Though the aircraft performed well, the F-12 interceptor program ended in early 1968. High costs, the ongoing war in Southeast Asia, and a lower priority on air defense of the US all contributed to the cancellation. The aircraft on display -- the second one built -- was recalled from storage in 1969 for a joint USAF/NASA investigation of supersonic cruise technology. It was flown to the museum in 1979, and it is the only remaining YF-12A in existence (the first YF-12A was damaged beyond repair after a landing mishap, and the third YF-12A was destroyed after the crew ejected to escape an inflight fire).
TECHNICAL NOTES:
Armament: Three Hughes AIM-47A missiles
Engines: Two Pratt & Whitney J58s of 32,000 lbs. thrust each (with afterburner)
Crew: Two
Maximum speed: Mach 3+
Range: 2,000+ miles
Service ceiling: Above 80,000 feet
Weight: 127,000 lbs. loaded