The Navy and DOD are developing three principal types of lasers for potential use on Navy surface ships—fiber solid state lasers (SSLs), slab SSLs, and free electron lasers (FELs). The Navy’s fiber SSL prototype demonstrator is called the Laser Weapon System (LaWS). Among DOD’s multiple efforts to develop slab SSLs for military use is the Maritime Laser Demonstration (MLD), a prototype laser weapon developed as a rapid demonstration project. The Navy has developed a lower-power FEL prototype and is now developing a prototype with scaled-up power. These lasers differ in terms of their relative merits as potential shipboard weapons.
For purposes of this report, the term “short range” generally refers to ranges of one or two nautical miles, while references to longer ranges or extended ranges refer to ranges of up to about 10 nautical miles. Lasers are one type of directed energy weapon (DEW); other DEWs include microwave weapons and millimeter wave weapons.
* Shipboard lasers could counter surface, air, and ballistic missile targets at a low marginal cost per shot. The shipboard fuel needed to generate the electricity for firing an electrically powered laser would cost less than a dollar per shot (some sources express the cost in pennies per shot). In contrast, the Navy’s short-range air-defense interceptor missiles cost roughly $800,000 to $1.4 million each, and its longer-range air- and missile defense interceptor missiles cost several million dollars each
* Deep magazine. Navy surface ships can carry finite numbers of interceptor
missiles in their missile launch tubes. In contrast, an electrically powered laser can be fired again and again, as long as the ship has fuel to generate electricity (and sufficient cooling capacity to remove waste heat from the laser).
* Fast engagement times.
* Line of sight.
Required Laser Power Levels for Countering Targets
A laser’s ability to disable a target depends in large part on the power and beam quality of its light beam. The power of the light beam is measured in kilowatts (kW) or megawatts (MW). Beam quality (BQ) is a measure of how well focused the beam is.
• atmospheric absorption, scattering, and turbulence,
• jitter—the degree to which the spot of laser light jumps around on the surface of the target due to vibration or other movement of the laser system, and
• target design features, which can affect a target’s susceptibility to laser damage.
The following conclusions might be drawn from the table regarding approximate laser power levels needed to affect certain targets:
• Lasers with a power level of about 10 kW might be able to counter some UAVs at short range, particularly “soft” UAVs (i.e., those with design features that make them particularly susceptible to laser damage).
• Lasers with power levels in the tens of kilowatts could have more capability for countering UAVs, and could counter at least some small boats as well.
• Lasers with a power level of about 100 kW would have a greater ability for countering UAVs and small boats, as well as some capability for countering rockets, artillery, and mortars.
• Lasers with power levels in the hundreds of kilowatts could have greater ability for countering targets mentioned above, and could also counter manned aircraft and some missiles.
• Lasers with power levels in the megawatts could have greater ability for countering targets mentioned above—including supersonic ASCMs and ballistic missiles—at ranges of up to about 10 nautical miles
In addition to the points above, one Navy briefing stated that lasers with power levels above 300 kW could permit a ship to defend not only itself, but other ships in the area as well (a capability referred to as area defense or escort operations or battle group operations).
Navy Surface Fleet’s Generalized Vision for Shipboard Lasers
This generalized vision can be summarized as follows (text based on a
Navy briefing slide):
• potential IOC around FY2017;
• Extended-range operations against targets such as EO sensors, small boats, UAVs, RAM, and MANPADs, as well as ASCMs that are flying on a crossing path (rather than at the ship);
Navy After Next—FEL:
• Self-defense operations against transonic and supersonic/highly maneuverable anti-ship missiles, and ballistic missiles.