Today, let’s delve into the unique instance when a missile launched from an American F-15 Eagle reached space and destroyed the Solwind P78-1 satellite. This extraordinary event occurred only once, making it a fascinating topic worthy of exploration.
Armed forces of developed nations rely heavily on a variety of spacecraft for critical operations, including navigation, communication, and reconnaissance. As a result, satellites in orbit often become high-priority targets for adversaries. Disabling even a portion of a satellite network can significantly impact an opponent’s military capabilities. Anti-satellite weapons have been developed in several countries, with some notable successes achieved over the years. However, existing systems still face significant limitations and are far from capable of targeting all objects in orbit.
Satellites in orbit are far from easy targets to neutralize. While most satellites follow predictable trajectories, which somewhat simplifies weapon targeting, their placement at altitudes of several hundred kilometers or more introduces significant challenges. These conditions demand specialized designs and capabilities for anti-satellite weaponry. As a result, intercepting and destroying a spacecraft in orbit is an inherently complex task that can be approached through various methods.
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Currently, approximately 1,300 satellites orbit the Earth. These satellites enable global communication, provide internet access to remote areas, broadcast satellite TV, deliver real-time weather updates, and support GPS navigation. While these capabilities have surrounded our planet with a dense network of orbital technology, not all satellites serve peaceful purposes. The near-Earth space, often regarded as “no man’s land,” remains one of the last unclaimed territories where nations can compete for dominance. Even satellites lacking offensive or defensive weaponry can serve strategic military roles. Their position in orbit makes them ideal platforms for housing radars and establishing observation points for real-time monitoring and control.
Discussions about future wars in space were initially the domain of science fiction writers. However, real developments in this area began with the Soviet Union’s launch of the first artificial Earth satellite in 1957. During the Cold War, nearly all space programs had either military or dual-use purposes. The Soviet Union hinted at the possibility of deploying nuclear weapons from orbit, prompting the United States to begin testing anti-satellite missiles in response.
The situation escalated further. In August 1958, the United States conducted several nuclear bomb tests in space. The secret operation, “Argus,” took place in the South Atlantic and involved three nuclear detonations aimed at studying their effects on the electronics and communication systems of satellites and ballistic missiles. The third explosion occurred at an altitude of 467 kilometers, making it the highest nuclear explosion in space during the short history of such experiments. The tests were deemed successful, proving that the electromagnetic pulse from a nuclear explosion in space could cause severe communication disruptions and even damage equipment. Later, The New York Times referred to “Argus” as “the largest scientific experiment in history.”
As part of the Starfish Prime operation in July 1962, a nuclear warhead with a W49 charge of 1.45 megatons was detonated at an altitude of 400 kilometers above Johnston Atoll in the Pacific Ocean, launched by a “Thor” rocket. The explosion caused a complete power outage on the Hawaiian Islands, 1,500 kilometers from ground zero, with widespread electronic failures and loss of telephone communication. At 2,200 kilometers away on Wake Island, the nuclear glow was visible for several minutes. It could also be seen 2,600 kilometers away on Kwajalein Atoll, and even as far as 7,000 kilometers in New Zealand. In the following days, unusual auroras were observed at unusually low latitudes. During the tests, three satellites were instantly disabled by the electromagnetic pulse, and seven more experienced rapid degradation of their solar panels and electronics. The explosion incapacitated about a third of the spacecraft in low Earth orbit.
If similar tests were conducted in space today, humanity would lose 90% of its current low Earth orbit satellites.
Details about the American “Argus” operation were declassified in 1982, and Starfish Prime was closely monitored by the media and the public. In contrast, the Soviet response to the U.S. tests, the “Operation K” carried out in 1961-62, remains classified to this day. According to expert theories, while the U.S. detonated nuclear bombs to study the impact of explosions on near-Earth space, the Soviet Union was likely testing its missile defense systems under the scenario of a nuclear war. Reports suggest that one of the explosions took place at an altitude of 300 kilometers, another at 150 kilometers, and two other launches were unsuccessful.
Witnesses of the explosions reported a bright, silent flash in the sky and the immediate loss of radio communication. The radar systems of missile defense networks ceased functioning normally within a radius of about 1,000 kilometers from the blast site. Additionally, the underground power cable “Tselinograd-Almaty,” buried nearly a meter deep, was disabled. A 570-kilometer-long underground telephone cable was also damaged. The intense electromagnetic pulse caused fires, including one at the Karaganda TPP-3.
The leadership of major countries, especially scientists, were deeply alarmed by the consequences of these space weapon developments. Immediate action was deemed necessary to prevent the potential destruction of the planet.
In August 1963, the USSR, the United States, and the United Kingdom signed the “Treaty on the Prohibition of Nuclear Weapons Testing in the Atmosphere, in Outer Space, and Under Water.” Then, in 1967, the “Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies” was established, also signed by the USSR, the United States, and the United Kingdom. Humanity recognized that further escalation could destroy not only Earth with its seas and oceans but also the Moon.
After the signing of these agreements, the primary mission of military satellites became space surveillance. It is no surprise, then, that spy satellites began to appear in orbit. In addition to performing optical and radio surveillance tasks, military satellites became part of the most complex early warning system for detecting and tracking nuclear missile launches. Furthermore, the space treaty did not prevent the USSR from developing and testing “space mines”—self-destructing spacecraft capable of neutralizing enemy spy satellites by hitting them with shrapnel.
A new phase in the space arms race began in 1983 when U.S. President Ronald Reagan announced the creation of the Strategic Defense Initiative (SDI). Its main goal was to develop a large-scale missile defense system with elements based in space. In other words, the plan was to create a missile defense shield that would securely protect U.S. territory and intercept and destroy enemy ballistic missiles at all stages of their flight.
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In the late 1970s, the U.S. became concerned about Soviet developments of “killer satellites” that could destroy vital reconnaissance and communication satellites.
As a result, the Strategic Defense Initiative launched a program to develop a new generation of highly mobile anti-satellite missiles. This was in response to reports that the USSR had already developed effective anti-satellite weapons in the form of interceptor satellites.
To counter this threat, the U.S. developed an anti-satellite missile, the ASM-135 ASAT. The missile was launched from the American fourth-generation fighter, the McDonnell Douglas F-15 Eagle. Due to its high thrust-to-weight ratio (approximately 1.04 for a nominally loaded F-15), this aircraft was chosen to carry out the satellite-killing mission.
The AGM-135 was the largest missile ever mounted on the F-15 Eagle. Developed by Vought, the weapon was initially known as the Prototype Miniature Air-Launched System (PMALS). It was based on the Short Range Attack Missile, a nuclear-tipped rocket used by the B-52 bomber. The PMALS was modified by adding a second stage and adjusting it to launch directly into space. Once in space, its infrared homing sensor would detect the target and guide the missile to impact.
The anti-satellite missile featured an infrared seeker (cooled with liquid helium) and did not carry any explosive material; instead, it relied on a direct impact to destroy the target. The F-15’s computer system and heads-up display were modified to provide the pilot with navigation directions to engage the target effectively.
The modified Boeing AGM-69 SRAM with a solid-fuel dual-pulse rocket engine from Lockheed Propulsion Company, LPC-415, was used as the first stage of the ASM-135 ASAT missile.
For the second stage of the ASM-135, the LTV Aerospace Altair 3 was utilized. This stage was already well-known to Pentagon scientists and engineers as it had also been used as the fourth stage of the Scout missile and had been previously employed in both the Bold Orion and Hi-Hoe (Caleb) anti-satellite systems. The Altair 3 was equipped with a solid-fuel rocket engine, the Thiokol FW-4S, which ran on hydrazine fuel and was designed to guide the missile toward the target satellite.
LTV Aerospace also developed the third stage for the ASM-135 ASAT, which was named the Miniature Homing Vehicle (MHV) interceptor. Before deployment, the second stage was used to spin the third stage at approximately 30 revolutions per second, guiding it towards the target.
The Honeywell ring laser gyroscope was used to measure the spin rate and provide inertial reference time before the MHV separated from the second stage. The infrared sensor was developed by Hughes Research Laboratories. It employed a strip detector, with four strips of indium-bismuth arranged in a cross pattern and four others in logarithmic spirals. As the detector rotated, it could measure the position of an infrared target as it crossed the strips within the sensor’s field of view. The infrared detector for the MHV was cooled by liquid helium from a dewar installed in place of the ammunition drum on the F-15, as well as a smaller dewar located in the second stage of the ASM-135. The cryogenic lines from the second stage were retracted prior to spinning the MHV.
The guidance system of the final stage tracked targets solely within the field of view of the infrared sensor, but it did not determine altitude, position, or range to the target. The direct proportional guidance based on line-of-sight used data from the detector to maneuver and eliminate any changes in visibility. Four capsules located at the rear of the third stage housed small position control thrusters. These thrusters were used to counteract the central rotation of the MHV.
At the time, the ASM-135 ASAT missile was considered one of the most advanced in the world. Its development was carried out under complete secrecy.
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On January 21, 1984, the first launch of the ASM-135 ASAT anti-satellite missile from an F-15 took place over the Pacific Ocean. The missile was fired at a designated point in space, meaning there was no actual target. However, the aim was to demonstrate the effectiveness of the new development by the U.S. Air Force to the world.
Upon hearing of the Pentagon’s plans, NASA intended to develop a small test target that could be sent into space to test the missile without creating harmful debris. However, this would have taken time, and the U.S. Department of Defense was rightly concerned that Congress might soon outlaw such space tests. The issue had to be resolved as quickly as possible.
The target for the test was the Solwind P78-1 orbital solar observatory, launched on February 24, 1979. It was a spectrometer satellite, which by then had almost become obsolete functionally. Moreover, Solwind was an ideal target simulator, as Soviet reconnaissance, maritime observation, and electronic surveillance satellites were typically placed in polar orbits.
On September 13, 1985, Major Wilbert Doug Pearson, aboard his F-15A Eagle (76-0084) took off from Edwards Air Force Base in Southern California (about 1.5 hours north of Los Angeles) for a unique mission: to demonstrate to the Soviet Union that the United States had the capability to destroy satellites. The ASM-135 ASAT anti-satellite missile was mounted on his aircraft. He had only one chance to hit the satellite.
At 320 km (200 miles), now over the Pacific Ocean, and traveling at a speed of 1.2 Mach, Major Pearson turned the control stick and began a steep climb at a 65º angle. This reduced his F-15’s speed to just under 1 Mach, generating 3.8 G (37 m/s²) during the climb.
At an altitude of nearly 12 km, precisely 11,600 meters, Wilbert Doug Pearson pressed the trigger and launched the ASM-135 ASAT missile towards the Solwind P78-1 satellite. The 14 kg MHV stage collided with the 910 kg Solwind P78-1 satellite at a speed of 24,000 km/h (6.7 km/s).
The hypersonic missile successfully destroyed the satellite at an altitude of 555 km. The United States demonstrated to the world that they could destroy any orbital satellites, and Major Wilbert Doug Pearson became the first, and so far the only, space ace.
The U.S. Air Force intended to modify 20 F-15A fighter jets from the 318th Fighter Interceptor Squadron, based at McChord Air Force Base in Washington, and the 48th Fighter Interceptor Squadron, based at Langley Air Force Base in Virginia, for anti-satellite missions. The aircraft from both squadrons were to be modified to support the ASM-135 ASAT missile. In total, operational forces with 112 such missiles were planned to be deployed, but…
Despite the successful tests of the new anti-satellite missile, Congress banned further testing due to the Soviet-American agreement on space weapons testing, and the program was officially concluded in 1986. The final chapter in this story was written in 1988. Although the program was promising, it was considered provocative, and many believed it would lead to the militarization of space. The Pentagon decided to shift focus to more promising technologies.
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The United States’ concern about sparking an arms race in space may have only delayed the inevitable due to the introduction of global positioning satellites, such as the American GPS, Russian GLONASS, and Chinese Beidou systems. These satellites have made anti-satellite weapons more useful than ever before.
Despite the exchange of “courtesies,” a full-scale arms race or direct conflicts in space have not occurred. The issue lies in the vulnerability of satellites, especially those in geostationary orbits (at 35,000 km). These satellites “hover” over the same point on Earth, making them easy targets. Any hostile action against them could easily provoke retaliatory measures, including nuclear strikes on the ground. Furthermore, the loss of several satellites significantly lowers a nation’s security. Superpowers refrain from engaging in conflicts, wary of the safety of their satellites.
Today, space is being explored by 60 countries, with thousands of spacecraft in low Earth orbit. Active commercial and scientific activities are taking place. However, not all countries in this rapidly expanding “space club” are willing to play by peaceful rules.
Developments continue to this day. There are successes as well as failures among all the participants in this race. But that is a story for another time.
