ASBM Defense Isn’t Easy


I was taken aback by one of the questions that came my and Toshi Yoshihara’s way last week at the Center for the National Interest: isn’t China’s much-discussed DF-21D anti-ship ballistic missile (ASBM), an “easy” problem for U.S. Navy surface warships, which boast high-tech shipboard defenses like the Close-In Weapons System (CIWS)?

The gentleman who posed the question appeared especially taken with CIWS, a super-fast Gatling gun installed on board American and many allied combatants. And it’s certainly a nifty piece of technology, disgorging radar-guided projectiles at a rate of 4,500 rounds per minute. But impressive technology isn’t always superior. A CIWS magazine only holds enough rounds to sustain that rate of fire for about 20 seconds. More importantly, the system is aptly named. “Close-in” means an effective firing range of “a couple of miles” according to one open-source estimate. This is truly a last-ditch defense considering the hypersonic speed of the threat.

Think about the scope of the problem. Terminal velocity for the DF-21 family of missiles is estimated at Mach 10 to Mach 12, on the order of 8,000 to 9,000 miles per hour. That means the missile covers up to 150 miles each minute, or 2.5 miles per second. At such speeds, CIWS gets around a second to engage a maneuvering target, correct its stream of projectiles onto the target, and make the kill. That’s tough even for a computer-controlled weapon system. And even if the engagement succeeds, detonating the warhead, the debris from the explosion keeps coming along roughly the same trajectory. In all likelihood, some of the debris peppers the ship. Metal shards traveling at hypersonic velocities retain enormous kinetic energy, more than enough to penetrate the lightly armored hulls of modern warships and inflict all manner of havoc within. That’s why CIWS was the subject of much gallows humor when I was a weapons officer—and that was during the pre-ASBM days when the threat consisted “only” of manned aircraft and anti-ship cruise missiles.

That such a question came from such a distinguished group of policy and academic experts suggests that knowledge about naval technology and tactics remains rudimentary among even learned audiences in Washington. By no means do I mean to counsel despair about challenges like the ASBM. There are no permanent victories in peacetime strategic competitions like the one unfolding in the Western Pacific. I fully expect our navy to prosecute the strategic competition with China vigorously, and indeed certain promising hardware is already in the works.

Extended-range missiles like the ‘Long-Range Anti-Ship Missile’ currently under development would let the U.S. Pacific Fleet hold the Chinese surface fleet at risk at distances that would attenuate the missile threat to U.S. vessels. CIWS itself is undergoing improvements, including an extended-range “SeaRAM” destined for use aboard the navy’s new Littoral Combat Ships. And exotic technologies like electromagnetic “railguns” and high-energy lasers hold considerable promise over the longer haul, both as self-defense systems and for offensive functions.

But no, the ASBM threat will be far from easy to counteract if the technology pans out. True, the ASBM or its associated sensors may not live up to their hype. The Soviet Union tried—and conspicuously failed—to field such a system. I remain agnostic myself. If Chinese rocketeers can loft ASBMs toward U.S. carrier or amphibious groups, though, the laws of physics will be on their side—and decidedly against shipboard defenders.


James Holmes is an associate professor of strategy at the U.S. Naval War College. The views voiced here are his alone.

February 13, 2014 at 19:02

DF21D does not work. I have not seen any evidence it work. USA , Pentagon , Congress etc etc should not be paranoia and think that it works when it does not. It will be extremely difficult to make and cue such a weapons. Besides USA has all the hi tech weapons from AEGIS ships & weapons systems, SM3 , Patriot, CIWS , rail gun, laser etc etc etc against such a DF21D system apart from radar scrubbing etc etc etc

February 2, 2013 at 18:13

Rule of law, huh? My foot!!!
Invading a sovereign country (Iraq – the second invasion to topple Saddam Hussien) by using deception claiming Iraq had Weapon of Mass Destruction AND without the sanction of the United Nation, you called that "rule of law"? I would conclude that US was acting on a principle called "might is right". or "the ends justify the means"..  Are they not correct????

October 25, 2012 at 07:52

@John Chan
it is not the philippines that squats the undesputed islands… it is you the chinesse people who bullies other countries just to get to those mineral rich islands… do you actually think that the whole world would believe that the REPUBLIC of CHINA owns those islands? even though it was a hundred miles away from your country?
well, for much of us we are thankful that there were such countries like the US that would back up their allies in times of troubles like this…
and for you to know? PHILIPPINES were never been a rogue country.. it was china who were acting like one…

August 9, 2012 at 21:06

@jc It is funny how you PRC morons always have it the other way around. We all knows what is going on, no need to copy everything from us and then regurtitate it like you understand what it means. I have never heard anywhere the phillipine described as a rogue state but plenty where you CCP idiots are so described.  This is the twenty first century, not a few century ago when a nation can not dare anything. It is about the rule of law, which you should consider yourselves lucky or countries which are stronger than you (even Russia will shoot the hell out of your so called fishing boats and only gets some whinings from you idiots) will simply destroy your country again, and again and again…. and there will be many in the region who will join in.

June 26, 2012 at 02:00

I think you people should realize that when ASBM are deployed, the PLAN is not gonna show it off to the world.  The best weapons are best kept under cloaks and the Chinese are not foolish enough to show it off to the world.

John Wen
April 30, 2012 at 23:01

I think this kind of missile technology is not real at least in present days. China is not as advanced as many people think. If there is one country first makes this technology into a practical product, it should be USA not China.

November 26, 2011 at 06:32

@John Chan
No problem admitting my ignorance of the capability of the US to track ballistic missiles. I would think that the number of missiles that would saturate such a capability is a highly classified parameter. If you say that China has a good guess at that number and will use its salvo of ASBMs in a way that it can not be misinterpreted by the US, fine.

Nevertheless, I think it is a dangerous gamble to use a weapon system that looks like a MAD attack and rely on the opponent’s sophistication to avoid an accidental escalation. Factor into this the human factor and the fact that it will, in all likelihood, be an exceptional use of new weapon system, during a very tense conflict.

In summary, I think that, with the proliferation of ballistic missiles, we are moving closer each day to an accidental MAD. Irresponsibly or voluntarily, the generals are blurring the frontier between conventional and nuclear warfare.

John Chan
November 25, 2011 at 14:58

Your ignorance does not mean USA and China do not have the capability to know exactly each ballistic missile is going. It is nothing worse than the ignorant are fear mongering relentlessly like a bad LP repeating the awful track over and over.

November 25, 2011 at 03:58

@John Chan,
We are talking about a salvo of 10-18 ballistic missiles. Unless the PLAN has a means to make them distinguishable from a nuclear strike, to the early detection network of the US (assuming they have its blueprint!?), the chance is big that such an attack is AUTOMATICALLY detected as a first strike. Can you imagine China leaders reassuring the US: no,no, don’t misunderstand us, we are just shooting at your carrier group.

November 25, 2011 at 03:50

Correct. I just wanted to point out that the SCS, the ASBM, the Underground Great Wall, the declarations of the generals, all seem to fit in a general line of thinking for “work in progress”.

John Chan
November 25, 2011 at 03:42

Nuclear strike is for national survival; sinking an aircraft carrier thousands miles away from the USA homeland is not endangering USA’s national survival, it is just a collateral loss in a hostile action like all other military adventure, it is a part of the costs that carry out imperialism. Exaggerating sinking an aircraft carrier to the trigger of nuclear exchange is fear mongering.

November 24, 2011 at 18:22

The day that CBG can hide in ocean is over for good. The technology has advance. China has 3 over horizon radar that can peer far into western pacific(approx 3500km rang) similar to Jindelle

Sean blog IMINT use to have very good information on china OVH but he in the process of converting it to PDF format

CBG emmit all kind of radio frequency with specific characteristic I can think of the constant take off and landing of plane to perform CAP

A very discrimination surveillance radar can pick this tell tale sign of CBG but OVH radar doesn’t have accuracy so They will cue in surveillance satellite like Yaogan series 9 that specially design to locate CBG. It is constellation of 3 satellites Read this

China has 20 dedicated military satellite for that purpose Yaogan series and Shijan series out of 70 satellites now in orbit

Then you need to confirm your finding. You can use long range UAV or even stealth fighter, Submarine,Marine patrol aircraft, Spy ships, Fishing trawler,

Once detected the information is fed into INS guidance system of ASBM it will be launch to approximate location of CBG and at midcourse it get update information from the satellite. Until it get close to the target,then the onboard synthetic aperture radar will be activated.

It will pick up the outline of the carrier compare it to stored image that was saved in its processor. When match is found. It will fire the weapon

November 24, 2011 at 14:47

China doesn’t have a viable undersea nuclear deterrent….


November 24, 2011 at 13:03

If it is used in salvo, it does not need to be very accurate. If each missile has 1/2 chance of a hit then 10 of them gives 99.9% chance of success. If each has only 1/3 of a hit then you need exactly 18. And if each has only 1/5 of a hit, 18 of them still achieve over 98% success rate.

Firstly what it is an extremely fast war head that may fan out into many bomblets to cover, say a 0.5 mile circle dead zone. Remember the kinetic energy is enough to make the bomblets lethal. So, secondly, it will be simple and low-cost. Thirdly, you have to hide them somewhere so that the preparation time for launch can be concealed. I think the Chinese solution have all three conditions above.

Now, somebody made a very relevant remark. Would the simultaneously launch of 10-18 ballistic missiles automatically trigger a second (in fact first) nuclear strike from the US? The answer is very probably yes, and the Chinese generals have already foreseen that: they have already publicly declared (2005, general Zhu) that they are prepared “for the destruction all the Chinese cities East of Xi’an”! This means, at the same time the ASBMs are launched, the commanders of the Chinese undersea deterrent force in the South China Sea would have already received the code for China second-strike nuclear response. Apocalypse is closer than we thought!

Tom Tran
November 24, 2011 at 09:59

OK, it is not easy to kill a ballistic missile, but it is not easy to aim such missile to a moving target of a few hundred foots thousands of kilometers away. Until one really sees it works, there is no need for too much hype over a hypothetical weapon. Even if the weapon has some capability, how many do you need to disable, needless to say to sink a carrier? Probably firing some dozen, if not hundreds, missiles to get a few hits, I bet no sailor is going to be scared to death.

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