How The U.S. Can Maintain The Undersea Advantage
By Adm. Jonathan Greenert
Defense One
October 21, 2013

Unrest around the world and budget constraints at home have many Americans concerned about the ability of our military to influence events abroad. It is clearly getting harder to remain preeminent in all “domains” – air, land, maritime, undersea and in the electromagnetic spectrum and cyberspace – as technology and geography combine to challenge our ability to counter threats in key regions around the world. One domain in which our superiority is assumed, however, is under the sea. Yet even this long-standing advantage is not guaranteed. Military and commercial activity under the ocean is rapidly increasing, which could detect or conflict with our forces’ operations or create new threats to our interests. Other nations are fielding increasingly capable and longer-range submarines while companies and scientists are sending unmanned vehicles and sensors throughout the ocean to find everything from fish stocks to oil deposits.
This increased undersea activity can benefit the world economy and environment – but it can also create new dangers. Imagine a scenario in the future where we find ourselves without electronic communication with Europe, Africa and Asia because an adversary cut the fiber optic cables that carry more than $4 trillion a year in international financial transactions. An undersea attack on a tanker or cargo ship coming into Long Beach, California, could shut down operations at our nation’s busiest port and cost our economy an estimated billion dollars a day. Overseas, our warships could come under unprovoked attack from midget submarines or mines while transiting straits or geographically constrained areas. Imagine another scenario like the sinking of the South Korean ship Cheonan by a North Korean submarine in 2010. While events such as these are unlikely, their consequences should give us pause.
For the last half century, submarines have been the centerpiece of our undersea capability. Today our Virginia class attack submarines are the best in the world and among the most economical. The last several Virginia submarines were completed early – the USS Minnesota, commissioned this month, was completed almost a full year early – and on or under budget. Every day, these ships and our guided missile submarines gather intelligence, deploy special operators and stand by to launch cruise missiles, as USS Florida did in support of Operation Odyssey Dawn, in Libya. Our submarines are a tremendous advantage for us because they can do these operations undetected anywhere in the world. Anywhere.
Other countries have seen the advantage submarines provide the United States and are following suit. There are about 150 diesel and air-independent propulsion submarines on order around the world – none of them American – and about a dozen new nuclear submarines under construction outside the United States. Many of these submarines will carry land-attack and anti-ship cruise missiles, advanced torpedoes and mines. Some will carry nuclear weapons.
Maintaining our undersea advantage with a growing number of other military, commercial and scientific players in the mix will require more than submarines. As capable as our Virginia-class subs are, a single submarine can only be in one place at a time. To keep our edge, we will instead have to employ a comprehensive approach to undersea warfare using aircraft, surface ships, submarines, satellites, electromagnetic and cyber capabilities, unmanned vehicles in the air and water, and fixed and portable underwater sensors.
We are fielding this broad portfolio of undersea warfare systems today and will endeavor to keep up the effort despite a tough budget environment. The P-8A Poseidon maritime patrol aircraft, based on the Boeing 737 design, will deploy to the Western Pacific at the end of this year. In international exercises such as “Rim of the Pacific” last summer, the P-8A exceeded all our expectations in its ability to find and track submarines. The P-8A is so good, in fact, that it will be our workhorse for anti-submarine warfare, using its speed and endurance to find and defeat more enemy submarines than any other platform.
As superb as the Poseidon is, a jet aircraft is not the best way to escort ships far from shore on long transits, or to provide close-in defense to carriers and amphibious assault ships. Surface ships remain well-suited for these missions. Our Arleigh Burke destroyers and their embarked MH-60R helicopters carry highly capable towed and dipping sonars and processors that have demonstrated their effectiveness empirically through the last several years of real-world operations. The same proven technology forms the core of the anti-submarine “Mission Module” of the littoral combat ship, or LCS. Our first LCS, the USS Freedome, is currently on deployment in the South China Sea and the first of these anti-submarine mission modules will begin testing next year.
The challenge to exploit our undersea advantage and find threats globally in the coming years is too big a job for only manned submarines, ships and aircraft. There is a finite number of these manned platforms and the number of places where we will have to rely on undersea capabilities is growing as more nations invest in advanced radars, electronic sensors and missiles to threaten anything on or above the water. Also, the growing number and sophistication of other nations’ submarines demands that our anti-submarine warfare systems be able to maintain a continuous and widespread effort to find and defeat undersea threats – including along our own coastlines.
To get that broad, enduring coverage we will complement our manned ships and aircraft with fixed and portable sonar arrays such as the Persistent Littoral Undersea Surveillance, or PLUS. The PLUS successfully completed its first deployment last year – sitting on the ocean floor, listening to undersea contacts and sending its results back home (in real-time) via an unmanned vehicle and satellite link. We are also fielding a whole family of unmanned underwater vehicles including a 20-foot long, 5-foot diameter vessel which can autonomously travel hundreds of miles and operate for weeks to months. Unlike the remote-control vehicles used for ocean exploration or aerial surveillance, this large unmanned vehicle is programmed with its mission before launching from a ship or pier. It is then smart enough to conduct its mission and avoid obstacles (including other ships) along the way. The only time an operator has to intervene is to change the mission or to respond to a fault in the vehicle.
Together, fixed and portable sonars, unmanned vehicles and mobile sensors will form a network to detect threats, especially around critical undersea infrastructure or ships, and direct manned platforms to investigate or respond. A key challenge in this will be to collect all the relevant data from these systems in real time and coordinate their operations with manned platforms. Today we are prototyping systems to communicate with underwater sensors and vehicles using sound or lasers and are fielding a new undersea warfare decision support system to manage the undersea network.
Unimpeded undersea access is a key contributor to our ability to gather intelligence and project power; unmanned vehicles will be part of these missions as well. Our large unmanned vehicles will be able to conduct surveillance or, if armed, conduct attacks far from our shores without being detected and without risking our Sailors. Smaller vehicles also can do these missions, launched from ships or submarines. We will expand the capacity of our next block of Virginia submarines to deploy unmanned vehicles with the Virginia Payload Module, which adds a section of hull with four large (7-ft diameter) payload tubes to the current submarine design. These large payload tubes will also carry missiles and will replace the current missile capacity that will be lost when our current guided missile submarines retire in the next decade.
Unmatched capability in the undersea domain is among our most important military advantages. However, what was once an open territory is becoming the domain of choice for industry, academia and potential adversaries. To retain and exploit our superiority we must sustain our investments in emerging technology and the training that keeps our Sailors proficient. This will remain a priority of our Navy as we address our budget challenges so we can assure access and maintain freedom of the seas.
Adm. Jonathan Greenert is the chief of naval operations and a career submariner.