R-37M Missiles on Iran’s New Su-35 Fighters Could Complicate Western and Israeli Attack Plans

Following confirmation from Iranian officials in January that orders had been placed for Su-35 fighter aircraft, leaked Russian government documents in October revealed that 48 of the aircraft were on order, which will be sufficient to replace approximately 15 percent of the country’s currently obsolete fleet. With personnel from Iran reportedly having long since begun training for Su-35 operations in Russia, while footage from two airbases have appeared to show preparations underway to host the aircraft, speculation has risen that the fighters may become operational within the next six months. Should deliveries occur within the next year, they will take place in the aftermath of a large scale air assault by Israel, which was supported by the United States and other Western Bloc states. Although the Iranian Revolutionary Guard Corps played a central role in deterring further escalation by launching mass ballistic missile attacks on Israel, the Iranian Air Force has been assessed to have played a negligible role in defending the country’s airspace during this assault.

Although the Su-35 remains behind the cutting edge, lacking comparably advanced avionics and stealth capabilities to the Chinese J-20 and J-16 or American F-35, the aircraft have the potential to allow Iran’s fighter fleet to play a much more active role in supporting the country’s air defences. Persistent bugs with the F-35, which is fielded in only small numbers by the Israeli Air Force, combined with Israel’s reliance on obsolete variants of the F-15 and F-16, make the Su-35’s deployment a potentially highly significantly development for the balance of power in the air between the two countries. Beyond the timing of deliveries, a leading question regarding Iran’s Su-35 procurement remains how well equipped they will be. Although the first Su-35 export deal that saw a small number delivered to China in the mid-2010s included fighters equipped only with R-77-1 and R-74 air-to-air missiles, both of which were far from outstanding by contemporary standards, newer missiles have since become available to modernise the Su-35.

The Su-35 in the early 2020s began to integrate the R-37M long range air-to-air missile, which is an oversized design developed for the much larger MiG-31 interceptor, and when launched from fighter sized aircraft has a range estimated at 350 kilometres. Its combination of a long range, large 61 kilogram warhead, and especially high Mach 6 speed, allows it to significantly increase the combat potential of the Su-35. Although the Su-35 lacks a comparably powerful radar to the MiG-31, which prevents it from using the missile to its full range when relying on onboard sensors, the aircraft can potentially network with Iran’s powerful ground-based air defence radars to achieve longer range kills. Against higher radar cross section targets such as strategic bombers, AEW&Cs, and aerial tankers, the fighter’s radar may be sufficient to support targeting at full ranges. The R-37M would allow Iranian fighter units to threaten targets far outside the country’s airspace, and could be a force multiplier for Su-35s allowing them to engage from well outside adversaries’ retaliatory ranges. Israeli and Western forces’ heavy reliance on tankers to refuel their fighters to reach Iran makes the deployment of such a missile a potential game changer.