September 6, 2019

XAIM-97 Seekbat: The long range ‘MiG-25 killer’ missile the F-15 never got

Once the realm of specialist interceptors like the MiG-31 and F-14, today long range air-to-air missiles capable of destroying aircraft at ranges in excess of 100 miles are coming into the mainstream. The European MBDA Meteor is already operational on the Typhoon and Gripen (and will soon arm Rafale), while similar efforts remain at an advanced stage in Russia, China and the US. Simply put, a longer range missile gives a fighter the same advantage of a boxer with a far longer reach than his opponent. The disadvantage historically was the missiles were huge, expensive and tied to a specialised weapon system. It was the latter issue that prevented the easy integration of the Navy’s AIM-54 Phoenix onto the F-15 or F-4, something that would have given these types an edge against the bogeyman of the Soviet MiG-25 ‘Foxbat’. An aircraft that in the early 1970s, was inspiring fear in US military planners. It was far faster than its Western counterparts and was believed to be agile, and equipped with a powerful advanced radar and long-ranged missiles. The F-4, then the mainstay of USAF, was seen as hopelessly outclassed. It was hoped that the new F-15 Eagle, then in development, would tip the balance in the West’s favour, but the new aircraft was to be armed with the same Sparrow medium-range missiles that armed the F-4. If the Soviets had a new longer-ranged missile, then even the Eagle would be vulnerable.

AIM-95 seekers being tested on a F-4. The missile was cancelled in 1975 due to spiralling costs, unlike the similar Soviet R-73 which alarmed the West when its superior performance was revealed in the 1980s.

It was planned that the F-15s short range infra-red guided would be the radical AIM-82; whereas contemporary missiles only really had a chance of locking out the extremely hot jet exhausts at the rear of the aircraft, it was hoped that the new generation weapon would be ‘all aspect’ — able to attack an enemy from any direction. But before a contract was awarded, the AIM-82 was cancelled for being an unnecessary duplication of work being done by the Navy on the conceptually similar AIM-95 AGILE. While the AIM-95 was intended for closer targets, destroying aircraft at long range required a new missile.

With a larger field of regard, helmet cueing and thrust vectoring the AIM-95 was the father of the new generation of IR missiles.

The MiG-25 was capable of such speeds and altitudes that killing it with Sparrow missiles would prove almost impossible. The new missile was a Foxbat killer and accordingly was dubbed ‘Seekbat’.

The Seekbat was based on the AGM-78 Standard ARM, itself derived from a the RIM-66 surface to air missile. The new weapon would have a maximum speed exceeding Mach 3.5 and a range of over 90 nautical miles. It employed semi-active radar homing with an infra-red seeker for terminal guidance of the missile. The operational ceiling was 80,000 ft (24,000 m), an important figure considering the ‘Foxbat’ could reach 78,000ft while carrying two missiles.

An F-105 Thunderchief armed with AGM-78 Standard ARM missiles.

Test firings began in late 1972, but by 1976 was it was mired in technical problems and spiralling programme costs. Allegedly one of the problems faced on the programme was the target drone the missiles faced. The Bomarc was not designed for high altitude testing, when the aircraft’s engines were oxygen starved by the thin air the unmanned aircraft rolled on its back shielding the engines behind the wings and denying the infra-red target the Seekbat needed for terminal guidance. The confused missile would instead lock onto the sun. The poor results of Seekbat, combined with new intelligence revealing the MiG-25 to be far less potent than anticipated signalled the end of the Seekbat. It was axed in 1976.