The Cold War was won in space, but not in the part of space that tourists visit. The competition that mattered strategically, that gave both sides confidence in their nuclear deterrent and made arms control agreements possible, was conducted by a fleet of imaging, signals, and early-warning satellites that the public rarely heard about. Most of these systems were classified while they operated; several of them remain classified today. The public story of the Space Race (Sputnik, Gagarin, Apollo 11) was the visible layer of a much larger contest that the open literature can describe only in outline.
The contest ran along four axes: photographic reconnaissance, electronic and signals intelligence, navigation, and early warning. The American program led in photographic reconnaissance and navigation; the Soviet program led in signals intelligence and was operationally important in the early-warning constellation. The two programs together produced the technical infrastructure that made the later arms-control treaties verifiable, and they were the reason that the final decade of the Cold War did not include a U.S.–Soviet shooting war.
Photographic Reconnaissance
The American photographic reconnaissance program began in 1956, when President Eisenhower authorized the development of an imaging satellite under a program that was publicly called the Air Force’s WS-117L and secretly called Corona. The technical challenge was the return of film from orbit. A camera system could be built, and a recovery capsule could be built, but a capsule containing exposed film had to reenter the atmosphere without burning up, without being shot down, and without being found by the Soviet Union. The recovery system was developed by Lockheed’s Skunk Works, and the camera was built by Itek; the film-return capsule would be caught in mid-air by a passing C-130 if possible, or splash down in the Pacific and be retrieved by a ship.
The first twelve Corona launches failed. Discoverer 14, launched on August 19, 1960, was the first successful mission, and its 1,680 images of the Soviet Union were the first unambiguous American look at Soviet strategic forces from above. The program continued for 12 years, with 145 successful missions and 800,000 returned images. Corona revealed the actual size of the Soviet ICBM force (about 30 missiles in 1961, far fewer than the U.S. Air Force had estimated) and documented the construction of new missile fields. The imagery was the foundation of the National Intelligence Estimates that the Kennedy and Johnson administrations used to argue against the missile gap rhetoric that had dominated the 1960 election.
Corona was declassified in 1995. By that time, the United States had moved on to the KH-7 and KH-9 film-return systems and then to the KH-11 electro-optical system, which transmitted digital images to ground stations in near real time. The Soviet Union developed the Zenit film-return series and the Yantar series, but its reconnaissance program was less productive than the American one; the Soviets relied more heavily on signals intelligence and on agent networks, chronic shortfall in their own imagery is one of the reasons they overestimated American military capabilities during the 1970s.
The most consequential single use of reconnaissance imagery in the Cold War came in October 1962, when an Air Force U-2 flight over Cuba on October 14 produced the first photographs of Soviet MRBM sites being constructed. Subsequent U-2 flights, and the Coral Sea–based Skywarrior flights of the Navy, produced the imagery that the Kennedy administration used to brief the Joint Chiefs and to formulate the quarantine declaration of October 22. The strategic balance was not changed by Corona or the Cuban overflights, but the policy decisions made on the basis of those images might have been different, and possibly worse, if the intelligence had been less reliable.
Signals Intelligence and Early Warning
The signals intelligence satellite programs were a parallel contest. The American program was led by the National Security Agency and used constellations of satellites in geostationary and highly elliptical orbits to intercept Soviet microwave and radio communications. The Soviet program, run by the GRU and supported by technical institutes in the Soviet Academy of Sciences, was at least as ambitious and was the most productive source of intelligence on U.S. military deployments in the 1970s and 1980s. The details of both programs remain classified.
The early-warning constellation was where the operational stakes were highest. The American Defense Support Program (DSP) used infrared sensors in geostationary orbit to detect the heat of ICBM launches and to provide warning of an attack. The first DSP satellite was launched in November 1970; the constellation reached operational capability with three satellites in 1971, and the Soviet Oko system reached initial capability in 1978. Both systems produced false alarms; the most famous was the Soviet Oko alert of September 26, 1983, when Lt. Col. Stanislav Petrov of the Soviet Air Defense Forces declined to report a launch warning to his superiors because the satellite system reported only five missiles when a real first strike would have been measured in hundreds. The decision not to report probably prevented a Soviet retaliatory launch. The episode is a useful reminder that satellites are not just sensors but also inputs to human decisions that have to be made in minutes.
Navigation and the GPS Revolution
The U.S. Global Positioning System was developed by the U.S. Air Force from a 1973 concept that merged two earlier programs, the Navy’s Transit and the Air Force’s 621B. The first Navstar GPS satellite launched on February 22, 1978. The constellation was declared fully operational in 1995, with 24 satellites in six orbital planes. The system provided three-dimensional position and time to any receiver that could see four or more satellites, with an accuracy that was originally 100 m for civilians (degraded by selective availability) and about 10 m for military users with the encrypted P(Y) code. Selective availability was turned off on May 1, 2000, and the current civilian accuracy is about 1–3 m.
GPS was the most expensive military space system ever built (about $12 billion in then-year dollars for the original constellation) and the most consequential for civilian life. The Soviet counterpart GLONASS was completed in 1995, collapsed in the 1990s, and was rebuilt through the 2000s; the European Galileo system reached initial services in 2016; the Chinese BeiDou system reached global coverage in 2018. The ubiquity of GPS in smartphones, precision weapons, and civilian logistics has made the U.S. military’s continued investment in space-based navigation a strategic given.
Anti-Satellite Weapons and the Treaty Regime
The Outer Space Treaty of 1967, signed by the United States, the Soviet Union, and 60 other countries, prohibited the placement of weapons of mass destruction in orbit and reserved the Moon and other celestial bodies for peaceful purposes. The treaty did not prohibit other military uses of space, and both superpowers continued to develop anti-satellite weapons.
The United States tested an ASAT missile launched from an F-15A in 1985, destroying the Solwind P78-1 satellite in orbit. The Soviet Union developed a co-orbital ASAT system that was tested 20 times between 1968 and 1982, with a successful destructive intercept of the Kosmos 1243 satellite in 1982. The two programs never produced a militarily significant capability, but they established the precedent that satellites were legitimate targets in wartime. The Convention on Registration of Objects Launched into Outer Space (1975) and the Rescue Agreement (1968) extended the legal regime, but the absence of a comprehensive ASAT or space-weapons treaty remains a gap in the international legal order.
The End of the Cold War and the Persistence of Military Space
The end of the Cold War did not end the military use of space; it changed its character. The declassification of Corona in 1995 and the launch of commercial imaging satellites (Ikonos in 1999, DigitalGlobe’s QuickBird in 2001, Planet Labs’ Dove constellation from 2014) made medium-resolution imagery of almost any point on Earth available to private buyers. The U.S. Air Force Space Command, established in 1982, became U.S. Space Force in 2019. The Soviet and Russian counterparts include the Russian Aerospace Forces (VKS), created in 2015 from the merger of the Russian Air Force and the Aerospace Defence Troops.
The strategic question of the 2020s is the same one the 1960s generated: how do two nuclear-armed states verify arms control agreements when each can spoof, jam, or destroy the other’s satellites? The question is unresolved.
Key sources
- Kevin C. Ruffner, ed., Corona: America’s First Satellite Program (CIA History Staff, 1995)
- Walter A. McDougall, The Heavens and the Earth: A Political History of the Space Age (Basic Books, 1985)
- John J. Klein, Space Warfare: Strategy, Principles and Policy (Routledge, 2006)
- Scott Pace et al., The U.S. and Russia in Space: Cooperation, Competition, and the New Geopolitics of the 21st Century (AIAA, 2017)
- CIA declassified Corona gallery (cia.gov/corona)