High-Altitude Project (HAP)
AIM-9L found its way into another China Lake development effort of the early 1970s known as HAP. The project was undertaken in response to the Soviet Union’s remarkable MiG-25 Foxbat aircraft. The MiG-25 could fly higher—far higher—than any fighter aircraft in the U.S. inventory. In fact, the MiG-25 still holds the Federation Aeronautique Internationale (FAI) absolute world altitude record for a ground-launched manned aircraft. The U.S. and its allies were concerned about MiG-25s that were flying reconnaissance missions over Israel in the run-up to the Arab-Israeli War of1973, and the proposal was made for an air-to-air missile that would be capable of reaching the MiG at altitude. Mike Ripley-Lotee, who worked on HAP, recalled:
"Some guys at China Lake had come up with a concept of taking the brand new Sparrow rocket motor that hadn’t even entered service yet for the AIM-7F and matching it with a Sidewinder front end with the new -9L canards, the big canards, and then some guidance algorithms to allow it to take advantage of the new, improved sensitivity of the seeker for Sidewinder. . . . The whole concept was that an F-4 would have one of these things on a rack and zoom up to about 55,000 feet where it was just flaming out and be in front of the MiG-25, which would be going at Mach 3 or 4, nice and hot, a good signature, get tone from the Sidewinder front end, and fire this thing, and it would have the oomph to engage the MiG-25 up at 70 or 80,000 feet."
The HAP missile also contained components from the ACV, the aerodynamic version of Agile, a program soon to be cancelled. A 1973 technical note on HAP by China Lake engineer Jim Irvine noted that eight missiles were built; six were tested with telemetry warheads, and the remaining two “were built up in a tactical configuration with live warheads.” In an interview decades later, Irvine recalled of the two tactical-configuration missiles that “we put them in the magazines and we left them there,” until, in the late 1970s, “If inally had the missiles torn down.”
