The "fine print" of America's strategic insurance policy

by Michael L. McHugh, Captain, U.S. Navy

With a growing percentage of the Nation’s strategic nuclear deterrent carried by the ballistic missile submarine (SSBN) force, credible pre-launch survivability of the SSBNs becomes a major strategic issue in its own right. This is not a new concern, and the question of U. S. submarine survivability was considered quite early in the Cold War. Late in the 1960s, the Department of Defense established a Vulnerability Task Force (VTF) to determine how safe the “41 for Freedom” SSBN force would be against enemy attempts to neutralize it before launching its strategic missile payload. When the VTF attempted to address this issue in all its generality, however, it quickly realized there were too many gaps in our knowledge of both the threat and the physical aspects of underwater detection, tracking, and engagement to arrive at a definitive answer.

This finding was a “wake-up call” for our SSBN force and naval strategic thinkers. It prompted then-Director, Defense Research and Engineering, John S. Foster, Jr., to issue a directive in October 1968 that established a requirement to investigate technical issues arising in the general area of SSBN vulnerability and survivability. This was the beginning of the Navy’s SSBN Security Program. Over the years, it has vigorously analyzed both acoustic and non-acoustic undersea threats and, when necessary, developed systems and tactics to counter them.

The SSBN Security Program Today
Today, the SSBN Security Program remains committed to its original charter – ensuring the security of our SSBN force now and well into the future. It consists of three divisions devoted to potential acoustic and non-acoustic vulnerabilities and operations security. The first two pursue research and development projects in detection and tracking, while the last focuses on non-technical, operational aspects of SSBN security. Together they comprise an active program of operations analysis, laboratory research, at-sea tests, and countermeasures or tactics development.

Acoustics and Non-Acoustics
The major efforts in these disciplines focus on the physics that governs detection of submarines at sea and on advanced technologies that might exploit these phenomena to create new vulnerabilities for the SSBN force. The resulting in-depth study of the undersea environment has produced the “lion’s share” of our science and technology base in submarine detection and vulnerability. While the results – and even the topics – of most of these studies remain highly classified, a number of unclassified program successes are highlighted in the accompanying sidebar. These accomplishments have been as important to the development of SSN and coordinated ASW tactics as they were to maintaining SSBN survivability.

Operations Security
The Operations Security area of the SSBN Security Program concentrates on monitoring, analyzing, and assessing real-world SSBN operations to identify improved tactics and techniques for raising the general security level of deterrent patrols. There are four primary focus areas:

  • SSBN Tactical Development Program

  • Operations Characterization Project

  • Force Security Assurance Project

  • SSBN Operations Assessment

SSBN Tactical Development Program (STDP)
Managed by Submarine Development Squadron Twelve in coordination with the Johns Hopkins University’s Applied Physics Laboratory (JHU/APL), the STDP develops and evaluates new tactics for minimizing the vulnerabilty of deterrent patrols. Successful new approaches, such as those learned in formal at-sea exercises, are embodied in the Submarine Security Manual. An active partnership in the STDP with all SSBN crew members has been the real key to maintaining the excellent security posture of the deterrent force.

Operations Characterization Project (OCP)
By continuously logging submarine operating parameters during every deterrent patrol, the OCP provides authoritative, real-world operations profiles for post-mission assessment. Thus, after each patrol, every SSBN receives a report that portrays its operating practices in detail. At the heart of the OCP is the Electronic Deck Log (EDL). Formerly, patrol data were collected, collated, analyzed, and reported “by hand.” In an effort to reduce manpower, save money, and increase accuracy, JHU/APL developed the EDL, which electronically logs and analyzes key parameters and formats its own reports. The EDL also permits SSBN Sailors to access its data, which include sonar, Electronic Support Measures (ESM), and engineering parameters for real-time analysis during the patrol. Already, the EDL is “spinning off” new technologies to other data-logging efforts and generating the most comprehensive database of operational information we have in the Fleet.

Force Security Assurance Project (FSAP)
The FSAP focuses on “big-picture” issues that go straight to the heart of submarine strategic deterrence. A recent example is the “Foundations Assessment,” which investigated whether today’s SSBN force operates under assumptions appropriate to the post-Cold War environment. This assessment spurred the development of new operating premises better suited to today’s conditions. Other assessments underway include a study of the value of the SSBN in deterring assymetric threats, such as information warfare and chemical and biological weapons.

SSBN Operations Assessment (SOA)
Typical tasks within the SOA project involve the analysis of individual unit-level and force-wide problems that arise in estimating the threat, devising tactics, and planning operations. Recent efforts
have included updating the threat to SSBNs from state-of-the-art ASW capabilities, reviewing and evaluating Standard Operating Procedures (SOPs) and Operational Security (OPSEC) procedures, and studying SSBN patrol patterns and their predictability. These independent analyses of SSBN operations provide feedback needed by commanders to assist them in employing the force effectively in the post-Cold War era.

“14 for Freedom”
In comparison with our earlier force of “41 for Freedom,” the SSBN fleet is slated to drop to 14 ships in the new century. With each individual platform thus representing a significantly larger percentage of America’s strategic deterrent, the importance of ensuring the security of each becomes more important than ever. Far from being an artifact of the Cold War, the SSBN Security Program remains a key element in maintaining the credibility of our strategic nuclear arsenal.

A sailor from USS Pennsylvania (SSBN-735)
(GOLD), enters ship's data into the Elctronic Deck Log.

SSBN Security Program Technology Highlights "Under Wraps" No More



  • Demonstrated first use of Fast Fourier Transform (FFT) techniques for real-time multi-channel beamforming and signal processing
  • Developed techniques for measuring deviations of a long towed array from straightness and demonstrated how these could be compensated for in signal processing
  • First evaluated submarine detectability in the 0.01 to 1.0 Hz infrasound region
  • Quantified detectability of acoustic transients in specific operating evolutions and showed how these could be exploited at low false alarm rates
  • Determined the physical mechanisms that give rise to submarine propulsion signatures


  • First investigated potential of very long-range, low-frequency active acoustics, including impulsive source technology, target strength, and shallow water effects
  • Demonstrated low-frequency bistatic active echo ranging
  • Developed first tactical decision aid for low-frequency active acoustics



  • Extensively investigated submarine-induced hydro-dynamic signature generation, propagation, and decay models
  • Quantified detectability of submarine hydrodynamic wakes


  • Developed first validated models of radar detection of submarine masts and antennas and quantified their detectability
  • Investigated the detection potential of advanced airborne Magnetic Anomaly Detection (MAD), including geologic effects and noise cancellation
  • Conducted first AC and DC electromagnetic signature measurements on fully submerged submarines

Infrared and Optics

  • Identified previously observed infrared surface “scars” as manifestations of the submarine wake
  • Developed first quantified bioluminescence detection model
  • Evaluated optical detectability of the submarine hull and associated systems
  • Employed first airborne digital laser radar system to determine potential for detecting submarine hulls

In addition to these accomplishments in understanding the physical phenomenology of submarine detection and tracking, the SSBN Security Program has also contributed significantly to the characterization of the natural ocean environment, its exploitation for ASW, and the development of numerous ASW tactical decision aids.

— Captain Mike McHugh retired in 1998 after 30 years of distinguished service. His last assignment was as the SSBN Security Program Manager on the staff of the Director, Submarine Warfare.