Editing Lockheed SR-71 Blackbird (section)

==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>