Captain Jim Patton is a retired submariner officer who is an active consultant in submarine mailers to government and industry. He commanded USS PARGO (SSN 650).
Background
More and more one sees the word “agility” used to describe an extremely desirable military characteristic. Due to a unique combination of stealth, mobility and endurance, there is probably no weapons system more physically agile than a nuclear submarine. However, being physically agile does not necessarily relate to being operation-ally agile if impediments exist between the issuance of directions by senior commanders and the reception of those orders by those who must execute them. Historically, this impediment didn’t affect the submarine’s mission terribly, since it operated largely independently under general mission orders and Rules of Engagement (ROE), and the time constant of these operations has been such that it was not significantly detrimental that an order to start (or stop) something might not be received until 12-24 hours after given. Some submarine missions are still characterized by this allowably long Command and Control (c2) latency, but they are becoming the exception rather than the rule. Tight C2 loops that support rapid targeting of time-critical targets are more the norm now.
Because of its unique attributes described above, the Joint Commander needs the submarine as part of his military portfolio, and the Submarine Force is ready and willing to provide those services. However, in order to provide the tight C2 loop required for operational agility, a submarine must presently forfeit much of its physical agility by loitering, at slow speeds, at periscope depth with a high data rate (HOR) antenna raised. There is virtually no one in the Submarine Community (or Navy, for that matter) who doesn’t recognize that this lack of comms at speed and depth is perhaps the submarines most critical shortcoming. Just as if you don’t own a computer the Internet doesn’t really exist, if you can’t plug in FORCEnet doesn’t really exist.
There are people and funds tasked and targeted to solve this problem, but efforts seem diffuse and desultory. One device-a joint US-UK project called RTOF (Recoverable Tethered Optic Fiber buoy) is being planned for installation and experimentation on the first SSBN to SSGN conversion, where ample outboard space is available for stowage and handling equipment for what is not a small object. At best, however, RTOF will bring periodic comms at depth, but not at speed, and is not easily back fitable to current SSNs. Another near-term partial response to the issue is the under development Submarine Expendable Communications Device (SSXCD), a fiber-optic tethered buoy launched from the ubiquitous 3 inch signal ejector which will provide 15 or so minutes of active connectivity at nominal transit speeds. For a communications event to be initiated by other than the submarine, however, both RTOF and SSXCD would be dependent on some sort of bel/ringer that would initiate their launch. Other wonderful connectivity options are projected for future Virginia-class SSNs (when they get their advanced, larger sail). With the exception of SSXCD, most projected solutions to this dilemma are programmatically targeted for implementation no earlier than the beginning of the next decade.
Meanwhile, as Admiral Bowman, then the senior active duty submariner noted at a recent annual Naval Submarine League symposium, the Submarine Force effectively consists of Los Angeles class SSNs. Even in the year 2011, these 688s will account for 86% of Submarine Force levels, and there are as yet no meaningful efforts to provide these platforms with a credible, preferably persistent, ability to at least listen at meaningful data rates while at tactically significant speeds and depths. Admiral Bowman has also added an additional get to his original “get electric, get modular, get payload, and get connected”. It is get real, stop creating Power Point shows, and work the difficult operational and hardware issues. In the spirit of that get, we need real efforts to develop real hardware and supporting concepts for the real fleet.
Discussion
As has been previously stated, it is almost universally recognized that there is an urgent requirement for the US Submarine Force to possess the ability to conduct higher data rate communications, both transmission (active) and reception (passive), at significantly higher speeds and safe non-cavitating depths. In further definition of this general requirement, the following postulates are offered as elemental technical or operational truths:
- Since the Submarine Force will overwhelmingly consist of 688s for the next decade, any solution which does not include this class (plus non-advanced sail Virginias), does not adequately address the Force requirement.
- Since much of the issue involves connectivity while in transit or during on-station repositioning, comms at speed is more important than comms at depth; to be connected while at 75% max speed and 25% max depth is far more operationally significant than the same at 25% max speed and 75% max depth.
- Although 11on-persiste111 solutions (i.e. SSXCD or RTOF) represent temporary answers to mitigate the problem, they are dependent on speed and depth capable be//ringers for non-submarine initiated connectivity.
If the above postulates are accepted, the following corollaries are proposed and subsequently discussed:
- Although the need for both passive and active connectivity modes have dramatically increased as regards quantity and quickness, properly operated stealth platforms such as submarines will remain far more heavily dependent on information receipt as compared with information transmission.
- In the active mode, the highest possible data rates obtainable are desirable to reduce the time of transmission rather than the quantity of information.
- Although true for all platforms, stealth platforms in particular should avoid the transmission and/or receipt of data, as opposed to information (processed data), and should furthermore strive to deal in knowledge (processed information).
- It is much more important for a submarine to be quickly co1111ectable on-demand, than to be actually connected to a network.
- Persistent passive connectivity is essential for any credible near-real time C2 of submarines at operational speeds and depths. Since the decision has been made to shut down ELF, a tethered lifting body for VLF reception capable of operations at tactically meaningful speeds would be required during transits or on-station repositioning (hereafter called transition phases).
Information receipt vs. information transmission
During the Maritime Strategy phase of the Cold War, a Carrier Battle Group (CVBG) Commander had at his disposal a tactical doctrine concept involving his acting as the Composite Warfare Commander and whose central precept was Command by Negation In other words, he and his subordinate commanders Anti-Submarine Warfare (ASW), Anti-Air Warfare (AA W) etc. would plan in advance what and how things would happen if a tactical Armageddon were to occur, with coordinated and simultaneous attacks from Soviet Naval Air, missile-firing surface combatants and submarine-launched torpedoes and cruise missiles. When this happened, the CWC would monitor the execution of pre-planned actions, injecting only negative directions if he saw an advantage in deviating from these actions in favor of some other more appropriate response. This almost Nelsonian approach of ” … no Captain can do wrong by placing his ship alongside one of the enemy” allowed the ewe to manage the unmanageable, and caught the very essence of a combat Observe-Orient-Decide-Act (OODA) loop long before the late Air Force Colonel John Boyd coined the term and the concept. The underlying assumptions of this Command by Negation philosophy are identical to those imbedded in legacy submarine C2 concepts-all action/reaction events needn’t be orchestrated in real time via active communications.
Transmission data rates
If stealth is not an issue, there is no compelling reason to consider the employment of submarines. Stealth involves strict management of all observables Perhaps the easiest of all observables to remotely detect and exploit as to source and geographic location is the emission of radio frequency (RF) energy. Since truly overt transmissions will not even be detected by the intended receiver, every effort must be made to deal with Low Probability of Intercept (LPI) transmissions. A key element of LPI transmission techniques is to dramatically reduce their footprint in the time domain. If such as video-teleconferencing and full-streaming periscope video are dismissed as non-essential options, then as Admiral Archie Clemens showed several years ago in the Pacific, there is nothing a submarine needs to communicate that cannot comfortably be handled with l 28K 256K bps. As previously implied, it is true that faster is always better, but in the submarine case, fast is to reduce the time of transmission not just to permit more of it.
Data versus information versus knowledge
Before a nearly infinite degree of processing power was afford-ably available in virtually infinitesimal volumes with low power requirements, many distributed subsystems were committed to sending raw data to the next higher element of a hierarchy (i.e. sonobuoys, SURTASS, etc.). Submarines were an exception to this generality because of then insurmountable technical barriers (in addition to stealth considerations). This resulted in an operational submarine culture that (among other things) had the Commanding Officer of an on-station submarine lower masts, go deep and clear datum upon copying a message that simply said “Get out of there!” -without asking “Who says? Based on what? I want a second opinion!” In a very real sense, technology has enabled more naval platforms, if they choose, to vastly reduce the quantity of traffic initiated by them while increasing the quality of mutual self-synchronization and coordination. In fact, much of the interoperability could be managed passively through the space-based Global Broadcast System (GBS) a direct analogue to the VLF submarine broadcast.
Quickly connectable on-demand
Before such features as call waiting a clever and articulate father of three teen-agers convinced them, rightfully, that the primary purpose of their home telephone was to permit anyone to contact anyone else at any time. Therefore, any time it was off the hook (i.e. in use), it was not fulfilling its primary purpose. In a similar fashion, being able to be quickly connectable on-demand while at operation-ally meaningful speeds provides the ship the ability to transfer information in a timely manner and (given a bel/ringer as described below) for those not aboard to direct the ship to establish a connec-tivity stance to receive important information.
Persistent passive connectivity
Being quickly co1111ectable for ship-initiated connectivity events is relatively simple. The key to being quickly connectable when such an event is desired by an external entity requires some form of persistent passive connectivity a bel/ringer For decades this was provided for the nation SSBN nuclear deterrent fleet by VLF or ELF transmissions received on either a floating wire or towed buoy. Since there was no need for an on-alert SSBN to be at any speed other than slow, these antennas were typically not designed to be employed or were they effective at transit speeds. Although ELF was also receivable throughout much of an attack submarine operating envelope through non-floating towed wires or on-hull antennas, the decision has been made to shut down the ELF system as a cost-saving measure. Now, if VLF is used as the means for persistent passive connectivity, the receiving antenna has to be placed within several tens offeet below the surface perhaps via a small deployable towed body designed for speeds in the order of 15 or so knots.
Conclusions
The submarine can meaningfully participate in a FORCEnet-like communications manner if adequate consideration is given to the platform unique nature due to the demands/limitations of its operating environment and the cost/benefit tradeoffs associated with exploiting its intrinsic stealth. With its operational agility enhanced through a means by which to be quickly connectable on-demand through persistent passive connectivity, it could be virtually present in any netted conglomeration of entities, and fully connected in near-real time when called upon to do so (accepting the resultant loss of physical agility). However, even given a technical solution (or set of solutions) that significantly improved passive and active connectivity capabilities through a large portion of the submarine operating envelope, there would still remain significant cultural C2 issues to address within the Navy as a whole.
What it is important for the Submarine Force to convey to the rest of the Navy is that, unlike a surface ship, a submarine has many different operating modes during the end-to-end course of a mission deployment. During the transit phase, it is most generally deep and fast. While on station it is typically at periscope depth and slow. When in transition phases, repositioning white on station or when a higher degree of readiness or weapons targetability is desirable as the submarine initially approaches or has just left station at mission end, the ship is likely to be at moderate speeds and moderate non-cavitating depths. What operational commanders then have the right to expect (and for which technology and procedures exist or are readily obtainable) is as follows:
-
Transit phase (25+ kts)
-Periodic passive, periodic active on demand -
Transition phase (-15 kts)
-Persistent passive, readily connectable periodic active on demand -
On-station phase (P/D, -6 or so kts)
-Persistent passive, capable of persistent active
It should be apparent that given an HOR mast, the on-station phase is well covered. Also, in the absence of ELF and placing exotic ocean-wide aco11stically-wired sea bottoms or space/aircraft-based Blue-Green laser systems in a maybe someday category, the transit phase will continue largely in the legacy manner by copying the VLF submarine broadcast a couple of times a day -connecting in an active sense when directed to or when the submarine has something important to say. Where a large improvement in opera-tional agility is likely in the short to mid-range term through the use of expendables or small, persistent tethered VLF antenna bodies, is in the so-called transition phase.
