Navy Lasers, Railgun, and Hypervelocity Projectile: Background and Issues for Congress

Three potential new weapons could improve the ability of Navy surface ships to defend themselves against enemy missiles — solid state lasers (SSLs), the electromagnetic railgun (EMRG), and the hypervelocity projectile (HVP).

Laser Weapon System (LaWS) on USS Ponce (Source: U.S. Navy)

Although Navy surface ships have a number of means for defending themselves against anti-ship cruise missiles (ASCMs) and anti-ship ballistic missiles (ASBMs), some observers are concerned about the survivability of Navy surface ships in potential combat situations against adversaries, such as China, that are armed with advanced ASCMs and ASBMs. Concern about this issue has led some observers to conclude that the Navy’s surface fleet in coming years might need to avoid operating in waters that are within range of these weapons, or that the Navy might need to move toward a different fleet architecture that relies less on larger surface ships and more on smaller surface ships and submarines. Such changes in Navy operating areas and fleet architecture could substantially affect U.S. military strategy and the composition of the Navy’s shipbuilding expenditures.

Navy surface fleet leaders in early 2015 announced a new organizing concept for the Navy’s surface fleet called distributed lethality. Under distributed lethality, offensive weapons such as ASCMs are to be distributed more widely across all types of Navy surface ships, and new operational concepts for Navy surface ship formations are to be implemented. The aim of distributed lethality is to boost the surface fleet’s capability for attacking enemy ships and make it less possible for an enemy to cripple the U.S. fleet by concentrating its attacks on a few very-high-value Navy surface ships (particularly the Navy’s aircraft carriers). Perspectives on whether it would be cost effective to spend money spreading offensive weapons across a wider array of Navy surface ships might be influenced by views on whether those surface ships can adequately defend themselves against enemy missiles.

Two key limitations that Navy surface ships currently have in defending themselves against ASCMs and ASBMs are limited depth of magazine and unfavorable cost exchange ratios. Limited depth of magazine refers to the fact that Navy surface ships can use surface-to-air missiles (SAMs) and their Close-in Weapon System (CIWS) Gatling guns to shoot down only a certain number of enemy unmanned aerial vehicles (UAVs) and anti-ship missiles before running out of SAMs and CIWS ammunition—a situation (sometimes called “going Winchester”), that can require a ship to withdraw from battle, spend time travelling to a safe reloading location (which can be hundreds of miles away), and then spend more time traveling back to the battle area.

Unfavorable cost exchange ratios refer to the fact that a SAM used to shoot down a UAV or anti-ship missile can cost the Navy more (perhaps much more) to procure than it cost the adversary to build or acquire the UAV or anti-ship missile. In the FY2016 defense budget, procurement costs for Navy SAMs ranged from about $900,000 per missile to several million dollars per missile, depending on the type.

In combat scenarios against an adversary with a limited number of UAVs and anti-ship missiles, an unfavorable cost exchange ratio can be acceptable because it saves the lives of Navy sailors and prevents very expensive damage to Navy ships. But in combat scenarios (or an ongoing military capabilities competition) against a country such as China that has many UAVs and anti-ship missiles and a capacity for building or acquiring many more, an unfavorable cost exchange ratio can become a very expensive—and potentially unaffordable—approach to defending Navy surface ships against UAVs and anti-ship missiles, particularly in a context of constraints on U.S. defense spending and competing demands for finite U.S. defense funds.

SSLs, EMRG, and HVP offer a potential for dramatically improving depth of magazine and the cost exchange ratio:

  • Depth of magazine. SSLs are electrically powered, drawing their power from the ship’s overall electrical supply, and can be fired over and over, indefinitely, as long as the SSL continues to work and the ship has fuel to generate electricity. The EMRG’s projectile and the HVP (which are one and the same) can be stored by the hundreds in a Navy surface ship’s weapon magazine.

  • Cost exchange ratio. An SSL can be fired for a marginal cost of less than one dollar per shot (which is the cost of the fuel needed to generate the electricity used in the shot), while the EMRG’s projectile/HVP has an estimated unit procurement cost of about $25,000.

This work was performed by Ronald O’Rourke for the Congressional Research Service. For more information, download the Technical Support Package (free white paper) at under the Optics, Photonics & Lasers category. CRS-0001

This Brief includes a Technical Support Package (TSP).
Navy Lasers, Railgun, and Hypervelocity Projectile: Background and Issues for Congress

(reference CRS-0001) is currently available for download from the TSP library.

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