SSGN(X) Large Payload Submarine

A new large payload submarine (LPS) class is to be launched, replacing the decommissioned Ohio-class ships that have been converted from ballistic missile carriers to floating tomahawk arsenals. This move will increase the level of the US Navy's ability to perform massive strikes at distant targets.

An SSGN can support battle group surface ships that are geographically constrained, due to the requirement of maintaining a prescribed number of TLAMs within a given area of operation. Consider that when an SSGN arrives on station, carrying at least 154 missiles, those surface assets would be less restricted in their distribution across the battlespace, offering them the ability to perform other missions.

The 18 Ohio-class SSBN and SSGN currently in service will be decommissioned from 2026. The 12 Columbia-class next-generation SSBNs are under continuous development, and they are scheduled to enter military service from 2031 to 2042. The Columbia-class SSGN derivative (Large Payload Submarine) project continues to be promoted. The initial plan is to enter the military service stage from 2043, and to complete the active service of 5 ships in 2049.

The October 9, 2019 Congressional Budget Office report, "An Analysis of the Navy’s Fiscal Year 2020 Shipbuilding Plan" examined this program. Like the Navy's 2019 plan, the 2020 plan [Department of the Navy, Report to Congress on the Annual Long-Range Plan for Construction of Naval Vessels for Fiscal Year 2020 (March 2019)] includes a submarine that would be similar to an SSGN but would be a “large-diameter, nextgeneration payload-based submarine.” The ship would perform missions similar to those currently conducted by SSGNs and, in the future, by Virginia class ships with the Virginia payload module (VPM), as well as other missions. The first ship would be ordered in 2036, after production of the Columbia class ceased; thereafter, the Navy would purchase 1 ship every three years, for a total of 5 by 2049. The 2020 plan did not indicate the fnal inventory objective for these ships. The Navy’s plan provided little information about the size and capabilities of the large payload submarine.

CBO’s estimates refect the assumption that it would be based on the Columbia class hull with its missile tube section reconfgured to perform whatever missions the Navy might want and that other sections of the ship would receive the necessary equipment and modifcations to support the payloads the submarine might carry. The Navy estimates that the cost of the 5 ships in the plan would average $7.1 billion per ship; CBO estimates that they would cost $7.8 billion per ship.

The continuing interest in the SSGN concept by transformation advocates stemmed from the SSGN's transformational features. First, the SSGN's stealth would be advantageous to survival in the crowded near shore waters where the Navy expected to operate in the 21st century. The SSGN would be able to operate covertly near enemy coasts undetected for weeks or months, if necessary. Second, its speed, mobility, and range combined with large, flexible payloads would enable it to respond to a variety of developing world events. Third, because submarines do not require extensive logistics support to operate forwardly they would not be dependent on vulnerable forward bases or surface assets.

Fourth, the SSGN's precision- guided Tomahawk missiles would reach distant targets about 1,000 miles away, providing extensive strike capability into areas denied other US forces. Furthermore, it would have the potential to carry follow- on weapons such as unmanned aerial and undersea vehicles, improved communications and other new technologies to counter emerging threats. Fifth, the Navy has made a concept known as network centric warfare the centerpiece of its efforts to transform its forces. With its improved communications, large antennas for sharing data and the ability to network with other naval and joint warfighting elements the SSGN would further contribute to the Navy's vision for network centric warfare. Sixth, the SSGNs combination of stealth, intelligence gathering, and special operations capability would enable it to conduct its own unique forms of information warfare. And finally, war games and experimentation with the SSGN show its potential for using a mix of shortreaction strike weapons and enhanced intelligence collection capabilities to counter the challenge of mobile targets.

SSGNs would have an advantage in that they could fire all their Tomahawk missiles in one salvo or launch operation. According to Navy officials, doing so can preserve the element of surprise, eliminate the opportunity for the targets to move, and allow a vessel to rapidly attack multiple targets. A maximum strike configured SSGN operating with a carrier battle group would still provide about 44 percent of the total Tomahawk missiles available at the beginning of the conflict.

The crews would be rotated during the middle of planned deployments and, on average, would allow the SSGNs to accrue more presence days. Having rotating crews allows the ship to be at sea about 70% of the year – an operational status that was (and continues to be) a requirement for the mission of nuclear deterrence. This is not new – the OHIO-class SSBNs were designed to support a high operational status from the beginning...they were tailor-made for this purpose. This ability to remain on station for extended periods fits in neatly with the vision of the SSGN mission, keeping a massive strike capability within range of the conflict for as long as necessary.

The SSGN would normally carry 66 special operations forces personnel for about 90 days and could surge to 100 for short periods of time, if needed. The SSGNs extended endurance would allow them to conduct multiple special operations forces missions. The dry deck shelter is a large steel structure attached to the outside of specially configured submarines. It can be used to transport and launch a SEAL Delivery Vehicle or to lockout special operations forces personnel. The SEAL Delivery Vehicle is a small, wet, battery- powered submarine that is stowed in, and launched from the dry deck shelter. It operates in shallow waters near the coastline. The SEAL Delivery Vehicle is termed a wet submarine since the interior, containing the crew and cargo, is fully flooded during submerged operations. Crew and passengers wear scuba gear or use the SEAL Delivery Vehicle?s auxiliary life support system during transit.