Near-term BMD defenses against Chinese anti-ship ballistic missiles fitted with MaRVs
As a long-time activist for ballistic missile defense (BMD) and one who has long sought low-cost unconventional ways to do BMD, I have followed the debate on land-based ASBMs for some time, starting with Soviet fixed-trajectory ASBMs during the Cold War and now looking at Chinese ASBMs fitted with maneuvering re-entry vehicles (MaRVs). Depending on how the latter are armed - and whether we can field BMD systems to extend defensive keep-out zones as far as possible - these MaRVs could pose an existential threat to Navy amphibious and carrier task forces.
The threat is existential because China may not share the US's ethnocentric, elite-culture devaluation of tactical nuclear weapons as militarily useless and likely to trigger central nuclear war if used to ambush US forward “strategic” forces like carriers. Indeed, given the precise hypersonic terminal maneuvering that anti-ship MaRVs need to deliver advanced kinetic or high-power-microwave (HPM) weapons against ships maneuvering evasively at 30+ knots, it may be that the Chinese MaRV has been designed for a precision nuclear warhead from the start. It may be operationally marginal otherwise.
In any case, the Navy's irresponsible and decade-long underestimation of these weapons approaches in its consequences the Royal Navy's systematic pre-1939 devaluation of German U-boat “Wolfpack” threats to North Atlantic convoy routes so that it could justify big-gun capital ships rather than smaller convoy escorts like corvettes and destroyers. By compromising our carrier task forces, this one Chinese weapon - especially if we believe it to be nuclear-armed - could “unhinge” US force projection in the Pacific, with vast geopolitical consequences and recovery times measured in decades. Yet although the Navy has known for years of this emerging threat, it has done nothing serious in BMD, in passive hardening or decoying of its capital ships, and in overhauling its carrier-centric surface forces to make them less vulnerable to ASBM attacks.
On the other hand, one can argue that counter-ASBM/MaRV BMD - both active and passive - is a lot cheaper, closer at hand and more effective than we think. Yet to arrive there we must first drop the belief that the Aegis/Standard ABM system is the benchmark for naval BMD - when it was never designed for BMD, offers far too limited a stock of at-sea interceptors and would be outclassed in a 'MaRV-catcher” role in real engagements.
First, ASBMs are not a new weapon. In fact, their history appears to go back to 1955, when the USSR's Chelomel missile-design bureau began to look at an ICBM (the SS-11) for targeting US and NATO task forces at sea. I first encountered this Soviet ASBM interest in the late 1970s while a SALT analyst at Boeing Aerospace. Particularly interesting was declassified Congressional testimony about the SS-11's Mod. 4 ASBM. As I recall, the flight tests of that missile's four lightweight MIRV/MRV (multiple (independently-targeted) re-entry vehicles) suggested they would deploy in a 'box the compass' pattern around the task-force being targeted.
This of course is ideal if the payload was BW agents, which would allow hits on task forces no matter what local wind directions might be at the ocean surface. (According to Ken Alibek, the former technical director of the Soviet 'Biopreparat' BW program and author of Biohazard, the Soviets worked on BW-weaponized ICBMs including their heavyweight SS-18.) According to declassified congressional testimony, the SS-11's four warheads descended much more slowly than the rapid re-entries of nuclear-armed RVs - suggesting that the Mod 4's MRVs carried BW payloads. Fortunately for the Navy and NATO, the Soviets never deployed the Mod 4, so we didn't have to worry about it.
There was also Navy concern - expressed in two late-1970s articles in the Naval Institute Proceedings - about the wartime role of Soviet missile subs firing SS-N-6 Yankee SLBMs (like our Polaris). It was not have been difficult for these subs to trail US and NATO task forces as a low-warning-time barrage weapon cued by TU-95 Bear F patrol aircraft and radar ocean-recon satellites (RORSATs) working as forward artillery observers. There was also a sub-fired Soviet ASBM called the SS-NX-13, which briefly triggered Navy interest in modifying its Standard SAMs to cope with it.
But in large part the Navy has not worried in any sustained way about defending its surface task forces from hypersonic ballistic weapons - and so it never looked at the technical requirements for doing so. Like the other services (except for USAF), the Navy assumed that all BMD activity - including BMD innovation - was properly the domain of the Missile Defense Agency; The Navy saw its BMD mission as tactical BMD to protect allies like Japan, Taiwan, South Korea and Israel against proliferators' missiles - vs. protecting itself from ASBMs.
Second, the Navy's BMD “architecture” employs a 50-year-old engagement geometry that is largely incompetent against ASBM MaRVs. The Aegis/Standard's engagement geometry is fully conventional, having been pioneered by the Army's 1955 Nike-Zeus nuclear ABM: a single-warhead interceptor firing back up the threat tube at a hypersonic target with a small cross section presenting itself nose-on to the defensive radar. Given interceptor fly-out times, such ABMs generally have just one intercept opportunity, with no 'shoot-look-shoot' multi-shot prospects. This one-warhead terminal-defense construct, pioneered by the Army, was later politically canonized and technically constrained by arms-control agreements like SALT and START. The baleful effects of these 1972-1974 SALT constraints on even conceptualizing small, very agile multi-warhead non-nuclear interceptors and small forward-deployed interceptors that need not be space-based are still being felt by naval BMD planners, Indeed, the US has lost at least three “technology cycles” in tactical BMD, thanks to these constraints.
Moreover, the Navy's BMD CONOP has focused not on protecting its capital ships against anti-ship MaRVs but on protecting US allies against rudimentary non-maneuvering, single-warhead missiles fired at US allies. To achieve the latter, the Navy modified its Standard SAM - originally designed as an air-defense missile against Soviet anti-carrier Backfire bombers and their anti-ship missiles) to tackle such RVs. Given the costs of this “hail Mary”approach, the Navy could not evolve it to counter MaRVs that would be tough to engage with Standard ABMs designed for non-maneuvering RVs. Yet for political and institutional reasons, the Navy could not propose or even explore nontraditional BMD concepts or forward BMD platforms. Rather, it was restricted to BMD systems that could operate on the ships being targeted - whose terminal-defense engagement geometry is the worst imaginable.Third, China's ASBM MaRV is not a first-ever “wonder weapon” but rather reflects Chinese persistence in occupying a MaRV weapon 'space' that was vacated by the US after we pioneered it 45 years ago. The US has not run a hypersonic maneuvering flight-test program (other than the recent X-43) since the SWERVE (Sandia Winged Energetic Reentry-Vehicle Experiment) project by DoE's Sandia National Laboratory about 20 years ago.
But an even more audacious program was two Air Force MaRV programs over 1961-1964 that saw Mach 10+ vehicles doing sharp turns while approaching their targets. During this period, the US designed MaRVs that came in at such low altitudes (500-1,000 feet) on their final (one minute) low-altitude run-in to their target that they would have needed terrain-avoidance radar to keep them from hitting elevated terrain while approaching their targets. The US pioneered hypersonic control flaps, nosetips and homing sensors for such MaRVs. However, none ever made it into service despite impressive, rapidly paced flight tests.
Given Chinese trade surpluses and a vigorous program in mining unclassified (and classified) US defense research, China's defense RDT&E establishment can draw on hundreds of unclassified documents from this formative US research, most of which remains state-of-the-art. Moreover, in addition to lavish spending in miniaturization, electronics, optoelectronics, radars, aerothermal materials and vehicle integration, China also produces ballistic missiles in quantities that allow rapid flight testing and iterative engineering of game-changing weapons like carrier-homing MaRVs.
China presumably also is working on the warheads for such MaRVs. Presumably the most attractive would be a high-yield high-power microwave (HPM) pulser - a Russian-pioneered technology which could easily have been transferred to China in recent years as hungry Russian defense institutes marketed their best technologies to countries like China and India. High-yield HPMs have also gone international, with nations like Sweden working on high-yield air-dropped munitions, according to a press release by their defense ministry some time ago. Other nations are tackling smaller tactical HPMs that include man-portable designs. Unfortunately, the US has largely forfeited this area to its allies and competitors.
Still, these HPMs require reasonably low CEPs (circular error probable) to ship targets to be effective. Given these CEP levels, it would make more sense for China to employ small nuclear weapons rather than HPMs. Although this sounds beyond the pale to US defense experts, it makes sense for China. Especially when one realizes that China's destruction of even a handful of US carriers and their escorts would represent a geopolitical pivot point equivalent to Germany's winning of the Battle of the Atlantic in 1943.
But given this extensive US history in MaRVs, why has the Navy been taken by surprise, by all indicators, at China's ASBM-MaRV combination?
First of all, very few DoD and defense-industry planners and engineers are aware of this remarkable US legacy, apart from a handful of older engineers who worked on these flight-test programs. This contributes to a conceptual vacuum when it comes to appreciating the operational impact of these weapons and to thinking creatively about defenses against them.
Second, the Navy's conceptual vacuum also applies to BMD, where Navy and DoD thinking remains fixated on the Aegis/Standard engagement geometry and by large expensive boosters that would be stressed by maneuvering RVs. Even more damaging is the Missile Defense Agency's (MDA) loss of innovation when compared to the extraordinary surge of novel defenses, including gun-fired miniature interceptors, developed under the SDI program over 1984-1994. There is no detectable MDA interest in different BMD engagement geometries and very small interceptors, with almost all funding going into a warmed-over Nike-Zeus-type ABM system on the West Coast and an airborne laser. Since the Navy depends on MDA for BMD technologies, MDA's loss of innovation and its disinterest in “end run” BMD concepts is now hitting the Navy hard is hitting hard at a time when China's MaRVs require a top-to-bottom rethinking of BMD at sea, including forward engagement using non-ship platforms.
Fourth, the US has an extensive history of counter-MaRV BMD technologies that can be tapped by the Navy. Over 1959-1964, the US flight-tested small, very agile “MaRV-catcher” ABMs as well as non-nuclear direct-impact or proximity-fuzed ABMs under DARPA's “Project Defender” that could be used for MaRV intercepts. For example, Defender addressed non-nuclear ground- and space-based interceptors and made a successful 1964 intercept of a simulated ICBM RV by a small direct-hit interceptor over White Sands, NM. This missile, called ARPAT (ARPA Terminal Defense), was a relatively crude-fix with a simple steering motor engineered quickly on to an unguided “Genie” air-to-air missile fired from an F-104 fighter.Project Defender's main “MaRV-catcher” ABM program was the small, agile Upstage ABM, whose flight tests left corkscrew contrails all over the sky as it homed in on simulated MaRVs. A last-ditch ABM called HiBEX (High-Acceleration Booster Experiment) launched from its silo at 1,000 G's - about 4x as fast the Sprint ABM. All of these programs (HiBEX, Upstage, ARPAT, others) ran on very fast timelines (36-48 months), culminating in multiple flight tests.
This rich Project Defender technology base was revisited 25 years later during the SDI program's numerous interceptor programs and flight experiments like Endo/Exo LEAP (Lightweight Exo-Atmospheric Projectile); HEDI KITE (High Endoatmospheric Defense Interceptor Kinetic Intercept Technology Experiment); SR-HIT (Short-range Radar-Guided Homing Intercept Technology); FLAGE (Flexible Lightweight Agile Ground-based Experiment); and others. These demonstrated miniaturization, divert and booster (axial) propulsion, kinetic-kill vehicles (KKVs) and direct-impact homing sensors. These proved they could work in extreme aerothermal conditions at Mach 10+ against endoatmospheric targets like a carrier-hunting MaRVs. Moreover, they all worked by direct impact.
Fifth, given this US technical heritage, there are numerous credible counter-MaRV defenses that could be implemented quickly. Candidates include forward-deployable defenses using an engagement geometry called TOP HAT (trajectory-optimized high-altitude targeting), as well as a high-launch-rate mechanical launcher firing a smart maneuvering projectile originally funded by the SDI program.
The TOP HAT engagement geometry involves a small single-warhead or multi-warhead booster launched from under the fly-out trajectory of the enemy missile, which allows the ascending booster to converge with the ascending missile - a stern-quarter attack, so to speak. The TOP HAT interceptor crosses the missile's trajectory right after apogee, when it is moving most slowly. The benefits include long engagement times (for intercepting ICBMs, up to 300 seconds), which allows shoot-look-shoot as well as cooperative multi-KKV/interceptor attacks. Engagement ranges are low, allowing simpler sensors - theoretically, including commercial off-the-shelf sensors - with converging velocities as low as 1-2 kilometers/second. The KKV could be the 1-kg Multiple Miniature Kill Vehicle (MMKV) being developed by Lockheed Martin for future Standard variants or other boosters.
The TOP HAT geometry, combined with a very small MMKV payload, opens up prospects for small boosters driven by small high-density rocket engines. These boosters should be small enough to be launched from forward-deployed UAVs orbiting at a safe standoff range from the ASBM launch site but still underneath the ASBM's fly-out trajectory. Alternatively, they could employ strap-on wings like those used on air-dropped standoff glide bombs like the JDAM, with propulsion provided by one of several small high-performance diesel engines being developed for UAVs. Or these air-loitering TOP HAT interceptors could use powered Rogallo-type parafoils or “ram air” parachutes like those being used for autonomous cargo delivery to remote ground forces. Loiter times of many hours are possible.
But where could these UAVs or “flying boosters” operate from? One possibility is midsize airships that could operate like aircraft carriers, launching such UAVs from standoff over international waters and refueling them as needed in flight either directly or by UAV “tankers.” Inflight refueling of small 45-lb UAVs like Boeing's Scan Eagle - which already can fly 29 hours on a new diesel - is being flight-tested by one small company. With further miniaturization of TOP HAT interceptors, it is possible to envision continuous 'down range' coverage of all ASBM fly-out trajectories from a given missile field where mobile ASBM launchers are known to be deployed.
Still, this deployment modality requires a major change of attitude toward BMD on the part of the White House, State Department, DoD and the Navy. It also must be considered a semi-permanent forward-stationing requirement as long as China fields ASBMs. On the other hand, the virtue of such forward defenses is that they compromise the calculability of any Chinese decisions to target our carriers with ASBMs because China won't know which - if any - ASBMs launched against our carriers will survive past apogee. That's because they won't know how many TOP HAT interceptors we'll have airborne at any time.
It also bears noting that TOP HAT boosters, once miniaturized, can be fired from UUVs (unmanned underwater vehicles), using encapsulation and float-up launch methods being tank- and sea-tested by two industrial consortia for launching non-marinized UAVs and tactical missiles from attack subs without sub modifications. Communications connectivity for launch orders and status checks could be maintained by small, low-profile floating acoustic modems whose float bladder embed a radio antenna.
However, these forward TOP HAT defenses must also be complemented by a high-launch-rate shipboard defense. The best near-term candidate is a mechanical “Slingatron” launcher that can launch 10-lb smart homing projectiles at 1.8 - 2.0 km/second from a gyrating 35-ft-diameter coil. Even higher exit velocities - or smaller coil diameters - are possible by substituting Kevlar for the steel moving parts of this surprisingly simple launcher. Unlike a railgun or powder gun, the Slingatron imposes its G loads in the transverse direction - vs. the axial loads experienced by conventional gun launch. Moreover, these G loads at launch build up progressively - vs. the abrupt 12,000-18,000 G loads of conventional gun launches.The projectile best suited for high-launch-rate counter-MaRV firing from the Slingatron is the General Electric D-2 endoatmospheric terminal-defense projectile developed under the SDI program for firing from the 90-mm HEROD railgun. This 28-inch long round incorporated a recessed IR scanner and tiny thrusters for direct impact with an RV. Two versions were planned: an IR-only version for tactical engagements and a longer-range variant that added semi-active radar to the IR. The D-2 launched at 100,000 G's. Although it never flew as an integrated projectile, D-2 aeroshells flew successfully in launches from powder guns before the program was canceled in 1995. The projectile is available for a restart and “technology refresh” should the Navy adopt it for shipboard defense.
Together, the Slingatron and D-2 projectile offer “deep magazine'” BMD at low cost. A rotary magazine of modest dimensions could hold several hundred D-2 rounds for a deck-palletized Slingatron. Launch rates would be limited only by fire-control considerations, not by the rapid-fire launcher. Should China opt for nuclear MaRVs, maximizing keep-out range will be crucial, along with kill mechanisms. Rapid fielding of Slingatron/D-2 is possible by mounting palletized Slingatrons on the fantails of reactivated Reserve Fleet FFG-7 frigates, which are fast enough to keep up with a carrier task force during ASBM engagements.
In conclusion, while the Chinese MaRV threat is serious, the US technology base for comprehensive defenses against this weapon is far deeper and more competent than is realized. The best solutions are not only “off the shelf” but even :out of the archives.” But the Navy must “run scared” if it is going to quickly field these defenses and must be willing to fight the White House, the State Department and OSD in order for these novel forward-based and high-launch-rate defenses to become realities.
About the Author:
John Bosma is a “technology scout” and former defense journalist whose current focus is defense, particularly special operations and naval force protection. His customers in recent years have included OSD (Advanced Systems and Concepts (AS&C) Office, Industrial Policy Office, DDR&E); the Office of Naval Research (Future Naval Capabilities program, Naval Research Advisory Committee); the Missile Defense Agency; and DARPA. He began his defense career as a SALT analyst, missile-defense advocate and business-development staffer at Boeing Aerospace, then spent two years (1981-83) as a congressional staffer for the congressman from Colorado Springs, Col., a member of the House Armed Services committee. During this time he helped organize pro-BMD support on the Hill, inside USAF (by pushing USAF to create a Space Command adjunct to the North American Aerospace Defense Command (NORAD) in Colorado Springs) and inside DARPA (short-wavelength lasers, free-electron lasers with orbital relay mirrors). He left the Hill in 1983 to found two defense newsletters on military space and SDI. He has continued to track developments in miniaturization (sensors, propulsion, kill mechanisms), materials and controls that promise orders-of-magnitude reductions in the weight and cost of BMD systems, with particular attention to smart projectiles launched from guns or mechanical accelerators, as well as compact UAV-launched boosters powered by MEMS-scale rocket engines. In addition to defense “technology scouting,' Mr. Bosma has surveyed other sectors that include energy, medical care (wearable sensors, biowarfare sensors), transportation (all modes), intermodal freight, shipbuilding, construction robotics, “green skyscrapers,” hard-rock mining and heavy lift in the Arctic. He lives in Baltimore.
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