The MiG-25 was designed in 1962 to intercept high altitude, high speed aircraft such as the F-108 Rapier program, the Mach 3 capable XB-70 Valkyrie and more important the A-12 which resulted in the SR-71 spy plane. Some say the posed threat of the XB-70 was the main (and only) reason for the MiG-25 design, but MiG OKB revealed recentlythat the mean reason was to counter the A-12/YF-12 program. Anyway, when the XB-70 Valkyrie development stopped, the development of the MiG-25 continued.
On 6 March 1964 the first MiG-25 prototype, designated Ye-155-R-1, made its maiden flight. Although this first prototype was a dedicated reconnaissance aircraft, it was soon followed up by an interceptor protype. The Ye-155-P-1 made its first flight on 9 September 1964.
The Ye-155-R-1 led to the first production type of the recce MiG-25, designated MiG-25R. In 1970 these aircraft were redesignated MiG-25RB when a bombing capability was added. In the mean time the Ye-155-P-1 led to the MiG-25P which was armed with up to four AAMs carried under the wings. The MiG-25P entered service in 1970 with the Soviet Air Forces.
More modifications were done over the years, one major variant change was with the MiG-25PD which had uprated engines and a Sapfir-25 radar. And finally the MiG-25BM was developed from the MiG-5RB recce-bomber.
Production of the fighter ended in 1983. The MiG-25 saw combat in several wars in the Middle East. Over 1200 have been built, of which about 75% were interceptors.
First prototype Ye-155-R-1
Ye-155-R-3, third recce prototype
MiG-25BM was armed with the Kh-58