Deterrence in the Last Sanctuary


There’s never been a war in the space domain, but some believe it won’t be that way forever. At the Reagan National Defense Forum in December, Air Force Gen. John Hyten, commander of U.S. Strategic Command, remarked that “any domain that humans move into will be subject to conflict.” Secretary of the Air Force Heather Wilson warned, “We must expect that war, of any kind, will extend into space in any future conflict.”

In the 60 years since the launch of the first human-made satellite, the space domain has evolved from a relatively benign environment with two primary actors to a much more complicated landscape — one with over 80 players operating more than 1000 satellites in orbit. This new space environment comes with uniquely modern threats against space systems. As Wilson explained, “The U.S. built a glass house before the invention of stones… The shifting of space [from] being a benign environment to being a warfighting environment requires different capabilities.”

What types of capabilities does the United States need for the modern space age? And how can the United States and its allies continue to maximize their use of space while minimizing the risk of attacks against space systems? An important first step is understanding how the space environment has changed over the past 60 years and how escalation and deterrence dynamics — including attribution, reversibility, resilience, thresholds, and asymmetries may have shifted along with it.

In the first space age, from 1957 to the fall of the Soviet Union, attribution was simpler than it is today. Before 1990, the United States and the Soviet Union were responsible for over 90 percent of all space launches, so any actions that interfered with space systems could be reasonably viewed as attacks by the opposing superpower. Attribution was assumed. Since the end of the Cold War—what some are calling the second space age—space has been more accessible to other countries. Last year, the United States and Russia were responsible only 32 percent of all space launches. As American strategists develop more tailored deterrence strategies, they will have to ensure that the United States can attribute aggressor actions in order to respond effectively and credibly. Due to its investments in space surveillance and situational awareness capabilities, the United States has a substantial edge in attribution capabilities, which could provide it with a major advantage over less capable adversaries. Yet, U.S. leaders will have to demonstrate their ability to attribute attacks, or else an adversary could believe that it could avoid retaliation by relying on attribution ambiguity.

During the Cold War, both the United States’ and the Soviet Union’s space programs were strongly tied to their nuclear forces. Before 1990, over 70 percent of satellites were military satellites, with many primarily dedicated to supporting nuclear attack warning and response and continuity of nuclear command and control on the ground. Any action that disabled a satellite, even temporarily, was treated as a potential prelude to a nuclear attack. Today, however, recent experiences with “gray zone” coercion suggest that reversible actions could blur escalation thresholds. This is particularly dangerous because simulated attacks in space indicate that reversible actions may be perceived differently by attackers and defenders. This phenomenon has already occurred in the cyber domain, where distributed denial of services attacks have been viewed as minor disruptions by their perpetrators, but major attacks by defenders. In space, a reversible dazzling of a satellite could prove even more complicated, as an attacker might not know the extent or duration of an attack’s success. Different views about reversibility in the second space age are therefore likely to increase the risk of inadvertent escalation.

Until recently, resilience in space was largely an afterthought. It was assumed that a conflict in space would likely lead to or precede a major nuclear exchange. Therefore, the focus was on cost-effective architectures that maximized satellite capabilities, often at the cost of resilience. Recently, however, some have hoped that new architectures could enhance resilience and prevent critical military operations from being significantly impeded in an attack. Although resilience can be expensive, American investments in smaller satellites and more distributed space architectures could minimize adversary incentives to carry out first strikes in space.

In the late 20th century, minor escalations against space systems were treated as major events, since they typically threatened the superpowers’ nuclear architectures. Today, the proliferation of counter-space capabilities and the wide array of possible types of attacks means that most attacks against U.S. space systems are unlikely to warrant a nuclear response. It is critical that policymakers understand the likely break points in any conflict involving space systems. Strategists should explore whether the characteristics of different types of attacks against space systems create different thresholds, paying particular attention to attribution, reversibility, the defender’s awareness of an attack, the attacker’s ability to assess an attack’s effectiveness, and the risks of collateral damage (e.g., orbital debris). Competitors may attempt to use non-kinetic weapons and reversible actions to stay below the threshold that would trigger a strong U.S. response. The 2017 National Security Strategy warns:

Any harmful interference with or an attack upon critical components of our space architecture that directly affects this vital U.S. interest will be met with a deliberate response at a time, place, manner, and domain of our choosing.

In order to fulfill this promise, the United States will want to ensure that it has capabilities to respond both above and below various thresholds to ensure a full-spectrum of deterrence options for the full range of potential actors.

In the first space age, the two superpowers had largely symmetric capabilities and interests in outer space (with a few notable exceptions). In the second space age, however, the space domain includes many disparate players with vastly different asymmetric capabilities and interests. The United States is more reliant on space than any other country in the world, but it also retains greater space capabilities than any of its competitors. Although the 2011 National Security Space Strategy states, “Space capabilities provide the United States and our allies unprecedented advantages in national decision-making, military operations, and homeland security,” this also means that that the United States has more to lose.

From the dawn of the first space age, Americans understood the many benefits that could come from the peaceful uses of space and the great harm that could result from hostile uses of space. In 1962, President John F. Kennedy addressed the dilemma of how to reap the benefits of space without conflict, stating

only if the United States occupies a position of pre-eminence can we help decide whether this new ocean will be a sea of peace or a new terrifying theater of war… space can be explored and mastered without feeding the fires of war, without repeating the mistakes that man has made in extending his writ around this globe of ours.

For 60 years, space has been the exception: the one domain that has remained free from the scars of war. By better understanding the dynamics of the second space age, we may be able to keep it that way.


Zack Cooper is senior fellow for Asian security at the Center for Strategic and International Studies (CSIS). Thomas G. Roberts is a research assistant and program coordinator for the Aerospace Security Project at CSIS. They are co-authors, with Todd Harrison and Kaitlyn Johnson, of CSIS’s Escalation and Deterrence in the Second Space Age report.