Can You Stop a Hypersonic Missile?
protortyp.github.io
protortyp.github.io
Spend enough time arguing with Claude and hearing that combination of words starts making you wince / twitch uncontrollably.
That said I enjoyed the article!
> The honest reading of those numbers is not that defense is winning on economics
> The honest 2026 answer is in three parts.
> The honest answer is that we do not know, because no one has tried
Firstly, I appreciated the article and especially the visuals. But I had the same reaction as the GP commenter. It was hard to read. I'm sick of this punchy, repetitive, LLM-generated prose.
"A 100 to 300 kW beam has perhaps one to three seconds of dwell on a hardened, ablating, plasma-shrouded glide body. That is orders of magnitude short of the joules per square centimetre needed for a thermal kill."
- wondering if you can elaborate more on whether a laser energy-based device would ever be able to have enough power to stop one of these?
And there are numerous such examples. “That was half true. The kill chain ran. The interceptor did not.”
LLMs produce staccato, ugly chains of sentence stumps like this all the time. They’re easy to spot, and your essay is littered with them.
If anything, spending a week on a project like this seems liable to blind you to the shortcomings of the prose, because after putting in a lot of effort you can’t read it with fresh eyes. That’s what editors are for, but an LLM is by nature very weak at editing LLM-generated text.
I want to be able to offer constructive feedback on the structure of the overall essay, for example that the interspersed animated/interactive models often don’t seem strongly connected to the text, but simply reading the words makes this a grind.
That was one of the ones that particularly stood out to me. As I read the article, I often found myself wishing for semicolons and colons instead of full stops; or in some cases a comma and some conjunction:
> That was half true: the kill chain ran, but the interceptor did not.
> The headlines say yes.
> Patriot crews shot down a Kinzhal over Kyiv on the night of May 4, 2023. Arrow-3 batteries killed Iranian ballistic missiles over Tel Aviv in April and October 2024. A pair of THAAD batteries in Israel emptied something close to a quarter of the US national inventory across twelve days of war in June 2025. The headline word in every one of those engagements was hypersonic.
> The headline is wrong.
> No maneuvering boost-glide hypersonic vehicle has ever been fired in combat against a defended target. Every “hypersonic intercept” the press has reported in the last three years was a different class of weapon: an air-launched aeroballistic missile, a quasi-ballistic short-range ballistic missile with a maneuvering reentry vehicle, or in one case a MIRV bus on an intermediate-range ballistic missile that the press could not stop calling hypersonic. The Avangard, the only Russian vehicle that meets the strict definition, has sat in silos in Orenburg since 2019 without being touched. The Chinese DF-17 has never been used. The American Dark Eagle has not yet been ordered to fire.
> So when we ask “can you stop a hypersonic,” we are partly asking “what would happen if anyone fired one.”
There are assorted other issues with the article as well, like excessive use of passive voice, lack of parallelism, and too much meta-talk.
> the interspersed animated/interactive models often don't seem strongly connected to the text
It's indeed the part I struggled with most. The intent was to make the constraint more "visceral", so that the "the interceptor can't catch up" point becomes something you feel by dragging a slider and wtaching the gap grow. But you're right that I didn't do enough to stitch each properly into the prose around it. It reads a bit too adjacent to the text.
For what it's worth, an earlier draft was nearly twice the length and even included a small missile-interception game as the introduction. I think cutting it was the right call though.
Thanks for the notes! I'll keep this in mind for the next post.
I don't know who the target audience is but if you talk about hitting supersonic missiles and kill chains, I don't think you need an interactive example to show that you can't hit a target that's faster than you if it has a head start.
(Also "honest" assessments; the word "honest" has gone the way of "delve".)
Use LLMs to proofread and critique structure. Don't take a single word they generate and put it in your copy, not even simple vocabulary suggestions. The more work you put into a piece, the more important this rule is.
???
Why in the world would that be an "ofc"?
If you're trying to establish yourself as a writer and communicator, LLM's are the last thing you want to color your personal voice with. They may have a role in cleaning up interpersonal communication or in helping non-professional communicators shape up their prose for formal occasions, but they are not some kind of magic neutral way to improve a writer's writing.
As you're seeing here, all that work would have been better received without the compromises and tells of LLM-ese because it would have been your writing, in your voice, as an intelligent analyst and communicator. The idiosyncrasies of that prose voice (your prose voice), are a durable signature that people come to associate with you individually and help them interpret tone, inflection, emphasis, insight in ways that the genericism and accent of an LLM scrubs out.
Give yourself more credit and don't do this; or at least don't treat it as an "of course"!
But jokes aside, I too prefer genuine human writing. Writing is complex enough that you can see a distinct style even if it's rough. LLMs tend to polish the roughness so much that everything reads like magazine ads.
I think of it like a power thesaurus. Thesauruses get a bad rap for people just using them to look for ten-dollar words, but they're super useful for finding ways to articulate things differently, which can sometimes lead to bigger insights or ideas about restructuring the content.
It's on the author to look at what's suggested by the LLM and decide whether or not to use it, and there's an inherent danger in having one's voice overridden by simply accepting too many of the recommendations as-is. But that's between the author and the tool. I won't make any comment here on the article author's prose or how they maybe did or didn't use LLMs.
I recommend prompting the LLM to mostly fix glaring grammatical and stylistic mistakes, not to rewrite the entire thing into a LinkedIn post style text.
This is not really meant to single you out, since there's a lot of this going around, but I really don't think this should be a matter of "of course". Why should it be the default to let a tool that doesn't have your context, or your voice, override your own usage of language?
I'm sure that in your head this is a witty rejoinder, but it really is quite a wild thing to say: that you place no value on the individual variations in how different human writers express themselves. It follows that you really don't care about voice on YouTube either, except in the most basic mechanical sense: you would be happy watching videos written by AI and narrated by the same monotone text-to-speech narrator, video after video, efficiently delivering that densely packed information you crave.
This is actually a thing, isn't it? Like those "shorts" with the AI narration and matching subtitles flashing by in the middle of the screen. I guess you must love those---somebody does, probably a lot of people, or they wouldn't exist.
I'm tempted to frame this as a new kind of illiteracy. People whose brains are so addled by the modern media landscape that to get them to pay attention to anything at all you have to resort to tricks like this; god forbid they ever encounter a writer or narrator who speaks differently, sounds differently, thinks differently, frames differently. Nobody should be surprised, I suppose, that the ability to parse different levels of meaning in Content that falls outside the AI cognitive monoculture is a dying skill.
This really gave it away:
"So can you stop a hypersonic? Sometimes, the wrong ones. Probably not the right ones, yet. The one defense working against the right ones today is a politician’s restraint, not a kill chain.
The worst one is still in its silo. And we are running out of interceptors against the second-worst ones."
It sounds like ChatGPT talking to me.
It's weird reading articles written by AI or helped by AI because it's a lot of words but no overarching narrative. It's almost like an expanded and fluffed up outline. It's very exhausting to read and I lose interest partway through. AI written text has a low "ROI".
AI code is similar. The individual parts are OK but even after reading the entire codebase it's hard to understand how it all fits together or what the over arching structure is.
(BTW, I don't mind what you're doing at all -- as long as you're honest and upfront about it. I love how you're exploring this way of working. I also love the widgets you embedded. It's cute but doesn't add a ton to understanding of the ideas in the article but it's the type of thing AI can really enable for writers.)
I can't tell if you made a mistake and meant the wallet isn't the constraint. These short burst sentences are really hard to read. Write "As we'll see, the constraint is x.". There's no need to split that, a single sentence conveys the whole point.
The article is full of similar wording, and that's why it feels choppy to read.
> The rest of this essay is about why that is harder than the press understands. And about a second problem hiding underneath it
I'd describe this as chain of thought writing. It's fine in casual conversation, with the words just tumbling out of our mouths, but it doesn't work in writing or speeches. There are so many ways the two concepts expressed there could be worded, combined or separated. "The press has an unfortunate tendency to use hyperbole and simple descriptions, but even with those stripped away there are deeper misconceptions..."
It's interesting that folks have honed in on AI as the problem. I'm my view the issue is that you haven't decided on your writing style, and as a non native speaker, you're unable to write a simple phrase and get AI to embellish it. Writing simple phrases is surprisingly difficult. Try making everything concise, with no repitition, and then adding style and flowery language afterwards.
Edit: sorry I may have read another person's comment about being a non native speaker. Writing concisely is something we can all work on.
I will only look at AI slop if paid to do so.
(Scouting ahead for alternatives, I wouldn't mind a Lobste.rs invite, to see whether that's pleasantly anti-slop.)
> Don't post generated comments or AI-edited comments. HN is for conversation between humans.
were extended to submissions as well. People submitting junk should get banned just as people commenting with LLMs do (or risk).
A big part of hypersonic/ICBM warfare is anti-detection tech. When you have the two most military capable countries with 'hypersonic' ICBMs that can in theory reach across the planet is < 30 minutes, a massive part of that is stopping the other country from realizing you even fired a missile in the first place. That detection is usually done through satellites afaik. One of the next steps in global warfare is going to be satellite degradation and interference.
It's a whole different world when you detect a launch in the silo and know you have half an hour to react versus not realizing a missile is in the air until it's 5 minutes off the west coast.
Missile submarines have basically made this reality for decades.
Hypersonics have two related technical challenges.
They are not maneuverable, at least not in the way people imagine, due to fundamental limits of material physics. They are more "straight line" fast. This requires very fast reaction times on the part of defensive systems but the intercept is otherwise pretty trivial using the same off-the-shelf intercept terminal guidance from 20-30 years ago.
The big advantage hypersonics have is they significantly reduce the amount of space an air defense system can cover due to their speed. Hypersonic air defense missiles can counter this to some extent, which the US has, but these have drawbacks related to the second point.
Terminal guidance for hypersonics is an extremely difficult engineering problem because none of the physical materials you can use in terminal guidance systems can survive endoatmospheric hypersonic travel. A hypersonic missile without effective terminal guidance is an ICBM with a shorter intercept window. This isn't that useful for many targets.
The US has been continuously developing and testing different hypersonic terminal guidance designs since (at least) the 1980s. The first viable design only went into production 15-20 years ago. Presumably they've improved on and generalized it since then. There isn't much evidence that any other country has effective terminal guidance for hypersonics.
It is worth noting that effective precision terminal guidance was a prerequisite for US deployment of hypersonic weapons. Everyone else touting "hypersonic missiles" skipped that part.
The US has deployed hypersonic missiles with precision terminal guidance, though not strike weapons, for almost 20 years in more limited domains. However, given the longstanding US doctrine to not deploy a hypersonic attack weapon without precision terminal guidance, and the demonstrated engineering capability in the domain, it is reasonable to assume that Dark Eagle has this capability. Any information about how the terminal guidance works will be closely guarded; it has no obvious engineering solution and it took the US several decades to figure it out.
A bunch of things in that article are incorrect or misleading. For example, the kill chain latency model isn't correct in several respects. It looks like an AI mashup of popular internet slop.
Absence of evidence, especially when dealing with China, is not evidence of absence.
I would rather our planners take China having that nut cracked as a base operational assumption at this point.
The current lasers are not powerful enough for this purpose, they may be efficient only against drones or other slower targets.
First, asymmetric ablation can destroy hypersonic vehicles extremely quickly. It is a major cause of failure in hypersonic vehicles even when no one is shooting lasers at it. A laser just needs to induce the ablation asymmetry; the physics of hypersonic vehicles will do the rest of the work.
Second, precision terminal guidance systems can't function behind ablative shielding. The terminal guidance system has no protection from high-power lasers.
Most people understand that no demonstrable air breathing lift-generating hypersonic missile actually exist. This article goes on to claim that various never launched paper-tigers created for sabre rattling propaganda do actually exist. But it also says they've never been successfully tested. And they haven't. This is a really hard problem.
"Can You Stop a Hypersonic (air breathing/lift generating) Missle?" is actually, "Can you Build a Hypersonic (air breathing/lift generating) Missle?" and the answer is "No, so there's no need to stop them." Conical rockets that travel at hypersonic speeds have existed since the 1950s and will continue to exist and be used as weapons though.
So, tldr; going hypersonic isn't special or new, but air-breathing or lift generating while doing it would be, if it existed, so nation states sabre rattle about fake weapons.
That's not true. Ground based radar can see over the horizon (hence the term Over-the-horizon radar) by taking advantage of the refractive index of air, allowing the radar waves to essentially curve along, as well as by bouncing radar waves off the ionosphere.
Given that this is the foundation of TFA's argument, it does not instill confidence.
For targeting at distance, you need antennas mounted on high masts or airborne radars.
We have detect/analyze/slew as three separate steps that must run in order. You don't consider whether the item is a decoy until you have plenty of tracking on it?? And if slew is even a step (I am aware of no US missile in this realm that moves it's a launcher) you can likewise do that while confirming your target.
And he's assigning a fixed flyout time--but flyout time is entirely a function of where your launcher is relative to the missile target. It's coming down your throat (launcher next to the target), flyout is nearly zero. Note that we saw Iron Beam successfully engage Iranian ballistic missiles. Targets aren't up in the sky, the missile has to come down into the envelope of the weaker weapons in order to actually hit something. (The original issue of targeting ICBMs didn't consider this because the warhead would salvage fuse. Useful if the payload is nuclear, basically useless otherwise.)
We elected not to deploy these weapons for whatever reason. So saying they don't exist at least in the case of the US is more like saying we threw them out because they were deemed useless. But the problem doesn't really seem unsolvable.
So what are the hypersonic low altitude capabilities for maneuvers for these platforms? I don't deny the maneuver but I have this hard time believe someone just throws out some grid fins while doing Mach 24 at 10,000 ft. If the course changes are done at high altitude I can't see what it matters either.
It discusses the hypersonic missiles that are maneuverable, which for now have not been deployed in combat yet, by any of the 3 countries known to possess such missiles.
In contrast, modern hypersonic weapons have plenty of use cases where they'd be fitted with conventional warheads, and used against targets like US Navy ships.
There is plenty that could go wrong if USN ships mounted nuclear interceptor missiles, ready to launch on a moment's notice...
The ABM systems we built in the early cold war worked by having nuclear payloads. We could absolutely not hit an incoming ICBM with the tech at the time, so we just slapped a nuke on it and hoped we could get within 1km at detonation.
Importantly, it was a completely dead end. They had no response to MIRVs and could not be built in sufficient numbers to deal with any actual launch. We threw them out because they were in fact useless.
Generally, we have moved away from Nuclear ABM systems because detonating a hundred warheads above a city is very unlikely to work out well.
Intercepting a cold war era ICBM turned out to be feasible with newer technology, and we currently have $2 billion missiles that can feasibly intercept ICBMs (at low quantity).
>No maneuvering boost-glide hypersonic vehicle has ever been fired in combat against a defended target
Nobody has fired one of those against a target because almost nobody has a functioning maneuvering hypersonic vehicle. Basically just China I think.
I would expect "real" hypersonic weapons like that are basically uncounterable. The physics just gets too obnoxious. Interceptors will struggle to get better than a coin flip, and they will be too expensive to use on anything else so they won't be general purpose, so equipping them will be full of tradeoffs.
That's the entire point of hypersonic weapons. $3 billion dollars to make that high value target go away, with extremely high probability. They replace 50 bombers launching still quite expensive anti-ship weapons at scale, which is the strategy it replaces.
This of course has rather negative implications for the concept of force projection in future wars. Which is why China made a hypersonic weapon.
It becomes a war of financial attrition at that point.
FWIW they were cancelled because they didn't have a particularly good kill ratio and proliferation and MIRV meant you'd need a ton of them to prevent an attack landing (and doing so would involve a significant number of nuclear blasts pretty close to the targets anyway). Deterrence was more credible.
And doesn’t the parent article to the Sprint article make it clear that they we didn’t deploy them because fall out shelters combined with building more nukes was deemed more cost effective at saving lives.
https://www.youtube.com/watch?v=YZZV464z9g8
I'm pretty sure that improvements in sensing, computation, actuation, and conventional warhead design over the past 50 years could have produced a reliable hit-to-kill Sprint. And in fact, some research was done on such a vehicle, the McDonnell-Douglas HEDI.
Russia/China insisted that Americans perfecting the nuke interception game is an existential threat to them, and threatened to do something horrible like retaliating militarily if cities and nations were to be rendered immune to nukes, as if it would remotely harm their own through a magical power in doing so. The US/EU played along with that logic and limited deployments of interceptor techs.
Terminal phase interception (It's moot using ABMs because of MIRV and decoys): (A missile similar to Sprint (but conventional) or Sentinel) or 300+ kW laser would be required to intercept a Mach 10-30 target. ABMD (SM-2 and SM-6) and THAAD aren't fast enough. If one had a lot of 1 MW class lasers that could serially engage many targets, that could work.
The other problem, as mentioned, is having radar(s) that can search and track HGVs and ballistic targets upwards of Mach 20-30 (7+ km/s).
The purpose of a rocket is really only for distance to drop to something like 10 meters for conventional munitions and something like 300 meters or so for nuclear, in practice this is a constant.
So what matters is the maximum speed of both rockets. Make that large enough and you can get the attacking rocket to make maneuvers that (assuming they cannot be predicted), make it mathematically impossible to intercept the attacking rocket. In practice this difference is only something like 130 km/h (for nuclear).
Lasers won't work until we're talking gigawatt lasers, and even then only at "medium range" (in other words, for stopping nuclear weapons, an optimal outcome can only be achieved at single-digit kilometers, in other words, it may be able to protect individual points like the president, but it will never protect a city against a fusion device). Oh and whether a laser weapon works or not will not be known until seconds before impact. I hope you have strong nerves.
Note that the attacking rocket does not need tracking, it needs a good random number generator.
TLDR: no, we cannot currently intercept a hypersonic controlled rocket ... and that won't change without an overwhelming technological advantage, which basically means better rocket motors. At a sufficiently high equivalent level of technology, attacking rockets cannot be stopped. That level is only slightly higher than the level the US is currently at (and we don't know. Both US and Russia may already be past that point)
insightful though