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).