It needs space, weight, power and cooling which can be a challenge on our current surface combatants. The engineering center of gravity of the engineering behind shipboard lasers is captured by that line, which, in an CRS collection, has been credited to Rear Adm. Fred Pyle: the beam was just the tip of a rather large onboard energy and thermal system.
Shipboard lasers have frequently been talked about as though they were just yet another weapon in a mount. Practically, however, the challenge is to cause a warship to act as a stable power plant and a heat sink at the same time as it is operating high-demand sensors, combat systems, hotel loads, and other auxiliaries to do with propulsion. Paper, lasers offer deep magazines since they require electricity generation as opposed to stocked munitions; the report by CRS indicates that the marginal cost of lasers is approximately $1 to less than 10 per shot of electricity generated by fuel. However, in a destroyer, the limiting reagent is often not the fuel tank-it is electrical headroom and thermal headroom at the point when the combat system may wish to have it all.
Such a strain is evident in the initial operational route through directed energy in the Navy. The Mk 5 Mod 0 HELIOS is a 60 kilowatt-size solid-state laser targeting drones, small craft, and some missiles; with a modular architecture that can be scaled to higher power levels. ELIOS is connected to the combat system of a ship, unlike bolt-on dazzlers, its firing solution and sensor image are coordinated with radar tracks and other engagements. The operationally appeal of that kind of integration is that, and there the power-and-cooling argument ceases being merely theoretical, since even the electronics that demand most of all the power in the ship must be packaged there as well, on the same constraints.
In the case of the Arleigh Burke community, those limits become even more acute, with the fleet moving to newer versions. Flight III destroyers feature significant sensor improvements, especially AN/SPY-6, and the generators used by the ship service become different, with three 4,000 kW units being listed in Flight III. Excessive generation is assistive, though it does not provide infinite margin; additional sensors and computer processing also turn electricity into heat, which needs to be carried out of equipment areas, via chilled-water circuits and air conditioning systems, and finally abandoned to the sea. Even the radar modernization program is indicative of this fact: DDG modernizations associated with SPY-6 retrofit are accompanied by direct cooling enhancements, a lesson that the performance limit of the combat system is frequently thermal in nature as well as software-driven.
The Navy has been very open on the trade space. CRS quotes reporting related to HELIOS integration planning, in which Rear Adm. Ron Boxall is quoted in no uncertain terms: The Navy will be required to either cut something or consider very aggressive power management. In a ship, power management is not a buzzword, a posture that is operational. It could refer to upgrading loads, elimination of unnecessary systems, scheduling of high-energy, and making sure that thermal transients do not propagate into degraded radar performance or decreasing availability of mission-important electronics.
Cooling, in its turn, is not a supportive operation per se-it is laser endurance. Solid-state lasers are not as efficient as older architectures, and still dissipate a significant fraction of input power in heat in laser modules, beam control, power conditioning and the rest of the combat-system integration stack. In cases where the laser is shot at a series of intervals, the question of engineering consideration is how fast this heat can be carried off without overloading the chilled water capacity or pushing temperatures to their limit causing throttling. In that frame, more kilowatts cannot possibly be separated off more heat, and enduring engagement becomes systemwide thermal and with tactical implications.
This is the reason why the following laser breakthrough at sea seems more of a ship-design story than of a weapons story. The concepts of the Navy future large surface combatants are based on added SWAP-C margin and integrated power systems specifically due to the directed energy and next-generation sensors being like variable high-amplitude electrical loads that can be absorbed without destabilizing the platform. It might be the beam that is being photographed but the actual battle is inside the hull: maintaining the flow of the electrons and the heat.
