How does a projectile get past a rapid-firing, hyper-accurate point defense system?

Question

Let's say that there's a point-defense system that's very good at hitting targets - as a matter of fact, it hits everything it shoots at. Moreover, it fires incredibly quickly and has, for the scope of this question, infinite ammunition (it's a directed-energy weapon powered by a high-yield power source); even if it didn't somehow hit everything it shoots at, it could afford to try again in a split second.

Therefore, attempting to dodge it is impossible, and "spamming" it - attempting to fake it out with a massive horde of decoy projectiles - is impossible.

Each individual hit from the directed-energy weapon has a maximum yield of 50 kilowatts, and it can fire such a shot ten times per second.

What would the design features of a projectile that can get past this point defense system be?

Answer 1

In the absence of any other further description a 50 kilowatt energy weapon is actually not very powerful. Probably just enough to destroy standard artillery shells and/or disable missiles at ranges of a couple of kilometers.

That being the case you have a number of options;

You can use larger/more well armored shells, perhaps even just high velocity armor piecing sabot rounds for example made from appropriately dense metals or metal/ceramic composites that are partially heat/shock resistant (At least for the second or so it takes to pass through the engagement envelope.)

Use fast moving smart weapons with sensors designed to lock onto the target (if its ground or sea based) just outside of the defense systems engagement range and which then shut down so they can't be damaged or destroyed when the defense system fires. Alternately they might launch some kind of protective 'shot' just ahead of themselves (like reactive armor) or otherwise put 'chaff' in between it and the beam. Depending on how long it takes the beam to burn through the interference the weapon may get close enough to detonate.

Then there's the option to blind/jam the devices sensors with your own energy weapons just prior to launching or firing (at close range) or as your rounds come in on final approach if fired from long range. (Perhaps every salvo fired contains one or more jamming platforms whose sole purpose is to target and blind defenses while the rest go bang!)

Or better yet, all of the above! Remember the defense system is short ranged so fast moving objects don't have to be able to survive for less than five seconds or so at most.

Answer 2

OP artillery:

In a book I read, a German Schwerer Gustav or Dora railway gun fired on an alien spaceship. Their anti-missile defenses couldn't stop a 7 ton projectile at artillery speeds. Your weapon might melt the shell, but not stop it unless internal explosives detonate (so use a solid shell).

Alternatively, a projectile can go REALLY fast. A projectile going a significant % of the speed of light can avoid your weapon by preventing it from ever having a chance to even register it's presence. While near-light speeds may be tough to manage, hypersonic projectiles are quite practical. Just keep speeding them up (by whatever means) until they get through.

Thirdly, your projectile could convert to energy or plasma before impact. A nuclear bomb-pumped laser or one that converts to a jet of focused plasma can't really be stopped by anything other than exotic conditions or distance.

Answer 3

Use Nap-of-the-earth (NOE) flying

A low flying vehicle can remain obscured from detection and targeting by staying out of line of sight from the detector and weapon by staying below the level of surrounding terrain features. This is currently utilised by helicopter tactics in particular, but could be used by intelligent projectiles capable of controlled flight, such as cruise missiles and drones.

This gets a lot more effective if the terrain features have things the really cannot be hit (friendly civilians in built up areas for example). This would force the point defence systems to be certain they do not fire near the horizon, giving the incoming projectile more leeway for maneuver.

Answer 4

It doesn't. You need something it can't shoot down--something that's not a solid in the first place.

Your means of attack is something akin to a Tomahawk missile--flies very low. However, while still outside the engagement range of the point defense is pops up high enough that it can aim straight for the target for the rest of the flight.

The front part of the missile is ablative, it can take the first hit without damage to anything vital. The warhead on the missile is a casaba howitzer with a salvage fuse that is armed once it's pointed at it's target. The point defense engages, the energy is expended on either the nose or the fins, in either case the warhead survives long enough to detonate. A hellish bolt of plasma rips through whatever it was pointed towards, spreading out a bit depending on distance.

Note that casaba howitzers are at a minimum fission devices. Only the basic idea has leaked out of military security, not the exact specs if such a device was ever even built.