The US is about to revolutionize naval combat

"Powder guns have been matured to the point where you are going to get the most out of them. Railguns are just beginning," Tom Boucher, the railgun program manager for Office of Naval Research, said to AFP.

There are two problems with the Navy's current onboard missile defenses.

Firstly, traditional naval missile defenses rely on ammunition. So no matter how effective surface-to-air missiles (SAMs) or close-in-weapons systems (CIWS) are, they have a finite amount of rounds that can be depleted.

Secondly, "Navy SAMs range from about $900,000 per missile to several million dollars per missile, depending on the type."

Since SAMs protect the lives of US Navy sailors, these costs are acceptable, but still unsustainable throughout a prolonged conflict. Simply put, the missiles and rounds used to defend navy ships hugely tax an already strained defense budget.

Source: Congressional Research Service

Solid State Lasers, (SSLs) spectacularly overcome the limitations of traditional defenses, while introducing a few limitations of their own.

Right now, naval planners are developing SSLs to provide defense against small boats and UAVs within the range of one to a few miles, "and potentially in the future for countering ASCMs and ASBMs as well."

The laser system offers brilliant advantages over traditional rounds both in depth of magazine and cost per shot.

An SSL can fire continuously until the ship supporting it runs out of fuel to generate electricity, which would take a long, long time. Additionally, the cost of firing an SSL is comparable to running a heavy duty appliance. The Navy cites the cost per shot of an SSL at around $1 per.

But SSLs rely on line of sight, and are therefore not all-weather weapons. Clouds, rain squalls, even particles in the atmosphere can sap effectiveness from the laser system. Additionally, it poses a threat to human targets, as it could blind them, and blinding weapons are prohibited by the Geneva convention.

Source: Congressional Research Service

The EMRG uses magnetic fields created by extremely high electrical currents to "accelerate a sliding metal conductor, or armature, between two rails to launch projectiles at [speeds of] 4,500 mph to 5,600 mph,” 30 or roughly Mach 5.9 to Mach 7.4."

The projectile, traveling at a mind-boggling 1.5 miles per second, rips through the atmosphere with such speed that the atmosphere around it, as well as the tungsten of the projectile itself, erupt into an awesome fireball despite the fact that no explosives are used.

With a range of up to 100 miles (in just a few seconds) the EMRG can take out distant targets as well as incoming threats.

Unlike the SSL, the EMRG fires physical rounds, and therefore has a much more limited magazine depth. However, the cost per shot of the inert rounds is a very small fraction of what today's guided missiles cost.

Source: Congressional Research Service

In developing the revolutionary EMRG, the Navy realized they needed an equally revolutionary projectile— enter the HVP, a streamlined, percision guided round.

Though it was designed for railguns, the aerodynamic design of the HVP lends itself to other, existing applications. For instance, when fired out of the Navy's 5 inch or 155 mm guns, the HVP reaches speeds of around Mach 3— about twice as fast as a normal round, but about half as fast as the EMRG fires it.

The HVP has GPS coordinates entered into it, and once fired, the fins on the rear of the round guide the projectile towards it's target in any weather conditions.

HVPs are much more expensive than the normal rounds a Navy gun fires, but their speed means they can intercept missiles, which makes them a much cheaper alternative to guided missiles. Plus, as they are backwards-compatible with existing Navy platforms, HVPs could be deployed tomorrow if need be.

Source: Congressional Research Service

This graphic shows how the US Navy can leverage HVPs and EMRGs to maintain their asymmetrical advantage over rising powers for years to come, without relying on million-dollar missiles.

Source: Congressional Research Service