A recent opinion piece in SpaceNews cast an optimistic view on space-based interceptors, labelling them as necessary, realistic, and affordable. The current system of interceptors, according to the piece, does not provide adequate protection against nuclear arsenals like Russia’s and China’s. Arguing that such interceptors would “dramatically augment U.S. terrestrially- and sea-based defense capabilities,” the author pushes back against critiques that such systems would be cost prohibitive, illegal, or generate damaging space debris. Even setting aside these critiques, however, the piece does not address a major issue with space-based interceptors. At a time when the world is struggling to develop solutions to today’s space issues, space-based interceptors would accelerate power projection into an environment that is growing exponentially more complex.
The United States’ military and intelligence apparatus is significantly reliant on on satellites. From military command and control to ballistic missile launch verification, America’s terrestrial deterrence rests on a constellation of systems that are increasingly threatened by rival powers. Other countries are increasingly relying on satellites as well, and there are growing concerns that this reliance is becoming a ‘single point of failure.’ The United States is working to make its assets more resilient, but is also preparing for a possible war in space. China has tested anti-satellite technology. Russia has been playing around with maneuvering satellites—an action that spooked American military analysts. The main point? Space is a potential powderkeg, on which the United States is staking its nuclear deterrence capabilities, conventional military capabilities, and even vital parts of the economy.
It is perhaps not wise to throw into this mix an unprecedented capability that changes the entire strategic stability equation. Space-based interceptors may well provide a “critical means of defense should deterrence fail,” but might also fundamentally undermine the deterrence structure as a whole. If the U.S. had the unfettered capability to destroy any nuclear attack on the homeland, Russia and China would be placed in an existential problem. Neither power has the conventional power (yet) to challenge the United States, but remain confident in their own territorial integrity because of their nuclear deterrence against us. If that deterrent is removed, what actions might they be compelled to take to retrieve that certainty?
This is not to say that they would launch a terrestrial attack on American assets. Their solution would likely be in the same environment as our new interceptors: space. To create a system of satellite-killers in orbit is as realistic and feasible, if not more so, as a space-based interceptor system. These satellite-killers would be able to preemptively degrade the U.S. space-based interception capability in the event of an American attack on Russian or Chinese interests. Of course, Moscow or Beijing could argue that these satellite-killers would only be used to defend against an existential threat—the same type of threat the nukes were supposed to protect against. And, unlike the American space-based interceptors, these satellite-killers would likely contribute to the space debris problem if used, expanding the effects beyond just one conflict. Debris fields would undermine the use of space for scientific and commercial uses as well.
These other countries may also deploy their own space-based interceptors. Instead of space being used as a verification system for weapons deployed from Earth, it would become a hair-trigger combat zone. In this brave new world, movements of satellites could be read as harmless maneuvering or the precursor to an attack. Is an interceptor in space pointed at the proper target, or could it be used to take down a nuclear command and control satellite? Outer space is not the only environment in which benign actions can be misinterpreted as hostile, but its importance gives this concern particular saliency. The United States, Russia, and China—not to mention other spacefaring countries like India, Israel, and Japan—may wind up pursuing a new space race to mitigate these risks.
Additionally, space is quickly shifting away from being solely used by great powers. Commercialization is happening, and companies are deploying their own assets, launching their own rockets, and ambitiously looking beyond Earth’s orbit. This will further complicate issues. Future commercial systems may look nothing like the relatively static systems we have today, and spacefaring countries will have to commit more and more bandwidth to monitoring these systems as well. A commercial space debris-clearing system may look very similar to a military satellite-killer.
Weapons in space are probably going to happen at some point. However, it’s not clear that benefits of taking this unprecedented step today would outweigh the costs. An equilibrium would be found, if conflict is avoided, but it would likely be right back to where we are today—great powers reserving the ability, albeit in a more complex manner, to existentially threaten rival great powers. A time when tensions between the major spacefaring countries—China, Russia, and the United States—are increasingly active is not the best time to try to find a new equilibrium for these capabilities.