The bright sun greets the International Space Station in this photo taken from the Russian section of the orbital outpost by one of the STS-129 crew members, November 2009.
The bright sun greets the International Space Station in this photo taken from the Russian section of the orbital outpost by one of the STS-129 crew members, November 2009
NASA Handout via REUTERS

Last year, when the Trump administration unveiled plans to create a Space Force—originally conceived as an independent branch of the military to oversee operations in the great beyond—public responses to the idea tended to fall into one of two extremes. Champions celebrated the move as essential for promoting U.S. dominance in space and protecting national security; critics warned that it would unnecessarily militarize a domain where peaceful cooperation should prevail and that it could spark a space arms race. China’s landing of a rover on the far side of the moon last January—a first-of-its-kind feat—further stoked this debate.

But in reality, the image of space as a zone free from military competition is as fanciful as the notion that it can be subject to outright American dominance. Space is already militarized, and it has been since the start of the space age six decades ago. Competitors such as China and Russia are already capable of threatening the United States’ military presence there—namely, the satellites that provide the information backbone of U.S. military power. President Donald Trump’s February directive to establish the Space Force as a sixth branch of the military under the U.S. Air Force—a modification from his original proposal to create a fully separate service—changes nothing in this regard.

Arguing over whether Washington should create a Space Force misses the point. Since space is already a competitive and a militarized domain, the task now is to protect U.S. and allied military interests in space to guard against catastrophe. That means both strengthening U.S. capabilities to deter and defend against strikes on its satellites and working with other nations to strengthen norms. The most important norms are against attacks on so-called strategic-warning satellites, which underpin nuclear deterrence by detecting missile launches in real time, because such attacks could be interpreted as a prelude to a nuclear strike and result in unintended nuclear war. Ignoring these problems will only make arms racing and conflict more likely.


In 1954, before the creation of NASA and before the Soviet Union launched Sputnik, U.S. policymakers decided to put military satellites in space, at first for surveillance purposes. These satellites soon became an essential tool for tracking the development of weapons systems deep in Soviet territory. They also eventually revealed that U.S. concerns about a “missile gap” with Moscow were unfounded—a realization that paved the way for Cold War arms control agreements—and provided assurance that the United States would be able to respond to a Soviet nuclear attack.

At first, Washington saw advantage in keeping weapons out of space in order to protect its newfound ability to monitor Soviet military and political targets. As a result, the Eisenhower administration promoted freedom of space operations as an international legal principle and limited U.S. development of space-based weapons. Eventually, both the United States and the Soviet Union supported the 1963 Limited Test Ban Treaty, which placed a prohibition on nuclear detonations in space, and the 1967 Outer Space Treaty, which prohibited the deployment of nuclear weapons in space.

Soon, however, the two superpowers began to use their surveillance satellites to directly support conventional military operations. In the mid-1970s, the United States started fielding reconnaissance satellites that provided near-real-time imaging of earth; by the end of the decade, U.S. space policy also included using satellites for military targeting. By that time Moscow also had reconnaissance satellites in place to track U.S. aircraft carrier groups in near real time and to target U.S. forces with long-range antiship missiles.

As each side’s military power grew increasingly reliant on satellite systems, developing antisatellite weapons became necessary to gain conventional military advantage and prevail in a future conflict. An antisatellite weapon is anything that can disrupt, disable, or destroy a satellite or its ability to collect and share data. Examples include nuclear weapons that kill satellites with radiation, hit-to-kill interceptors that physically crash into satellites, electronic jammers and lasers that block signals or damage satellite sensors, or cybertools that enable access to or control of satellite systems. These weapons can be based on the ground, in the air, or in space itself.

By the mid-to-late 1970s, both the United States and the Soviet Union were moving aggressively to field antisatellite weapons to blunt each other’s space targeting capability. Moscow had limited ground- and space-based antisatellite weapon capabilities, and was investigating using lasers for the same purpose. Washington’s increasing concerns about Soviet satellite (and antisatellite) capabilities led President Jimmy Carter to approve the development and testing of new kinds of non-nuclear antisatellite weapons in 1978. By 1985, the United States successfully tested an air-launched hit-to-kill missile against a U.S. Air Force satellite, but the program was later cancelled due to the winding down of the Cold War and congressional opposition.


The end of the Cold War alleviated military competition in space, but only temporarily. The first Gulf War made clear just how important satellites had become to Washington—and how important space would be for fighting and winning future wars. Some called it the “first space war” because Washington’s use of satellite-based navigation, communications, and mapping enabled a quick and decisive U.S. victory. The Kosovo conflict helped drive this point home, with global positioning satellites (GPS)—which provide positioning, navigation, and timing signals from over 12,000 miles above the earth’s surface—helping U.S. weapons systems target Serbian forces.

Today, satellites are even more integral to Washington’s ability to project power far from its borders, including in support of its allies in Europe and Asia. They provide critical military services, including secure communications; weather and navigation data; and a ballistic missile launch early-warning system to guard against surprise attacks. And they enable U.S. military forces to coordinate across wide geographic spaces, supporting missions ranging from kinetic conflicts to nuclear deterrence to humanitarian assistance.

Today, satellites are even more integral to Washington’s ability to project power far from its borders, including in support of its allies in Europe and Asia.

Militaries across the world have taken notice, but none more so than in China and Russia. Beijing’s 2015 Military Strategy referred to outer space as part of the new “commanding heights in strategic competition,” and Chinese leaders have established a Strategic Support Force, designed to bring its military space and cyber missions under one umbrella. Moscow has similarly created an integrated Aerospace Force, tasked with missions including detecting and “meeting” threats from space.

Both countries are developing and deploying antisatellite weapons to undermine U.S. military effectiveness in the event of a conflict. China has an operational ground-based hit-to-kill antisatellite missile intended to target satellites in low orbit, and its military has begun training with antisatellite missiles. Russia, meanwhile, is likely developing a similar system, and has also claimed to be developing air-launched missiles to target U.S. satellites. And both countries are developing laser technologies to damage satellite sensors, with Russia recently fielding a ground-based laser weapon, likely for an antisatellite mission. Both are also building electronic warfare capabilities to block signals from U.S. communications and navigation satellites.

China and Russia also appear to be developing space-based antisatellite capabilities. According to the U.S. Department of Defense, China is working toward having the ability to launch antisatellite strikes from other satellites. And at the UN Conference on Disarmament in Geneva in 2018, the U.S. State Department expressed concerns about the abnormal behavior of a Russian military satellite. Moscow claims it is intended to support satellite inspection missions, but the State Department argues that the satellite’s behavior is inconsistent with this claim.

China may also be working toward targeting satellites in higher-altitude orbits. In May 2013, Beijing launched an object with a peak altitude above 30,000 kilometers, which a Pentagon report argues could have been a test aimed at achieving high-orbit antisatellite capability. These higher orbits are home to many of the United States’ most important space assets, including strategic warning and nuclear command and control satellites, which alert decision-makers of ICBM launches and enable the president and military commanders to control tactical and strategic (including nuclear) forces. Attacks against these satellites would be particularly dangerous because they could prompt fears of an impending nuclear strike and lead to runaway nuclear escalation during a crisis or conflict.

U.S. President Donald Trump holds a space astronaut toy as he participates in a signing ceremony for Space Policy Directive at the White House in Washington, December 2017
U.S. President Donald Trump holds a space astronaut toy as he participates in a signing ceremony for Space Policy Directive at the White House in Washington, December 2017
Carlos Barria / REUTERS


As Russia and China continue to push forward, U.S. policymakers may be tempted to use treaties and diplomacy to head off their efforts entirely. This option, although alluring on paper, is simply not feasible. Existing treaties designed to limit military competition in space have had little success in actually doing so. The 1967 Outer Space Treaty bans parties from placing nuclear weapons or other weapons of mass destruction in space, on the moon, or on other celestial bodies, but it has no formal mechanism for verifying compliance, and places no restrictions on the development or deployment in space of conventional antisatellite weapons.

Even if it were possible to convince Moscow and Beijing of the benefits of comprehensive space arms control, existing technology makes it extremely difficult to verify compliance with the necessary treaty provisions—and without comprehensive and reliable verification, treaties are toothless. Moreover, regulating the development and deployment of antisatellite weapons is extremely difficult, both because they include such a broad and diverse range of technologies and because many types of antisatellite weapons can be concealed or explained away as having some other use. Unsurprisingly, Russia and China’s draft Treaty on the Prevention of Placement of Weapons in Space, which they have been pushing for several years now, has an unenforceable definition of what constitutes a “weapon” and does nothing at all to address ground-based antisatellite weapons development.

Washington should thus shift its focus away from formal treaties and toward strengthening norms around especially worrying space operations. The most important norms to pursue relate to the targeting of satellites that support strategic warning and command and control, since these systems help maintain strategic stability between nuclear-weapons states. The United States should immediately start a serious and sustained dialogue with China and Russia to at least build a consensus against attacking these systems, if a more wide-ranging agreement is out of reach.

The United States could also explore informal measures to strengthen operational rules of the road in space. A useful model for these measures is the 1972 maritime agreement on the Prevention of Incidents On and Over the High Seas, also known as the INCSEA treaty. The spirit of INCSEA’s provisions map over to the space domain rather well—including its focus on maintaining a safe distance from other ships; avoiding maneuvers in heavy sea traffic; not simulating attacks on, launching objects toward, or illuminating the bridges of other ships; and using accepted international signals when maneuvering near another ship. In fact, since none of these measures rely on intrusive inspection activities, one can imagine the possibility of reaching agreement on a similar treaty for space.


Accepting that space is already militarized, Washington should also make sure that U.S. space capabilities are resilient enough that an adversary would doubt that an attack on them would have a meaningful effect. This will probably require an increase in both the number and types of satellites supporting critical U.S. military capabilities, to provide defense in depth. It also requires Washington to vigorously pursue military space partnerships with its allies and the commercial sector, including opportunities to host U.S. payloads on partner countries’ satellites, and to share critical data collected by partner satellites. Such initiatives will strengthen collective defense while limiting the burden on any single country, which is the core organizing principle of U.S. alliances and partnerships.

At the same time, the United States also needs to take more proactive steps to deter and defend against antisatellite attacks. Senior U.S. military officers and Defense Department officials clearly and rightly recognize that this necessitates Washington developing some of its own antisatellite weapons to, at a minimum, counter adversaries’ evolving offensive arsenals. But the United States should also keep the bar for developing specific capabilities high so as to avoid setting off an arms race.

Satellites and antisatellite weapons will increasingly shape future military competition between the United States and its adversaries. Accepting that reality, and acting accordingly, is necessary in order to protect the space environment, advance U.S. and allied interests, and make peace a more likely outcome.

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