The SR-71 was the USAF’s two-seat version of the CIA’s A-12 reconnaissance aircraft. Capable of the same high speed and altitudes as the A-12, it was slightly heavier due to the increased camera/radar sensor payload, which is housed in interchangeable nose and fuselage bays. The aircraft had an empty weight of 30 tons, and carried 40 tons of fuel when full.
The aircraft on display at the main museum is the 6th prototype, S/N 61-7955. Assembly started on 13 May 1964 and #955 first flew on 17 August 1965. Throughout its career, this aircraft served as the Palmdale test aircraft until being replaced by SR-71A #61-7972 in 1985. Last flown on 24 January 1985, #955 accumulated 1993.7 hours of flight time.