The F-15 Eagle accurately launched an ASM-135 ASAT missile to destroy the Solwind P78-1 satellite in orbit in 1985 during a unique test.
A unique mission was carried out by the US Air Force in 1985. A specially modified F-15A Eagle dropped an ASM-135 ASAT anti-satellite missile from an altitude of 11,600 meters. The target was the Solwind P78-1 satellite, at an altitude of approximately 555 km. The pilot, Major Wilbert D. “Doug” Pearson, executed a zoom-climb trajectory at Mach 1.22 and 3.8 g to launch the missile into the early stages of space. The impact produced a high-speed collision, destroying the satellite by “hit-to-kill” and generating a debris field that was tracked for several years. This test was the only one of its kind ever conducted to date. It reveals a rare intersection between advanced aeronautical engineering, space strategy, and arms control.
The ASM-135 ASAT program since 1982
The ASM-135 ASAT program was launched by the US Air Force in 1982 with a clear operational objective: to intercept low-orbit satellites using an F-15A fighter jet. The missile had to be compatible with an already proven aircraft to avoid the development of a new platform. Twenty F-15As were specially modified. These modifications included the addition of a central pylon to support the missile, an upgrade of the mission computer to manage ballistic firing, and the integration of a specific cooling system for the interceptor vehicle’s infrared sensors. Ground tests were followed by a series of captive flights, conducted without launch, to test the stability of the system under real conditions. These tests validated the mechanics of the system and its behavior at high altitude. The first live launch took place in January 1984, without a target, and demonstrated that the missile could reach the upper layers of the atmosphere. This validation phase was essential before any orbital interception attempts could be made. The program was at the frontier between tactical aeronautics and space experimentation, with a level of technical complexity rarely seen in weapons systems at the time.
The September 13, 1985 test: a detailed account
On September 13, 1985, the US Air Force conducted a single experimental launch from a modified F-15A. The aircraft, registered 76-0084 and nicknamed Celestial Eagle, was piloted by Major Wilbert D. Pearson from Edwards Air Force Base in California. The aircraft performed a high-angle climb to 65 degrees, reaching a speed of Mach 1.22 at an altitude of approximately 11,600 meters, while undergoing a load of 3.8 g. The purpose of this maneuver was to reach the optimal ballistic window for launch. The ASM-135 ASAT missile was automatically released from the central pylon. Once the propulsion stages had separated, the interceptor vehicle, or MHV (Miniature Homing Vehicle), continued on its trajectory to intercept the Solwind P78-1 satellite, located at an altitude of approximately 555 kilometers. The MHV, weighing 14 kg, struck the satellite at an estimated relative speed of 6,700 m/s, causing it to disintegrate completely. This launch is the only successful destruction of an orbital satellite from a fighter jet in flight to date. It represents a technical milestone in the history of US anti-satellite capabilities, with a level of precision and coordination rarely matched since.
Technical aspects of the ASM-135 missile
The ASM-135 ASAT missile was based on a two-stage architecture designed to engage low-orbit targets from a tactical aircraft. The first stage used an engine derived from the AGM-69 SRAM missile, modified to provide initial thrust at high altitude. The second stage, powered by an Altair 3 propulsion system, provided the ascent to the exosphere and accelerated the interceptor vehicle. The latter, called MHV (Miniature Homing Vehicle), weighed approximately 14 kilograms and was equipped with a passive infrared sensor cooled by liquid helium. This detection system was mounted inside the aircraft, in place of the Vulcan M61A1 cannon, and kept at cryogenic temperature until separation.
After release, the MHV began a rapid stabilizing rotation. It had 56 microthrusters, powered by compressed gas, which allowed it to fine-tune its trajectory during the last seconds of flight. The interception method was based on direct kinetic impact, without a warhead. The “hit-to-kill” principle involved a high-speed collision with the target to destroy it. The 1985 launch remains the only documented success of an air-to-air missile neutralizing a space object using this method.
Space debris and consequences for research
The interception of the Solwind P78-1 satellite by the ASM-135 missile resulted in the creation of approximately 285 pieces of orbital debris identified by tracking systems. These fragments scattered at altitudes between 400 and 600 kilometers, in an orbit similar to that of the target satellite. At the time, NASA estimated that some of this debris could remain in orbit until the early 1990s or even beyond, depending on its mass, projected surface area, and atmospheric density.
Most of the objects identified were small and non-reflective. They were not detected by traditional radar, probably due to deposits of soot or absorbent composite materials. This characteristic limited their long-term traceability. In 2004, nearly 20 years after the test, only eight pieces of debris remained officially catalogued by space surveillance networks.
This test fueled the first concrete discussions on the risks associated with anti-satellite weapons and persistent orbital debris. It also contributed to institutional awareness of the need to limit kinetic tests in space due to their impact on scientific and military activities in low Earth orbit.
End of the program and geopolitical repercussions
Despite its technical success, the US Congress halted the program in 1988 for several reasons: excessive cost (estimated at over $3.6 billion), the risk of reigniting the space arms race, and debates over compliance with space treaties. The program remained unique. The ASM-135 test demonstrated the ability of a fighter such as the F-15 to reach space defense. The use of zoom climb proved its impressive thrust-to-weight ratio for reaching an area outside the dense atmosphere. The “hit-to-kill” approach ruled out any risk of nuclear or chemical explosion in orbit. However, this type of weapon generates problematic debris, even if in this case it was short-lived. Diplomatically, the test sent a clear message to the USSR, while raising the question of the extension of conflicts into space—an issue that has never been resolved.
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