US Should Propose a Hypersonic Missile Test Moratorium & Ban

UPDATE: Bill Gertz reported on Dec. 4 that China had conducted “this week” a third test of its WU-14 hypersonic boost-glide vehicle, according to his unnamed military sources. I expect that a test was conducted, although its outcome remains publicly unknown. Gertz quoted Carnegie expert Lora Saalman as saying that a third test (the quote gave no indication that Saalman had independent information about it) showed that the WU-14 “is a priority program for China”; Gertz also quoted China threat monger Richard Fisher as saying the test shows the need for more funding of rail guns, which “offer great potential for early solutions to maneuvering hypersonic weapons.” [I don’t think that makes even a little bit of sense. The problem with shooting at fast objects with fast guns is that they tend to shoot past each other, and the problem with rail guns is that rocket motors are cheap but guidance systems less so. But I digress.] The main point is that if, in fact, China did conduct another test, successful or not, there is nothing the United States can say about it, since we continue to say nothing about a possible test ban. Indeed, the more likely response is to accelerate US hypersonic programs, as advocated by another of Gertz’s sources.

Note: a souped-up and tangy sauced-down version of this post can now be found at Bulletin of the Atomic Scientists. [Just kidding, JM, just kidding.]

Recent Chinese (Aug. 7) and American (Aug. 25) hypersonic missile development tests have highlighted an otherwise little-noted element of the resurgent technological arms race, an element that now involves at least the United States, China, Russia and India, with France and Britain lurking in the wings and no doubt other nations watching closely. The failures of those tests have highlighted also another fact: hypersonic propulsion and flight are difficult technologies involving extreme airspeeds, temperatures, pressures, stresses and combustion rates, combined with the usual requirements for compact airframe construction and low weight. These technical challenges have frustrated hypersonic development programs for decades, and if their solution may now be within reach, using new materials and high-performance computing to solve the exquisite problems of extreme engineering, it remains inconceivable that hypersonic weapons could be developed, perfected and validated for operational use without actual testing.

Two Evil Birds, One Good Stone

A bit of clarification is in order here: hypersonic missiles actually fall into two distinct categories. In boost-glide, the hypersonic weapon is first “boosted” onto a ballistic trajectory, using a conventional rocket. It may cover considerable distance as it flies to high altitude, then falls back to Earth, gaining speed and finally, at some relatively low altitude, pulling into unpowered, aerodynamic horizontal flight. After that, it glides at hypersonic speed toward its final destination. The second category is powered hypersonic cruise missiles, which typically are launched with a small rocket to high speed, and then drop the rocket and ignite a supersonic combustion ram jet, aka scramjet, for powered flight at Mach 5 or greater.

The recent failed Chinese and American tests were of boost-glide systems, while the X-51 WaveRider, which the US successfully tested last year after a string of failures, is an example of the scramjet cruise. The boost-glide test failures were probably caused by issues with the booster rockets rather than with the hypersonic gliders, although system integration can also cause problems. In any case, these systems didn’t work, and that demonstrates that both boost-glide and powered cruise missiles require testing. Such tests are easily observable from space, radar, signals intelligence and old-fashioned spying. A test moratorium would thus throw a huge obstacle in the path of all these programs, and a permanent test ban would  make it clear that they aren’t going anywhere. And that would be a good thing, because where they are going is nowhere good.

It’s not often that one can say an entire technology is evil and should be stopped and banned because it has no positive use. Hypersonic missiles present such a case. There is simply nothing they are likely to be useful for outside of war between major, nuclear-armed powers.  LA to Tokyo in an hour? As unlikely as that is to become technologically possible in the near future, let alone economically justifiable in an era of high-cost energy and low-cost video telepresence, if it ever could make sense it would take the form of a large airplane, not a small missile. Low-cost satellite launches? Hypersonic space planes such as DARPA’s planned XS-1, which would lift rockets to high altitude and initial speeds around 3 km/s, might make sense, but again, to achieve economies of scale, they would tend toward large size; when cost is the driver it would make no sense to build them small.

What’s all this hype about anyway?

Back in the crazy days after 9/11, hypersonic weapons were sold as a form of “conventional prompt global strike” to fulfill the supposed need for a weapon that could be launched from fortress America and strike Osama bin Laden’s lair on the other side of the world in less than an hour. That was an idea so nutty that, unfortunately, few people took the matter seriously, even when it was later revealed that another killer app for prompt global strike was to destroy Chinese anti-satellite weapons before they could be launched. Of course, when the US military finally did get bin Laden, it was a Special Forces raid launched by helicopter from nearby Afghanistan. And it was never very clear why China would be any less offended by our targeting their strategic weapons and facilities, deep inside the Chinese mainland, with hypersonic cruise missiles rather than somewhat faster ballistic missiles. The vague reasoning is that the Chinese (or Russians, in some other scenarios) might mistake ballistic missiles with conventional warheads for those with nuclear ones. However, hypersonic missiles could also carry nuclear warheads, and more to the point, in an attack on China or Russia the likely targets would include Chinese or Russian nuclear weapons, and other systems of strategic importance in a major war between nuclear-armed powers. To imagine that such exchanges could be kept polite by using a fancier, slower, and hardly any stealthier type of missile is the kind of airy fantasy that survives in political discourse precisely because it obviously isn’t serious. But the race to develop and deploy hypersonic weapons is serious.

Although these weapons are slower than ballistic missiles, they are still very fast, and offer a different attack profile, presenting a qualitatively different threat to adversaries. The idea that they might be used to attack a nuclear power, and even its nuclear weapons and related strategic faciliites, because they would be easily distinguished from ballistic missiles, and the enemy might be willing to believe that no hypersonic weapons carried any nuclear warheads, can hardly be expected to be stabilizing. Rather, this theory purports to pose a credible threat of strategic strikes in spite of nuclear deterrence. It must be expected that potential adversaries will seek countermeasures including symmetrical capabilities; indeed, this is apparently just what China and Russia are doing. Hypersonic missiles are not only intended for deep land attack, however. They are also likely to be used at sea, for attacking ships, island bases and shore facilities. Shortening the strike time for naval missile warfare is a recipe for hair-trigger confrontation between major powers contending for regional or global dominance. If there is a way to stop or slow this development, we should take it.

How to stop a speeding hypersonic missile race dead in its tracks

Fortunately, a hypersonic missile test ban would be one of the most rigorously verifiable arms control measures one could think of. It could begin with an informal moratorium, which might be agreed and announced among the major players, and followed up by negotiations for a binding, permanent ban treaty. I would propose a moratorium on tests of any aerodynamic vehicle of less than, say, 10 meters length and 1 meter diameter, traveling in powered or unpowered flight at speeds in excess of 1 km/s over a horizontal distance greater than 100 km. These numbers are somewhat arbitrary and could be fine-tuned or adjusted substantially while preserving the intent of the agreement. However, it is desirable to maintain as wide a margin as possible between what is allowed and what we seek to prevent. The numbers suggested here would just barely permit Russia and India to retain their joint BrahMos 1 supersonic cruise missile, while forcing them to cancel the hypersonic BrahMos 2. The US and China would then be permitted to develop comparable systems, but would have to cancel their hypersonic programs. While an even lower speed limit would be desirable, canceling future programs verifiably via a test ban should be easier to agree on than eliminating existing proven and deployed systems. We should just do it – and later do more.

The United States should take the lead in proposing a hypersonic missile test moratorium and seeking a permanent test ban. Production, stockpiling, deployment, transfer and use should also be prohibited under a permanent treaty, but the test ban is the critical element which makes any such agreement feasible, because it would be reliably verifiable and all but preclude the rest. Nations do not go to war relying on untested weapons, particularly not aggressive war, when they have a choice. Hypersonics are a technology particularly in need of thorough testing both to perfect and to validate weapon systems. Fortunately, it is also a technology, and a new type of weapon, that we are not in need of.  Neither are any other nations, but of course we can’t expect that just because the United States proposes a test ban, other nations will line up to join in renouncing hypersonic missiles. That is one reason why I am not proposing the US self-impose a unilateral moratorium, although it wouldn’t hurt if we suspended testing for a while to show good faith. What we can reasonably hope is that other nations will see their shared interest in avoiding or slowing a dangerous escalation of the arms race. If not, we will resume our programs, while still advocating that everybody agree to stop. Let the Russians, the Chinese, the Indians or the French play the spoilers, and let’s seize the moral high ground. The fact that others might not join us there is no excuse for not going to the mountaintop and calling them to join us. Indeed, if we are unwilling to do so, others have every reason to be cynical about our real motives and intentions. I’m not sure myself that I know what those are. But I am reasonably sure that hypersonic missiles will not help to make America stronger or more secure, because everybody we might want to target with them will soon enough get their own, and the world will then be a more dangerous place.

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6 thoughts on “US Should Propose a Hypersonic Missile Test Moratorium & Ban

  1. Hypersonic missiles nullify the advantage enjoyed by USA at negligible cost compared to the huge amount that is already spent by USA to deploy aircraft carriers . Yes I agree that USA will be worried about a situation were their costly weapon platforms do not have an answer to an incoming hypersonic missile. Now every body know this analyst call it a useless and evil technology. LOL

    • Thanks for your comment. Your “every body know” suggests that you might be Chinese. However, I wonder if that is actually the case, or if you are only pretending to be a Chinese commentator. Your first sentence sounds more like a native English speaker. But whatever.

      Hypersonic missiles do not pose a unique threat to aircraft carriers; in fact, the US seems to have concluded that subsonic but stealthy and highly maneuverable missiles will turn out to be more effective naval weapons. Hypersonic missiles are probably better suited to attacking fixed targets on land. Note the distinction between hypersonic missiles with long horizontal flight, and maneuvering reentry vehicles with far less cross-range (e.g. DF-21D). The latter would probably be excluded from the present proposal.

      More fundamentally, war with the US is no more in China’s interest than war with China is in America’s interest. No doubt many Chinese take the view you’ve displayed, just as many Americans are prone to both exaggerate the military advantages of new technologies and insist that the US must get them first in order to maintain peace or prevail in war. This kind of thinking leads us into arms races and arms races continue until they either peter out, are blocked by arms control, or erupt into war.

      The US must come to grips with the fact that it can’t expect to be able to park its carriers in the Western Pacific and bomb China or another “peer competitor” with impunity. The carriers are simply too vulnerable to attack by relatively cheap missiles, and a hypersonic test ban would not change this emerging reality.

  2. Thanks for your detailed reply.

    Yes I agree, it is not a unique threat but an aggravated threat particularly for USA as the most prominent carrier based fleet in the world. Currently USA is in search of augmented defensive capabilities that can protect its carrier based fleet with much more assurance. One of the important parameter they are concerned with is the speed of the incoming weapon. As you have mentioned even the currently available weapons are capable to threaten the carrier based fleet. But an increased speed makes the design of any defensive platform extremely challenging to US current efforts. More over if the reaction time is very very short, then much maneuvering may not be required at all to hit the target successfully. Also some of the recent designs like Russian Brahmos have maneuvering capability too. Basically I just want to convey that speed is an important parameter for the defending fleet and current defensive platform developments in USA may succeed (in future) against supersonic missiles , but hypersonic missiles pose a much much difficult challenge to fight against.When the incoming speed change from mach 2 to mach 7 the system requirements in defensive end increases exponentially and reach many order of magnitude.If multiple missiles are coming at same time again the things reach to a situation where the probability of a successful hit is greatly enhanced.

    For a defending platform the odds are against it. It has to succeed 100 percent while defending but the incoming missiles can have 90 percent failure rate and still be successful in its mission to neutralist fleet based capabilities .This is a inherent vulnerability built in to the defender’s side in a carrier based scenario. This vulnerability further exaggerated by the introduction of hypersonic weapon systems. USA force projection across the glob is heavily dependent on its carrier fleet and thus USA will be much more affected by this development than any other navy.If these hypersonic weapons are coming from a fighter jet based platform (brahmos integrated successfully with Su-30 MKI last week if the reports from India is correct) then you know how it will tilt the balance in a carrier based conflict.

    Regarding the question of – in whos interest the war will be, I think any war is based on a big “WHAT IF” as always. If we want to attack this empire, it will be much more meaningful for us to challenge your main weapon, the dollar( but yes we also got lot of investment in dollar, so not an option as of now). During quantitative easing you have released trillions of dollars in to the market with out loosing its purchasing power (in form of inflation). That was incredible. This empire just put ink on paper and tangible materials with value and services are coming to you from everywhere just for that newly printed money which actually does not have any real wealth to back it. Let us see how things pan out. Previous world powers like Briton lasted for few hundred years with glory. Your current empire also may not be too different in terms of those years. Signs are already flashing in the horizon.

    In a lighter note, arguably your country population will be much more affected by obesity inducing food habits rather than any Chinese weapon in the next 10 -20 years.If the current situation prevail for few decades you country will decline naturally with out any external intervention in my opinion. Am I Chinese or native English speaker?. let it continue to be a small secret between us.Again thanks for your time.

    • To what I wrote before, I will only add that IF your analysis is correct, or if people think so anyway, it suggests that Chinese militarists may resist the proposal for a test ban. But by the same token, American militarists should embrace the idea. We have nothing to lose by trying. And if we do give it an honest try, it’s possible that reason may prevail in China and globally as well.

    • Yes, and Russia, too. Although I tend to take stories like that one (about a new “powerful recipe” for missile fuel) with a grain of salt.

      I’d be happy if the US would simply put Russia and China to shame by declaring its desire for a test ban, and starting it off with a unilateral moratorium. This would hardly compromise US national security. Let the “bad guys” refuse. That’s how we’ll all know who they are.

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