How the Navy Could Fire 5,600 MPH 'Hyper Velocity Projectiles
[Zachary Keck](http://nationalinterest.org/profile/zachary-keck "Zachary Keck") 
Zachary Keck is the Wohlstetter Public Affairs Fellow at the Nonproliferation Policy Education Center. Before that, he was a researcher at the Belfer Center for Science and International Affairs. Previously, he was the managing editor of The National Interest. Keck has also been the managing editor of The Diplomat. You can find him on Twitter: @ZacharyKeck.
The Pentagon is pursuing an innovation missile-defense system that could address some of the shortcomings of the existing systems it deploys.
There are a number of major (somewhat interrelated) obstacles to defending against a missile attack. The first is simply the sheer technological challenge of using a missile to destroy another fast-moving missile. This is sometimes compared to trying to shoot a bullet with another bullet. The other is the cost equation: because of the technological challenges involved, missile-defense interceptors are inherently more expensive than the offensive missiles they are trying to destroy. Furthermore, because of the extreme difficulty of shooting down a missile, numerous interceptors are usually used against a single missile. All of this means that an adversary can merely use more offensive missiles to overcome defensive systems, especially when they know how many interceptors they are up against. This is easy to do when the interceptors cost so much compared to the missiles they are trying to destroy.
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Welcome to World War III.
Enter the Hyper Velocity Projectile. Developed by the Pentagon’s Strategic Capabilities Office (SCO), the program aims to use the U.S. Army’s existing 155-millimeter howitzers to fire the new Hyper Velocity Projectile (HVP). These projectiles will have speeds of 5,600 miles per hour and only cost $86,000, compared to about $3 million for the interceptors of existing high-level missile defense systems like the Patriot.
Vincent Sabio, the program manager of the Hyper Velocity Gun Weapon System (HGWS) at SCO, discussed the project at an event on January 25 at the Center for Strategic and International Studies (CSIS), a Washington, DC think tank. “That projectile has been independently costed—not by me, I wouldn’t expect to you believe my costing — but . . . by Navy IWS [Integrated Warfare Systems] at about $85,000 a round,” Sabio said, [according to a report by****Breaking Defense****](https://breakingdefense.com/2018/01/86000-5600-mph-hyper-velocity-missile-defense/ "<span> </span>according to a report by<span> </span><em>Breaking Defense</em>") . “You can shoot a lot of those things and not feel badly about it.”
$86,000 + 5,600 MPH = Hyper Velocity Missile Defense
CENTER FOR STRATEGIC & INTERNATIONAL STUDIES: The Pentagon’s Strategic Capabilities Office will test-fire a radical new missile defense system in less than a year. The Hyper Velocity Projectile, a supersonic artillery round, is fired from ordinary cannon at 5,600 miles per hour and can kill incoming threats for a mere $86,000 a shot. Compare that to Patriot missiles, which require special launchers and cost roughly $3 million each. The Hypervelocity Gun Weapon System (which comprises the HVP itself plus cannon, fire control, and radar) won’t replace high-cost, high-performance missiles, but it could provide an additional layer of defense that’s cheaper, more mobile, and much harder for an enemy to destroy. Today’s missile defenses are “brittle,” “inflexible,” and “expensive,” said Vincent Sabio, the HVP program manager at the Pentagon’s Strategic Capabilities Office. “We need to be able to re-engineer (missile defense) from the bottom up (and) go back to Congress and say, ‘We have a choice here: We can either have an effective defense, or we can continue inching along the way we are with our heads in the sand.'” Cost and the “Plus One ” Problem The most basic problem is a simple, if daunting one: we can’t afford many interceptors. In addition, current systems require bulky launch systems an enemy can easily detect: a trailer for Patriot, a truck for THAAD, a silo for GBI. “As a result, the adversary is able to count interceptors; they know where our sites are; and they can simply play what we call the plus-one game,” Sabio said at CSIS. “They know if you have x number of interceptors, the absolute most they need to throw at you is x threats. And once you have fired your x interceptors, they pretty much own you.” Note that Sabio’s presenting the best possible case: Since real-world reliability rates and “shot doctrine” require firing two interceptors at each incoming threat, an adversary can probably run us out of ammo by firing half as many offensive weapons as we have interceptors. What’s more, a typical offensive missiles — which just has to hit the right coordinates on the ground — is much cheaper than a defensive missile — which has to hit a rapidly moving target. Today’s missile defense interceptors are ultra-high-performance systems, Sabio said, designed to take out an incoming threat in a single shot with a high Probability of Kill (Pk). (Whether they live up to that specification in practice is a matter of much debate and testing). But there’s another way to get a high Probability of Kill, Sabio says: Fire lots of cheap weapons, each with a low Pk on its own, but a high probability that one will hit eventually. (Sabio didn’t offer numbers, but to give an extreme case, even a weapon with a 10 percent Probability of Kill per shot — i.e. it misses 90 percent of the time — has a 90 percent chance of killing the target if you fire it 22 time). That’s where the Hyper Velocity Projectile comes in. “That projectile has been independently costed — not by me, I wouldn’t expect to you believe my costing — but … by Navy IWS at about $85,000 a round,” Sabio said. “You can shoot a lot of those things and not feel badly about it.” In rough terms, for the $3 million price of one late-model Patriot, you could buy about 35 HPVs. Admittedly, $85,000 is more than triple the early estimates for a single HVP round. But the original $25,000 figure was probably for the surface-to-surface version, intended to hit ships and ground targets, which didn’t require the same sensors and maneuverability as an HVP would to catch a high-speed missile. In fact, Sabio wants his weapon to be able to adjust how it operates to catch different kinds of missile — something current interceptors don’t do well. Flexibility “That projectile is being designed to engage multiple threats,” Sabio said of the HVP. “There may be different modes that it operates in (in terms of) how does it maneuver, how does it close on the threat, and whether it engages a (explosive) warhead or whether it goes into a hit-to-hill mode. Those will all be based on the threat, and we can tell it as it’s en route to the threat, ‘here’s what you’re going after, this is the mode you’re going to engage in.'” Versatility is a priority for the Strategic Capabilities Office. Created by the last administration, SCO has helped turn the Navy’s SM-6 anti-aircraft missile into a ballistic missile defense interceptor and even ship-killer, for example. It’s trying to turn the Army’s ATACMS artillery missile into an anti-ship weapon too. But most missile defenses today are optimized to kill ballistic missiles ranging from Scuds to ICBMs, not cruise missiles, drones or hypersonic weapons. “We need to be able to address (all) types of threats: subsonic, supersonic; sea-skimming, land-hugging; coming in from above and dropping down on top of us,” said Sabio. “There are many different trajectories that we need to be able to deal with that we … cannot deal with effectively today.” A ballistic missile is the fastest way to get a warhead from A to B, but it’s also a pretty predictable target.After its rocket motors have finished burning — the heat can be detected from space — it follows a smooth ballistic curve (hence the name). If you’re worried about ballistic missile threats from a particular country, like North Korea, there are only so many possible trajectories it can take. By contrast, cruise missiles and drones are harder to detect and predict because they fly like aircraft. “Our adversaries are …. developing weapons that can come in and engage on multiple axes,” said Sabio. “We cannot allow our adversaries to simply fly around our sensor systems and come in and attack us on an axis where we’re blind.” But getting 360-degree coverage is “prohibitively expensive” with current fire control radars, Sabio said. HVP’s using an off-the-shelf Marine Corps G/ATOR radar for long-range surveillance, he said. When the G/ATOR picks up a target, it passes the data to a radar interferometer for fire control. Each interferometer covers a 90 degree arc from ground level to zenith, so four of them together cover all directions. The first interferometer, now being built, costs $23 million, Sabio said. Assuming that price doesn’t come down — as usually happens after the first unit produced — that means $92 million to have 360-degree fire control for a battery of guns. Many Shooters The final expense is trickier to calculate: the cost of the launchers. Patriot launchers can only fire Patriots interceptors; THAAD launchers can only fire THAADs, “but those (HVP) projectiles…are shot out of Army 155 (mm) howitzers and they’re shot out of Navy five-inch deck guns,” Sabio said. The military has hundreds of those, already paid for. There will be some additional cost. While the Navy deck gun can fire HVP without modifications, Sabio said, the Army howitzer must be upgraded with a longer barrel, better muzzle brake, and other improvements. This kit, called Extended Range Cannon Artillery, was already being developed to fire conventional shells further. Its cost is not yet clear. Using howitzers and deck guns also gives HVP a major tactical advantage. “Any place that you can take a 155 (howitzer), any place that you can take your navy DDG (destroyer), you have got an inexpensive, flexible air and missile defense capability,” Sabio said. The impact on the Navy is significant. Destroyers can already carry missile defense interceptors, but only limited numbers, so the HVP would give them many more shots. The impact on the Army is dramatic: Howitzers — both towed M777s and M198s and self-propelled M109s — are much more mobile and vastly more numerous than Patriot or THAAD launchers. The more missile defense units you have, and the more mobile they are, the more you can disperse them to cover multiple angles of attack on many potential targets. Dispersion also makes it much harder for the enemy to find your missile defenses and wipe them out. The enemy’s problem gets even harder if those missile defenses can also take out his launchers preemptively, as guns firing HVP could do. (Remember, the Hyper Velocity Projectile is also capable of hitting static targets). So when will the Army and Navy actually get Hyper Velocity Projectiles? Both services are already working with SCO to plan a handover of the program, Sabio said. His role is just to prove the key technology works: specifically, to demonstrate that an HVP can maneuver close enough to “an inbound, maneuvering threat” that it could have destroyed it if fitted with the proper warhead. Sabio’s not developing that warhead. “We are building out the full fire control loop including the sensors, the coms links, the projectile, the launchers (i.e.) the guns,” he said. “The command and control…. I leave that to my independent transition partners, Navy and Army.” And by when will the demonstration happen? “Well,” said Sabio, “my program ends less than a year from now.”
Indeed, as Sydney J. Freedberg Jr., the Breaking Defense reporter, noted in the article, at the $86,000 price tag the Army could purchase thirty-five HVPs for the same cost as a single Patriot interceptor. And, as Freedberg went on to point out, even if each HVP had only a 10 percent chance of hitting its target, using twenty-two of them against a missile would give the Army a 90 percent chance of successfully intercepting it.
The U.S. Army howitzers are uniquely suited to firing this many rounds in the short time that a missile would be airborne. As Kyle Mizokami [points out](https://www.popularmechanics.com/military/weapons/a15927141/army-howitzer-hvp-navy-missiles/ "points out") , “a typical six-to-eight-gun field artillery battery could fire up to two dozen rounds in 15 seconds.” And since the U.S. Army already has hundreds of howitzers, it wouldn’t have to purchase a bunch of new launchers to take advantage of the HVP.
The U.S. Army’s Big Artillery Guns Will Try to Shoot Down Missiles
The service plans to test the Hyper Velocity Projectile later this year.
Sabio pointed out other advantages of the HGWS. Namely, the current missile defense systems are all large, have limited mobility, and are easy for adversaries to detect and track. “As a result, the adversary is able to count interceptors; they know where our sites are; and they can simply play what we call the plus-one game,” Sabio noted at the CSIS event. “They know if you have x number of interceptors, the absolute most they need to throw at you is x threats. And once you have fired your x interceptors, they pretty much own you.” The HGWS’s mobility, as well as being able to fire many cheap projectiles in such a short time period, would greatly complicate an adversary’s ability to out game America’s defenses.
Another advantage of the HGWS, according to Sabio, is that it will be able to deal with multiple different threats. “There may be different modes that it operates in and . . . we may tell it shortly after it comes out of the gun which type of a threat it is going after, and it will configure itself for that type of threat in terms of the dynamics—how does it maneuver, how does it close on the threat,” Sabio said, and National Defense [magazine reported.](http://www.nationaldefensemagazine.org/articles/2018/1/26/sco-developing-affordable-flexible-missile-defense-weapon-system "<span> </span>magazine reported.") 
The Army will not be the only recipient of the HVPs, as the Navy is also expected to adopt them. Specifically, HVPs will be fired out of the five-inch (127-millimeter) [Mark 45 deck guns](https://en.wikipedia.org/wiki/5%22/54_caliber_Mark_45_gun "Mark 45 deck guns") on some of the Navy’s destroyers (cruisers also have the same deck gun). These guns can fire a maximum of twenty shots per minute. And, [according to Kyle Mizokami](https://www.popularmechanics.com/military/navy-ships/news/a27396/hypervelocity-projectiles-navy-deck-guns/ "<span> </span>according to Kyle Mizokami") , while a normal Mark 45 only has a range of fourteen miles, the HVPs will be able to reach targets at up to forty miles away.
5"/54 caliber Mark 45 gun - Wikipedia
The 5-inch/54 caliber (Mk 45) lightweight gun is a modern U.S. naval artillery gun mount consisting of a 127 mm (5 in) L54 Mark 19 gun on the Mark 45 mount. Originally designed and built by United Defense, it is now manufactured by BAE Systems Land & Armaments after the former was acquired.
Mach 3 Ammo Will Make Navy Guns Much More Lethal
Five-inch guns on cruisers, destroyers will destroy everything from ballistic missiles to enemy ships.
Sabio said at the CSIS event that the Strategic Capabilities Office will spend another year refining the HVP and conducting further testing. It has asked Congress for $67 million in fiscal year 2018 for these efforts. After that, SCO will be handing off the capability to the Army and Navy, which will determine exactly how to integrate the new system into their operations.
Zachary Keck ([@ZacharyKeck](https://twitter.com/ZacharyKeck "<em>@ZacharyKeck</em>") ) is a former managing editor of theNational Interest.
Zachary Keck (@ZacharyKeck) | Twitter
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--- This story originally appeared inThe National Interest---
[Image](https://commons.wikimedia.org/wiki/File:Railgun_usnavy_2008.jpg "<em>Image</em>") : Wikimedia Commons
File:Railgun usnavy 2008.jpg - Wikimedia Commons
Photograph taken from a high-speed video camera during a record-setting firing of an electromagnetic railgun (EMRG) at Naval Surface Warfare Center, Dahlgren, Va., on January 31, 2008, firing a 3.2 kg projectile at 10.64MJ (megajoules) with a muzzle velocity of 2520 meters per second. The Office of Naval Research's EMRG program is part of the Department of the Navy's Science and Technology investments, focused on developing new technologies to support Navy and Marine Corps war fighting needs. This photograph is a frame taken from a high-speed video camera. U.S. Navy Photograph (Released)