Tango Bravo, Future Attack Submarine, Improved Virginia, SSN(X), New SSN: these are the different avatars since 2004 of the idea that the United States Navy (USN) has successively had of the Nuclear Attack Submarine (SNA Or Ship Submersible Nuclear (SSN) which will succeed the last Virginia in American shipyards. As the years go by, the US Navy no longer wishes to extend the series of Virginia-class SSNs but to begin a new series of this type of boat which would include the replacement of the Virginia-class SSNs. Seawolf. This future program is based on a great promise: designing the world's best SSN for the 21st century.
The beginnings: Tango Bravo (2004 - 2009)
The affair really began with a first research program carried out jointly by DARPA (Defense Advanced Research Projects Agency) and the US Navy which ended in May 2004. Its results were to be continued by 79,3 million additional expenditures. between 2004 and 2009 as part of a new program: Tango Bravo, that is to say the initials of Technological Barriers.
This research was used to prepare technological choices for the design of a new nuclear submarine equipped with all the operational capabilities of a Virginia-class SSN (115 meters in length) in a hull. half as long (~ 70 meters) and therefore half as expensive. These efforts were aimed at an annual order of two SSNs for the cost of a single Virginia. The simultaneous laying down of two SSNs has not been carried out since 1992.
Several areas of research were explored by DARPA in the Tango Bravo project:
- propulsion concepts without shaft line,
- weapon storage outside the durable hull,
- alternatives to spherical and flank sonar such as, for example, an array of conformal sonar antennas,
- technologies reducing or simplifying electrical, mechanical and electrical systems,
- automation technologies to reduce crew workload.
At the launch of the program in May 2005, DARPA retained only three of these areas: shaftless propulsion, storage of tactical weapons outside the hull resistant and the rationalization of networks for the benefit of electric actuators instead of hydraulic and pneumatic systems. Northrop Grumann had been working on these issues since 2005 and even won the Tango Bravo contract in 2007. Communication was silent regarding the follow-up given to this program, the schedule of which extended until 2009.
Between 2007 and 2012, another solution was found in order to successfully order two SSNs for each fiscal year: increase the budget dedicated to these orders and increase the volume of orders up to four, then ten submarines in order to optimize the industrial tool, give it a long-term vision and therefore obtain economies of scale.
Improved Virginia (2012 - 2018)
The search resumed in 2012 from another angle: finding a successor to the Virginias. This is the role of the project Future Attack Submarine. It had to be based on the architecture of the Virginia program which is divided into five “blocks”. Each of them incorporates more or less significant developments in order to build boats at the best cost and keep them up to date.evolution of underwater technologies. This is why the Future Attack Submarine was quickly becoming theImproved Virginia in order to save on the development of the study of an entirely new submarine.
THEImproved Virginia was to succeed the Virginia Block V in the holds through a first order in 2025, ultimately postponed to 2033 with a view to being laid down in 2038. 13 Improved Virginia were planned. The construction rate was to be one or two SSNs laid down each year until 2042. These submarines could have integrated certain significant developments targeted by the Tango Bravo program. Enjoy the full performance of technological breakthroughs of the Tango Bravo program required the design of a new SSN rather than adding “blocks” to the Virginia program. This amounted to postponing the SSN from “complete rupture” to the end of production of Improved Virginia, that is to say in 2042.
On the strategic level, the US Navy preferred in 2012 accelerate the production rate of the Virginia program thanks to the annual order of two SSNs. It was not until 2018 that, for the first time since 1992, two SSNs were laid down simultaneously. And the pace will continue until the 2030s.
Preliminary studies of the program to enable the replacement of SSBNs (Ship Submersible Ballistic Nuclear (SSBN) or Ohio-class nuclear ballistic missile submarine (SSBN) reach the limits of what is possible in terms of reducing the acoustic signature with current technologies (understand the system allowing the turbines propulsion to transmit the power to a shaft line driving the propeller). The integration of a magnet electric motor permanent on the Columbia-class SSBN(X) is one of the last possibilities for improving the existing propulsion system.
SSN(X) or New SSN (2018 – 2024?)
Between 2012 and 2018, several factors explained the passage ofImproved Virginia at SSN(X):
The increase inChinese underwater activity as far as the Atlantic and Russian Oceans led part of the American naval establishment to revise strategic priorities. The future SSN(X) will no longer have as a horizon coastal action, the raison d'être of the Virginias, but rather theaction on the high seas (submarine hunting, destruction of naval groups).
These underwater activities were put into perspective by some who were told that Russian submarines served as “ mother ships » (pocket submarines and remotely operated robots) for clandestine underwater operations should not be neglected. The American admiralty would still have been favorably impressed with the new SSGN (Ship Submersible Guided Nuclear) Russian from project 885 Yasen/Yasen-M.
And in the Chinese case, the appearance of a large-scale infrastructure in the Bohai shipyards (CSIC) suggests a change of gear in terms of underwater construction, more particularly for nuclear-powered boats.
The evolution of the international context towards a return to competition between great powers and an increase in probability of symmetrical conflicts and high intensity forces the Navy to revise its plans. The existence of the torpedo with a long autonomy and carrying a charge of the order of megatons called Status-6 Kanyon is cited as one of the threats to be taken into account.
Back to the Seawolf concept
If the need to design a new class of SSN for this threat is debatable, this raises the question of the use of American SSNs for the hunt for SSBNs other strategic competitors. This mission is not mentioned but would amply justify financial efforts in a general strategic framework where the United States has withdrawn from two major treaties (ABM (2002), INF (2019) in order to call into question strategic parity with the Russia and free itself from commitments considered to be obstacles towards China. Claiming to be able to reduce or even annihilate the second strike capacity of these countries could participate in this maneuver.
In the context of institutional communication, the SSN(X) is then logically compared with the Seawolf class the design of which began in 1983. The program aimed at a submarine entirely designed for operations on the high seas and endowed with superiority over all its rivals, in particular Soviet ones. The program target provided for 30 then 12 SSNs for $33 billion ($2,75 million/SSN). But the end of the East-West conflict (1947 – 1991) revises this target to only 3 SSNs, the unit cost of which adjusted in 2018 by the Congressional Budget Office to 5,5 billion dollars (or 4,82 billion euros (2018 ).
This first comparison makes it possible to establish and legitimize the future financial effort that will be required because it is in line with the intrinsic ambitions of the Seawolf program: the SSN(X) program takes up the same rationales and will therefore be much more expensive than the 1810 million euros necessary for the acquisition of a Virginia Block IV. This will raise the question of how many SSN(X) can be ordered each year as each of them will likely represent the cost of more than two Virginia. But the 2030s will see the United States become accustomed to the simultaneous laying down of a Columbia (7000 million) and two Virginias (~ 3620 million euros).
The second comparison concerns nautical and operational characteristics. It is a future SSN capable of operating at a immersion depth beyond 350 to 500 meters who is wanted. The Seawolf dives to more than 610 meters, the Russian Yasen/Yasen-M (project 885) are known to dive as deep. And the tactical weapons on board will have to be able to intercept the Status-6 Kanyon which would dive up to 950 to 1000 meters of immersion. Is the American Navy refraining from considering such immersions?
The third favorable comparison helps justify the target of the SSN(X) program: there were to be 30 Seawolf-class SSNs, there will be 30 SSN(X)The 38 Virginias now planned are few compared to the 62 Los Angeles-class SSNs that preceded the Seawolves.
In addition to comparisons with the predecessors of the Seawolf class, the US Navy specified in 2018 the objectives of the SSN(X) program: faster, stealthier and capable of carrying more torpedoes than the Virginia class. The Virginias can operate at up to 32 knots, and are certainly among the quietest submarines in the world. The only ones who compare are Americans, British and Russians. And the tactical weapons bay of a Virginia already accommodates 37 weapons. The US Navy raises the target to 62 weapons on the SSN(X).
The program schedule would aim for decision to be made in 2023, 2024 at the latest. This would correspond to the start of the various studies with a view to first order in 2033, 2034 at the latest upon completion of the last Virginia (Block VII?).
Towards a technological paradigm shift
It appears that the US Navy is ready for a paradigm shift in the technologies used for the design and construction of nuclear submarines. Part of the areas of development, or even technological breakthroughs, explored by the Tango Bravo program would be retained within the framework of the SSN(X) program. Hence, also, the preparation for the importance of the necessary expenses, particularly for studies.
From a propulsion point of view, the SSBN(X) would be the last class of submarines featuring a tree line. The SSN(X) would no longer feature rotating mechanical systems. Only turbo-generators would allow the transformation of the steam supplied by the nuclear reactor into mechanical energy transformed into electricity transmitted to the electric motor which would directly operate the thruster. It would even be considered that this electric propulsion motor would be placed outside of the resistant hull. Biomimetic propulsion is even mentioned. This would allow reduce by a third the length of the future building compared to a Virginia.
62 Tactical weapons by submersible
The operational characteristics aim, first of all, at the embarkation of 62 tactical weapons, that is 25 more than on board the Virginia, 12 more than on board the Seawolf. The number of torpedo tubes would be increased compared to the Virginia (IV x 550 mm) and the Seawolf (VIII x 660 mm). The storage of these tactical weapons outside the resistant hull suggests a certain number of torpedo tubes powered by automatons via storage units or a very large number of launching devices for these same weapons.
The US Navy also mentions for its future operational characteristics the ability to interact with a drone network whether deployed from the edge of the SSN(X) or by other platforms, air and naval. The US Navy reportedly demonstrated at RIMPAC 2018 the ability of a Virginia to support extended tactical watch above and below the surface (via communications provided by laser or radio waves received via a buoy?). The main advantage of these capabilities is to allow the SSN(X) to be able to fire very long-range torpedoes, that is to say having a range of around 220 to 230 km. THE remote sensors would allow discreet firing and a network of drones would guide the weapon to its target.
But the American Navy also mentions the possible ability to fire hypersonic weapons. From this perspective, how can we launch such weapons and drones? The existing "standard" in the US Navy is the missile launch tube which equips the recast Ohio, the Virginia, the Columbia class SSBN(X) and the SSGN(X) which will be derived from it. Without a vertical launch system on board the SSN(X), the US Navy will have to develop an additional method of launching these weapons and charges. Will this be done through torpedo tubes? Launchers dedicated to each load and embarked punctually according to the mission?
Conclusion
The importance of this paradigm shift is measured, to the point that questions arise on the relevance of launching the SSN(X) in one go, without any intermediate step. It was the strength ofImproved Virginia to be built on the Block VI and VII of the Virginia class in order, once again, to incrementally incorporate developments that would eventually become breakthroughs and to smooth out the effort over time. It goes without saying that the Virginia benefits from the efforts produced for the benefit of the Seawolves and, in a way, the Virginias are a reduced version of the latter. technological disappointments of the Littoral Combat Ship (LCS) and DDG-1000 programs of the Zumwalt class or the serious difficulties of the CVN-78 aircraft carrier program Gerald R. Ford invite a certain caution.
The US Navy no longer maintains a prototype policy. But it has been able, in the past, to launch unique submarines intended to make it possible to explore new technological avenues in preparation for a major program with a target of several dozen units. The SSN(X) and its technological breakthroughs could require revision.