTtSUV8&t=2129s |website=YouTube |date=22 October 2022 |publisher=Air Zoo |access-date=17 September 2023}}</ref> However, the amount of fuel that leaked, measured as drops per minute on the ground from specific locations, was not enough to make refueling necessary.{{sfn|Graham|2013|p=110}}

The SR-71 also required [[Aerial refueling|in-flight refueling]] to replenish fuel during long-duration missions. Supersonic flights generally lasted no more than 90 minutes before the pilot had to find a tanker.<ref>Marshall, Elliot, The Blackbird's Wake, Air and Space, October/November 1990, p. 35.</ref>

Specialized [[Boeing KC-135 Stratotanker|KC-135Q]] tankers were required to refuel the SR-71. The KC-135Q had a modified high-speed boom, which would allow refueling of the Blackbird at near the tanker's maximum airspeed. The tanker also had special fuel systems for moving [[JP-4 (fuel)|JP-4]] (for the KC-135Q itself) and JP-7 (for the SR-71) between different tanks.{{sfn|Graham|1996|pages=38–39}} As an aid to the pilot when refueling, the cockpit was fitted with a [[peripheral vision horizon display]]. This unusual instrument projected a barely visible [[artificial horizon]] line across the top of the entire instrument panel, which gave the pilot [[subliminal stimuli|subliminal]] cues on aircraft attitude.{{sfn|Crickmore|2004|p=233}} If a KC-135Q was not available any tanker with JP-4 or JP-5 could be used in an emergency to avoid losing the aircraft, but with a Mach 1.5 speed limit.{{sfn|Graham|1996|p=46}}

On hot days, when approaching the maximum fuel load of {{cvt|80285|lb|kg|round=5}},{{sfn|Graham|1996|p=46}} the left engine had to be run with minimum afterburner to maintain probe contact.{{sfn|Graham|2008|page=120}}

===Astro-inertial navigation system{{Anchor|Astro-Inertial Navigation System|Astro-inertial navigation system}}===
Nortronics, [[Northrop Corporation]]'s electronics development division, had developed an [[astro-inertial guidance]] system (ANS), which could correct [[inertial navigation system]] errors with [[Celestial navigation|celestial observations]], for the [[SM-62 Snark]] missile, and a separate system for the ill-fated [[AGM-48 Skybolt]] missile, the latter of which was adapted for the SR-71.<ref>{{Cite book |last=Crickmore |first=Paul F. |url=https://books.google.com/books?id=9I1gDQAAQBAJ&dq=Nortronics+astro-inertial+guidance+system+(ANS)+SR-71&pg=PA173 |title=Lockheed Blackbird: Beyond the Secret Missions |date=2016-11-17 |edition=Revised |publisher=Bloomsbury Publishing |isbn=978-1-4728-1524-8 |language=en}}</ref>

Before takeoff, a primary alignment brought the ANS's inertial components to a high degree of accuracy. 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.<ref name="Shul"/> 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. The system's digital computer [[ephemeris]] contained data on [[List of selected stars for navigation|a list of stars used for celestial navigation]]: the list first included 56 stars and was later expanded to 61.<ref name="manual4-3">[http://www.sr-71.org/blackbird/manual/4/4-3.php "SR-71A-1 Flight Manual, Section IV, p. 3."] ''sr-71.org''. Retrieved: 13 December 2011.</ref> The ANS could supply altitude and position to flight controls and other systems, including the mission data recorder, automatic navigation to preset destination points, automatic pointing and control of cameras and sensors, and optical or SLR sighting of fixed points loaded into the ANS before takeoff. According to Richard Graham, a former SR-71 pilot, the navigation system was good enough to limit drift to {{cvt|1000|ft|m}} off the direction of travel at Mach&nbsp;3.<ref>{{cite web|url=https://www.youtube.com/watch?v=CeBu6mRDaro|title=SR-71 Pilot Interview Richard Graham Veteran Tales|work=YouTube|date=6 August 2013 }}</ref>

===Sensors and payloads===
[[File:SR-71 Defensive System B.jpg|thumb|The SR-71 Defensive System B]]

The SR-71 originally included optical/[[Thermographic camera|infrared imagery]] systems; [[side-looking airborne radar]] (SLAR);<ref>{{cite web |title=SR-71 Online – SR-71 Flight Manual: Section 4 |url=https://www.sr-71.org/blackbird/manual/4/4-86.php |website=Sr-71.org |pages=4–86}}</ref> [[electronic intelligence]] (ELINT) gathering systems;<ref>{{cite web |title=SR-71 Online – SR-71 Flight Manual: Section 4 |url=https://www.sr-71.org/blackbird/manual/4/4-99.php |website=Sr-71.org |pages=4–99}}</ref> defensive systems for countering missile and airborne fighters;<ref>{{cite web |title=SR-71 Online – SR-71 Flight Manual: Section 4 |url=https://www.sr-71.org/blackbird/manual/4/4-123.php |website=Sr-71.org |pages=4–123}}</ref><ref>{{cite web |title=SR-71 Online – SR-71 Flight Manual: Section 4 |url=https://www.sr-71.org/blackbird/manual/4/4-129.php |website=Sr-71.org |pages=4–129}}</ref><ref>{{cite web |title=SR-71 Online - SR-71 Flight Manual: Section 4 |url=https://www.sr-71.org/blackbird/manual/4/4-132.php |website=Sr-71.org |pages=4–132}}</ref><ref>{{cite web |title=SR-71 Online - SR-71 Flight Manual: Section 4 |url=https://www.sr-71.org/blackbird/manual/4/4-146.php |website=Sr-71.org |pages=4–146}}</ref> and recorders for SLAR, ELINT, and maintenance data. The SR-71 carried a [[Fairchild Camera and Instrument|Fairchild]] tracking camera and an [[Thermographic camera|infrared camera]],<ref>{{cite book |url=https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/books-and-monographs/a-12/Archangel-2ndEdition-2Feb12.pdf |archive-url=https://web.archive.org/web/20120926211605/https://www.cia.gov/library/center-for-the-study-of-intelligence/csi-publications/books-and-monographs/a-12/Archangel-2ndEdition-2Feb12.pdf |url-status=dead |archive-date=26 September 2012 |title=Archangel: CIA's Supersonic A-12 Reconnaissance Aircraft |edition=2nd |first=David |last=Robarge |publisher=CSI Publications |date=January 2012 |access-date=19 March 2019}}</ref> both of which ran during the entire mission.

As the SR-71 had a second cockpit behind the pilot for the RSO, it could not carry the A-12's principal sensor, a single large-focal-length optical camera that sat in the "Q-Bay" behind the A-12's single cockpit. Instead, the SR-71's camera systems could be located either in the fuselage chines or the removable nose/chine section. Wide-area imaging was provided by two of [[Itek]]'s [[Operational Objective Camera]]s, which provided stereo imagery across the width of the flight track, or an [[KA-80 Optical Bar Camera|Itek Optical Bar Camera]], which gave continuous horizon-to-horizon coverage. 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.{{sfn|Crickmore|1997|p=74}} 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.{{sfn|Crickmore|1997|p=74}}{{sfn|Crickmore|1997|p=563}}

SLAR, built by [[Goodyear Aerospace]], could be carried in the removable nose. In later life, the radar was replaced by Loral's Advanced [[Synthetic Aperture Radar]] System (ASARS-1). Both the first SLAR and ASARS-1 were ground-mapping imaging systems, collecting data either in fixed swaths left or right of centerline or from a spot location for higher resolution.{{sfn|Crickmore|1997|p=74}} ELINT-gathering systems, called the Electro Magnetic Reconnaissance System, built by AIL could be carried in the chine bays to analyze electronic signal fields being passed through, and were programmed to identify items of interest.{{sfn|Crickmore|1997|p=74}}{{sfn|Crickmore|1997|p=77}}

Over its operational life, the Blackbird carried various [[electronic countermeasures]] (ECMs), including warning and active electronic systems built by several ECM companies and called Systems A, A2, A2C, B, C, C2, E, G, H, and M. On a given mission, an aircraft carried several of these frequency/purpose payloads to meet the expected threats. Major Jerry Crew, an RSO, told ''[[Air & Space/Smithsonian]]'' that he used a [[Radar jamming and deception|jammer]] to try to confuse [[surface-to-air missile]] sites as their crews tracked his airplane, but once his threat-warning receiver told him a missile had been launched, he switched off the jammer to prevent the missile from homing in on its signal.<ref>{{cite journal|url=http://www.airspacemag.com/flight-today/blackbird-diaries-180953373/ |title=Blackbird Diaries {{!}} Flight Today |journal=Air & Space Magazine |page=45 |date=December 2014 |access-date=24 July 2015}}</ref> After landing, information from the SLAR, ELINT gathering systems, and the maintenance data recorder were subjected to postflight ground analysis. In the later years of its operational life, a datalink system could send ASARS-1 and ELINT data from about {{convert|2000|nmi|km|abbr=on}} of track coverage to a suitably equipped ground station.{{Citation needed|date=February 2012}}

===Life support===
[[File:Brian Shul in the cockpit of the SR-71 Blackbird.jpg|thumb|right|SR-71 pilot [[Brian Shul]] in full flight suit]]
[[File:SR71 crew.jpg|thumb|The crew of a NASA Lockheed SR-71 Blackbird standing by the aircraft in their pressurized flight suits, 1991]]

Flying at {{convert|80000|ft|m|abbr=on|sigfig=2}} meant that crews could not use standard masks, which could not provide enough oxygen above {{convert|43000|ft|m|abbr=on|sigfig=2}}. Specialized protective [[pressurized suit]]s were produced for crew members by the [[David Clark Company]] for the A-12, YF-12, M-21 and SR-71. Furthermore, an emergency [[Ejection seat|ejection]] at Mach&nbsp;3.2 would subject crews to temperatures of about {{convert|450|°F|°C|-1}}; thus, during a high-altitude ejection scenario, an onboard oxygen supply would keep the suit pressurized during the descent.<ref name=weaver/>

The cockpit could be pressurized to an altitude of {{convert|10000|or|26000|ft|m|abbr=on|sigfig=1}} during flight.<ref>Donald 2003, p. 172.</ref> The cabin needed a heavy-duty cooling system, as cruising at Mach&nbsp;3.2 would heat the aircraft's external surface well beyond {{convert|500|°F|°C|-1}}<ref name="PM06/91">''[[Popular Mechanics]]'', June 1991, p.&nbsp;28.</ref> and the inside of the windshield to {{convert|250|°F|°C|-1}}. An air conditioner used a [[heat exchanger]] to dump heat from the cockpit into the fuel prior to combustion.<ref>{{Cite book|title=Stratonauts: Pioneers Venturing into the Stratosphere|last=Ehrenfried|first=Manfred|year=2013|publisher=Springer |isbn=978-3-319-02901-6}}</ref> The same air-conditioning system was also used to keep the front (nose) landing gear bay cool, thereby eliminating the need for the special aluminum-impregnated tires similar to those used on the main landing gear.<ref name="SR-71 Maintenance (July 1984 - December 1989)">{{cite web|url=http://www.blackbirds.net/u2/c_bennett/bbird-03.html |title=SR-71 Maintenance |website=Blackbirds.net |access-date=29 October 2015}}</ref>

Blackbird pilots and RSOs were provided with food and drink for the long reconnaissance flights. Water bottles had long straws which crewmembers guided into an opening in the helmet by looking in a mirror. Food was contained in sealed containers similar to toothpaste tubes which delivered food to the crewmember's mouth through the helmet opening.<ref>{{Cite book|title=Sled Driver|last=Shul|first=Brian|publisher=Midland Publishing Limited|year=1992|isbn=978-1857800029|location=Earl Shilton, Leicester, England|pages=38–40}}</ref><ref name="Dowling">{{cite web |last=Dowling |first=Stephen |title=SR-71 Blackbird: The Cold War's ultimate spy plane |url=https://www.bbc.com/future/article/20130701-tales-from-the-blackbird-cockpit |website=[[BBC Future]] |date=2 July 2013 |access-date=30 November 2024 |archive-date=15 October 2024 |archive-url=https://web.archive.org/web/20241015211701/https://www.bbc.com/future/article/20130701-tales-from-the-blackbird-cockpit |url-status=live}}</ref>

==Operational history==
===Main era===
The first flight of an SR-71 took place on 22 December 1964, at USAF [[Plant 42]] in [[Palmdale, California]], piloted by Bob Gilliland.<ref>{{Cite web|url=https://www.kesq.com/news/first-man-to-fly-the-world-s-fastest-aircraft-dies-in-rancho-mirage/1092463937 |title=First man to fly the world's fastest aircraft dies in Rancho Mirage |first=Jesus |last=Reyes |date=6 July 2019 |website=KESQ |access-date=6 July 2019 |archive-url=https://web.archive.org/web/20190706041642/https://www.kesq.com/news/first-man-to-fly-the-world-s-fastest-aircraft-dies-in-rancho-mirage/1092463937 |archive-date=6 July 2019 |url-status=dead}}</ref>{{sfn|Crickmore|1997|pp=56-58}} The SR-71 reached a top speed of Mach 3.4 during flight testing,<ref>{{cite web |last= Graham |first=Richard |title=SR-71 Pilot Interview Richard Graham, Veteran Tales interview at Frontiers of Flight Museum (at 1:02:55) |url=https://www.youtube.com/watch?v=CeBu6mRDaro#t=3775 |work=YouTube |date=6 August 2013 |publisher=Erik Johnston |access-date=29 August 2013 |ref=none}}</ref><ref>{{cite web |title=Col. Richard Graham (USAF, Ret.) |url=http://www.habu.org/graham/graham-bio.html |publisher=The Online Blackbird Museum |website=Habu.org |access-date=16 January 2016}}</ref> with pilot Major [[Brian Shul]] reporting a speed in excess of Mach 3.5 on an operational sortie while evading a missile over Libya.<ref name="Shul M3.5">{{cite book |last=Shul |first=Brian |title=The Untouchables |year=1994 |publisher=Mach One |isbn=0929823125 |page=173}}</ref> The first SR-71 to enter service was delivered to the [[9th Reconnaissance Wing#Beale Air Force Base|4200th (later, 9th) Strategic Reconnaissance Wing]] at [[Beale Air Force Base]], California, in January 1966.{{sfn|Crickmore|1997|p=59}}

SR-71s first arrived at the 9th SRW's Operating Location (OL-8) at [[Kadena Air Base]], Okinawa, Japan on 8 March 1968.{{sfn|Crickmore|1997|pp=62-64}} These deployments were code-named "Glowing Heat", while the program as a whole was code-named "Senior Crown". Reconnaissance missions over North Vietnam were code-named "Black Shield" and then renamed "Giant Scale" in late 1968.<ref>{{cite web |url=https://www.cia.gov/library/readingroom/docs/CIA-RDP79B01709A001900060005-2.pdf|archive-url=https://web.archive.org/web/20170123150906/https://www.cia.gov/library/readingroom/docs/CIA-RDP79B01709A001900060005-2.pdf|url-status=dead|archive-date=23 January 2017|title=Memorandum for the Chairman, Sanitization and Decontrol Working Group Black Shield Photography|publisher=Central Intelligence Agency|date=19 November 1968|access-date=16 July 2020}}</ref> 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 {{USAF serial|61|7976}} from Kadena AFB, Okinawa.{{sfn|Crickmore|1997|pp=62-64}} During its career, this aircraft (976) accumulated 2,981 flying hours and flew 942 total sorties (more than any other SR-71), including 257 operational missions, from Beale AFB; Palmdale, California; Kadena Air Base, Okinawa, Japan; and [[RAF Mildenhall]], UK. The aircraft was flown to the [[National Museum of the United States Air Force]] near [[Dayton, Ohio]] in March 1990.

[[File:SR-71 Blackbird & Farnborough Air Show 1974.webm|thumb|''Advanced Development Projects: The Record Breakers'' (1974) Official [[United States Department of Defense|Department of Defense]] promotional film reel, at the 1974 Farnborough Air-show.]]

The USAF could fly each SR-71 on average once per week because of the extended turnaround required after mission recovery. Very often an aircraft would return with rivets missing, delaminated panels, or other broken parts such as inlets requiring repair or replacement. There were cases of the aircraft not being ready to fly again for a month due to the repairs needed. Rob Vermeland, [[Lockheed Martin]]'s manager of Advanced Development Program, said in an interview in 2015 that high-tempo operations were not realistic for the SR-71. "If we had one sitting in the hangar here and the crew chief was told there was a mission planned right now, then 19 hours later it would be safely ready to take off."<ref>Norros, Guy, "Hyper ops", ''Aviation Week & Space Technology'', 20 July – 2 August 2015, p. 28.</ref>

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. By 1970, the SR-71s were averaging two sorties per week, and by 1972, they were flying nearly one sortie every day. Two SR-71s were lost during these missions, one in 1970 and the second aircraft in 1972, both due to mechanical malfunctions.<ref>Hobson p. 269.</ref><ref>Donald 2003, p. 167.</ref> 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.<ref>{{cite web |url=http://breakingdefense.com/2015/09/bye-bye-u-2-cia-legend-allen-predicts-end-of-manned-reconnaissance/ |title=Bye Bye U-2: CIA Legend Allen Predicts End Of Manned Reconnaissance |first=Richard |last=Little |work=Breaking Defense |date=22 September 2015 |access-date=29 May 2017}}</ref> Pilots did report that missiles launched without radar guidance and no launch detection, had passed as close as {{convert|150|yd}} from the aircraft.<ref>Quote from Reg Blackwell, SR-71 pilot, interviewed for "Battle Stations" episode "SR-71 Blackbird Stealth Plane", first aired on History Channel 15 December 2002.</ref>

[[File:Early project logo Habu SR-71.jpg|thumb|right|upright=0.7|Early project [[Protobothrops flavoviridis|Habu]] logo]]

While deployed at Okinawa, the SR-71s and their aircrew members gained the nickname [[Trimeresurus flavoviridis|Habu]] (as did the A-12s preceding them) after a [[Viperidae|pit viper]] indigenous to Japan, which the Okinawans thought the plane resembled.{{sfn|Crickmore|1997|p=64}}

Operational highlights for the entire Blackbird family (YF-12, A-12, and SR-71) as of about 1990 included:{{sfn|Graham|1996}}
*3,551 mission sorties flown
*17,300 total sorties flown
*11,008 mission flight hours
*53,490 total flight hours
*2,752 hours Mach 3 time (missions)
*11,675 hours Mach 3 time (total)

Only one crew member, Jim Zwayer, a Lockheed flight-test reconnaissance and navigation systems specialist, was killed in a flight accident.<ref name=weaver/> The rest of the crew members ejected safely or evacuated their aircraft on the ground.

An SR-71 was used domestically in 1971 to assist the FBI in their manhunt for the skyjacker [[D.B. Cooper]]. The Blackbird was to retrace and photograph the flightpath of the hijacked 727 from Seattle to Reno and attempt to locate any of the items that Cooper was known to have parachuted with from the aircraft.<ref>{{cite report |date= 6 December 1971|title= SR 71 Flight |url= https://vault.fbi.gov/D-B-Cooper%20/d.b.-cooper-part-60/view |publisher= Federal Bureau of Investigation |page= 340 |quote="Beale Air Force Base, California, had offered, free of charge to the Bureau, use of an SR-71 aircraft to photograph terrain over which the hijacked airplane had flown on its trip to Reno"}}</ref> Five flights were attempted but on each occasion no photographs of the flight path were obtained due to low visibility.<ref>{{cite report |date= 6 December 1971 |title= SR 71 Flight |url= https://vault.fbi.gov/D-B-Cooper%20/d.b.-cooper-part-60/view |publisher= Federal Bureau of Investigation |page= 340 |quote="photographic over-flights using SR-71 aircraft were conducted on five separate occasions with no photographs obtained due to limited visibility from very high altitude."}}</ref>

==== European flights{{Anchor|European flights|Baltic Express}} ====
European operations were flown from RAF Mildenhall, England, with two weekly routes. One was along the [[Coastline of Norway|Norwegian west coast]] and up the [[Kola Peninsula]], monitoring several large naval bases belonging to the Soviet Navy's [[Northern Fleet]]. Over the years, there were several emergency landings in Norway, four in Bodø and two of them in 1981, flying from Beale, in 1985. Rescue parties were sent in to repair the planes before leaving. On one occasion, one complete wing with engine was replaced as the easiest way to get the plane airborne again.<ref name="SpionflyNO">{{cite news |last1=Bonafede |first1=Håkon |date=22 April 2012 |title=SPIONFLY, DEN KALDE KRIGEN – Spionfly landet i Bodø |trans-title=Spy plane, The Cold War – Spy plane landed in Bodø |url=http://www.side3.no/spionfly-landet-i-bod/3380954.html |url-status=dead |archive-url=https://web.archive.org/web/20140404143706/http://www.side3.no/spionfly-landet-i-bod/3380954.html |archive-date=4 April 2014 |access-date=11 September 2017 |work=[[Vi Menn]] |location=Norway |language=NB |via=[[:nb:Side3]] |quote=}}</ref><ref>{{cite web |url=http://www.wvi.com/~sr71webmaster/bodo.html |title=SR-71 Bodo Norway Operations |first=Leland |last=Haynes |access-date=7 October 2017}}</ref>

[[File:Baltic Sea map.png|thumb|right|upright=1|The Baltic Express route entered through [[Denmark]] and the narrow corridor between Sweden and [[East Germany]].]]

The other route was known as the ''Baltic Express'', which started from Mildenhall and went through [[Jutland]] and the [[Danish straits]] before going out over the [[Baltic Sea]].<ref name=Skuddhold /> At the time, the [[USSR]] controlled the airspace from the [[Deutsche Demokratische Republik|DDR]] to the [[Gulf of Finland]], with [[Finnish neutrality|Finland]] and [[Swedish neutrality#The Cold War|Sweden pursuing neutrality]] in the Cold War. This meant that [[NATO]] aircraft entering the Baltic Sea had to fly through a narrow corridor of international airspace between [[Skåne County|Scania]] and [[Western Pomerania]], which was monitored by both the [[Swedish Air Force|Swedish]] and [[Soviet Air Forces]]. Starting a counter-clockwise 30-minute loop, the Blackbirds would then [[reconnoiter]] along the Soviet Union's coastal border, before slowing down to Mach 2.54 to make a left turn south of [[Åland]], and then follow the Swedish coast back towards Denmark. If the SR-71s attempted the turn at Mach 3, they could end up violating Swedish airspace, and the Swedes would [[Ground-controlled interception|direct]] [[Interceptor aircraft|fighters]] to intercept the offending aircraft.<ref name=Skuddhold /><ref name=AGCViggen />

The combination of a monitored entry point and a fixed route allowed the Swedes and the Soviets a chance to [[Scrambling (military)|scramble]] interceptors.<ref name=Skuddhold /> Swedish radar stations would observe the [[15th Air Army#After 1945|15th Air Army]] dispatch [[Su-15]]s from [[Latvian Soviet Socialist Republic|Latvia]], and [[MiG-21]]s and [[MiG-23]]s from [[Estonian Soviet Socialist Republic|Estonia]], although only the Sukhois would have even a slim chance of successfully intercepting the American aircraft.<ref name=AGCViggen /> The greater Soviet threat came from the MiG-25s [[16th Guards Fighter Aviation Division|stationed]] at [[Eberswalde#Transport|Finow-Eberswalde]] in the DDR. The Swedes noted that the Soviets usually would send a single [[MiG-25|MiG-25 "Foxbat"]] from Finow to intercept the SR-71 on their way back out of the Baltic Sea. With the Blackbird flying at {{convert|22|km|ft|order=flip|abbr=on}}, the Foxbat would regularly close to an altitude of {{convert|19|km|ft|order=flip|abbr=on}}, precisely {{convert|3|km|mi|order=flip|abbr=on}} behind the SR-71, before disengaging. The Swedes interpreted this regularity as a sign that the MiG-25 had successfully simulated a shoot-down.<ref name=Skuddhold /><ref name=AGCViggen>{{cite news |last1=Leone |first1=Dario |title=VIGGEN Vs BLACKBIRD: HOW SWEDISH AIR FORCE JA-37 FIGHTER PILOTS WERE ABLE TO ACHIEVE RADAR LOCK ON THE LEGENDARY SR-71 MACH 3 SPY PLANE |work=The Aviation Geek Club |date=9 January 2018 |access-date=9 October 2023 |archive-date=10 January 2019 |archive-url=https://web.archive.org/web/20190110152553/https://theaviationgeekclub.com/viggen-vs-blackbird-swedish-air-force-ja-37-fighter-pilots-able-achieve-radar-lock-legendary-sr-71-mach-3-spy-plane/ |url=https://theaviationgeekclub.com/viggen-vs-blackbird-swedish-air-force-ja-37-fighter-pilots-able-achieve-radar-lock-legendary-sr-71-mach-3-spy-plane/ |url-status=live |quote=Almost every time the SR-71 was about to leave the Baltic, a lone MiG-25 Foxbat belonging to the 787th IAP at Finow-Eberwalde in [East Germany] was scrambled. […] Arriving at its exit point, the “Baltic Express” was flying at about 22km and the lone MiG would reach about 19km in a left turn before rolling out and always completing its stern attack 3km behind its target. We were always impressed by this precision; it was always 22km and 3 km behind the SR-71. [this would seem to suggest that these were the parameters necessary for its weapons system to effect a successful intercept if the order to fire was ever given.]}}</ref><ref name=rbth2012>{{cite news |last1= Simha |first1= Rakesh Krishnan |title= Foxhound vs Blackbird: How the MiGs reclaimed the skies |work= [[Russia Beyond the Headlines]] |publisher= [[Rossiyskaya Gazeta]] |date=3 September 2012 |access-date=30 May 2015 |archive-date=9 August 2019 |archive-url= https://web.archive.org/web/20190809232332/https://www.rbth.com/articles/2012/09/03/foxhound_vs_blackbird_how_the_migs_reclaimed_the_skies_17363 |url= https://www.rbth.com/articles/2012/09/03/foxhound_vs_blackbird_how_the_migs_reclaimed_the_skies_17363 |url-status= live |quote=Swedish air defense [...] radar screens [...] could see the much older but faster MiG-25 screaming in towards the Blackbird. Shortly after the MiG-31s had harried the SR-71 in the Arctic area, a lone MiG-25 Foxbat stationed at Finow-Eberswalde in the former GDR would intercept it over the Baltic. The Swedes observed the SR-71 would always fly at 72,000 ft and the MiG-25 would reach 63,000 ft before completing its stern attack 2.9 km behind the Blackbird. “We were always impressed by this precision, it was always 63,000 ft and 2.9 km behind the SR-71," a retired Swedish Air Force flight controller told Crickmore.}}<!--page 2 only clickable, not linkable or archivable--></ref>

The Swedes themselves would typically assert their neutrality by dispatching [[Saab 37 Viggen|JA37 Viggen]]s from [[Scania Wing|Ängelholm]], [[Bråvalla Wing|Norrköping]] or [[Blekinge Wing|Ronneby]]. Limited by a top speed of Mach&nbsp;2.1 and a [[Ceiling (aeronautics)|service ceiling]] of {{cvt|18|km|ft|order=flip}}, the Viggen pilots would line up for a frontal attack, and rely on their [[state-of-the-art]] [[avionics]] to climb at the right time and attain a [[missile lock]] on the SR-71.<ref name=Skuddhold /><ref name=AGCViggen /> Precise timing and target illumination would be maintained with target location data supplied to the Viggen's [[fire-control computer]] from [[Fire-control radar|ground-based radars]],<ref name=FlyghistoriskRevy>{{cite book |editor-last1=Edlund |editor-first1=Ulf |editor-last2=Kampf |editor-first2=Hans |year=2009 |title=System 37 Viggen |series=Flyghistorisk Revy |volume=Specialnr 2009 |url= |language=SV |location=Stockholm |publisher=[[:sv:Svensk Flyghistorisk Förening|Svensk Flyghistorisk Förening]] |issn=0345-3413}}</ref> with the most common site for the [[Missile lock-on|lock-on]] being the thin stretch of international airspace between [[Öland]] and [[Gotland]].<ref name=Mach14>{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Mach 14 |url= |magazine=Mach |language=SV |location=Sweden |publisher= |year=1983 |volume=4 |issue=3 |page=5 |issn=0280-8498}}</ref><ref name=Mach25>{{cite magazine |author=<!--Staff writer(s); no by-line.--> |title=Mach 25 |url= |magazine=Mach |language=SV |location=Sweden |publisher= |year=1986 |volume=7 |issue=2 |pages=28–29 |issn=0280-8498}}</ref><ref>Darwal 2004, pp. 151–156.</ref> Out of 322 recorded Baltic Express sorties between 1977 and 1988, the Swedish Air Force claims that they succeeded in attaining missile lock on the SR-71 in 51 of them.<ref name=Skuddhold>{{cite news |last1=Bonafede |first1=Håkon |title=På skuddhold av SR-71 Blackbird |trans-title=At weapons range of the SR-71 |work=[[Vi Menn]] |date=10 May 2018 |access-date=12 May 2018 |archive-date=10 May 2018 |archive-url=https://web.archive.org/web/20180510102459/http://www.side3.no/historie/pa-skuddhold-av-sr-71-blackbird/3423484769.html |url=http://www.side3.no/historie/pa-skuddhold-av-sr-71-blackbird/3423484769.html |url-status=dead |language=NB |location=Norway |via=[[:nb:Side3]] |quote=To vanlige "melkeruter" ble fløyet ukentlig [...] Den andre som ble kalt for "Baltic Express" dekket marinebasene og militærinstallasjonene til DDR og de baltiske landene. På grunn av det trange farvannet, bød ruten på utfordringer med å holde seg utenfor territorialgrensene, og flygerne fulgte nesten alltid den samme identiske ruten. [...] SR-71 kom alltid inn over radiofyret "Codan" 80 km sør for København på kurs rett østover.|trans-quote=Two common "[[milk run]]s" were flown weekly [...] The second, which was called [the] "Baltic Express" covered the Navy bases and military installations of the DDR and the Baltic countries. Because of the cramped waters, the route presented challenges as to keeping outside the territorial borders, and the pilots almost always followed the same identical route. [...] SR-71 always came in over the radio beacon "Codan" 80 km south of Copenhagen[,] heading east.}}</ref><ref name="NTSEFlygplan">{{cite news |author=<!-- Not stated --> |date=2 May 2017 |title=TV: Kärnvapensäkra bunkern styrde flygplanen |trans-title=TV: Aircraft controlled from nuclear weapon secured bunker |url=http://www.nt.se/nyheter/ostergotland/tv-karnvapensakra-bunkern-styrde-flygplanen-om4626725.aspx |url-status= |archive-url=https://web.archive.org/web/20170502185029/http://www.nt.se/nyheter/ostergotland/tv-karnvapensakra-bunkern-styrde-flygplanen-om4626725.aspx |archive-date=2 May 2017 |access-date=7 October 2017 |work=Kundservice |location=Sweden |language=SV |via= |quote=Look at time 5:57.}}</ref> However, with a combined closing speed of Mach 5, the Swedes were reliant on the Blackbird not changing course.<ref name=Skuddhold /><ref name=AGCViggen />

[[File:2018-11-28, Swedish Air Force pilots receive USAF Air Medal (45203706835).jpg|Swedish [[Saab 37 Viggen|Viggen]]-pilots being presented with the [[Air Medal|US Air Medal]] in 2018.|thumb|right|upright=1]]

On 29 June 1987, an SR-71{{refn|AF serial number 61-7964<ref name=Skuddhold />|group=N}} was on a mission around the Baltic Sea to spy on Soviet postings when one of the engines exploded. The aircraft, which was at {{cvt|20|km|ft|order=flip}} altitude, quickly lost altitude and turned 180° to the left and turned over Gotland to search for the Swedish coast. Thus, Swedish airspace was violated, whereupon two unarmed<ref>{{Cite AV media |title=When the Swedish Air Force Saab 37 Viggen Saved the Lockheed SR-71 Blackbird |via=YouTube |url=https://www.youtube.com/watch?v=y5Z2Bb-wnls&t=455s |first=Kelly |last=OConnor |publisher=100th Air Refueling Wing Public Affairs |access-date=15 December 2022}}</ref> Saab JA 37 Viggens on an exercise at the height of [[Västervik]] were ordered there. The mission was to do an incident preparedness check and identify an aircraft of high interest. It was found that the plane was in obvious distress and a decision was made that the Swedish Air Force would escort the plane out of the Baltic Sea. A second round of armed JA-37s from Ängelholm replaced the first pair and completed the escort to Danish airspace.<ref name=Skuddhold /><ref name=AGCViggen /><ref name=AFMil181129 /> The event had been classified for over 30 years, and when the report was unsealed, data from the [[National Security Agency|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. A MiG-25 had locked a missile on the damaged SR-71, but as the aircraft was under escort, no missiles were fired. On 28 November 2018, the four Swedish pilots involved were awarded medals from the USAF.<ref name=AFMil181129>{{cite web |last1=Fratini |first1=Korey |title=AF.mil: Swedish pilots presented with US Air Medal |publisher=[[US Air Force]] |date=29 November 2018 |access-date=7 May 2023 |archive-date=8 May 2023 |archive-url=https://web.archive.org/web/20230508075739/https://www.af.mil/News/Article-Display/Article/1700869/swedish-pilots-presented-with-us-air-medal/ |url=https://www.af.mil/News/Article-Display/Article/1700869/swedish-pilots-presented-with-us-air-medal/ |url-status=live |language=EN |location=Stockholm |via= |quote=The U.S. was flying regular SR-71 aircraft reconnaissance missions in international waters over the Baltic Sea known as “Baltic Express” missions. But on June 29, 1987, during one of those missions, an SR-71 piloted by retired Lt. Cols. Duane Noll and Tom Veltri, experienced an inflight emergency. [...] presented the Air Medals to Swedish air force Col. Lars-Eric Blad, Maj. Roger Moller, Maj. Krister Sjoberg and Lt. Bo Ignell.}}</ref>

===Initial retirement===
The two most widely proposed reasons for the SR-71's retirement in 1989, offered by the Air Force to Congress, were that the plane was too expensive to build and maintain, and had been rendered redundant by other evolving reconnaissance methods, such as unmanned vehicles (UAVs) and satellites. Another view held by officers and legislators is that the SR-71 was terminated due to [[United States Department of Defense|Pentagon]] politics.{{citation needed|date=September 2024}}

In 1996, a former 1st-SRS and 9th-SRW commander, Graham, presented a strongly supported opinion that the SR-71 provided some intelligence capabilities that none of its alternatives could provide in the 1990s, when the SR-71 was retired.{{sfn|Graham|1996|pages=205–217}} Opinion remained divided as to how crucial, or disposable, those unique advantages properly were.

Graham noted that in the 1970s and early 1980s, to be selected into the SR-71 program, a pilot or navigator (RSO) had to be a top-quality USAF officer, so SR-71 squadron and wing commanders often pursued career advancement with promotion into higher positions within the USAF and the Pentagon. These generals were adept at communicating the value of the SR-71 to a USAF command staff and a Congress who often lacked a basic understanding of how the SR-71 worked and what it did. However, by the mid-1980s, these "SR-71 generals" all had retired, and a new generation of USAF generals had come to believe that the SR-71 had become redundant, and wanted to pursue newer, top secret programs like the new [[B-2 Spirit]] [[strategic bomber]] program.{{sfn|Graham|1996}} Graham said that the last-mentioned one was only a sales pitch, not a fact, at the time in the 1990s.<!--Graham 1996 states this clearly: there was no secret replacement that had even started development yet (in the 1985-1995 decade), let alone being close to finished. Have to find the page number.{{rp|000}}-->

The USAF may have seen the SR-71 as a bargaining chip to ensure the survival of other priorities. Also, the SR-71 program's "product", which was operational and strategic intelligence, was not seen by these generals as being very valuable to the USAF. The primary consumers of this intelligence were the CIA, NSA, and DIA. A general misunderstanding of the nature of aerial reconnaissance and a lack of knowledge about the SR-71 in particular (due to its secretive development and operations) was used by detractors to discredit the aircraft, with the assurance given that a replacement was under development.{{sfn|Graham|1996}} [[Dick Cheney]] told the Senate Appropriations Committee that the SR-71 cost $85,000 per hour to operate.<ref>Marshall, Eliot, "The Blackbird's Wake", Air & Space, October/November 1990, p. 35.</ref> Opponents estimated the aircraft's support cost at $400 to $700&nbsp;million per year, though the cost was actually closer to $300&nbsp;million.{{sfn|Graham|1996}}

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. This meant that much of the SR-71's imagery and radar data could not be used in real time, but had to wait until the aircraft returned to base. This lack of immediate real-time capability was used as one of the justifications to close down the program. The counterargument was that the longer the SR-71 was not upgraded as aggressively as it ought to have been, the more people could say that it was obsolescent, which was in their interest as champions of other programs (a self-fulfilling bias). Attempts to add a datalink to the SR-71 were stymied early on by the same factions in the Pentagon and Congress who were already set on the program's demise, even in the early 1980s. 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.{{sfn|Graham|1996}}

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. However, the USAF refused to spend the money.{{sfn|Graham|1996|p=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 [[United States Navy|US Navy]],{{sfn|Crickmore|1997|pp=84-85}}{{sfn|Graham|1996|pages=194–195}} the decision to retire the SR-71 from active duty came in 1989, with the last missions flown in October that year.{{sfn|Crickmore|1997|p=81}} Four months after the plane's retirement, General [[Norman Schwarzkopf Jr.]], was told that the expedited reconnaissance, which the SR-71 could have provided, was unavailable during [[Operation Desert Storm]].<ref name="Remak">Remak and Ventolo 2001, {{page needed|date=August 2014}}</ref>

The SR-71 program's main operational capabilities came to a close at the end of fiscal year 1989 (October 1989). 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. The squadron finally closed in mid-1990, and the aircraft were distributed to static display locations, with a number kept in reserve storage.{{sfn|Graham|1996}}

===Reactivation===
{{Blockquote|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. When we are trying to find out if the [[Serbs]] are taking arms, moving tanks or artillery into [[Bosnia and Herzegovina|Bosnia]], we can get a picture of them stacked up on the Serbian side of the bridge. We do not know whether they then went on to move across that bridge. We need the [data] that a tactical, an SR-71, a U-2, or an unmanned vehicle of some sort, will give us, in addition to, not in replacement of, the ability of the satellites to go around and check not only that spot but a lot of other spots around the world for us. It is the integration of strategic and tactical.|Response from Admiral [[Richard C. Macke]] to the Senate Committee on Armed Services.<ref name="Senate"/>}}

[[File:Lockheed SR-71s.jpg|thumb|SR-71A (2) and SR-71B trainer (center), Edwards Air Force Base, California, 1992]]

Due to unease over political situations in the Middle East and [[North Korea]], the US Congress re-examined the SR-71 beginning in 1993.<ref name="Remak"/> 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. And the determination was that if one could take advantage of technology and develop a system that could get that data back real time... that would be able to meet the unique requirements of the tactical commander." Hall also stated they were "looking at alternative means of doing [the job of the SR-71]."<ref name="Senate">"Department of Defense Authorization for Appropriations for Fiscal Year 1994 and The Future Years." ''United States Senate'', May–June 1993.</ref>

Macke told the committee that they were "flying U-2s, [[Boeing RC-135|RC-135s]], [and] other strategic and tactical assets" to collect information in some areas.<ref name="Senate"/> Senator [[Robert Byrd]] and other senators complained that the "better than" successor to the SR-71 had yet to be developed at the cost of the "good enough" serviceable aircraft. They maintained that, in a time of constrained military budgets, designing, building, and testing an aircraft with the same capabilities as the SR-71 would be impossible.{{sfn|Graham|1996}}

Congress's disappointment with the lack of a suitable replacement for the Blackbird was cited concerning whether to continue funding imaging sensors on the U-2. 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."{{sfn|Graham|1996}} It was agreed to add $100&nbsp;million to the budget to return three SR-71s to service, but it was emphasized that this "would not prejudice support for long-endurance [[Unmanned aerial vehicle|UAVs]]" such as the [[Global Hawk]]. The funding was later cut to $72.5&nbsp;million.{{sfn|Graham|1996}} The Skunk Works was able to return the aircraft to service under budget at $72&nbsp;million.<ref name="Jenkins">Jenkins 2001</ref>

Retired USAF Colonel Jay Murphy was made the Program Manager for Lockheed's reactivation plans. Retired USAF Colonels Don Emmons and Barry MacKean were put under government contract to remake the plane's logistic and support structure. Still-active USAF pilots and Reconnaissance Systems Officers (RSOs) who had worked with the aircraft were asked to volunteer to fly the reactivated planes. The aircraft was under the command and control of the [[9th Reconnaissance Wing]] at Beale Air Force Base and flew out of a renovated hangar at [[Edwards Air Force Base]]. Modifications were made to provide a data-link with "near real-time" transmission of the Advanced Synthetic Aperture Radar's imagery to sites on the ground.{{sfn|Graham|1996}}

===Final retirement===
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. Also, with the allocation requiring yearly reaffirmation by Congress, long-term planning for the SR-71 was difficult.{{sfn|Graham|1996}} In 1996, the USAF claimed that specific funding had not been authorized, and moved to ground the program. Congress reauthorized the funds, but, in October 1997, President [[Bill Clinton]] attempted to use the [[line-item veto]] to cancel the $39&nbsp;million (~${{Format price|{{Inflation|index=US-GDP|value=39000000|start_year=1997}}}} in {{Inflation/year|US-GDP}}) allocated for the SR-71. In June 1998, the [[Supreme Court of the United States|US Supreme Court]] ruled that the [[Clinton v. City of New York|line-item veto was unconstitutional]]. All this left the SR-71's status uncertain until September 1998, when the USAF called for the funds to be redistributed; the USAF permanently retired it in 1998.

[[NASA]] operated the two last airworthy Blackbirds until 1999.<ref>{{cite web |title=SR-71 Blackbird |url=https://www.nasa.gov/wp-content/uploads/2021/09/495839main_fs-030_sr-71.pdf?emrc=0612db |website=NASAFacts |publisher=NASA |access-date=5 September 2024}}</ref> All other Blackbirds have been moved to museums except for the two SR-71s and a few [[Lockheed D-21|D-21]] drones retained by the NASA [[Dryden Flight Research Center]] (later renamed the [[Armstrong Flight Research Center]]).<ref name="Jenkins"/>

===Timeline===

====1950s–1960s====
* 24 December 1957: First J58 engine run
* 1 May 1960: [[Francis Gary Powers]] is shot down in a [[Lockheed U-2]] over the Soviet Union
* 13 June 1962: SR-71 mock-up reviewed by the USAF
* 30 July 1962: J58 completes pre-flight testing
* 28 December 1962: Lockheed signs contract to build six SR-71 aircraft
* 25 July 1964: President Johnson makes public announcement of SR-71
* 29 October 1964: SR-71 prototype (AF Ser. No. 61-7950) delivered to [[Air Force Plant 42]] at Palmdale, California
* 7 December 1964: [[Beale AFB]], California, announced as base for SR-71
* 22 December 1964: First flight of the SR-71, with Lockheed test pilot Robert J "Bob" Gilliland at Palmdale, California<ref name=Landis_p58>{{harvp|Landis|Jenkins|2004|p=58}}</ref>
* 21 July 1967: Jim Watkins and Dave Dempster fly first international sortie in SR-71A, AF Ser. No. 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. No. 61-7978) arrives at [[Kadena AB]], Okinawa to replace A-12s
* 21 March 1968: First SR-71 (AF Ser. No. 61-7976) operational mission flown from Kadena AB over Vietnam
* 29 May 1968: CMSgt Bill Gornik begins the tie-cutting tradition of Habu crews' neckties
* 13 December 1969: Two SR-71s deployed to [[Taiwan]].

====1970s–1980s====
* 3 December 1975: First flight of SR-71A (AF Ser. No. 61-7959) in "big tail" configuration
* 20 April 1976: TDY operations started at [[RAF Mildenhall]], United Kingdom with SR-71A, AF Ser. No. 61-7972
* 27–28 July 1976: SR-71A sets speed and altitude records (altitude in horizontal flight: {{convert|85068.997|ft|m|abbr=on}} and speed over a straight course: {{convert|2193.167|mph|km/h}})
* August 1980: [[Honeywell]] starts conversion of AFICS to DAFICS
* 15 January 1982: SR-71B, AF Ser. No. 61-7956, flies its 1,000th sortie
* 29 June 1987: 61-7964 flying a reconnaissance mission over the Baltic Express when its experienced an engine failure, causing it to drop into Swedish airspace. Swedish [[Saab 37 Viggen|Viggens]] were sent to intercept an SR-71 for violating Swedish airspace. They assessed the emergency situation and rendered support to the aircraft by defending it from potential Soviet threats. The Swedish interceptors escorted the Blackbird until it reached Danish airspace where it was safely recovered. The incident was declassified in 2018 and the four Swedish air force pilots received U.S. Air Medals over 31 years after the incident.<ref>{{Cite web |last=Fratini |first=Korey |date=29 November 2018 |title=Swedish pilots presented with US Air Medal |url=https://www.af.mil/News/Article-Display/Article/1700869/swedish-pilots-presented-with-us-air-medal/#:~:text=According%20to%20the%20Air%20Medal,have%20tried%20to%20threaten%20it. }}</ref>
* 21 April 1989: SR-71, AF Ser. No. 61-7974, is lost due to an engine explosion after taking off from Kadena AB, the last Blackbird to be lost.<ref name="Landis_p98-101"/><ref name="Pace_p126-7"/>
* 22 November 1989: USAF SR-71 program officially terminated

====1990s====
* 6 March 1990: Last SR-71 flight under Senior Crown program, setting four speed records en route to the Smithsonian Institution
* 20 March 1990: SR-71A #61-7964 (17964) last flight. Delivered to [[Offutt Air Force Base|Offutt AFB]] for permanent display. On display at the [[Strategic Air Command & Aerospace Museum|Strategic Air and Space Museum]] in Ashland, Nebraska.
* 25 July 1991: SR-71B, AF Ser. No. 61-7956/NASA No. 831 officially delivered to NASA Dryden Flight Research Center at [[Edwards AFB]], California
* October 1991: NASA engineer [[Marta Bohn-Meyer]] becomes the first female SR-71 crew member
* 28 September 1994: Congress votes to allocate $100&nbsp;million for reactivation of three SR-71s
* 28 June 1995: First reactivated SR-71 returns to USAF as Detachment 2
* 9 October 1999: The last flight of the SR-71 (AF Serial No. 61-7980/NASA 844)

===Records===
[[File:View from the SR-71 Blackbird.jpg|thumb|right|View from the cockpit at {{convert|83000|ft|m}} over the Atlantic Ocean<ref name="untouchables114">Shul and Watson 1993, pp. 113–114.</ref>]]

The SR-71 was the world's fastest and highest-flying air-breathing operational manned aircraft throughout its career and it still holds that record. On 28 July 1976, SR-71 serial number {{USAF serial|61|7962}}, piloted by then Captain Robert Helt, broke the world record: an "absolute altitude record" of {{convert|85069|ft|m|sigfig=5}}.<ref name=FAI_records>[https://web.archive.org/web/20100729111021/http://records.fai.org/general_aviation/aircraft.asp?id=779 "Records: Sub-class: C-1 (Landplanes) Group 3: turbo-jet."] ''records.fai.org''. Retrieved: 30 June 2011.</ref><ref name="landis_jenkins_p77-8">{{harvp|Landis|Jenkins|2004|pp=77-78}}</ref><ref>{{cite web|url=http://www.wvi.com/~sr71webmaster/spd_run001.html|title=SR-71 World Record Speed and Altitude Flights|website=Wvi.com}}</ref><ref name="voodoo-world.cz">{{cite web|url=http://www.voodoo-world.cz/sr71/timeline.html|title=A-12, YF-12A, & SR-71 Timeline of Events|website=Voodoo-world.cz}}</ref> Several aircraft have exceeded this altitude in [[zoom climb]]s, but not in sustained flight.<ref name=FAI_records/> That same day SR-71 serial number {{USAF serial|61|7958}} set an [[Flight airspeed record|absolute speed record]] of {{convert|1905.81|kn|mph km/h|sigfig=5}}, approximately Mach&nbsp;3.3.<ref name=FAI_records/><ref name="voodoo-world.cz"/><ref>{{Cite web |date=10 October 2017 |title=Eldon W. Joersz (USA) (8879) |url=https://www.fai.org/record/8879 |access-date=11 April 2022 |website=www.fai.org |language=en}}</ref> SR-71 pilot [[Brian Shul]] states in his book ''The Untouchables'' that he flew in excess of {{cvt|3.5|Mach}} on [[1986 United States bombing of Libya|15 April 1986 over Libya]] to evade a missile.<ref name="Shul M3.5" />

The SR-71 also holds the "speed over a recognized course" record for flying from New York to London—distance {{convert|3461.53|mi|km}}, {{convert|1806.964|mph|km/h}}, and an elapsed time of 1 hour 54 minutes and 56.4 seconds—set on 1 September 1974, while flown by USAF pilot James V. Sullivan and Noel F. Widdifield, reconnaissance systems officer (RSO).<ref name="Blackbird Records">[http://www.sr-71.org/blackbird/records.php "Blackbird Records."] ''sr-71.org''. Retrieved: 18 October 2009.</ref> This equates to an average speed of about Mach&nbsp;2.72, including deceleration for in-flight refueling. Peak speeds during this flight were likely closer to the declassified top speed of over Mach&nbsp;3.2. For comparison, the best commercial [[Concorde]] flight time was 2 hours 52 minutes and the [[Boeing 747]] averages 6 hours 15 minutes.

On 26 April 1971, 61–7968, flown by majors Thomas B. Estes and Dewain C. Vick, flew over {{convert|15000|mi|km}} in 10 hours and 30 minutes. This flight was awarded the 1971 [[Mackay Trophy]] for the "most meritorious flight of the year" and the 1972 [[Harmon Trophy]] for "most outstanding international achievement in the art/science of aeronautics".<ref>[http://www.vam.smv.org/pdfs/VAMHistoricAircraft.pdf "1966 Lockheed SR-71."] {{webarchive|url=https://web.archive.org/web/20110728032420/http://www.vam.smv.org/pdfs/VAMHistoricAircraft.pdf |date=28 July 2011 }} ''vam.smv.org''. Retrieved: 14 February 2011.</ref>

[[File:Pilot-RSO last flight SR-71.jpg|thumb|Pilot Lt. Col. Ed {{not a typo|Yeilding}} and RSO Lt. Col. Joe Vida on 6 March 1990, the last SR-71 Senior Crown flight|alt=The "Last Flight" of a SR-71. In background SR-71 S/N {{USAF serial|61|7972}}. Foreground pilot Lt. Col. Raymond E. "Ed" {{not a typo|Yeilding}} and RSO Lt. Col. Joseph T. "JT" Vida, 6 March 1990.]]

When the SR-71 was retired in 1990, one Blackbird was flown from its birthplace at USAF [[Plant 42]] in [[Palmdale, California]], to go on exhibit at what is now the [[Smithsonian Institution]]'s [[Steven F. Udvar-Hazy Center]] in [[Chantilly, Virginia]]. On 6 March 1990, Lt. Col. Raymond E. {{not a typo|Yeilding}} and Lt. Col. Joseph T. Vida piloted SR-71 S/N {{USAF serial|61|7972}} on its final Senior Crown flight and set four new speed records in the process:
*Los Angeles, California, to Washington, D.C., distance {{convert|2299.7|mi|km|abbr=on}}, average speed {{convert|2144.8|mph|km/h|abbr=on}}, and an elapsed time of 64 minutes 20 seconds.<ref name="Blackbird Records"/><ref>[https://www.nytimes.com/1990/03/07/us/spy-plane-sets-speed-record-then-retires.html "Spy Plane Sets Speed Record, Then Retires."] ''The New York Times'', 7 March 1990.</ref>
*[[West Coast of the United States|West Coast]] to [[East Coast of the United States|East Coast]], distance {{convert|2404|mi|km|abbr=on}}, average speed {{convert|2124.5|mph|km/h|abbr=on}}, and an elapsed time of 67 minutes 54 seconds.
*Kansas City, Missouri, to Washington, D.C., distance {{convert|942|mi|km|abbr=on}}, average speed {{convert|2176|mph|km/h|abbr=on}}, and an elapsed time of 25 minutes 59 seconds.
*St. Louis, Missouri, to Cincinnati, Ohio, distance {{convert|311.4|mi|km|abbr=on}}, average speed {{convert|2189.9|mph|km/h|abbr=on}}, and an elapsed time of 8 minutes 32 seconds.

These four speed records were accepted by the [[National Aeronautic Association]] (NAA), the recognized body for aviation records in the United States.<ref>National Aeronautic Association</ref> Additionally, ''Air & Space/Smithsonian'' reported that the USAF clocked the SR-71 at one point in its flight reaching {{convert|2242.48|mph|km/h}}.<ref>Marshall, Elliot, The Blackbird's Wake, Air & Space, October/November 1990, p. 31.</ref> After the Los Angeles–Washington flight, on 6 March 1990, Senator [[John Glenn]] addressed the [[United States Senate]], chastising the [[United States Department of Defense|Department of Defense]] for not using the SR-71 to its full potential:

{{Blockquote|Mr. President, the termination of the SR-71 was a grave mistake and could place our nation at a serious disadvantage in the event of a future crisis. Yesterday's historic transcontinental flight was a sad memorial to our short-sighted policy in strategic aerial reconnaissance.{{sfn|Graham|1996}}}}

===Successor===
{{update section|date=April 2024}}
{{Main|Lockheed Martin SR-72}}
Speculation existed regarding a replacement for the SR-71, including a rumored aircraft codenamed [[Aurora (aircraft)|Aurora]]. The limitations of [[reconnaissance satellite]]s, which take up to 24 hours to arrive in the proper orbit to photograph a particular target, make them slower to respond to demand than reconnaissance planes. The fly-over orbit of spy satellites may also be predicted and can allow assets to be hidden when the satellite passes, a drawback not shared by aircraft. Thus, there are doubts that the US has abandoned the concept of spy planes to complement reconnaissance satellites.<ref>Siuru, William D. and John D. Busick. ''Future Flight: The Next Generation of Aircraft Technology''. Blue Ridge Summit, Pennsylvania: TAB Books, 1994. {{ISBN|0-8306-7415-2}}.</ref> [[Unmanned aerial vehicle]]s (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.

On 1 November 2013, media outlets reported that Skunk Works has been working on an unmanned reconnaissance airplane it has named [[Lockheed Martin SR-72|SR-72]], which would fly twice as fast as the SR-71, at Mach 6.<ref>{{cite web|url=http://aviationweek.com/awin-featured-story/exclusive-skunk-works-reveals-sr-71-successor-plan |title=Exclusive: Skunk Works Reveals SR-71 Successor Plan |last1=Norris |first1=Guy |date=1 November 2013 |work=Aviation Week |publisher=Penton |access-date=1 November 2013 |url-status=dead |archive-url=https://web.archive.org/web/20140811145707/http://aviationweek.com/awin-featured-story/exclusive-skunk-works-reveals-sr-71-successor-plan |archive-date=11 August 2014 }}</ref><ref>{{cite web|url=http://www.flightglobal.com/news/articles/pictures-skunk-works-reveals-mach-6.0-sr-72-concept-392481/ |title=Skunk Works reveals Mach 6.0 SR-72 concept |last1=Trimble |first1=Stephen |date=1 November 2013 |website=Flightglobal.com |publisher=Reed Business Information |access-date=1 November 2013 |url-status=dead |archive-url=https://web.archive.org/web/20140121021903/http://www.flightglobal.com/news/articles/pictures-skunk-works-reveals-mach-6.0-sr-72-concept-392481/ |archive-date=21 January 2014 }}</ref> However, the USAF is officially pursuing the [[Northrop Grumman RQ-180]] UAV to assume the SR-71's strategic ISR role.<ref>{{cite web |url=http://aviationweek.com/defense/secret-new-uas-shows-stealth-efficiency-advances |title=EXCLUSIVE: Secret New UAS Shows Stealth, Efficiency Advances |last1=Butler |first1=Amy |last2=Sweetman |first2=Bill |date=6 December 2013 |work= Aviation Week |publisher=Penton |access-date=6 December 2013}}</ref>

==Variants==
[[File:Air Zoo - Lockheed SR-71B Blackbird.jpg|thumb|SR-71B on display at the [[Air Zoo]]]]

* '''SR-71A''' was the main production variant.
* '''SR-71B''' was a trainer variant.<ref>{{harvp|Landis|Jenkins|2004|pp=56-58}}</ref>
* '''SR-71C''' was a hybrid trainer<ref name="Only one">{{cite web|url=https://www.avgeekery.com/there-can-be-only-one-the-saga-of-the-only-sr-71c-ever-built/ |title=There Can Be Only One: The Saga of the Only SR-71C Ever Built |first=Bill |last=Walton |work=avgeekery.com |location=US |access-date=16 May 2021 |date=17 May 2017}}</ref> aircraft composed of the rear fuselage of the first YF-12A (S/N {{USAF serial|60|6934}}) and the forward fuselage from an SR-71 static test unit. The YF-12 had been wrecked in a 1966 landing accident. It has been reported that this Blackbird was seemingly not quite straight and had a yaw at supersonic speeds.<ref>{{harvp|Landis|Jenkins|2004|pp=62, 75}}.</ref> However, this was caused by a mis-aligned pitot tube reporting a 4° yaw that was not actually present. It was soon corrected and then flew normally.<ref name="Only one"/><ref>{{cite web |url=https://www.thesr71blackbird.com/Aircraft/Blackbird-Aircraft/sr-71c-blackbird-17981-2001 |title=SR-71C Blackbird #17981 / #2001 |website=The SR-71 Blackbird |access-date=24 January 2023}}</ref> It was nicknamed "The Bastard".<ref>{{harvp|Merlin|2005|p=4}}</ref><ref>{{harvp|Pace|2004|pp=109-110}}</ref>

==Operators==
;{{flagu|United States}}
* [[United States Air Force]]<ref>{{cite web|url=http://umcc.ais.org/~schnars/aero/ol-det.htm |title=U-2 and SR-71 Units, Bases and Detachments |website=Umcc.ais.org |access-date=29 October 2015}}</ref><ref>{{cite web |url=http://www.mybaseguide.com/air_force/19-89-13397/beale_afb_99th |title=BEALE AFB 99TH Reconnaissance Squadron |website=Mybaseguide.com |access-date=29 October 2015 |archive-date=12 September 2019 |archive-url=https://web.archive.org/web/20190912045123/https://www.mybaseguide.com/air_force/19-89-13397/beale_afb_99th |url-status=dead }}</ref><ref>{{cite web|url=http://blackbirds.net/sr71/fallblackbird.html|title=Fall and Rise of the Blackbird|website=Blackbirds.net}}</ref>
:[[Air Force Systems Command]]
*[[Air Force Flight Test Center]] – [[Edwards AFB]], California
::4786th Test Squadron 1965–1970
::SR-71 Flight Test Group 1970–1990
:[[Strategic Air Command]]
*[[9th Strategic Reconnaissance Wing]] – [[Beale AFB]], California
::[[1st Strategic Reconnaissance Squadron]] 1966–1990
::[[99th Strategic Reconnaissance Squadron]] 1966–1971
::Detachment 1, [[Kadena Air Base]], Japan 1968–1990
::Detachment 4, [[RAF Mildenhall]]. England 1976–1990
:[[Air Combat Command]]
*Detachment 2, [[9th Reconnaissance Wing]] – Edwards AFB, California 1995–1997
:(Forward Operating Locations at Eielson AFB, Alaska; Griffis AFB, New York; Seymour-Johnson AFB, North Carolina; Diego Garcia and Bodo, Norway 1973–1990)
* [[National Aeronautics and Space Administration]] (NASA)<ref>[http://www.nasa.gov/centers/armstrong/news/FactSheets/FS-030-DFRC.html Fact Sheet: SR-71 Blackbird] {{Webarchive|url=https://web.archive.org/web/20190912045121/https://www.nasa.gov/centers/armstrong/news/FactSheets/FS-030-DFRC.html |date=12 September 2019 }}. NASA Armstrong Flight Research Center. Retrieved 28 April 2015.</ref>
** [[Dryden Flight Research Center]] – Edwards AFB, California 1991–1999

==Accidents and aircraft disposition==
[[File:Lockheed Sr-71.jpg|thumb|SR-71 at Pima Air & Space Museum, Tucson, Arizona]]
<!-- [[File:Lockheed SR-71A.jpg|thumb|A Lockheed SR-71A at the Science Museum of Virginia, Richmond.]] Not enough room here for this one and it is ppor view. -->
[[File:SR71 closeup.jpg|thumb|Close-up of the SR-71B operated by NASA's Dryden Flight Research Center, [[Edwards AFB]], California]]
[[File:U.S. Air Force Museum B (10).jpg|thumb|SR-71A at the [[National Museum of the United States Air Force]]]]

Twelve SR-71s were lost and one pilot died in accidents during the aircraft's service career.<ref name="Landis_p98-101"/><ref name="Pace_p126-7">{{harvp|Pace|2004|p=126-127}}</ref> Eleven of these accidents happened between 1966 and 1972.

{| class="wikitable sortable" style="text-align:left"
|+ List of SR-71 Blackbirds
|-
! scope="col" | AF serial number
! scope="col" | Model
! scope="col" class="unsortable" | Location or fate
|-
! scope="row" | {{USAF serial|61|7950}}
| SR-71A|| Lost, 10 January 1967, in fire caused by failed braking test. Aircraft departed runway and burned.<ref name="SR-71 Online – Blackbird Losses">{{Cite web |title=SR-71 Online – Blackbird Losses |url=https://www.sr-71.org/blackbird/losses.php |access-date=26 September 2024 |website=www.sr-71.org}}</ref>
|-
! scope="row" | {{USAF serial|61|7951}}
| SR-71A|| [[Pima Air & Space Museum]] (adjacent to [[Davis-Monthan Air Force Base]]), [[Tucson, Arizona]]. Loaned to NASA as [[Lockheed YF-12#Variants|"YF-12C #06937"]].<ref>{{cite web |url=http://www.habu.org/sr-71/17951.html |title=61-7951 |website=habu.org |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7952}}
| SR-71A|| Lost in Mach 3 mid-air breakup near [[Tucumcari, New Mexico]], 25 January 1966<ref name=weaver>[http://roadrunnersinternationale.com/weaver_sr71_bailout.html "Bill Weaver SR-71 Breakup."] ''Roadrunners Internationale,'' 10 September 2011. Retrieved: 3 March 2012. <!-- https://web.archive.org/web/*/http://roadrunnersinternationale.com/weaver_sr71_bailout.html --></ref><ref>{{cite AV media |people= Bill Weaver & Maury Rosenberg |title= BD-0066 Oral History, Bill Weaver and Maury Rosenberg Lockheed SR-71 Pilots |medium= Video |url= https://www.youtube.com/watch?v=vGA8Jej_JtI?t=4360 |time =1h12m40s |publisher =[[San Diego Air & Space Museum]] }}</ref>{{sfn|Graham|2013}}
|-
! scope="row" | {{USAF serial|61|7953}}
| SR-71A|| Lost, 18 December 1969<ref>[http://www.check-six.com/Crash_Sites/SR-71_953_crash_site.htm "SR-71 #953 crash."] ''check-six.com''. Retrieved: 12 November 2012.</ref>
|-
! scope="row" | {{USAF serial|61|7954}}
| SR-71A|| Lost, 11 April 1969, in fire caused by failed brake test.<ref>{{Cite web |title=SR-71 Online - Blackbird Losses |url=https://www.sr-71.org/blackbird/losses.php |access-date=26 September 2024 |website=www.sr-71.org}}</ref>
|-
! scope="row" | {{USAF serial|61|7955}}
| SR-71A|| Air Force Flight Test Center Museum, [[Edwards Air Force Base]], California<ref>[http://www.afftcmuseum.org/exhibits_24.html SR-71A Blackbird] {{webarchive |url=https://web.archive.org/web/20131016113144/http://www.afftcmuseum.org/exhibits_24.html |date=16 October 2013 }} ''Air Force Flight Center Museum''. Retrieved: 10 February 2009.</ref>
|-
! scope="row" | {{USAF serial|61|7956}}
| SR-71B|| [[Air Zoo]], [[Kalamazoo, Michigan]] (ex-NASA831)<ref>{{cite web |url=https://www.airzoo.org/cold-warjet-age/airplanes-6/lockheed-sr-71b-blackbird-1963-1999#quick-facts |title=Lockheed SR-71B Blackbird 1963–1999 |website=airzoo.org |access-date=15 September 2021 }}</ref><ref>{{cite web |url=http://www.habu.org/sr-71/17956.html |title=61-7956 |website=habu.org |access-date=15 September 2021 }}</ref><ref>{{cite web |url=http://www.habu.org/sr-71b/956dismantle6.html |title=B-Model Dismantlement Pictures |website=habu.org |access-date=26 August 2024}}</ref>
|-
! scope="row" | {{USAF serial|61|7957}}
| SR-71B|| Lost, 11 January 1968. Double generator failure followed by double flameout on approach; crew ejected safely.<ref name="SR-71 Online – Blackbird Losses"/>
|-
! scope="row" | {{USAF serial|61|7958}}
| SR-71A|| [[Museum of Aviation (Warner Robins)|Museum of Aviation]], [[Robins Air Force Base]], [[Warner Robins, Georgia]]<ref>{{cite web |url=https://museumofaviation.org/portfolio/sr-71a-blackbird/ |title=SR-71A "Blackbird" |publisher=Museum of Aviation Foundation |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7959}}
| SR-71A|| [[Air Force Armament Museum]], [[Eglin Air Force Base]], Florida<ref>[https://web.archive.org/web/20070428195658/http://afarmamentmuseum.com/exhibits.shtml Exhibits]. ''Air Force Armament Museum''. Retrieved: 10 February 2009.</ref>
|-
! scope="row" | {{USAF serial|61|7960}}
| SR-71A|| [[Castle Air Museum]] at the former [[Castle Air Force Base]], [[Atwater, California]]<ref>{{cite web |url=https://www.castleairmuseum.org/collection |title=Our Collection |publisher=Castle Air Museum |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7961}}
| SR-71A|| [[Cosmosphere]], [[Hutchinson, Kansas]]<ref>{{cite web |url=http://cosmospheretour.com/audiogallery.php?id=1 |title=SR-71A Blackbird #17961 Audio Gallery |work=Cosmosphere |access-date=16 September 2021 |archive-date=22 September 2021 |archive-url=https://web.archive.org/web/20210922110106/https://cosmospheretour.com/audiogallery.php?id=1 |url-status=dead }}</ref>
|-
! scope="row" | {{USAF serial|61|7962}}
| SR-71A|| [[American Air Museum in Britain]], [[Imperial War Museum Duxford]], Cambridgeshire, England<ref>[https://web.archive.org/web/20040718190453/http://aam.iwm.org.uk/server/show/ConWebDoc.1134 "Aircraft On Display: Lockheed SR-71A Blackbird."] ''The American Air Museum,'' Imperial War Museum. Retrieved: 10 February 2009.</ref>
|-
! scope="row" | {{USAF serial|61|7963}}
| SR-71A|| [[Beale Air Force Base]], [[Marysville, California]]<ref>{{cite web |url=http://www.habu.org/sr-71/17963a.html |title=61-7963 |website=habu.org |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7964}}
| SR-71A|| [[Strategic Air Command & Aerospace Museum]], [[Ashland, Nebraska]]<ref>{{cite web |url=https://sacmuseum.org/what-to-see/aircraft/sr-71a-blackbird/ |title=SR-71A "Blackbird" |publisher=Strategic Air Command & Aerospace Museum |access-date=16 September 2021 }}{{Dead link|date=September 2025 |bot=InternetArchiveBot }}</ref>
|-
! scope="row" | {{USAF serial|61|7965}}
| SR-71A|| Lost, 25 October 1967. Crashed in Nevada desert following instrument failure. Crew ejected safely.<ref name="SR-71 Online – Blackbird Losses"/>
|-
! scope="row" | {{USAF serial|61|7966}}
| SR-71A|| Lost, 13 April 1967 following high-speed subsonic stall near [[Las Vegas, New Mexico]]. Crew ejected safely.<ref name="SR-71 Online – Blackbird Losses"/>
|-
! scope="row" | {{USAF serial|61|7967}}
| SR-71A|| [[Barksdale Air Force Base]], [[Bossier City, Louisiana]]<ref>{{cite web |url=https://www.barksdale.af.mil/News/Article/1193015/sr-71-gets-a-lift/ |title=SR-71 gets a lift |last=Bright |first=Stuart |work=Barksdale Air Force Base |date=24 May 2017 |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7968}}
| SR-71A|| [[Science Museum of Virginia]], [[Richmond, Virginia]]<ref>{{cite web |url=https://www.smv.org/explore/exhibits/speed |title=Speed |publisher=Science Museum of Virginia |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7969}}
| SR-71A|| Lost, 10 May 1970 near Korat Royal Thai Air Force Base. Flameout in turbulent thunderstorm, engine restart failed. Crew ejected successfully.<ref name="SR-71 Online – Blackbird Losses"/>
|-
! scope="row" | {{USAF serial|61|7970}}
| SR-71A|| Lost, 17 June 1970 after colliding with the KC-135 refueling it. Crew ejected with injuries.<ref name="SR-71 Online – Blackbird Losses"/>
|-
! scope="row" | {{USAF serial|61|7971}}
| SR-71A|| [[Evergreen Aviation Museum]], [[McMinnville, Oregon]]<ref>{{cite web |url=https://www.evergreenmuseum.org/sr-71-blackbird |title=Pure Speed! |publisher=Evergreen Aviation Museum |access-date=16 September 2021 |archive-date=19 September 2021 |archive-url=https://web.archive.org/web/20210919171053/https://www.evergreenmuseum.org/sr-71-blackbird |url-status=dead }}</ref>
|-
! scope="row" | {{USAF serial|61|7972}}
| SR-71A|| Smithsonian Institution [[Steven F. Udvar-Hazy Center]], [[Washington Dulles International Airport]], Chantilly, Virginia<ref>{{cite web |url=https://airandspace.si.edu/collection-objects/lockheed-sr-71-blackbird/nasm_A19920072000 |title=Lockheed SR-71 Blackbird |publisher=Smithsonian National Air and Space Museum |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7973}}
| SR-71A|| Blackbird Airpark, [[Air Force Plant 42]], [[Palmdale, California]]<ref>{{cite web |url=https://www.afftcmuseum.org/blackbird-airpark |url-status=dead |archive-url=https://web.archive.org/web/20210427011422/https://www.afftcmuseum.org/blackbird-airpark |archive-date=27 April 2021 |title=Blackbird Airpark |publisher=Flight Test Museum Foundation |access-date=16 September 2021}}</ref>
|-
! scope="row" | {{USAF serial|61|7974}}
| SR-71A|| Lost, 21 April 1989 after compressor failure caused catastrophic left engine failure. Remains of aircraft recovered then on 24 December 1989 buried at sea in the [[Mariana Trench]].<ref>{{cite web | url=https://www.planehistoria.com/sr-71-ichi-ban/? |title=SR-71 "Ichi-Ban" – Buried in the Deepest Ocean on Earth |first=Nathan |last=Cluett |work=Plane Historia |location=US |date=29 September 2022 |access-date=19 October 2023}}</ref>
|-
! scope="row" | {{USAF serial|61|7975}}
| SR-71A|| [[March Field Air Museum]], [[March Air Reserve Base]] (former [[March AFB]]), [[Riverside, California]]<ref>{{cite web |title=Aircraft: Lockheed SR-71A Blackbird |url=http://www.marchfield.org/sr71a.htm |url-status=dead |archive-url=https://web.archive.org/web/20000304181849/http://www.marchfield.org/sr71a.htm |archive-date=4 March 2000 |access-date=5 May 2009 |website=March Field Air Museum}}</ref>
|-
! scope="row" | {{USAF serial|61|7976}}
| SR-71A|| [[National Museum of the United States Air Force]], [[Wright-Patterson Air Force Base]], near [[Dayton, Ohio]],<ref>{{cite web |url=https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/198054/lockheed-sr-71a/ |title=Lockheed SR-71A |work=National Museum of the United States Air Force™ |publisher=National Museum of the United States Air Force |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7977}}
| SR-71A|| Lost, 10 October 1968. Aborted takeoff after wheel assembly failure. Cockpit section survived and located at the [[Seattle Museum of Flight]].<ref>{{cite web |url=http://www.habu.org/sr-71/17977a.html |title=61-7977 |website=habu.org |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7978}}
| SR-71A|| Nicknamed "Rapid Rabbit" and wearing a [[Playboy#Rabbit logo|Playboy bunny]] image as tail art.<ref>{{cite web |url=http://www.warriorflightcharity.org/fear-the-bunny |title=Fear the Bunny! |website=Warrior Flight Charity |access-date=24 March 2018}}</ref> (wearing a "black bunny" logo on its tail). Lost, 20 July 1972 after departure from runway.<ref name="Landis_p98-101"/><ref name="SR-71 Online – Blackbird Losses"/>
|-
! scope="row" | {{USAF serial|61|7979}}
| SR-71A|| [[Lackland Air Force Base]], [[San Antonio]], Texas<ref>{{cite web |url=http://www.habu.org/sr-71/17979c.html |title=61-7979 |website=habu.org |access-date=16 September 2021 }}</ref>
|-
! scope="row" | {{USAF serial|61|7980}}
| SR-71A||[[Armstrong Flight Research Center]], [[Edwards Air Force Base]], California<ref>{{Cite web|title=Where Are They Now: SR-71A #844|url=http://www.nasa.gov/centers/armstrong/history/where_are_they_now/SR-71A_844.html|last=Conner|first=Monroe|date=20 October 2015|website=NASA|access-date=4 May 2020}}</ref>
|-
! scope="row" | {{USAF serial|61|7981}}
| SR-71C|| [[Hill Aerospace Museum]], [[Hill Air Force Base]], [[Ogden, Utah]] (formerly YF-12A {{USAF serial|60|6934}})<ref>{{cite web |url=https://www.aerospaceutah.org/museum/our-collections/aircraft-collection/lockheed-sr-71c-blackbird/ |title=Lockheed SR-71C 'Blackbird' |date=30 August 2021 |publisher=Hill Aerospace Museum |access-date=16 September 2021 }}</ref>
|}

Some secondary references use incorrect 64-series aircraft serial numbers (''e.g.'' SR-71C {{USAF serial|64|17981}})<ref>[http://www.u2sr71patches.co.uk/a12U2loction.htm U-2 / A-12 / YF-12A / SR-71 Blackbird & RB-57D – WB-57F locations.'] {{webarchive|url=https://web.archive.org/web/20110218033158/https://www.u2sr71patches.co.uk/a12U2loction.htm |date=18 February 2011 }} ''u2sr71patches.co.uk''. Retrieved: 22 January 2010.</ref>

After completion of all USAF and NASA SR-71 operations at Edwards AFB, the SR-71 Flight Simulator was moved in July 2006 to the [[Frontiers of Flight Museum]] at [[Dallas Love Field|Love Field Airport]] in Dallas, Texas.<ref>[http://www.flightmuseum.com/ "Frontiers of Flight Museum."] ''flightmuseum.com''. Retrieved: 14 March 2010.</ref>

==Specifications (SR-71A)==
[[File:Lockheed SR-71A 3view.svg|thumb|right|upright=1.4| SR-71A Blackbird]]
[[File:Lockheed SR-71B trainer model 3view.png|thumb|right|upright=1.4| SR-71B trainer model]]
[[File:Sr-71-composit.gif|350px|thumb|right|upright=1.4|SR-71 epoxy asbestos composite areas]]

{{Aircraft specs
|ref= Lockheed SR-71 Blackbird<ref name=Pace_p110>{{harvp|Pace|2004|p=110}}</ref>
|prime units?=kts
<!--  General characteristics
-->
|crew=2; Pilot and reconnaissance systems officer (RSO)
|length ft=107
|length in=5
|length note=
|span ft=55
|span in=7
|span note=
|height ft=18
|height in=6
|height note=<br/>
*'''Wheel track:''' {{cvt|16|ft|8|in|0}}
*'''Wheelbase:''' {{cvt|37|ft|10|in|0}}
|wing area sqft=1800
|wing area note=
|aspect ratio=1.7
|airfoil=
|empty weight lb=67500
|empty weight note=
|gross weight lb=152000
|gross weight note=
|max takeoff weight lb=172000
|max takeoff weight note=
|fuel capacity={{cvt|12219.2|USgal|impgal l}} in 6 tank groups (9 tanks)
|more general=
<!--  Powerplant
-->
|eng1 number=2
|eng1 name=[[Pratt & Whitney J58]] (JT11D-20J or JT11D-20K)
|eng1 type=afterburning turbojets
|eng1 lbf=25000
|eng1 note=<br/>
::::'''JT11D-20J''' {{cvt|32500|lbf|kN|2}} wet (fixed inlet guidevanes)
::::'''JT11D-20K''' {{cvt|34000|lbf|kN|2}} wet (2-position inlet guidevanes)
<!--  Performance
-->
|max speed kts=1910
|max speed note=at {{cvt|80000|ft}}
|max speed mach=3.3{{refn|Maximum speed limit was Mach 3.2, but could be raised to Mach 3.3 if the engine compressor inlet temperature did not exceed {{convert|801|°F|°C|abbr=on}}.{{sfn|Graham|2002|pages=93,223}}|group=N}}
|cruise speed kts=
|cruise speed note=
|stall speed kts=
|stall speed note=
|never exceed speed kts=
|never exceed speed note=
|minimum control speed kts=
|minimum control speed note=
|range nmi=
|range note=
|combat range nmi=
|combat range note=
|ferry range nmi=2824
|ferry range note=
|endurance=<!-- if range unknown -->
|ceiling ft=85000
|ceiling note=
|g limits=<!-- aerobatic -->
|roll rate=<!-- aerobatic -->
|glide ratio=<!-- sailplanes -->
|climb rate ftmin=11820
|climb rate note=
|time to altitude=
|sink rate ftmin=<!-- sailplanes -->
|sink rate note=
|lift to drag=
|wing loading lb/sqft=84
|wing loading note=
|fuel consumption lb/mi=
|thrust/weight=0.44

|more performance=
|avionics={{cvt|3500|lb|0}} of mission equipment
:* Itek KA-102A {{cvt|36|-|48|in|mm}} camera
:*[[Signals intelligence|Signals and Electronic Intelligence]] equipment in the following compartments
::* A – nose radar
::* D – right chine bay
::* E – electronics bay
::* K – left forward mission bay
::* L – right forward mission bay
::* M – left forward mission bay
::* N – right forward mission bay
::* P – left aft mission bay
::* Q – right aft mission bay
::* R – radio equipment bay
::* S – left aft mission bay
::* T – right aft mission bay
}}

==See also==
{{Portal|Aviation|United States}}
{{aircontent
|see also=<!-- other related articles that have not already linked: -->
*{{annotated link|Henry Combs}}
*{{slink|Aircraft in fiction#Lockheed SR-71 Blackbird}}
*[[Linear Aerospike SR-71 Experiment]]
*[[Measurement and signature intelligence]]
|related=<!-- designs which were developed into or from this aircraft: -->
*[[Lockheed A-12]]
**[[Lockheed M-21]]
*[[Lockheed YF-12]]
|similar aircraft=<!-- aircraft that are of similar role, era, and capability as this design: -->
*[[Bristol 188]]
*[[English Electric P.10]]
*[[Handley Page HP.100]]
*[[Mikoyan-Gurevich MiG-25]]
*[[Tsybin RSR]]
|lists=<!-- relevant lists that this aircraft appears in: -->
*[[List of Lockheed aircraft]]
*[[List of military aircraft of the United States]]
*[[List of United States Air Force reconnaissance aircraft]]
<!-- See [[WP:Air/PC]] for more explanation of these fields. -->
}}

==References==

===Footnotes===
{{Reflist|group=N}}

===Citations===
{{Reflist|30em}}

===Bibliography===
{{Refbegin}}
* {{Cite news |last=Ruane |first=Michael E. |date=7 March 1990 |title=A bittersweet, and fancy, flight |volume=321 |pages=[https://www.newspapers.com/article/the-philadelphia-inquirer-a-bittersweet/130222946/ 1-A], [https://www.newspapers.com/article/the-philadelphia-inquirer-this-blackbir/130223067/ 4-A] |work=[[The Philadelphia Inquirer]] |issue=66 |via=[[Newspapers.com]]}}
* {{cite journal |last=Crickmore |date=January 2009 |first=Paul F. |title=Blackbirds in the Cold War |journal=[[Air International]] |pages=30–38 |publisher=Key Publishing |location=Stamford, UK}}
* {{cite journal |last=Crickmore |date=1997 |first=Paul F. |title=Lockheed's Blackbirds – A-12, YF-12 and SR-71A |journal=[[Wings of Fame (magazine)|Wings of Fame]] |volume=8 |pages=30–93 |publisher=Aerospace Publishing |location=London, England}}
* {{Cite book |last=Crickmore |first=Paul F. |url=https://archive.org/details/lockheedsr71secr0000cric |title=Lockheed SR-71: The Secret Missions Exposed |publisher=Osprey |year=2000 |isbn=978-1841760988 |edition=Revised |location=Oxford, England |url-access=registration}}
* Donald, David, ed. "Lockheed's Blackbirds: A-12, YF-12 and SR-71". ''Black Jets''. [[AIRtime]], 2003. {{ISBN|1-880588-67-6}}.
* Goodall, James. ''Lockheed's SR-71 "Blackbird" Family''. Hinckley, UK: Aerofax/Midland Publishing, 2003. {{ISBN|1-85780-138-5}}.
* {{Cite book |last=Graham |first=Richard H. |title=SR-71 Blackbird: Stories, Tales, and Legends |date=2002 |publisher=Voyageur Press |isbn=0-7603-1142-0}}
* {{Cite book |last=Graham |first=Richard H. |url=https://archive.org/details/sr71revealedinsi00colr |title=SR-71 Revealed: The Inside Story |publisher=Motorbooks |year=1996 |isbn=978-0760301227 |location=Osceola, Wisconsin |oclc=34319406 |url-access=registration}}
* {{cite book |last=Graham |first=Richard H. |title=Flying The SR-71 – In The Cockpit On A Secret Operational Mission |year=2008 |publisher=Zenith Press |location=Minneapolis, Minnesota |isbn=978-0-7603-3239-9}}
* {{Cite book |last=Graham |first=Richard H. |title=SR-71: The Complete Illustrated History of the Blackbird, The World's Highest, Fastest Plane |date=2013 |publisher=MBI Publishing Company |isbn=978-0760343272}}
* Jenkins, Dennis R. ''Lockheed Secret Projects: Inside the Skunk Works''. St. Paul, Minnesota: [[MBI Publishing Company]], 2001. {{ISBN|978-0-7603-0914-8}}.
* Johnson, C. L. ''Kelly: More Than My Share of it All''. Washington, DC: [[Smithsonian Books]], 1985. {{ISBN|0-87474-491-1}}.
* {{Cite book |last1=Landis |first1=Tony R. |url=https://archive.org/details/lockheedblackbir0000jenk |title=Lockheed Blackbirds |last2=Jenkins |first2=Dennis R. |publisher=Specialty Press |year=2004 |isbn=978-1580070867 |edition=Rev. |location=North Branch, Minnesota |oclc=60250245 |url-access=registration}}
* {{Cite journal |last=McIninch |first=Thomas P. |title=The Oxcart Story |journal=[[Studies in Intelligence]] |publisher=Center for the Study of Intelligence |volume=15 |issue=1 |pages=1–34 |date=1971 |access-date=23 March 2024 |url=https://www.cia.gov/resources/csi/static/The-Oxcart-Story.pdf |archive-url=https://web.archive.org/web/20240324012512/https://www.cia.gov/resources/csi/static/The-Oxcart-Story.pdf |archive-date=24 March 2024}}
* {{Cite book |last=Merlin |first=Peter W. |title=From Archangel to Senior Crown: Design and Development of the Blackbird |location=Reston, Virginia |publisher=[[American Institute of Aeronautics and Astronautics]] (AIAA) |year=2008 |isbn=978-1-56347-933-5 |editor-last=Allen |editor-first=Ned |series=Library of Flight |oclc=190761298}}
* {{Cite journal |last=Merlin |first=Peter W. |title=The Truth is Out There... SR-71 Serials and Designations |journal=[[Air Enthusiast]] |volume=118 |date=July 2005 |publication-place=Stamford, UK |publisher=Key Publishing |pages=2–6 |issn=0143-5450}}
* {{Cite book |last=Pace |first=Steve |title=Lockheed SR-71 Blackbird |location=Swindon, UK |publisher=[[Crowood Press]] |year=2004 |isbn=1-86126-697-9}}
* Remak, Jeannette and Joe Ventolo Jr. ''A-12 Blackbird Declassified''. St. Paul, Minnesota: MBI Publishing Company, 2001. {{ISBN|0-7603-1000-9}}.
* {{Cite book |last1=Rich |first1=Ben R. |first2=Leo |last2=Janos |title=Skunk Works: A Personal Memoir of My Years at Lockheed |location=New York |publisher=Little, Brown and Company |year=1994 |isbn=0-316-74330-5}}
* Shul, Brian and Sheila Kathleen O'Grady. ''Sled Driver: Flying the World's Fastest Jet''. Marysville, California: [[Gallery One]], 1994. {{ISBN|0-929823-08-7}}.
* Shul, Brian and Walter Watson Jr. ''The Untouchables''. Chico, California: [[Mach 1, Inc.]] 1993. {{ISBN|0-929823-12-5}}.
* Suhler, Paul A. ''From RAINBOW to GUSTO: Stealth and the Design of the Lockheed Blackbird (Library of Flight Series) ''. Reston, Virginia: American Institute of Aeronautics and Astronautics (AIAA), 2009. {{ISBN|978-1-60086-712-5}}.
{{Refend}}

;Additional sources
{{Refbegin}}
* Brandt, Steven A., Randall J. Stiles and John J. Bertin. [https://books.google.com/books?id=NJE3wTL6IDYC&pg=PA141 ''Introduction to Aeronautics: A Design Perspective''.] Reston, Virginia: American Institute of Aeronautics & Astronautics, 2004, pp.&nbsp;141–150. {{ISBN|1-56347-701-7}}.
* Brown, Kevin V. [https://books.google.com/books?id=JNQDAAAAMBAJ&pg=PA59 "America's SuperSecret Spy Plane."] ''Popular Mechanics'', June 1968, pp.&nbsp;59–62, 190.
* Clarkson, Jeremy. ''[[I Know You Got Soul (book)|I Know You Got Soul]]''. London: Penguin Books Limited, 2006. {{ISBN|0-14-102292-2}}.
* {{cite book |last=Crickmore |first=Paul F. |url={{Google books|id=MQtbvgAACAAJ|plain-url=yes}} |title=Lockheed Blackbird: Beyond the Secret Missions |location=Oxford, UK |publisher=Osprey Publishing |year=2004 |isbn=1-84176-694-1}}
* {{cite book |last1=Crickmore |first1=Paul |last2=Laurier |first2=Jim |url={{Google books|id=14wVvgAACAAJ|plain-url=yes}} |title=Lockheed SR-71 Operations in the Far East |location=Oxford, UK |publisher=Osprey Publishing |year=2008 |isbn=978-1-84603-319-3}}
* Darwall, Bjarne. ''Luftens Dirigenter'' (Air Conductors) (in Swedish). Nässjö, Sweden: Air Historic Research AB, 2004. {{ISBN|91-973892-6-9}}.
* Goodall, James and Jay Miller. "Lockheed's SR-71 'Blackbird' Family A-12, F-12, M-21, D-21, SR-71". Hinckley, UK: AeroFax-Midland Publishing, 2002. {{ISBN|1-85780-138-5}}.
* Grant, R.G. ''Flight: 100 Years of Aviation''. New York: DK Publishing, 2007. {{ISBN|978-0-7566-1902-2}}.
* Hobson, Chris. ''Vietnam Air Losses, USAF, USN, USMC, Fixed-Wing Aircraft Losses in Southeast Asia 1961–1973''. North Branch, Minnesota: Specialty Press, 2001. {{ISBN|1-85780-115-6}}.
* {{Cite conference |last=Merlin |first=Peter W. |date=January 2009 |title=Design and Development of the Blackbird: Challenges and Lessons Learned |url=https://ntrs.nasa.gov/api/citations/20090007797/downloads/20090007797.pdf |conference=47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition |location=Orlando, Florida |publisher=[[American Institute of Aeronautics and Astronautics]] (AIAA) |doi=10.2514/6.2009-1522 |id=AIAA 2009-1522 |access-date=23 June 2024}}
* {{Cite book |last=Merlin |first=Peter W. |url=https://www.nasa.gov/wp-content/uploads/2021/04/88796main_yf-12.pdf |title=Mach 3+: NASA/USAF YF-12 Flight Research, 1969-1979 |publisher=NASA History Division Office |year=2002 |series=Monographs in aerospace history, No. 25 |id=NASA SP 2001-4525 |access-date=23 June 2024}}
* Pappas, Terry. [https://books.google.com/books?id=KuYDAAAAMBAJ&pg=PA27 "The Blackbird is Back."] ''Popular Mechanics'', June 1991, pp.&nbsp;27–31, 104–105.
* [https://www.sr-71.org/blackbird/manual/ ''Sr-71 Blackbird Pilot's Flight Manual''].
* Reithmaier, Lawrence W. [https://books.google.com/books?id=sUHuZiBYSKYC&pg=PA219 ''Mach 1 and Beyond''.] New York: [[McGraw-Hill]], 1994, pp.&nbsp;220–237. {{ISBN|0-07-052021-6}}.
{{Refend}}

==External links==
{{Commons|SR-71 Blackbird}}
* {{cite AV media |url=https://www.youtube.com/watch?v=sQ8qCvLRbkE&ab/ |title=Lockheed SR-71 Blackbird {{!}} The Story of the untouchable U.S. Aviation Marvel |via=YouTube}}
* {{cite news |url=http://awin.aviationweek.com/Portals/aweek/media/PDF/SR-71.pdf |url-status=dead |archive-url=https://web.archive.org/web/20140617233006/http://awin.aviationweek.com/Portals/AWeek/media/PDF/SR-71.pdf |archive-date=17 June 2014 |title=SR-71 Impressive in High-speed Regime |at=Pilot Report |last=Ropelewski |first=Robert R. |work=[[Aviation Week & Space Technology]] |date=18 May 1981}}
* {{cite news |url=http://www.airspacemag.com/military-aviation/what-blackbird-drinks-180953422/ |title=What a Blackbird Drinks |work=Air & Space Magazine |first=Roger |last=Mola |date=20 November 2014 |publisher=[[Air & Space/Smithsonian]]}}
* {{cite news |url=http://www.airspacemag.com/flight-today/blackbird-diaries-180953373/?all |title=Blackbird Diaries |work=Air & Space Magazine |date=December 2014 |publisher=[[Air & Space/Smithsonian]]}}
* {{cite web |url=http://www.sr-71.org/ |title=SR-71 Online |first=Paul |last=Kucher}}
* {{cite web |url=http://www.habu.org/ |title=The Online Blackbird Museum}}
* {{cite web |url=https://ntrs.nasa.gov/api/citations/20090007797/downloads/20090007797.pdf |title=Design and Development of the Blackbird: Challenges and Lessons Learned |publisher=[[NASA]]}}
* {{cite AV media |url=https://www.youtube.com/watch?v=gkyVZxtsubM&t=190s |title=How the Lockheed SR-71 Blackbird Works |publisher=Animagraffs |first=Jacob |last=O'Neal |date=19 March 2024 |via=YouTube}}
* {{cite web |url=https://www.TritiumSoft.com/sr-71-blackbird |title=Satellite Imagery & GPS Coordinates of SR-71 Blackbirds & Project Oxcart Articles}}

{{Lockheed Martin aircraft}}
{{USAF bomber aircraft}}
{{US reconnaissance aircraft}}
{{Electronic warfare navbox}}
{{USAF fighters}}
{{Authority control}}

[[Category:1960s United States military reconnaissance aircraft]]
[[Category:Aircraft first flown in 1964]]
[[Category:Aircraft related to spaceflight]]
[[Category:Aircraft with retractable tricycle landing gear]]
[[Category:Lockheed aircraft|SR-071]]
[[Category:NASA aircraft]]
[[Category:Signals intelligence]]
[[Category:Stealth aircraft]]
[[Category:Strategic reconnaissance aircraft]]
[[Category:Supersonic aircraft]]
[[Category:Tailless delta-wing aircraft]]
[[Category:Twinjets]]