Feasibility and practical consequences of the 2025 "golden dome" missile interception project

Some questions about the “golden dome” project announced by Trump in Spring 2025. Trying to keep this FQ.

  • Is it technically feasible with technology available in the 2025-2035 timeframe?
  • Given orbital mechanics, would a system like this blanket the entire world with a layer of satellites? Could it surveil and protect/attack any point on the planet?
  • For a satellite to be able to shoot an energy weapon at targets in the atmosphere, how much larger/more massive must it be compared to a communications satellite such as Starlink’s?
  • How low/high would the orbits need to be?
  • If a system can intercept ICBMs in midcourse, can it destroy other satellites?
  • If a system can intercept ICBMs in boost phase, can it destroy/damage other objects of similar size at high altitude, such as military planes and airliners?
  • If a system can intercept cruise and hypersonic missiles, can it target anything of similar size that hugs the ground? Ships? Ground vehicles? Buildings?

The obvious reaction is this sounds like Reagan’s “Star Wars” all over again.

Which never really amounted to anything practical, as far as I know.

Yes. That’s one reason why “boost phase” interception is a dangerous and destabilizing idea since it’s not actually a defensive system at all. It’s an orbital bombardment system. It means that everyone in the world has to stay constantly on edge, worried that they might suffer a massive attack with zero warning.

Not really. One can create a PowerPoint showing any capability you want to imagine. That’s called Science Fiction.

Here in the real world, targeting boost phase ICBMs is a totally different detection and tracking problem from targeting shorter range missiles, much less airplanes or surface targets.

Agree this whole thing is like Reagan’s program: a boondoggle for the usual military industrial suppliers. But now with an added overlay of lots of shadow companies being paid billions for “consulting”. All of whom are somehow controlled by trump and his cronies.

Some historians believe that SDI, as Reagan’s program was named (short for Strategic Defense Initiative) accelerated the decline and downfall of the Soviet Union and the end of the Cold War: It forced Moscow to increase its own military spending, but the Soviet government ultimately couldn’t afford to keep up with America without giving up on its promises to increase the standard of living of its own population.

Tracking and detection of other targets is much easier (especially since buildings and cities can’t dodge, and the payload might be nuclear warheads). And the big issue is the fact that any weapon that can hit a boost phase missile can hit surface targets, and therefore is a bombardment system.

Eh, that was pretty clearly after-the-fact rationalization by the Reaganites to take the credit for the USSR’s collapse, which wasn’t for budgetary reasons anyway. They started pushing the idea almost immediately, it was a right wing talking point for years.

Note that SDI lives on inside the Missile Defense Agency, which has the added goals (by Clinton) of defense against short and medium range missiles:

AFAIK effective defense against long range ballistic missiles is still a pipe dream, but there has been a lot of success against shorter range missiles via Patriot and similar “theater defense” systems. Israel’s Iron Dome is based on this technology. If someone lobbed an ICBM at Tel Aviv the Iron Dome could do nada.

My dad worked on SDI, as a computer scientist (his company had experience modeling complex systems like air traffic). He said that one of the biggest problems was being able to distribute targets to the missile killers. At the time, it was too computationally difficult to track, and coordinate which weapon platform was tasked with killing which missile (so you didn’t end up with multiple killers attacking the same missile, or missing one because you thought that someone else had it as a target), and that problem got dramatically worse if you wanted to handle post-MIRV targets. I’m sure that there’s a lot more computer power available these days, but it’s still a difficult problem.

Back in 1986-87 or so, when I was studying, one of my political sciences professors liked to call what was officially called SDI (Strategic Defense Initiative, not Star Wars) SCI, claiming it was really a Strategic Computer Initiative. It was not so much about a shield against incoming missiles, but a program to boost US hard- and software capabilities.
I did not believe it was true back then, or only marginally. Today, with hindsight, I must admit he was more right than wrong. It was very much practical, and the USA are still the world leader in all things computer.
Maybe the golden dome will help mantain the advantage vis a vis China and other advancing informatic powers. Not that trump would understand it, of course, but perhaps there is somebody in his administration (and I use this word generously) has a couple of brain cells left.

Yes, a lot of corruption is there too. Probably the only thing that trump understands. He’ll probably screw that up, like everything else he has ever done.

Given the lack of any real definition, even in conceptual detail, of “Golden Dome”, any answers are necessarily going to be speculative and require caveats and conditional qualifiers. Given what little has been presented about it from official sources, it appears to be a recycling of the “Brilliant Pebbles” concept under the George H.W. Bush administration which basically took Reagan’s “Strategic Defense Initiative” (SDI, a.k.a. the “Star Wars” anti-ICBM system), stripped off the more Edward Teller wet dream science fiction aspects such as space-based X-ray lasers, neutral particle beam weapons, et cetera, and hewed toward relatively space-based kinetic interceptors. It should be noted that even this concept had significant criticism not only from entrenched critics of intercontinental ballistic missile defense but also from the Government Accounting Office which published a report that questioned basic assumptions and the simulation-based validation methodology. The program was ultimately cancelled in 1994 following the end of Cold War tensions, a desire to cut back defense spending on strategic defense, and cost overruns and test failures in multiple aspects of the system and supporting capabilities some of which was blamed on overly aggressive schedules, cutbacks that actually ended up increasing costs, and contract mismanagement.

As for questions:

  • Is it technically feasible with technology available in the 2025-2035 timeframe?

Building and deploying a novel space-based interceptor system by the 2035 timeframe is ‘sporty’ to say the least. How possible it is depends on the scope of the system, the amount of subsystem and integration testing that is performed before declaring it operational, and whether it actually has to function reliably or just be ‘for show’ as a deterrent.

  • Given orbital mechanics, would a system like this blanket the entire world with a layer of satellites? Could it surveil and protect/attack any point on the planet?

Satellites are in constant motion in whatever orbital azimuth and other parameters. The ability of a satellite system to identify a threat and deploy some kind of interceptor to a target at any point in time depends upon the density of satellites occupying that orbital azimuth, their ability to affect a plane change, modifying right assertion, et cetera. This becomes more difficult the hight the latitude of the intercept or less time available for intercept. The “Brilliant Pebbles” system would have had an initial deployment of somewhere on the order of ten thousand satellites and that was specifically for defending against Soviet ICBMs and SLBMs launched from a relatively constrained geographic zone. To “blanket the entire world” and defend against hundreds of ICBMs in a strategic launch would require hundreds of thousands or millions of satellites in Low Earth Orbit.

  • For a satellite to be able to shoot an energy weapon at targets in the atmosphere, how much larger/more massive must it be compared to a communications satellite such as Starlink’s?

There are so many problems with space-based directed energy weapons that from the standpoint of this proposed system it may as well be considered completely infeasible with extrapolation of current technology. The basic concept proposed (by Ed Teller, naturally) used a thermonuclear pumped X-ray laser basically exploding a small nuclear device to ionize a medium to release electrons and pump them up to X-ray/gamma ray energies, or else a massively powerful or free electron laser with throughput that still doesn’t exist today. Other proposals involved using exotic excimers which would somehow be generated in space-based platforms for years and maintained for use at a moment’s notice.

  • How low/high would the orbits need to be?

This is as much a matter of the periodicity of the orbits as it is distance but these would obviously have to be in Low Earth Orbit.

  • If a system can intercept ICBMs in midcourse, can it destroy other satellites?

Any space-based mid-course interceptor is essentially by definition also capable of being an anti-satellite (ASAT) weapon for satellites or spacecraft at comparable altitude. There are some specific challenges involved in hitting an orbiting satellite that are different from a ballistic missile but the degree of complexity and difficulty is comparable, and in fact ABM systems like the Aegis-based Standard Missile-3 (SM-3) has been demonstrated in an ASAT test in 2008 (albeit with some enhancements for satellite interception). That satellites follow predictable orbits makes them actually easier to discriminate and intercept than an ICBM, assuming the satellite doesn’t have significant maneuvering and evasion capability.

  • If a system can intercept ICBMs in boost phase, can it destroy/damage other objects of similar size at high altitude, such as military planes and airliners?

Boost phase kinetic interception of an ICBM is something of a pipe dream, not because it is physically impossible to hit a missile during boost but because the combination of having to rapidly discriminate a launch, have a sufficiently fast interceptor somewhere downrange within interception arc, and being able to track whatever maneuvers a vehicle under boost might perform. Sending a physical interceptor down from LEO to intercept a missile during its boost phase (~3 minutes) is essentially physically impossible just because of the distance and time involved to make an intercept. This was actually the purpose of directed energy weapons which would weaken the structure of a missile under boost by shining the laser and causing thermal degradation and buckling. How well this would even work with modern solid propellant ICBMs, which have a lot of thermal mass and insulation to absorb heating versus metallic fuselage liquid boosters is even questionable. However, if you did have a directed energy weapon or high precision kinetic interceptor system in space it could certainly be used to attack aircraft or bombard ground targets with massive kinetic energy, which was actually the idea behind the “Rods from God” concept. The cost of this would be prohibitive compared to conventional options, however.

  • If a system can intercept cruise and hypersonic missiles, can it target anything of similar size that hugs the ground? Ships? Ground vehicles? Buildings?

The problem with cruise and hypersonic missiles isn’t so much interception as it is detection; they can fly very low to the ground and even follow terrain contours (TERCOM) using advanced guidance systems making them very difficult to discriminate from radar ‘clutter’. The use of radar-absorbing/scattering materials, thermally-shielded exhaust, and other ‘stealth’ technologies that are now readily available to even modest-sized industrial states makes them even more difficult to find and track even if you know the threat is coming.

The Strategic Defense Initiative Office (SDIO) was absorbed into the Ballistic Missile Defense Office (BDMO) which had long worked on theatre-level defense systems and eventually morphed into the current Missile Defense Agency, where it has deployed the Ground-Based Midcourse Defense System (GMD). This system, which has ~30 interceptors at Ft. Greely, AK, and a few interceptors at Vandenberg Space Force Base, was declared ‘operational’ after very limited testing in 2004, and has enjoyed a pretty mixed success rate in orchestrated demonstration tests since. It is advertised as a defense against “rogue states” (specifically North Korea) and there was discussion at one point about basing a wing of interceptors in Poland with an X-band radar in the UK or somewhere in continental Europe (presumably against Iran) but nobody is under any illusion that it will provide a defense against a concerted strategic attack, or even can intercept more than perhaps two or three simultaneous threats. Whether you regard this as ‘anything practical’ or not is a somewhat subjective judgment but at an estimated cost of US$53B it certainly bears critical discussion about how to best allocate resources for defense against nuclear threat under an increasingly multipolar and proliferative world.

It is an enormously difficult problem, and as challenging as the physical elements of any interception system are (i.e. building a reliable booster and kill vehicle, logistics, et cetera) the “command, control, communications and intelligence” (C3I) elements of a system which has to be both highly automated, extremely reliable and with high ‘uptime’, failsafe but also provide critical discrimination with sparse and perhaps conflicting data, is a massive challenge regardless of the computing power available. It is also the kind of application for which heuristic machine intelligence (‘AI’) is really made because you can essentially feed a system an endless number of contrived simulations until it becomes highly adept and far more responsive than human operators could ever be. And if you don’t have concerns about where that will lead and the problems with entrusting strategically critical systems without effective oversight or even a deep understanding of how they make decisions, maybe you should play a game.

I think it is pretty clear that whatever you think about the concept and application of missile defense, this “Golden Dome” is not a well thought out and detailed proposal but rather just a warmed over notion revived from a system which proved to be impractical and unaffordable decades ago and no real plan or expectation to make changes that would mitigate those issues. In fact, it is so lazy that they didn’t even give it a creative name or a good pitch deck, instead literally just stealing the “Iron Dome” moniker from Israel’s much less sophisticated theatre defense system that protects only a portion of that small nation from mostly primitive and slower moving threats and figuratively gilding it to make it sound more impressive. That Elon Musk immediately jumped on board in hopes of getting tens of billions of dollars of government contracts to support and deliver the system to orbit (even while hypocritically cutting ‘government waste’ in the form of whole service agencies) tells you everything you need to know about the true intent behind this system and the people who will be enriched from it.

Stranger

Two other issues need to be kept in mind. First, that it’s much cheaper and easier to increase the number of incoming missiles than it is to increase the ability to intercept them, so the side on the offensive can spend the defensive side into ineffectuality if they want. Assuming they have anywhere near the same resources at least; Hamas versus Israel is a bad model for a US missile shield for that reason, because one side is a nation state and the other isn’t.

There’s also an issue that was brought up as far back as Reagan and never addressed; it’s very easy to destroy satellites in orbit if you don’t care about collateral damage. Just blow up rockets in the right orbits and let the resulting cloud of orbital velocity shrapnel shred everything; something vastly cheaper and easier than setting up the orbital defense system in the first place. There’s a strong likelihood of causing a Kessler syndrome cascade in the process (and that might well be the intended result), filling near-Earth space with debris and rendering orbit largely inaccessible but a nation defending itself wouldn’t care about that or would consider it a positive.

Seems the best “Golden Dome” approach would be to make a new Standard Missile iteration (whatever designation, maybe “SM-4” or “SM-7”) with double or triple the altitude kill envelope of the SM-3 aboard Aegis destroyers currently, then have a few such destroyers stationed around the USA coastline at all times. Still not very cost-effective, but far cheaper than some $300 billion Trump nonsense.

I certainly don’t have anywhere near the expertise of the Dopers who have already posted.

I am reminded of a full page ad about SDI/Star Wars thar ran, in all places, in an issue of the comic book Boris The Bear. It was instructions for a simple demonstration on how useless SDI was. You put a paper plate on top of a map of the USA, after poking a few holes in the plate. You dumped a large number of beans on the plate from a certain height. White beans were dummy missiles. Black beans were missiles armed with nuclear warheads. The last few panels asked how many beans got through the plate and reminded us that while the plate protected the map from above, it did not protect from the sides.

Having read this thread, technology has advanced but the situation remains basically the same.

The RIM-161/174 ‘Standard Missile’ family of interceptors are size-limited by the need to be compatible with the MK 41 Vertical Launch System. They are designed as a theatre defense system capable of intercepting intermediate range ballistic missiles (IRBM) and could not achieve the altitude necessary for midcourse interception of ICBM/SLBM class weapons. Thought its much varied an ill-fated career the much larger Kinetic Energy Interceptor (KEI, you can see a size comparison with an SM-3 in the link) which was originally conceived as a late midcourse/terminal phase interceptor was at one point proposed as a boost phase interceptor deployed on a “sea-based platform” (i.e. a US Navy ship, which I’m sure they were thrilled about) until it was realized that there was no way to effectively deploy it on any existing destroyer or frigate platform, and a purpose designed ship to carry the system would cost many billions of dollars of development for a platform with no other real application. Even KEI wouldn’t be able to reach up to most of midcourse trajectory; for that, you need something in the class of the Orbital Boost Vehicle (OBV) used for GMD, which is a roughly Minuteman-length three stage vehicle (although smaller diameter) about half again as long as the KEI booster. So, there is no way to scale up existing sea-based systems for midcourse intercept, and making a marine platform for a sea-based system would be enormously expensive, would doubtless take a very long time given the current challenges with domestic shipbuilding, and really wouldn’t be able to serve any other purpose. But I’m sure if you sprayed on gold paint and called the lead ship of class the “Donald J. Trump” you could get it through Congress.

Stranger

This is an excellent idea; I hope some artist makes it real with papier-mâché or similar. It would fit in the carnival processions in Cologne or in the Fallas in Valencia.

Bonus points for Valencia: They set the sculptures on fire at the end of the celebrations. Eigen-nitpick: except the Ninot Indultat, which ends up in the Museo Faller de Valencia.

Israel has multiple levels of defense against projectiles. Iron Dome, David’s Sling, and Arrow. The Arrow defense system is for long range missiles. I’m wondering if the US & Israel will work together on some kind of anti-ballistic missile defense technology. I have no idea how feasible it is, but Israel seems like a testing ground for these kinds of anti-projectile technologies.

Development and testing of the Arrow family of theatre defense missile interceptors was overseen jointly by the Israel Missile Defense Organization and the US Missile Defense Agency, and much of the funding and some key technology elements come from the United States. Because of those key technology elements the the US maintains export controls over foreign sales of the Arrow system such as when Germany wished to acquire Arrow 3 systems last year.

“Long range” in this context means from regional threats and specifically Iran using ‘Scud B’ derived ‘Shahab-3’ and ‘Fattah’ intermediate range ballistic missiles (IRBM). The United States already has multiple systems for this regime (PAC-3, THAAD, Aegis/Standard Missile) and has used Arrow testing and field use experience to inform development of its own programs, but these systems are exclusively deployed internationally or sold for export to allies because the continental United States has natural geographic barriers to intermediate range weapons in the form of the vast oceans of the Atlantic and Pacific and no threats from immediate neighbors of Canada and Mexico.

Stranger

Not really. Processors, for instance, are mostly made in Taiwan.

“Relatively constrained”? Baikur Cosmodrone is at over 45º latitude, which means that the geographic zone you have to cover is over 70% of the Earth’s surface, and they have ICBM silos even further north.

Most of the Soviet-era ICBM complexes whose weapons would be directed at the United States and Europe were located in southern and eastern Russia and in Ukraine. The sites in western Russia such as Gladkays, Drovyanaya, Olovyannays, and Svobodnyy would have been targeting China, South Korea, Japan, and other nations to the west and south. The SS-18 ‘Satan” could have virtually global reach in some configurations but the SS-11, SS-24, and SS-25 missiles based in the western Soviet Union would not have range to reach the continental United States, and while the Soviet fleet of SLBM-carrying nuclear submarines could ostensibly go anywhere in the oceans they tended to remain in the Barrens and Arctic Seas because of their relatively short patrols, maintenance issues that made long range patrols risky, and being penned in by the SOSUS net and US attack submarines that could easily track and follow Soviet boo ers with low risk of counterdetection.

Baikur Cosmodrone has never been an operational ICBM launch facility although it was used to test early liquid propellant ICBMs including the R-7 which became the basis of the long-lived Soyuz space launch booster.

Stranger

…would be real peace talks and efforts, which we could promise to name after Trump’s head if he was successful