THE F-15 SATELLITE KILLER AND THE ASM-135A ASAT MISSILE

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The F-15 satellite killer and the ASM-135A ASAT missile

On Jan. 21, 1984, the first launch of an anti-satellite missile from an F-15 took place over the Pacific Ocean. The ASAT missile was launched at a specified point in space; no actual target was involved

The F-15 is a twin-engine, high-performance, all-weather air superiority fighter. First flown in 1972, the Eagle entered U.S. Air Force (USAF) service in 1974. The Eagle’s most notable characteristics are its great acceleration and maneuverability. It was the first U.S. fighter with engine thrust greater than the basic weight of the aircraft, allowing it to accelerate while in a vertical climb.

In fact thanks to its high thrust to weight ratio (which amounted at about 1,04 for a nominally loaded F-15) the Eagle was selected to perform the satellite killer mission.

In the late 1970s, the U.S. anticipated Soviet development of “killer satellites” that could destroy vital U.S. reconnaissance and communication satellites.

The chosen weapon to counter this threat was the Vought ASM-135A Anti-Satellite (ASAT) missile. The ASM-135A featured several interesting characteristics such as the first stage of the AGM-69 SRAM-A nuclear air-to-surface missile and the lack of any warhead, meaning that it had to physically hit the target to destroy it. This result could be achieved thanks to a small IR-guided “homing kinetic kill vehicle” which had to guide the ASAT on the heat source of the oncoming satellite.The F-15 satellite killer and the ASM-135A ASAT missile

A typical engagement for an anti satellite mission would have seen the F-15 positioned in a holding pattern determined by North American Aerospace Defense Command (NORAD) controllers who would have used their satellites to track data of the target to ensure the exact position. Then following NORAD’s command, the F-15 would have headed towards the target in a supersonic zoom climb to launch the missile: as described by Steve Davies and Doug Dildy in their book F-15 Eagle Engaged, the ASAT had to be launched from extremely high altitude (80,000ft) and high angle (60-65 degrees).

Airborne tests with “captive” (not launched) ASAT missiles (designated CASM-135As) on modified F-15 fighters began in 1982.

After zoom tests conducted by two different F-15As from 6512th Test Squadron, on Jan. 21, 1984, the first launch of an anti-satellite missile from an F-15 took place over the Pacific Ocean. The ASAT missile was launched at a specified point in space; no actual target was involved. This first launch was followed by three more in 1985, with the IR seeker locked to the IR-signature of a star (that was technically called “celestial IR source”).

However these tests were the prelude to the only real ASAT launch that occurred on Sept. 13, 1985, when the F-15A 77-0084 destroyed the Solwind P78-1 satellite.The F-15 satellite killer and the ASM-135A ASAT missile

The Solwind P78-1 was a spectrometer satellite placed in polar orbit in February 1979 that by 1985 had become useless: the Solwind made a perfect target simulator, since Soviet reconnaissance, maritime surveillance and electronic intelligence satellites were usually placed in polar orbits.

The mission, dubbed the “Celestial Eagle Flight,” saw the F-15 flown by Maj. Wilbert D. “Doug” Pearson launching the missile at 38,100 feet. Streaking into space, the missile homed in on the Solwind at 345 miles above the Earth. The ASAT, travelled at 11,000 mph and hit the 17,000 mph travelling satellite at 320 miles above the hearth: these huge combined velocities disintegrated the Solwind.

The test was a remarkable success, but the indignant outcry of the solar scientists that they were still receiving data from the satellite drowned out the celebrations. Moreover the ASAT test was against the recently signed US-USSR treaty that banned the use of weapons in space: due to these concerns the Congress had to cut the funding for the program, enforcing the USAF to terminate the development of the anti-satellite mission in 1988.

In the interesting video below Pearson explains how he was able to become the only fighter pilot in history to accomplish the incredible feat of shooting down an orbiting satellite.

Photo credit: U.S. Air Force

Additional source: National Museum of the U.S. Air Force