During the Cold War, the U.S. Navy’s principal antisubmarine warfare (ASW) detection method was passive acoustics—the seafloor sound surveillance system (SOSUS), passive sonars in submarines and surface ships, and air-launched sonobuoys. The Soviet Navy had similar acoustic systems, but it also developed an array of nonacoustic detection systems.
The Soviet Navy’s nonacoustic ASW program was intended, at least in part, to compensate for shortcomings in transducer and computer technologies. Despite periodic claims of operational success, however, it is unlikely that Soviet nonacoustic systems were in widespread use— except under special conditions—until near the end of the Cold War.
Background
According to Soviet publications, in 1963 priority was given to “a new physical phenomenon based on the appearance, development, and dissipation of turbulent formations of natural and artificial origin”—that is, submarine wake effects. The Soviet Union’s Academy of Sciences in 1967 established a council for the integrated problem of “hydrophysics” to coordinate national efforts in this field. The hypothesis that optical instruments could locate and identify undersea wakes was said to have been confirmed in tests in the Northern and Black Sea Fleet areas.1
An experimental model of such an electro-optical device—designated Snegir’, the Russian word for “bullfinch”—was installed in a nuclear-powered submarine in 1969. During a two-month trial period, in September and October 1969, the Soviet submarine was purported to have detected a U.S. nuclear submarine departing Guam and performed “continuous covert tracking of her based on her wake right up until the [U.S. submarine] surfaced in the vicinity of that base.” The Soviet evaluation noted: “The snegir’ apparatus demonstrated its exceptional effectiveness for the first time during this deployment, since it permitted increasing the nuclear submarine’s search potential by many times compared with one equipped only with an acoustic [sonar] complex.”2
In the 1970s, there was increasing concern within the U.S. Department of Defense over a possible Soviet “ASW breakthrough.” The Chairman of the U.S. Joint Chiefs of Staff, Admiral Thomas H. Moorer, in 1972 told Congress:
The Soviets are believed to be working on a number of new ASW developments which could significantly improve their antisubmarine warfare capability in those waters in which our [ballistic missile] submarines are now required to operate. Therefore, as the Soviet antisubmarine warfare capability improves, we need to expand our area of operations in our constant effort to maintain our survivability.3
The secret Soviet General Staff journal Voennaya Misl’ (“Military Thought” in English) as early as 1975 provided a lengthy list of “physical fields [that] appear and are retained for a fairly long period around submarines when they depart from their bases. . .” Among them were “salinity and temperature of the water, the amount of plankton, the temperature gradient. . . and a number of other phenomena which have not yet been fully studied to a sufficient degree.”4
In 1976, a Central Intelligence Agency (CIA) analysis—one that was heavily redacted for public release—stated:
There is evidence that the Soviets have employed, periodically over the past three years, a limited number of nonacoustic sensor systems in operations against their own submarines possibly on a trial or experimental basis [deleted] our knowledge of Soviet programs in this area [deleted] limited. . . . [deleted] Our judgment. . . is that an effective system for long-range nonacoustic trail will not be fully operational during the next ten years.”5
The CIA report contained an interesting admission: “We have limited knowledge of Soviet progress in certain technical areas in which an effective sensor system might be developed.”6 The Soviets did develop and deploy advanced wake-detection and related systems.
A visible indication of Soviet interest in nonacoustic submarine detection appeared in the 1980s, when a disarmed Hotel (Project 658)-class ballistic missile submarine was fitted as a multisensor test bed. Several sets of “probes” were mounted on the submarine to detect in-situ water temperature, radioactivity, and turbulence. By the late 1980s, several Victor-class attack submarines similarly had been fitted, indicating that these nonacoustic detection systems had become operational, at least on a trial basis. Installations in other attack-type submarines followed. The Russian term “soks” (COKC in the Cyrillic alphabet) was applied to these systems. The Victor (Project 671)-class submarine K-147, for example, was credited in Soviet literature with the continuous tracking of the U.S. submarine Simon Bolivar (SSBN-641) for six days during a 1985 exercise.
Other nonacoustic detection systems were being examined if not developed. In 1990, two Soviet naval officers listed six methods of nonacoustic submarine detection: radar, infrared, gas analysis, laser, bioluminescent effects, and magnetometric effects.
Discussing the last, the authors noted that the steel hull of a submarine could cause distortions of the earth’s magnetic field:
a change in the electromagnetic conductivity of sea water (which lasts for several hours) in the wake of a submarine in relation to the remaining mass of water. As far as the wake is concerned, if there is sufficient intensity it can create a magnetic anomaly. And as a consequence of the great extent of a wake, it is easier to detect this anomaly than the magnetic anomaly due to the metallic hull of a submarine.7
Of special interest in Soviet writings of the period was the use of lasers—in aircraft and possibly satellites—to detect the physical phenomena of a submarine’s wake. Researchers admitted that “the range of possible detection of underwater targets with the aid of laser gear is rather contradictory . . . estimates of possible [depth] vary widely from 100–150 to 450 meters.”8 The use of lasers, like certain other ASW detection schemes, sought to identify a submarine’s wake, which could represent a “target” thousands of yards and even several miles in length compared to the size of the submarine itself.
Both the U.S. and Soviet navies have claimed the detection of submerged submarines by shipboard radars, perhaps by underwater wakes affecting the atmosphere above the water.9 When the missile cruiser-helicopter carrier Moskva and the first Kresta-class large ASW ship, the Admiral Zozulya, went to sea in 1967, there were indications that their large surface-to-air missile-control radars were employed with their antisubmarine missiles. These were G/H-band radars with a range of some 40 nautical miles, slightly more than that of the ships’ antisubmarine missiles. There were claims that these radars could detect above-surface phenomena related to the passage of submerged submarines.
Possibly supporting these observations, Russian and U.S. scientists have claimed detectable aerosols that persist above surface and submerged wakes. Based on satellite imagery, these water droplets in some situations persist longer than other wake indicators, at least for surface ship wakes.10
In an overall appraisal of Soviet nonacoustic ASW research, a U.S. intelligence report in 1980 stated, “The [deleted] Soviet R&D program in nonacoustic phenomena and sensors is expected to continue until a breakthrough occurs or all approaches to achieving significant detection ranges have proven fruitless.”11 Shortly thereafter, a senior Department of Defense official told Congress of his concerns over Soviet progress in such technologies as “aerodynamics/fluid dynamics, nonacoustic submarine detection, nuclear warheads, radar, and directed energy.”12
The Soviet and, subsequently, Russian research and experimental efforts in this field have been impressive. According to a history of the Kometa Scientific Research Institute in Moscow,
in the period 1975–2000 . . . large-scale experimental and theoretical research were conducted, aimed at the discernment of the main physical mechanisms of the development upon the sea surface of hydrodynamical disturbances caused by the movement of submerged objects.
From 1973 to 1990, on the test ranges of the Black, Barents, and Okhotsk seas, as well as on the Pacific test range near the shore of the Kamchatka peninsula, over 2000 experiments were conducted using various classes of optical and radiophysical apparatus situated upon rotary-wing and fixed-wing laboratories.13
While Soviet progress in advanced, nonacoustic detection was striking during the Cold War, most Western scientists and analysts believed such efforts could be successful only under ideal ocean and atmospheric conditions. The oceans are rarely “ideal” in this context. Coupled with Soviet limitations in computer capability compared to the West, the near-term success of such methods was questionable, despite Soviet claims to the contrary—possibly a disinformation effort. However, the especially high level of understanding of oceanography and physics in the Soviet scientific community, coupled with the Soviet multipath approach to submarine detection, suggests their methods are different from those in the West and not necessarily inferior.
A CIA report addressing Soviet acoustic and nonacoustic sensors stated:
Such a breakthrough would substantially increase the Soviet Navy’s ability to perform the . . . strategic defensive task of destroying enemy ballistic missile and land attack cruise missile submarines before they launched their missiles. It would also increase the Soviets’ ability to protect their SSBNs, because enemy attack submarines could be identified and attacked before they approached Soviet SSBN havens.14
A key component of Soviet/Russian efforts has been the potential of satellite detection. By 1968, the Soviets were testing their first-generation ocean surveillance satellites for detecting surface ships. The first system became operational by 1974. Satellites offer many advantages for maritime reconnaissance, among them high search rates and autonomy from land bases. Passive electronic intelligence (ELINT) satellites sought emissions from shipboard radars and then cued active radar satellites that would be focused on the target area for ship and formation identification and more accurate positioning. The active radar ocean reconnaissance satellites (RORSAT) were nuclear powered because of the large amount of power needed for their radars. Soviet RORSAT and ELINT satellites sought to detect surface ships.
But U.S. political scientist Dr. Hung P. Nguyen wrote in 1993:
In fact, the Russians now make no secret of the fact that they are developing remote-sensing systems to detect submerged submarines. Valentin S. Etkin, head of the applied space physics department of the Space Research Institute in Moscow, has reportedly described to U.S. military personnel how submarines. . . had been detected by using microwave reflections from the sea surface. Vyacheslav M. Balebanov, deputy director of the Space Research Institute, openly claimed that “in principle, it’s not so difficult to see a submarine at less than 100 meters, and we have got positive results.”15
While 100 meters may seem shallow for submarine operations, undersea craft do operate at such depths often. Nguyen also cited statements of success in “overhead” detection by senior Soviet officers.
There are physical limitations on the employment of satellites for submarine detection beyond the ability of their sensors to discriminate between natural ocean disturbances and those produced in the depths, on the surface, or even in the atmosphere by a submerged submarine. Optical sensors in particular are limited at night and under cloud cover, although the detection of bioluminescence phenomena caused by a submarine’s underwater transit could be detectable at night under some conditions.16
Two knowledgeable Soviet Navy officers in 1988 stated that space reconnaissance “is accomplishing many missions, including the detection of submerged submarines” and that radars deployed on aircraft and satellites were being used to “detect the wakes of submarines.” These specific statements, by Captain First Rank Ye Semenov and Rear Admiral Yuri Kviatkovskii—the latter the head of Soviet naval intelligence—apparently referred to systems for submarine detection that already had been deployed—at least on a trial basis.17 A 1993 report in Voennaya Mysl’ declared, “All-weather space reconnaissance and other types of space support will allow detecting the course and speed of movement of combat systems and surface and subsurface naval platforms [submarines] at any time of day with high probability, and providing high-precision weapons systems with targeting data in practically real time.”18
There has been difficulty in the West in confirming these claims and reports. It is conceivable that they were meant to explain what could be achieved, a method of calling for more support from the government. Are such claims believable—or are they part of a disinformation effort? Nguyen observed that “(1) such claims tend to be made by senior figures in the military leadership and (2) these leaders would not commit their prestige to making such claims if the relevant concepts had not been at least tested and validated.”
A review of Soviet/Russian literature and discussions with knowledgeable Russians indicate their belief that the U.S. Navy has “simplified” Russian detection requirements by operating submarines in the epidermis of the oceans—at depths of less than 1,300 feet.19 The Mike (Project 685)-class submarine Komsomolets, with a titanium-hull, was credited with an operating depth of at least 3,300 feet.20 Soviet/Russian confidence in the effectiveness of nonacoustic ASW may have motivated the drive for such operating depths. If so, operations by Western submarines at shallower depths may indeed simplify Russian ASW requirements.
As recently as the spring of 2017, Russian submarine experts, citing advances in their sonar systems, stressed that effective ASW requires a “comprehensive” or “all source” approach, employing all possible means to locate and track enemy submarines. While there have been major cutbacks in funding for most aspects of the Navy since the demise of the Soviet regime in 1991, there have been significant investments in undersea warfare. This priority is understandable in the context of the two primary missions of today’s Russian Navy: (1) defending the homeland from attacks by Western missile submarines, and (2) providing an effective and survivable strategic submarine force. Both missions demand effective ASW.
It is difficult to determine, at least on an unclassified basis, the current state of Russian nonacoustic submarine detection capabilities. Given the incredible advances in signal processing, computational power, and artificial intelligence during the past two decades, it would seem plausible that at least some of the past Soviet/Russian research in this area has progressed to operational capabilities.
It would be prudent for the U.S. Navy to pay close attention to all detection vulnerabilities of the submarine force as well as future submarine designs—including potential vulnerabilities in the nonacoustic spectrum—lest it find itself on the horns of a “known or unknown unknown.”
1. Rear Admiral Ye. Buzov, Soviet Navy, “From the History of the Creation of NonAcoustic Means of Detecting Submarines,” Morskoy Sbornik, no. 7 (2003), 58.
2. Ibid., 59.
3. Admiral Thomas H. Moorer, USN, Chairman, Joint Chiefs of Staff, “United States Military Posture for FY [Fiscal Year] 1973,” 8 February 1972, 10–11. Moorer had previously served as Chief of Naval Operations from 1966 to 1970.
4. Rear Admiral V. Saakyan, Soviet Navy, “Some Aspects of an Operation to Destroy Enemy Missile Submarines,” Voennaya Mysl’, no. 2 (1975).
5. Central Intelligence Agency, “Soviet Approaches to Defense against Ballistic Missile Submarines and Prospects for Success,” NIO IIM 76–012J (Washington, DC: March 1976), 15.
6. Ibid., 17.
7. Captain 2nd Rank V. Surnin and Captain 2nd Rank V. Ponomarev, Soviet Navy, “Nonacoustic Means of Detecting Submarines,” Morskoy Sbornik, no. 4 (1990), 69. Also see Tom Stefanick, Strategic Antisubmarine Warfare and Naval Strategy (Lexington, MA: Lexington Books, 1987), 15–25, 181–215.
8. Captain 1st Rank Ye. Buzov, Soviet Navy, “Trends in the Development of NonAcoustic Means of Detection, Morskoy Sbornik, no. 9 (1974), 86.
9. See, for example, M. Formwalt, et al., “A Proposed Program for the Exploitation of NIDAR,” Report No. 285, U.S. Naval Underwater Ordnance Station, 2 March 1959; and Merrill I. Skolnik, “A Review of NIDAR,” Memorandum Report 3025, Naval Research Laboratory, April 1975.
10. Philip A. Durkee, Kevin J. Noone, and Robert T. Bluth, The Monterey Ship Track Experiment (Monterey, CA.: Naval Postgraduate School, 23 February 1999).
11. U.S. Naval Intelligence Support Center, Soviet Surveillance Capabilities against U.S. Naval Forces, DST-1280S-607-79 (Washington, DC, 1 August 1979), 3-6.
12. Dr. Arden L. Bement, Deputy Under Secretary of Defense for Research and Engineering, in response to questions submitted by Sen. John Culver, in Research and Development, part 6 of Hearings before the Committee on Armed Services, Senate, Department of Defense Authorization for Appropriations for Fiscal Year 1981, (Washington, DC: 1980) 2735–36. Bement stated that Soviet technology levels were superior to those of the United States in the deployment of several military systems.
13. V. P. Misnik, ed., Kometa—35 let [Kometa: Thirty-Five Years] (Moscow: Weapons and Technologies, 2008), 149.
14. Central Intelligence Agency, Soviet Naval Strategy and Programs through the 1990s, NIE 11-15-82 (Washington, DC: March 1983), 56.
15. Dr. Hung P. Nguyen, Submarine Detection from Space: A Study of Russian Capabilities (Annapolis, MD: Naval Institute Press, 1993), 1-2. At the time, Dr. Nguyen was with the Center for Naval Analyses.
16. See, for example, John A. Strand, Clarence G. Pautzke, and Gordon L. Mitchell, “The Antisubmarine Warfare (ASW) Potential of Bioluminescence Imaging,” (Washington, DC: Office of Naval Research and Naval Research Laboratory, January 1980).
17. Captain 1st Rank Ye. Semenov, Soviet Navy, “On the Survivability of Submarines under the Threat from the Air,” Morskoy Sbornik, no. 1 (1988), 23; and Rear Admiral Yuri Kviatkovskii, Soviet Navy, “Current Status and Development Prospects of Forces and Means for Combating Submarines,” Voennaya mysl’, no. 1 (1988), 39.
18. General Major M. A. Borchev, Soviet Army (Ret.), “On the Military Organization of the Commonwealth of Independent States,” Voennaya mysl’, no. 3 (1993), 7.
19. The acknowledged operational depth of the USS Thresher (SSN-593) was some 1,300 feet; that class is believed to have been the deepest-diving U.S. combat submarines.
20. Rear Admiral Nikolay P. V’yunenko, Captain 1st Rank Boris N. Makeyev, and Captain 1st Rank Valentin D. Skugarev, Soviet Navy, The Navy: Its Role, Prospects for Deployment and Employment (Moscow: Military Publishing House, 1988), 77 (U.S. Naval Intelligence Command translation).