Transmuting Iron to Gold

More likely, from your pocket to Elon's

Golden- vs Iron Dome analogy

Within days of assuming the presidency, President Trump signed an executive order [1] for a US program named after the Israeli Iron Dome missile defense system, in effect reviving the Strategic Defense Initiative (SDI, aka “Star Wars”) that sucked some $320 Billion from the US economy during the Reagan-Bush years without producing anything of practical use. (And the executive order calls for more! But here we focus exclusively on the SDI part.)

The administration quickly labeled it “Golden Dome”, and as you read this in May 2025 Trump's drones in Congress are scurrying around injecting it into the budget. Our dear Leader, as well as various esteemed members of Congress and the mainstream press are clearly impressed by the advertised successes of the Iron Dome system, and infer that it implies that a successful anti-ICBM system is feasible. For the reality, please consider the above illustration. A professional baseball shortstop, like the athlete shown at right, is highly effective in catching a line drive hit his way. That baseball is representative of the kinds of missiles launched by Hezbollah, Hamas or the Houthis against Israel, pretty effectively countered by Iron Dome, here the shortstop. Now suppose we replace the batter with a rifleman, firing a bullet flying more than seven times as fast as the baseball. How well do you think the shortstop will do in snagging it? That's the analogy: baseballs versus bullets.

SDI was a bad idea forty five years ago, and it's a bad idea today; perhaps more so now because of the deteriorated geopolitical situation and the status of treaties intended to limit nuclear weapons inventories and proliferation. From a purely technical point of view, very little has changed: There have been no sufficiently grand technological breakthroughs to make any of the approaches more feasible or even affordable. A recent report from the American Physical Society [2] on Strategic Ballistic Missile Defense outlines the problem of countering an attack from North Korea in terms of numbers of assets required and their costs. Basically, it says that even if we can develop a 100% effective system (which is to say, one which destroys each and every ICBM North Korea launches against us) and that system is 100% effective in distinguishing the actual ICBM warheads from the numerous decoys deployed concurrently and in defeating all other countermeasures, a system would require 6,600 space-based interceptors to intercept a raid consisting of 12 North Korean ICBMs, including at least some of their latest model, launched in burst salvos of 4, during the boost phase of ICBM flight. [3] Assuming a one tonne interceptor unit cost of $20 Million (at the low range of an 2012 estimate) and use of the Falcon Heavy launch vehicle, the cost of these is estimated to be $142 Billion, not including sensors, command and control, and maintenance. Notice that, for an ICBM cost of $10 Million, the defense to offense cost ratio is over 1000:1. Notice also that a linear extrapolation of this cost to counter a Russian attack involving 1200 missiles (of their 870 land based + 640 sub launched = 1510 ICBMs under New START limits[4]) would be $14.2 Trillion, about half the current US annual GDP. As we spend about 3.5% of GDP annually on defense, this number represents about 14 years of DoD spending, so the DoD budget would need to double during the period of a 14 year SDI production and deployment. The first question that comes to mind is, “How could we possibly afford it?”

The next question we might ask concerns the reasonableness of the effectiveness and counter-countermeasures assumptions. As we are dealing with nuclear weapons here, there is a distinction In comparison to conventional weapons in terms of the effectiveness required. For a North Korean scenario in which the adversary might launch, say, 12 missiles, our defense has to have an effectiveness of 0.99916 if we can accept a probability of 1% that a missile succeeds in getting through and decimating a city. In air defense circles, an effectiveness in the range 80 – 90% is considered outstanding. (For the Iranian attack in 2024, the US-Israeli success rate in countering ballistic missiles was in the 60-80% range.) We ask ourselves, how many shots would we have to take against those 12 missiles with a system having 85% single shot effectiveness to achieve that 1% probability of a single US city being vaporized? The answer is 4 independent shots per missile, or 48 missiles engaging actual warheads for the entire North Korean attack.

The requirement for shots per target grows with the number of threats being countered. For a 150 missile raid representing a limited Russian or Chinese attack, the number of shots per target needs to be 5, leading to a requirement for 750 shots. For the quoted Russian attack, we would need 6 shots per valid warhead leading to an inventory of 7,200 shots. [5] It is emphasized that these calculations assume a perfect ability to distinguish between a true target and a decoy during the engagement, an entirely unjustifiable assumption. Prudence would demand an increase in the number of shots per target to account for enemy decoys and countermeasures. [6] In any event, it is clear that any system that is remotely affordable will have to be imperfect, with a significant number of enemy weapons reaching their targets. In an earlier post [7] I illustrated the immediate effects of a single weapon attack on a US city, and asked how many such events would be considered tolerable.

The most damning aspect of the Golden Dome program is not its cost or risk of infeasibility, but rather its effect on efforts to limit nuclear weapons inventories. Since there is a huge cost advantage of offensive nuclear weapons over ballistic missile defense, both the Russians and Chinese will respond to Golden Dome by simply deploying more weapons. In fact, there are indications that they already are, in response to the existing, $10 Billion per year US ballistic missile defense effort. Both adversaries know full well that our present capability is minimal, with the pitiful level of success-oriented testing to date achieving only about 50% effectiveness, but they must hedge their bets against the possibility of a breakthrough.

In the US, proponents for Golden Dome include the nuclear weapons and defense industries, the space industry (aka Elon Musk), and various political entities such as the Heritage Foundation. Also included in the mix are politicians, motivated by factors including a fear of Trump, a fear of being tarred as weak on defense, or who, like the Russians and Chinese, want to hedge their bets. Once again, it is up to the people to provide the leadership.

Notes

[1] https://www.whitehouse.gov/presidential-actions/2025/01/the-iron-dome-for-america/ In reviewing it I found no less than four architectural elements that would involve massive expenditures of public funds to the benefit of Elon Musk's companies.

[2] American Physical Society Panel on Public Affairs, Strategic Ballistic Missile Defense: Challenges to defending the United States, February 2025, https://www.aps.org/publications/reports/strategic-ballistic-missile-defense

[3] The reason why it takes so many interceptors has to do with the fact that they would be placed in low earth orbit, with each interceptor in position to engage the boost-phase ICBMS for only on the order of 2 minutes per day. Hence the need for a huge constellation of interceptors. There is a similar problem, albeit perhaps not so acute, for space-based lasers.

[4] Kristensen, H.M., et al. Russian nuclear weapons, 2024 Bulletin of the Atomic Scientists 80(2) pp 118-145, 2024 https://doi.org/10.1080/00963402.2024.2314437

[5] These calculations are based on the assumption of independent trials, and the number of shots per target has been rounded. Paid subscribers will be provided the details on request.

[6] Since the US systems deployed or in development to counter ICBMs have never been field tested against meaningful countermeasures, it would be meaningless to even speculate about the numerical requirements for additional anti-missile weapons.

[7] https://stephenschiff.substack.com/p/nuclear-sufficiency