The SR-71 impressive mission record was reached thanks to some unique features of its airframe, such as its ability to fly at more than three and a half times the speed of sound at 88,000 feet, its small (for the time) Radar Cross Section (RCS) and its sophisticated electronic countermeasures (ECM).
These flight characteristics made the Blackbird safe against any attempt of interception conducted by enemy fighters or surface-to-air missiles (SAM), during its reconnaissance missions in the Russian skies during the Cold War years.
In fact the Phoenix was developed to shoot down Soviet cruise missiles which flew at an altitude similar to the one reached by the Blackbird. Moreover with a speed between Mach 4 and Mach 5, the AIM-54 was fast enough to cause serious problems to the SR-71.
But, the capabilities featured by the Tomcat and its long range missiles, weren’t matched by any Russian interceptor, and to stop SR-71s’ overflights, the Soviets developed an aircraft which had similar characteristics to those owned by the F-14.
As we have recently explained, the only aircraft that had a speed close to the one of the SR-71 was the MiG-25. But even if it could fly at Mach 3.2, the Foxbat wasn’t able to sustain such speeds long enough to reach the Blackbird.
Another serious problem which affected the Foxbat was the lack of effectiveness of its R-40 missiles (AA-6 Acrid based on NATO designation) against an air-to-air target smaller than a large strategic bomber.
These deficiencies were settled when a more advanced MiG-25 development, the MiG-31, entered in service in the 1980s: the Foxhound was armed with a missile very similar to the US AIM-54 Phoenix, the R-33 (AA-9 Amos as reported by NATO designation).
This weapon was ideal not only for shooting down the American bombers, but also to intercept and destroy fast reconnaissance aircraft, such as the SR-71.
This statement was dramatically confirmed in Paul Crickmore’s book Lockheed Blackbird: Beyond The Secret Missions.
In this book one of the first Foxhound pilots, Captain Mikhail Myagkiy, who had been scrambled with its MiG-31 several times to intercept the US super-fast spy plane, explains how he was able to lock on a Blackbird on Jan. 31, 1986:
“The scheme for intercepting the SR-71 was computed down to the last second, and the MiGs had to launch exactly 16 minutes after the initial alert. (…) They alerted us for an intercept at 11.00. They sounded the alarm with a shrill bell and then confirmed it with a loudspeaker. The appearance of an SR-71 was always accompanied by nervousness. Everyone began to talk in frenzied voices, to scurry about, and react to the situation with excessive emotion.”
Myagkiy and its Weapons System Officer (WSO) were able to achieve a SR-71 lock on at 52,000 feet and at a distance of 120 Km from the target.
The Foxhound climbed at 65,676 feet where the crew had the Blackbird in sight and according to Myagkiy:
“Had the spy plane violated Soviet airspace, a live missile launch would have been carried out. There was no practically chance the aircraft could avoid an R-33 missile.”
After this interception Blackbirds reportedly began to fly their reconnaissance missions from outside the borders of the Soviet Union.
But the MiG-31s intercepted the SR-71 at least another time.
On Sept. 3, 2012 an article written by Rakesh Krishman Simha for Indrus.in explains how the Foxhound was able to stop Blackbirds spy missions over Soviet Union on Jun. 3, 1986.
That day, no less than six MiG-31s “intercepted” an SR-71 over the Barents Sea by performing a coordinated interception that subjected the Blackbird to a possible all angle air-to-air missiles attack.
Apparently, after this interception, no SR-71 flew a reconnaissance missions over the Soviet Union and few years later the Blackbird was retired to be replaced with the satellites.
Even if claiming that the MiG-31 was one of the causes of the SR-71 retirement is a bit far fetched, it is safe to say that towards the end of the career of the legendary spyplane, Russians proved to have developed tactics that could put the Blackbird at risk.
The Mig-31 is still in service, but the SR-71 successor, dubbed SR-72 and capable to reach Mach 6, should be quite safe at hypersonic speed.
David Cenciotti contributed to this post.
In the Cold War the SR-71 missions were no secret. When SR-71 arrived in Mildenhall/UK det. 4 from Beale/USA this went not unnoticed and was phoned to Moscow. The engines were started 40 minutes before take-off. This was phoned to Moscow too. When climbing up over the North Sea, it was spotted by alerted Russian recce trawlers there. 7 minutes after start the SR-71 reached KC-135Q for topping-up.
Than the SR-71 started the typical “Dipsy” manouver to overcome the transonic-range, before climbing with a constant KEAS to ~ 80000 feet.
When SR-71s arrived in the UK some MiG-25s in the GDR were put on alert readiness.
Similar the alert status of interceptors units alongside known SR-71 recce-runs were risen. When the SR-71 started its engines, similar was done at the alerted ABs. At a given height and speed the SR-71 becomes a unique spot on every radar. Flying at Mach 3+ its flight was a straight line and the main direction of interest no longer a secret. In reality the Russian trained high-speed intercepts against a high and fast target. During the “Baltic-run” the SR-71 and MiG-25 came very close in a confined airspace between Denmark and the GDR, when the MiG-25 zoom-climbed behind the SR-71 for a single fire solution by that. For the USA it was more interesting to learn, what sensors were shut down before an imminent SR-71 fly-by. The SR-71 route was chosen to keep it outside the danger-zone, which was vastly reduced by the flight-level and speed of the SR-71.
Those “Peace-time operations” had nothing to do with “War-time operations”, when the SR-71 would have passed over Sweden to avoid such interception attempts.
When in the European theatre the national borders were respected, the situation looked different at the polar-circle. Flying into the Kara Sea for example was still international airspace, while the Russians saw it as their personal backyard. First naval units with SA-N-6 and MiG-31s with new intercept capabilities brought an end of those incursions. Too risky without third-party observers any longer.
Mig-25 defector Viktor Belenko “left the service” before seeing the R-40TD long range heat seeker (which is still carried by Mig-31s today as a very long range IR missile), which had plenty of speed (Mach 4.5) and a perfect target (A friction heated lump of Ti surrounded by a large cold sky). You have to remember that the SR-71 was detected by Chinese radars when it took off for overflights of South and North Vietnam… it was no stealth plane. With plenty of warning (and no ID problems… not many other aircraft flew at that height or speed) Interception would not have been that hard. With SA-5s well able to reach its height and Mig-25s able to fly very high too the SR-71s would have had a very difficult time of things. With the introduction of the S-300 and S-300V series SAMs (SA-10 and SA-12) and the introduction of the Mig-31 it wouldn’t have a chance.
Jane’s Fighter Combat in the Jet Age page 116-117 “SR71 the Ultimate Target”. June 3, 1986 an SR was on a mission over the Barents Sea. “Six Mig 31 Foxhounds, vastly superior to the Mig 25 Foxbat, performed a coordinated intercept that would have subjected the SR71 to an all-angle AAM attack that even a combination of high-altitude maneuverability and ECM could not have defeated. Fortunately for the American jet, the interception took place over international waters, but the Soviets proved their point.”
The SR-71 and MiG-25 are both limited by temperature at first.
The SR-71 is red-lined at Mach 3.2 and the MiG-25 at Mach 2.83.
The SR-71 travels with Mach 3-3.2 up to 90 minutes.
The MiG-25 travels with Mach 2.35 up to 40 minutes. Mach 2.6 possible but limited to 20 minutes. Mach 2.83 is the dash-speed for a few minutes only.
Both aircraft could pass the red line, for the SR-71 it was Mach 3.5 and for the MiG-25 it was Mach 3+, but doing so outside the safe envelope by that.
The Ye-266/Ye-266M were tweaked with some more heat-resistant material in certain areas and limited to essential avionics only.
R. A. Belyakov MiG p 194 gives range on int. fuel for MiG-25P at supersonic speed 1250 km (= < 30 minutes at Mach 2.35) at subsonic speed 1730 km (endurance on a coverage mission, 2 h 5 min)
[1730:125= 830.4 km/h average) translates into Mach 0.85 or 910 km/h at travel-height.
The MiG-25R (p 401) supersonic = 1635 km and subsonic = 1865 km with 5300 litre auxiliary fuel tank the values became 2130 km supersonic and 2400 km subsonic. (Mach 2.35 and Mach 0.85)
All MiG-25s were limited to subsonic speeds at sea-level due to their R-15s engines.
The MiG-31s were no longer limited due to their much different DF-30s engines.