Two characteristics seem certain to define the military environment for the immediate future: rapid, radical technological change, and increased budget pressure on service accounts. There is a temptation to think that our acquisition community, along with R&D and industry, must take the lead in these technology-based competitions; that the Fleet must wait for Office of the Chief of Naval Operations to buy solutions to our problems. In fact, nothing could be further from the truth—or less aligned with our history.
When our Navy has faced times like these before, notably the interwar period of 1919–1941, progress most often was driven by Fleet innovation using existing technologies. As Captain Wayne Hughes noted in his exceptional work Fleet Tactics and Coastal Combat, the pages of Proceedings from that era were filled with articles by naval operators debating the merits of various tactics and recommending innovative uses of existing means to achieve new ends. The current era demands a similar approach, and the Fleet must step forward to lead the debate.
What follows is offered in that spirit—a vision for implementation of modern radio-frequency obscurants, an existing U.S. Army passive-defense technology recently advocated by Thomas Culora, a professor at the Naval War College.1 It would require returning to tactics the Navy has not trained to since World War II, but the potential benefits might include substantial improvement in ship defense against what are arguably the most pressing threats: antiship cruise and ballistic missiles.
From Kamikaze Attacks To Antiship Missiles
Through the end of World War II, an indispensable defensive capability for nearly every surface combatant was the ability to generate copious amounts of smoke to visually obscure itself and other vessels from enemy aircraft, surface ships, and submarines. Timely employment of a visual obscurant effectively screened an untold number of combatant, amphibious, and cargo ships from aerial bombs, gunfire, and torpedoes. The widespread use of radar for target detection and fire control by the end of the war eventually led to the retirement of smoke-generation equipment on naval ships. Although the Navy still has a tactical smoke employment manual, it has been decades since any ship has deployed any type of obscurant, or has even considered the use of smoke at sea.2
That could soon change. The growing threat from increasingly sophisticated radar-guided missiles is generating interest in a new type of obscurant for surface-ship defense. Rather than blocking visual observation, this new shield—a carbon aerosol-fiber dispersed in a cloud—blocks a broad swath of the radio-frequency (RF) bands that the radars on modern missile-seekers use. RF obscurant already has been fielded by the Army in its M56 Coyote system and shows promise for missile-defense of ships at sea.
Japan’s introduction of the kamikaze was a deadly harbinger of what arguably is the most significant development in non-nuclear naval warfare since the end of World War II—highly effective guided antiship missiles. Since the 1950s, the evolving antiship missile has continued to outpace “active defenses,” i.e., efforts to shoot down (hard kill) antiship missiles en route their target. Newer antiship missiles, having features such as radar stealth, supersonic speed, sea-skimming profiles, and radical terminal maneuvers may be effective in countering even the most advanced hard-kill systems. The prospective future introduction of an antiship ballistic missile—likely exhibiting extremely high speeds and maneuvers during flight—might decrease the effectiveness of a hard-kill active defense to an unacceptably low level.3
Hard-Kill Alternatives Have Limits
This is not to say that an individual antiship missile might not be intercepted and destroyed. But against a medium- to high-end opponent, a warship should expect to encounter salvoes of many antiship missiles arriving nearly simultaneously to overwhelm missile-defense systems. In littoral waters or restricted areas, such as the Strait of Hormuz, cruise missiles might well pose a similar magnitude of threat. As the Hezbollah attack on the Israeli corvette Hanit with a Chinese-designed C802 missile demonstrated in 2006, such advanced antiship weapons are no longer restricted to high-end opponents. The Hanit was fortunate to survive relatively intact. Britain’s experience in the Falklands in 1982 against a lesser naval power demonstrated clearly the operational impact of even a small arsenal of modern antiship weapons, and the lethality of a single missile hit on a modern warship.4
Given the increasing challenges of shooting down a missile with a missile, much attention has been focused on efforts to kill the missile prior to launch. Attack operations against mobile missile launchers have proved even more demanding than killing a missile in flight. Scud-hunting efforts during the two wars with Iraq—in which the United States enjoyed near-total air and sea superiority—offer no cause for optimism in finding and killing missile launchers, even if they are not heavily protected by sophisticated air defenses and surrounded by high-fidelity decoys.
Other missile-defense efforts have focused on the possibility of employing advanced cyber-attack techniques to effectively cut or corrupt missile-control signals to prevent an effective antiship missile shot. There may be some possibilities for cyber attack against some opponents—and efforts along those lines should be pursued. But cyber attack likely requires timely access, which could be defeated by an inability to gain timely entry into the correct cyber network, unanticipated changes in computer code, or simply an adversary’s low level of reliance on cyber communications. Consider the case of the attack on the Hanit, where the command-and-control nodes were all co-located, and there were evidently no communications lines to interdict.
The Potential for Passive Defense
Since active defenses and attack operations appear insufficient for defending against the modern antiship missile threat, are there viable passive-defense options? Denial of initial missile targeting is one method of foiling an antiship missile. It is clear that the growing threat from increasingly sophisticated antiship missiles requires very serious pursuit of advanced efforts at countering an adversary’s long-range targeting capabilities in both technology and fleet training. Counter-targeting options include restrictions on radar and communications emissions, unpredictable movements, and presentation of false targets to an enemy’s sensors. However, counter-targeting is most effectively conducted on the open sea, far from land, with the targeted ship remaining as stealthy as possible. To carry out their mission, naval forces generally must move toward land and operate there for some time, often in confined areas. Activities associated with normal operations such as radio communications, radar emissions, and aircraft flight activity inevitably reveal a ship’s location to enemy sensors.
Another passive defense option to defeat the antiship missile focuses on countering the missile’s seeker to prevent it from “seeing” the target. Historical evidence indicates that those counter-seeker measures—electronic interference with missile seekers, decoys, and chaff—have been extremely effective; vastly more effective in antiship missile defense than efforts to shoot down an incoming missile. A study published by the Navy’s Surface Warfare Development Group in 2007 concluded that out of more than 200 antiship missiles launched operationally by 13 belligerents between 1967 and 2007, only one was successfully defeated by hard kill (after it had missed its intended target), while more than 100 were defeated by passive defenses or soft kill.5
The increasing sophistication of antiship missiles will make soft-kill measures such as spoofing or intelligent jamming far more challenging. It often can take years after a new threat appears for enough to be learned about it to develop effective counter-seeker solutions.
The best option that might be employed at sea—the highest payoff, in the shortest time, and likely at the lowest cost—would appear to be an extremely simple solution: some variant of the Army’s M56 Coyote RF obscuration system, whose radar-absorbing smoke might mask the target ship, potentially even an aircraft carrier, from an incoming missile’s seekers. Little exquisite knowledge of seeker capability is required if one is able to deny the use of large segments of the RF spectrum.
The Case for RF Obscurants
The M56 Coyote is a smoke generator mounted on a Humvee that can deliver three different types of obscurants, simultaneously or independently: visual, infrared (IR), and RF.6 Although all three have some role in countering missiles, the RF obscurant is the one that has the greatest potential for countering the high-end antiship missile threat. In the Army system, the RF obscurant is a carbon aerosol-fiber, about the consistency of human hair, designed to counter missile radar-seeker frequencies that operate in the 9-96 GHz range—virtually the entire spectrum used by modern antiship missile radar-seekers.
Eight 30-pound boxes of the obscurant are fed into the M56 on a Humvee for dispersal. The area covered and the persistence of the cloud depend on the amount of obscurant employed and environmental conditions, but a platoon of six Humvees (a total of 48 boxes of obscurant) potentially can cover an area of multiple square kilometers for an hour or more.7 The RF obscurant has a number of attributes that make it highly favorable for modern missile defense at sea:
• It simultaneously blocks a wide range of frequencies from the traditional area of the RF bands used by past missile seekers, all the way up through the higher- millimeter wave bands likely to be used by future missiles. Thus the exact frequency and seeker characteristics of the enemy missile’s seeker don’t need to be known for the obscurant to be effective.
• It is relatively inexpensive and extremely quick to produce and field. The cost of a single cloud, covering several kilometers, probably large enough to mask an aircraft carrier from several missiles approaching from many directions and angles, might be in the low tens of thousands of dollars.
• It is an inert substance with no specific handling restrictions; it can be carried and employed in large capacities. Given the large quantity and low cost, multiple clouds could be generated on even low warning of missile attack.
• While dispersal clearly is sensitive to environmental conditions, it potentially could be laid low to cover approaches of sea-skimming missiles, and also blown high over the tops of ships to cover approaches of ballistic missiles.
• With proper employment equipment, an effective cloud might be produced within tens of seconds.
• It could be employed preemptively to cover littoral or chokepoint transits, or when counter-targeting measures must be abandoned to conduct operations. Thus a preemptive screen might be generated prior to flight operations, choke-point transit, underway replenishment, or prior to a need to break radio and radar silence.
• The obscurant cloud probably does not need to be perfect, or provide complete coverage. It simply needs to mask enough of the ship so that the radar cross-section of the vessel visible to the missile radar-seeker is below that of surrounding sea clutter or decoys.
• It has been fully tested and operationally fielded by the Army, and it is available for deployment now.
Shipboard Smoke Systems
Employment of the RF obscurant at sea obviously requires the development and integration of tactics, and it would be improved by development of dispersal systems optimized for maritime use. At-sea tests are needed to determine its adequacy for use in screening moving ships, and the optimum method of timely dispersal. In the near term, an employment option could be as simple as a half dozen Army M56 Humvees strapped to the back of a high speed vessel spewing a cloud that a target ship would then maneuver behind, into, or under—depending upon the threat.
In the future—if the Fleet proves the approach—self-contained, relocatable smoke-generation systems with capacities far in excess of that which can fit on a Humvee could be deployed on destroyers, helicopters, or even aircraft carriers themselves. The RF obscurant also might be deployed using explosive charges fired by mortars, similar to our current chaff dispensers and Rheinmetall’s MASS (Multiple Ammunition Softkill System) capability already fielded by nine nations to protect frigate-sized ships.8 An obscurant-generation system would be a logical element of a counter-targeting/counter-seeker module on the high speed LCS to screen high-value units.
There are obvious considerations with respect to the potential effect on humans who ingest the RF obscurant material and on sensitive equipment such as jet engines and electronic systems. Interviews with Army operators of the M56 Coyote conducted by Naval War College researchers indicate that no special precautions are taken during routine employment in the field, and expected exposures to high concentrations can be mitigated with the use of a common dust mask.
Likewise, Army testing has not revealed any detrimental effect on battlefield systems due to RF obscurant exposure. Nonetheless, testing on naval systems would be prudent to determine the obscurant’s negative effects, if any, on aircraft engines, and whether additional filters would be recommended for some ship and aircraft systems. Testing is also needed to evaluate the possible fratricidal effects on blue-force sensors, hard-kill defense systems, and communications. In any event, the possible costs and risks of own-system degradation due to exposure to the obscurant material must be viewed in the context of those systems’ likely effectiveness against these new threats and weighed against the alternative—the ship itself being hit by cruise or ballistic missiles.
RF obscurants deployed to protect ships from cruise- or ballistic-missile attack appear to be a promising, cost-effective solution available today. The goal here is not to argue for obscurants as a be-all/end-all solution, but rather to present a compelling case to look at promising, existing technologies as a way to rapidly counter emerging threats. At the very least the technology merits rigorous Fleet experimentation. If obscurants prove tactically effective they might not only provide the strategic benefits that Professor Culora discusses, but also open a tremendous number of vertical launch system cells currently filled with defensive weapons, allowing them to carry offensive loads.
The answer to the most demanding current threat at sea might well be a tried and true technique from the last major war: Make smoke!
1. Culora, Thomas J. “The Strategic Implications of Obscurants,” U.S. Naval War College Review, Summer 2010, pp. 73-84.
2. NWIP 1-2, Smoke Screen Manual, June 1953.
3. For discussions of antiship ballistic missile developments in China, see Office of the Secretary of Defense, Annual Report to Congress, Military Power of the People’s Republic of China: 2009, p. 21, and Andrew S. Erickson and David Yang, “On the Verge of a Game-Changer,” U.S. Naval Institute Proceedings, May 2009, pp. 26-32.
4. HMS Sheffield (4,800 tons) and M/V Atlantic Conveyor (15,000 tons) were destroyed by Exocet missiles, with only one and two hits, respectively, out of five air-launched Exocets in the Argentine inventory. HMS Glamorgan (6,200 tons) was seriously damaged by a single surface-launched Exocet hit.
5. TM 3-01.1-07, Single Ship Integrated Hard Kill and Soft Kill Tactics in Anti-Ship Missile Defense, Surface Warfare Development Group, April 2007.
6. Promotional material of the manufacturer, L3 Communications/Linkabit, at http://www.l-3com.com/products-services/docoutput.aspx?id=1302
7. U.S. Army Field Manual No. 3-50, Smoke Operations, Headquarters, Department of the Army, Washington, DC, 4 December 1990, at http://www.scribd.com/doc/2513900/Army-fm3-50-Smoke-Operations.