Probably because of its relation to space, I’ve been fielding a lot of questions recently about the recently announced “Golden Dome” initiative. Since this is tangentially related to my “real” job, I’m going to be somewhat careful with what I say, but there’s plenty we can discuss conceptually and technically. Mainly, this essay will examine the geopolitical considerations, some possible architectures, the technical, industrial, and intelligence challenges involved in actualizing the concept, and a little reflection on how likely it is for the system to be realized. As usual with these off-topic essays, if this is not of interest to you, our more usual programming will resume with Thursday’s book review.
Golden Dome is often described as analogous to Israel’s Iron Dome, which is a localized missile defense interceptor system. Iron Dome has received significant attention due to its role in Israel’s success in swatting down the missile barrages launched against it be Iran, the Houthis, Hezbollah, and other groups in the region, although, in reality, it is simply the most recognizable name in a collection of air defense systems functioning together to achieve an unprecedented level of success in defeating these missile and drone attacks. Through a combination of systems, along with allied support, Israel has been remarkably successful in defeating airspace incursions, and the basic premise of Golden Dome is to provide the continental United States with analogous protection.
On the surface, this seems a worthwhile idea, but complications arise almost immediately. First, the US covers a far larger geographic area than Israel. Our potential adversaries have capabilities far more advanced and difficult to defeat than those which Israel presently faces. These are the core technical hurdles: enormous geographic span, and more advanced threats. There are geopolitical concerns, as well, with some commentators and analysts contending a successful, or even partial, implementation of Golden Dome would be destabilizing to the principles of international relations between nuclear-armed powers which have heretofore prevented nuclear war. Assuming that the technical hurdles can be overcome, and that the geopolitical concerns are addressed, the final obstacle to implementing Golden Dome is financial. Proposals for its cost range from the hundreds of billions into the dozens of trillions of dollars.
Let us begin by examining the technical side of Golden Dome, on which I consider myself most qualified to write. Fanciful notions of forcefields aside (I never have managed to get the diamagnetic force field I developed in high school to work), defensive systems like Golden Dome all operate on similar principles. They detect an incoming threat, identify it, predict its trajectory, launch an interceptor, refine the target, intercept the target, and assess the interception. These basic steps haven’t changed much since Britain erected the world’s first RADAR air defense system, which alerted them to incoming German bombers, prompted interceptor planes to launch, and helped guide the British planes into battle. Of course, threats these days are more advanced, and so are interceptors. Coming out of the Cold War, the focus was on intercontinental ballistic missile defense, with long-range radars positioned around the country to detect missiles and cue interceptors. A whole miniature arms race developed in detection, concealment, targeting, and countermeasures. Ultimately, it is possible to “hit a bullet with a bullet,” as the saying goes. Space-based systems observing the infrared part of the spectrum can detect and track missile launches, cueing various types of radars to refine the trajectory. Since ballistic missiles are, well, ballistic, their paths are relatively predictable. An interceptor is launched, which can perform minimal maneuvering and has an algorithm to help it distinguish between countermeasures and the actual warhead, and, if all goes well, the interceptor kinetically destroys the warhead before it reaches its target.
This works, after a fashion. It can be reasonably assumed that most nations with significant spacefaring capability can accomplish this feat, although ability to account for countermeasures surely varies, and the probability of interception per interceptor launched will obviously vary from system to system and from threat to threat. Still, if you have an interceptor with an 80% probability of a successful intercept, just launch a few of them. The overlapping probabilities will result in an almost 100% chance of interception. Missile defense accomplished.
Well, not quite. Two factors make this tested and proven approach untenable for a comprehensive missile defense system like Golden Dome. First is a matter of scale. If you must launch, say, five interceptors to have a near-guarantee of success against one incoming ICBM, the arsenal depth required to defeat a full strike from a peer power is enormous. Still, you might say, if this is enough of a priority, it could be done. That might even be true, except for the second factor. Missile technology hasn’t been sitting still, either. Traditional countermeasures like decoy warheads with fake radar cross-sections were one thing. Advanced, maneuvering, hypersonic glide vehicles with unpredictable trajectories are something else entirely. These kinds of advanced threats are what put the biggest technical question mark in Golden Dome.
Traditional missile defense works because either a) the missiles follow ballistic trajectories, which are predictable using basic physics, or b) the threats are slow enough that they can be characterized and responded to in a reasonable envelope based on current interceptor performance. Both factors get tossed out in the face of modern capabilities, which puts missile defense in a tricky position. Maneuverable hypersonics are fast enough, and unpredictable enough, that even a comparably capable hypersonic interceptor will usually fail against the threat, even if they are prepositioned strategically around likely targets (major cities, key defense sites, governmental facilities, et cetera). The solution currently being proposed for the Golden Dome initiative is boost-phase intercept.
Missiles (and rockets – same thing, different purpose) don’t instantly go hypersonic and start maneuvering wildly. Though they can accelerate rapidly, they do have launch and boost phases, where they are moving slower, less maneuverable, and, perhaps most importantly, more detectable, especially with infrared. There is a tentative consensus that most advanced missile threats could be successfully intercepted during boost phase with minimal innovation to the interceptor concept itself. From a technical perspective, the problem becomes pervasive detection capability, rapid cueing of interceptors, and interceptors prepositioned where they can intercept in the relatively brief boost phase window. Again, from a technical perspective, these are problems we can solve. A proliferated LEO constellation of spacecraft, each bearing multiple advanced interceptors, cued by a slightly higher orbiting constellation of infrared observing spacecraft augmented by multiphenomenology sensor networks, could do the job. Assuming, that is, that we know during the boost phase that a given launch is, in fact, a threatening missile launch against the homeland, not something more innocuous, a test, or a threat to someone else. That becomes an intelligence problem, and it’s not clear how reliably these differentiations could be made.
This brings us to the geopolitical concerns surrounding the Golden Dome initiative. Obviously, it would be a massive incident if a successful Golden Dome intercepted the wrong launch, but just by existing, there is concern that Golden Dome is destabilizing. Now, putting a bunch of interceptors in low Earth orbit is not quite as bad as it sounds. It’s not forbidden by treaty – the Outer Space Treaty only prohibits weapons of mass destruction in orbit, not other kinds of weapons – and the principle of satellite overflight is well-established. It might make people a little nervous, but interceptor vehicles are usually kinetic, not armed, meaning their only destructive power comes from their mass and the velocity at which they hit things, so this should not be a deal-breaker.
The facet of Golden Dome that truly has the potential to be destabilizing is that, if it works, it alters the calculus behind nuclear first strike mentality. At least, that is the allegation lodged against it. The argument is at least as old as the Strategic Defense Initiative, often lampooned as the “Star Wars” program (yes, it involved shooting lasers at missiles, but the lasers were for tracking the missiles, not shooting them down, and were quite successful in doing that and more complicated tasks), which likewise faced condemnation for destabilizing the Cold War. The crux of the argument is that a comprehensive missile defense system like Golden Dome, with the ability to protect the homeland from devastating nuclear attack, would cause adversaries to think us more likely to use nuclear weapons against them, since we would no longer be held at threat by their nuclear weapons. It’s essentially the same conversation as mutually assured destruction. Mutually assured destruction is often taught as the determining factor in avoiding nuclear war, but the veracity of that claim is subject to debate, and it is certainly a case of misplaced monocausationalism. However, it is certainly true that potential adversaries would view the development of a system like Golden Dome as impetus to improve their own strike capabilities to circumvent its defenses. It is likely that Golden Dome would have some destabilizing impact (as does any new capability), but not to the extent which its most vehement opponents suggest.
Let’s say that the geopolitical concerns are addressed, and all the technical and intelligence problems can be solved. There remains the question of cost, which is really a question of the system’s value. Estimates of Golden Dome’s cost are enormous. It’s far too early in the program to lend any particular estimate much credence, but it is reasonable to assume, between research and development, launch costs, manufacturing, and maintenance, the program will be colossally expensive. The launch costs alone for the proliferated constellations involved will likely be tens of billions of dollars. So, is it worth it? There’s a school of thought that says absolutely, yes. After all, the government’s most fundamental responsibility, one of its foundational reasons for existing, is to protect the governed from external threats. By this reasoning, Golden Dome is not just worth it, but an imperative for the government to develop. Resources are not unlimited, though, so we must answer the relative value of a missile defense system that may or may not ever be used against other priorities, both in national security and in other areas, like infrastructure, social services, energy, fundamental research, diplomacy, et cetera. There is no single answer to this question, no perfect, objective, universal way to measure all these relative values. Everyone will have their own judgement on the matter.
There is one, final concern which bears mentioning. Golden Dome is intended to go toe-to-toe with the most advanced, exquisite capabilities that could be launched against the continental US. Obviously, such a system would retain the ability to defend against less advanced threats, like traditional ICBMs, cruise missiles, and so forth. I question, though, if these are the main threats which should be addressed. Oh, they are threats, but warfare is constantly evolving. A key tenet of warfighting is to seek an asymmetric advantage. Faced with a successful Golden Dome, an adversary could develop ever more advanced missile threats to penetrate our defenses, pouring billions into research and development, testing and deployment, in an escalating arms race between offense and defense, like the contest between artillery and armor in Verne’s From the Earth to the Moon. Or an adversary could let us focus on a Golden Dome to protect against these exquisite threats, and instead do something more pernicious. Imagine swarms of disposable drones launched from a semitruck, cyberattacks against infrastructure targets. My greatest concern with Golden Dome is not its technical feasibility, its geopolitical impact, or even its cost. It is that Golden Dome may prove a distraction from addressing the threats we are far more likely to face, and breed complacency in the process.
IGC Publishing 