The SSN(X) Program: A New Generation of U.S. Navy Attack Submarines

The United States Navy is planning to develop a new class of nuclear-powered attack submarines, known as the SSN (X) program, to replace its current Virginia -class and Seawolf -class submarines. The SSN (X) program is expected to incorporate advanced technologies and capabilities to ensure that the new submarines will be able to meet the evolving challenges of the modern maritime environment. In this blog post, I will provide an overview of the SSN (X) program, its objectives, its design options, and its projected schedule.

What is the SSN(X) Program?

The SSN (X) program, also known as the Next-Generation Attack Submarine program, is a United States Navy program to develop a class of nuclear attack submarines to succeed its Virginia -class and Seawolf -class attack submarines. The SSN (X) program is still in the early stages of development and no official details have been released about its design or capabilities. However, it is believed that the SSN (X) program will focus on improving stealth, sensor capabilities, and firepower to enable the new submarines to operate effectively in a variety of missions, including intelligence gathering, special operations, and anti-submarine warfare. Along with the Columbia -class ballistic missile submarine, the SSN (X) program is seen as a critical component of the Navy’s future submarine force and is expected to play a key role in maintaining the United States’ naval superiority in the coming decades.

Why Does the Navy Need the SSN(X) Program?

The Navy’s current fleet of attack submarines consists of 66 Virginia -class and three Seawolf -class submarines. The Virginia -class submarines, which entered service in 2004, are designed to be versatile and adaptable to a wide range of missions, such as land attack, anti-ship, anti-submarine, and covert operations. The Seawolf -class submarines, which entered service in 1997, are designed to be faster, quieter, and more heavily armed than the Virginia -class submarines, but are also more expensive and less numerous. The Navy plans to procure a total of 66 Virginia -class submarines, with the last one scheduled for delivery in 2043.

However, the Navy faces several challenges and threats that may require a new generation of attack submarines. These include:

• The aging and retirement of the Los Angeles -class submarines, which currently make up the majority of the Navy’s attack submarine fleet. The Los Angeles -class submarines, which entered service in 1976, are expected to reach the end of their service lives by the late 2020s and early 2030s, reducing the Navy’s attack submarine force to below its current requirement of 66 boats.
• The emergence of new and advanced submarine technologies and capabilities by potential adversaries, such as China and Russia. These include quieter and more lethal submarines, unmanned underwater vehicles (UUVs), and anti-submarine weapons and sensors. These pose a significant challenge to the Navy’s ability to maintain its undersea dominance and superiority.
• The increasing demand for attack submarine presence and operations in various regions and scenarios, such as the Indo-Pacific, the Arctic, and the littorals. These require the Navy to deploy more submarines with greater endurance, speed, and stealth to support the joint force and the allies.

To address these challenges and threats, the Navy initiated the SSN (X) program to develop a new class of attack submarines that will be better optimized and designed to combat future surface and underwater threats, taking advantage of the latest silencing, propulsion, and combat submarine technologies.

What are the Design Options for the SSN(X) Program?

The Navy is examining three broad design options for the SSN (X) program — a design based on the Virginia -class SSN design, a design based on the Columbia -class SSBN design, and a brand new design. Each design option has its own advantages and disadvantages, and the Navy will have to balance various factors, such as cost, performance, risk, and schedule, to determine the optimal design for the SSN (X) program.

• A design based on the Virginia -class SSN design would leverage the existing design and production infrastructure of the Virginia -class submarines, which could reduce the cost and risk of the SSN (X) program. However, a design based on the Virginia -class SSN design would also inherit the limitations and constraints of the Virginia -class submarines, such as the hull diameter, the propulsion system, and the weapon capacity. These could limit the potential improvements and innovations that the SSN (X) program could achieve.
• A design based on the Columbia -class SSBN design would take advantage of the larger hull diameter and the electric drive propulsion system of the Columbia -class submarines, which could provide more space and power for the SSN (X) program. This could enable the SSN (X) program to incorporate more advanced and diverse capabilities, such as larger weapons, more sensors, and more UUVs. However, a design based on the Columbia -class SSBN design would also entail higher cost and complexity, as well as potential interference with the Columbia -class submarine production schedule, which is a top priority for the Navy.
• A brand new design would allow the Navy to explore new and innovative concepts and technologies for the SSN (X) program, such as a new hull shape, a new propulsion system, and a new combat system. This could result in a breakthrough design that would significantly enhance the performance and capabilities of the SSN (X) program. However, a brand new design would also involve higher cost and risk, as well as longer development and testing time, which could delay the delivery and deployment of the SSN (X) program.

What is the Projected Schedule for the SSN(X) Program?

The Navy’s projected schedule for the SSN (X) program is still uncertain and subject to change, depending on the availability of funding, the progress of research and development, and the outcome of the design selection. According to the Navy’s FY2020 30-year shipbuilding plan, the first SSN (X) would be procured in FY2031, along with a single Virginia -class boat. In FY2032 and FY2033, the final four Virginia -class boats would be procured, at a rate of two per year. Procurement of follow-on SSN (X)s, at a rate of two per year, would then begin in FY2034. The 30-year plan’s sustained procurement rate of two SSNs per year would achieve a force of 66 SSNs — the Navy’s current SSN force-level goal — in FY2048.

However, a subsequent 30-year Navy shipbuilding document that the Trump Administration released on December 9, 2020 — a document that can be viewed as the Trump Administration’s final published vision for future Navy force structure and/or a draft version of the FY2022 30-year shipbuilding plan — proposed a new SSN force-level goal of 72 to 78 boats. To meet this goal by the latter 2040s, it projected an SSN procurement rate of three boats per year during the period FY2035-FY2041, and two and two-thirds boats per year (in annual quantities of 2–3–3) during the period FY2042-FY2050.

The Navy’s budget request for Fiscal Year 2022 included $98.0 million to continue research and development for the SSN (X) program, including $29.8 million for general class development and $68.1 million for developing its nuclear propulsion. The related budget lines (0603570N and 0604850N) were included unchanged in the FY 2022 National Defense Authorization Act signed into law by President Joe Biden in December 2021. The Navy’s FY2023 budget requests included $237.0 million, including $143.9 million for general class development and $93.1 million for its nuclear propulsion. As in 2021, the requested budget lines were included unchanged in the FY 2023 NDAA signed into law by President Biden in December 2022.

The Navy expects to complete the analysis of alternatives for the SSN (X) program by 2024 and to select a preferred design option by 2025. The Navy also plans to conduct a technology readiness assessment for the SSN (X) program by 2026 and to start the engineering and manufacturing development phase by 2027. The Navy anticipates that the lead ship of the SSN (X) program will be delivered in 2043 and will enter service in 2044.

Conclusion

The SSN (X) program is a major and ambitious undertaking by the United States Navy to develop a new class of nuclear-powered attack submarines that will be able to counter the emerging and future threats and challenges in the undersea domain. The SSN (X) program will require significant investments in research and development, as well as careful trade-offs and decisions on the design and capabilities of the new submarines. The SSN (X) program will also have a significant impact on the Navy’s force structure, budget, and industrial base. The SSN (X) program is expected to be a key element of the Navy’s future submarine force and a vital asset for the national security and interests of the United States.