[combat] mobile shield

[MC.STEEL]

Alas the real world will not be a one full of dramatic space battles that drag along as the craft dig trough their shields and then their armor.Because for one we have absolutely no idea how to make energy shields and modern weaponry is a one hit kill, not to think of an shaped charge missile,almost impossible to dodge.

And armoring a ship sounds a bit silly as you will have less deltaV,even if you use a Whipple shield^{(seen below)} wrapping an entire ship is not ideal.

So here is my take on things:

Why dont we take a big shield and mount it on a long robotic arm that adjusts to incoming weapons fire.

It tracks via radar incoming projectiles and positions itself accordingly.

PROs

Suddenly placing armor everywhere seems overredundant as a patch can cover the entire ship,this means you can have your deltaV cost back from armoring the entire thing.

can be used for tilting pitching yawing when you are out of monopropellant.

CONs

it will be hard to block things like smart missiles, relativistic projectiles,lasers and enemy fire incoming from multiple sides(unless you have more than one) and depending on how fast the arm moves it will be hard for it to block arcs of fire or a missile that dodges the shield last second.

All that moving will make some annoying swaying of the ship unless rcs/gyros can counteract it.

So this is my idea you are welcome to shoot it full of holes and/or congratulate me for thinking of something fairly original.

[Nibb31]

It's a clever idea, but why put the shield on the end of an arm? You could give it it's own propulsion and avionics system so that it could move around with the ship without the complications of being physically attached. At that point, you could actually let it move away from the ship and towards any incoming projectile. And instead of making it out of some sort of fantasy shield material, just make it light and expendable and pack dozens of them.

Oops, your mobile shield has just turned into an anti-missile missile.

[MC.STEEL]

It's a clever idea, but why put the shield on the end of an arm? You could give it it's own propulsion and avionics system so that it could move around with the ship without the complications of being physically attached. At that point, you could actually let it move away from the ship and towards any incoming projectile. And instead of making it out of some sort of fantasy shield material, just make it light and expendable and pack dozens of them.

Oops, your mobile shield has just turned into an anti-missile missile.

Haha i was thinking about making an armor drone out of it but as far as its my design choice,i wouldn't have it expend propellant.I am conservative about that sort of stuff.

but as even with these shields battles wont last long,one is bound to miss so they wont be expending much fuel.

[KOCOUR]

Forget shields! Employ active countermeasures. Forexample lasers or projectile weapons that would vaporize the missile before it reaches your ship.

[Winter Man]

When I last checked Rutherford Appleton were working on a rudimentary energy shield for satellites, to with the intention of eventually scaling it up to ship-size. Don't know what their progress has been, this was about 5 years ago.

[JumpsterG]

An early episode of Robotech/Macross had them using an energy shield system where the shields themselves were tiny in comparison to the ship and were moved around the ship's surface to intercept incoming missiles. The operators controlling the shields moved them by frantically rolling trackballs, which was kind of funny. Trying to find pics or a clip...

[Seret]

Forget shields! Employ active countermeasures. Forexample lasers or projectile weapons that would vaporize the missile before it reaches your ship.

Absolutely. Destroy the threat and vector the fragments away from you at the greatest distance possible. Similar technology is already in use on ships and tanks.

[Mazon Del]

If we are talking about real world technology in real world battles, one of the most important things to recognize is the limitations imposed by distance. We are all well aware of the issue of needing sufficient deltaV to move from one orbit to another, but there is another that people often forget, light speed lag.

Simply put, because it takes time (lots of time) for weapons fire to move from one ship to another, in 99% of all cases of ship to ship combat, the defender has the advantage. Let us examine why.

Weapons tech for space battles tends to fall into three categories: Ballistics (bullets, railguns, asteroids, anything that is fired and can never maneuver), Directed Energy (lasers, particle weapons, etc), Missiles (any weapon system that is fired and has terminal guidance, IE the ability to change its path to maximize the chances of a hit).

Let us assume for the moment that the battle is taking place over the course of 1 light second, which is 186,282 miles of distance. For referance, the average distance between the Earth and Moon is 238,900 miles, a little less than 1.5 light seconds. In an actual space battle this would be considered quite close range, not necessarily knife fight ranges, but very close. Why? Because they greater the distance, the greater the defender is favored, so it makes sense to keep your ship as far away from an enemy as possible, while maintaining the ability to still hit him.

Ballistics:

Pros: Kinetic energy kicks ass. Relatively cheap on mass compared to missiles (easy to use lots of them), and in a pinch can double as a maneuvering thruster or in some cases a main engine (when you fire a cannon, equal and opposite reaction, your ship will 'accelerate' in the opposite direction).

Cons: Ballistics are just that, ballistic. When you fire, they are on a set path that will not change. Very slow! Requires saturation fire!

Assuming a muzzle velocity of 4,000 ft/sec (a Barret M82 can reach 3,200 ft/sec) it would take that bullet/shell 2.85 DAYS to reach its target (ignoring whatever closing velocity you have with the enemy ship.), assuming you are closing at 33,000 ft/sec (the speed Curiosity traveled on a transfer orbit to Mars) with a total closing velocity for the round of 37,000 ft/sec the round still takes 7.38 HOURS to reach its target. For ballistic weapons, a miss by an inch was as close as a miss by a mile, it's still a miss. All the defending ship needs to do is to nudge itself EVEN SLIGHTLY sometime within the next 7.3 hours and that round is CERTAIN to miss. Why is it certain? Because the guy that shot it was aiming where he thought you were going to be, and even the effect of a tiny push over several hours can cause a ship to be 50-100 feet away from where it going to be. So, in order to ensure maximized chances of getting a hit, you either need to fire a massive blanket of shots across where the enemy is going to be, so large a blanket that they cannot dodge with their main engines, or you need to be able to surprise them (not suprise them as in unexpectedly fire. Surprise them as in, the first moment they realize you shot at them was the moment the rounds started impacting their hull), or you get in stupidly close ranges. Considering the problems with carrying that much ammunition (it weighs a lot in bulk!), this type of weapon is really only suitable for targets that cannot maneuver (large space stations or planet/rock bound targets) or very close in work.

Missiles:

Pros: Terminal guidance, different warheads, versatile.

Cons: VERY large, VERY heavy, low ammo count, susceptible to ECM (electro-magnetic countermeasures) and counter-fire.

Missiles at first glance seem pretty great, they are just basically mini-ships themselves. They have the ability to steer into their target, you can give them nuclear warheads, conventional warheads, claymore-esque burst warheads, etc, and you can program them to do interesting things like drift behind a planet before slingshotting around into a target while never using its engine while in view of the enemy. Unfortunately, with all of this comes the downsides. Missiles relative to ballistics will tend to be very large. This is because over the distances involved in space you need a lot of propellant for deltaV and maneuvering. As a result of all this rotundness, missiles will also be very heavy which will slow YOU down as you maneuver around. As a result of wanting to be nimble enough to dodge ballistics, you are not likely to desire to carry too many of these around with you. Additionally, even if the scenario lines up where a missile is capable of hitting a target despite counter-fire and dodging, it is still possible that enemy countermeasure will confuse the missile enough that it misses or explodes outside its useful range (even a powerful nuke will have to be within a mile of its target. No shockwaves move through space to extend this range.). And this comes to a problem that missiles share with their ballistic fellows, the target may dodge. The missile needs to always be working to optimize its path towards the target, the sooner you adjust your path the cheaper it is in fuel. Waiting until the end risks being completely unable to make up the deltaV necessary to reach the target. So any time the enemy ship activates a thruster, fires a weapon, uses its engine, dumps seweage, the missile is going to have to spend fuel to match the new vector. One problem for the missile is when it sees the enemy ship using its engines or thrusters, the enemy has already been doing that for 1 full second (1 second light speed delay due to range). But the missile does not know how long the ship has been using its engines, or how long it WILL use them. So even if the missile spends enough fuel to catch up, when the enemy engine shuts off the missile will likely have to spend extra fuel to correct its overshoot. A ship has a LOT more disposable mass (fuel) than a missile will. As a result this becomes a numbers game of how much can the ship afford to dodge, for how long, and how much can the missile afford to correct, and for how long. All this time, we have to keep in mind that the missile is probably large enough that the enemy ship will be able to shoot its weapons at it, a single hit will likely destroy the missile. The defender also has the advantage that even if the missile dodges all of its counter-fire, the missile HAD to spend some of its limited fuel to do so and then to correct its path, making it less able to perform final aiming.

Directed Energy:

Pros: (near) lightspeed weaponry, very mass efficient.

Cons: heat! low-damage yield.

Directed energy weapons (DEW) (such as lasers or particle beams) move at incredible speeds. Lasers/Masers/Grasers all fire at basically lightspeed, particle weapons slower, but comparable. This makes them very hard to dodge because as the target you have no warning that they are headed your way. You just have to assume they are firing at you and therefor "constantly" be dodging. Constantly being relative in that only a few course adjustments per unit of time may be necessary because likely the beam weapons will need some pretty awesome precision to hit. Laser weapons (such as the Navy's new massive laser diode, electric only, non-chemical laser) only require electricity to fire and therefor have no extra consumables that you must carry saving on mass for you. The problem with DEW is that they all tend to release a LOT of heat when they fire. That heat has to go somewhere, space is actually very hard to dump heat into, if you don't have good cooling then you will eventually need to stop firing just to let your heat slowly bleed away into space. Conversely, whatever heat sink you have for this purposes will in general be a nice target for enemy DEW. DEW tend to work by heating up your enemy to either cause physical damage (LOTS of heat really fast) or to simply cook them to death (low heat). If the enemy has good cooling systems, then you need to score a higher percentage of hits in order to acheive your goal.

In the end DEW weapons, despite their low damage output, end up being the winner of these three types. This is primarily because they are NOT easy to dodge. In our 1 light second battle, the speed of light weapons force the defending ship to dodge more forcefully, faster, than the other weapons do. Additionally, it is possible to easily bracket an enemy ship to prevent dodging from being truly effective. This is similar to the blanket fire of the ballistics, but better because you don't have to carry the extra mass. So if the enemy wants to dodge, they have to constantly be expending fuel. A hot enemy that is constantly expending fuel is good.

Obviously at longer ranges DEW are effectively the new ballistic weapon, but think, if DEW get THAT bad, how much worse has ballistics and missiles gotten?

[Coldfinger008]

Oka excuse me, but if you gonna go imperial, then at least put the metric conversion next to it so the civilized world can understand it.

Sorry, it´s just something that really pisses me off.

That out of the way,

you have a wonderful post there.^^

However there is a couple of things.

A chemical shaped charge in vacuum can actually achieve jet-speeds of 100km/sec. I am not sure exactly what setup you need for that though.

I know this doesn´t change much, but i felt i should just drop that here.

Another thing is, that at relativisitc speeds,

yes a small course change will make quite a difference,

HOWEVER, yu will need tons of thrust and energy for that, simply because your ship is flying relativistic speeds.

Plus, if you have relativistic ships, you also can make relativistic cannons, at least if your ships can go to a large fraction of c in a somewhat reasonable time.

If they can´t, relativistic dodging might not work as good as you would like it to.

But when we talk small dumb KE weaponry we´re talking railguns or coilguns anyways. Higher Vo then chemical guns and ofc you don´t need to lug around all that propellant. Because of that you also can have much higher RoF then any oldschool peashooter is mechanically able to.

On that note, i would say that space battles might lead to the revival of APHE ammunition.

Sure at 90%c and up, even an antimatterfiller won´t give you more energy at target, but if you have a small burstcharge, you can drastically increase your surface area...although you might already have mentioned that.

And to get back to the actual thread XD,

while we know what projectiles do at very high velocities, see whipple shield, we can still only speculate about how relativistic munitions will behave.

Maybe they will just turn into a plasma and whipple shields are effective, or maybe they will be like the popculture railgun and just plow through.

Also does someone know wether or not railgun or gasgun test with DU or tungsten core projectiles have been conducted? Because as far as i know, it´s been mostly aluminium.

One of the neat things with KE weapons in "low"-velocity fights (read, near future) i guess would be the fact that you transfer kinetic energy.

If you can use the recoil for thrusting, the impact will be able to mess with the flightpath and orientation of the target, forcing it to either expend propellant or suffer decreased accuracy.

I agree with you when it comes to missiles, they could be very impractical and/or useful for niche jobs.

Now with DEWs........

First off, charged particle beams will have very limited ranges, due to the electromagnetic force pluming out the beam.

Also let´s not forget, if you have an ion-powered craft, your engine is essentially such a weapon.

A gun that could shoot relativisitic neutrons however would be incredibly useful, since even if it doesn´t directly damadge components, it irradates everything.

On that matter,

yes it is possible to create concentrated neutron radiation with a particle accelerator, but untill someone finds some really good superconductors that work at high temperatures....... well have a look at the cooling system of CERN.

Good old photons will probably give you a better weight to energy ratio.

Now as for the EM-beamers....

Grasers(gamma-quant) and Xrasers/Xasers(X-rays, go figure) due to their high energy properties, would in praxis most likely be nuclear shaped-charge submunitions.

Unless of course you can afford to carry around some big heavy-metal cathodes to change every few shots.

The category under that would be UV-Lasers, and then visible ones.

The classic death-rays we all know and love.

Besides the incredible requirements for cooling, you also need very good targeting systems.

Because in order to deliver a good blow you need maximum focus on target.

And that brings us to the next issue: if you don´t want to just laserdesignate your target, but actually hurt it, a lasr has a maximum practical effective range.

While the Laser doesn´t have to plow through an atmosphere in free-space, you need to focus it. For that you need a lens.

And the further away you want to be able to concentrate your beam, the bigger that lens got to be.

Now in an ideal universe, you would just have a beam of 100% coherent photons in a beam with the wavelength for the diameter.

In praxis that doesn´t quite work unfortunately :C

At least yet.

Then there woul also be Masers, but here you have even less energy density then with Lasers, without any good decrease in requirements.

As for countermeasures.

Dumb bullets as well as missiles can be intercepted with every category of weapon listed here.

EM-beams when sufficiently strong and concentrated to be useful can´t really be deflected, sorry, but no mirror shields.

What you want for that is a low-density high warmth capacity material with good conductivity. It sould also be very flexible so that the plasmablast on hit doesn´t shatter away pieces of your armour.

Unfortunately, we are talking about Lasers so no fancy mobile shield would be fast enough to react to it. Although if you can maintain a stable "broadside" position, that isn´t sobad, depending on the number and formation of your enemy, so you could get away with having a moveable shield thing that only covers 90°.

However...... you necessarily need to cover your ship in whipple shields, especially if you fly relativistic, lest you want every tiny piece of just about anything to wreck the soft belly of your ship.

So basically, take lots of ammunition for your space-CIWS, and develope a material like the afore mentioned, by which you basically allow your hull to work as a radiator, while not being as vulnerable as a radiator, soyoucan bring more heatsinks, propellant or CIWS ammo.

So there, my little take on it.

[vger]

At some point in time, I had pondered about such a concept for oldschool naval vessels. Armor that would be extended out some distance from the hull for the purpose of deflecting torpedoes.

In space though, I would think interceptors are your best bet.

[jwenting]

best bet is not to get in a fight in the first place...

second best bet is to move out of the way of the incoming threat. Which, given that that threat will be launched far away you'll have hours to accomplish.

[The Silent Majority]

I'm surprised nobody has said this, but ignoring whether shields would be effective or not, using radar would probably not be effective as a detection device.

Passive sensors would be twice as fast, do to not having to send and receive the radio waves. (if this is incorrect, please let me know) (also ignoring analyzing software delay time, I am assuming that computers will be powerful enough that this is minimized)

[Seret]

Let us assume for the moment that the battle is taking place over the course of 1 light second, which is 186,282 miles of distance. For referance, the average distance between the Earth and Moon is 238,900 miles, a little less than 1.5 light seconds. In an actual space battle this would be considered quite close range, not necessarily knife fight ranges, but very close.

I'd like to back the truck up and challenge this assumption. The military aren't going to be deploying combat spacecraft into deep space. The strategically important "ground" worth fighting over is Earth orbit, and the maximum distance you're likely to get is the distance between two objects in geostationary orbits, which is about 83,000km if my back of napkin sums are correct. That's about a quarter of a light second. Engagement ranges in LEO would be a lot shorter, down to a maximum of 1,000km between two vehicles in the lowest orbits once you take obscuration from the atmosphere into account.

[Stargate525]

At some point in time, I had pondered about such a concept for oldschool naval vessels. Armor that would be extended out some distance from the hull for the purpose of deflecting torpedoes.

In space though, I would think interceptors are your best bet.

The biggest problems with this are that the hydrodynamics of a pseudo-secondary hull would be a pain in the rear, and that water is nearly uncompressable. Most torpedoes never make contact with the enemy vessel; they detonate a small distance off, and let the shockwave of the water annihilate the hull.

The only way I can think of that an outrigger armor could protect from that would be deploying large balloons to absorb that shockwave, and that would DEFINITELY mess up the ship's performance.

[Seret]

Old warships did actually have torpedo bulges at the waterline. Like you say though, warheads back then were contact fused, and they'd be ineffective against modern back-breakers.

[Aghanim]

Forget shields! Employ active countermeasures. Forexample lasers or projectile weapons that would vaporize the missile before it reaches your ship.

How do you counter laser weapon? You could try shooting their heat sinks off though

snip

Reported for doing physics in imperial units

[Mazon Del]

Oh god...I'm sorry...I don't know why I did physics in imperial units...I submit to my firing squad with all the grace and stoicism I can muster.

Secret: You are right about fights taking place in orbit above a singular body, this actually falls under the 1% that my statements did not cover, though admittedly I never spelled that out. Even at those distances however, you are still talking about whole minutes of time for one ship to dodge the fire of another if it is ballistic munitions. I assume whenever we get around to building battle stations and ships in orbit (even if only for orbit fights) they will be optimized for this ability to dodge.

Additionally, the situation gets more complex in orbit above an industrialized target, mainly because you now have the joyous problem that whenever your orbit moves over the nation of your enemy, their planet-bound weaponry can come into play (likely to be missiles and DEW, while its possible for railguns to happen here, it is a little less effective than the others because of the problems atmosphere causes you).

Mostly I assume that once we get into a serious possible space battle its at the point where it is like Earth VS Mars or something similar.

The Silent Majority: You do in fact bring up one of the big problems with space warfare, that of detection. Conventional radar as it stands is not really suited towards massive sweeps of space. We do have some fancy games we can play when you have systems like the Arecibo radio telescope down in Puerto Rico (the one used in Goldeneye), which we have used before to "brighten" other planets so other radio telescopes can see them better. But in general it is assumed that over the distances involved with planetary combat (Earth-Mars, not just Earth orbit) your primary sensors are going to be infrared and telescopic. Part of the reason is as you stated, these methods only require you to see energy that was already transmitted from the target, so you only have the time delay imposed by the distance. If you sent out radar to a target 1 light second away, you would have to wait 2 seconds to get a return, 1 for it to reach the target and 1 for it to come back. Also, the signal loss involved would be quite tremendous.

Aghanim: There has been many theories and tactics thought about this, but nobody is really certain how well they will work. On one hand you can deploy disposable shields (throwing out clouds of crystal particles to diffuse/absorb the lasers, or even just a solid slab of material) but these are extremely high mass defenses. On the other hand you can design the armor of your ship to basically absorb the energy and flake away (as the armor cracks and flakes away, the flakes are VERY hot, and since they are no longer touching the rest of their ship, that heat is no longer damaging you). And on the gripping hand (points to those who get it), you have tactics you can employ such as rolling your ship around its exposed axis. Think about a tube, if you are looking at it from the side and you are firing a laser at it, if the laser is not able to get an instant-kill, then that means it needs to take some time to burn through or to heat up the target armor for effect. This means that you MUST keep the beam pointed at the exact same spot on the enemy ship (or near enough to it), so all the defender has to do to make your weapon 'worse' is to rotate the ship. Even if your weapon had perfect tracking, you could only maintain the beam on your target location for 180 degrees of the spin. This gives that section of hull time to cool while the battle continues.

Someone had said that mirrors wont work, and to a point that is true. You cannot make a mirror perfect enough to relect ALL the incoming light, some will be absorbed and if the enemy laser is worth its salt then it is pouring enough energy into your mirror that the slight amount that gets absorbed warps the mirror (degrading its ability to reflect) quite quickly. You may incorporate reflective elements into your ship armor because every little percentage of heat you deflect is heat you don't have to suffer from, but it will not 'solve' the problem.

[jwenting]

Old warships did actually have torpedo bulges at the waterline. Like you say though, warheads back then were contact fused, and they'd be ineffective against modern back-breakers.

they were the equivalent of what you'd build today, a strengthened keel...

[KOCOUR]

How do you counter laser weapon? You could try shooting their heat sinks off though

Oh ****! Good point man. I totally forgot about Lasers.

[Seret]

Secret: You are right about fights taking place in orbit above a singular body, this actually falls under the 1% that my statements did not cover, though admittedly I never spelled that out. Even at those distances however, you are still talking about whole minutes of time for one ship to dodge the fire of another if it is ballistic munitions. I assume whenever we get around to building battle stations and ships in orbit (even if only for orbit fights) they will be optimized for this ability to dodge.

That wouldn't be a problem to counter. Aircraft are able to dodge too, and missiles are able to hit those. I think you'll find a guided weapon for space use would use an initial boost to accelerate and close the distance, enter into a fairly dormant cruise phase, then use a separate terminal guidance maneuver system.

I think orbital engagements would be 99% rather than 1%, but I suspect you're envisaging a situation further into the future than me.

[Javster]

It's a clever idea, but why put the shield on the end of an arm? You could give it it's own propulsion and avionics system so that it could move around with the ship without the complications of being physically attached. At that point, you could actually let it move away from the ship and towards any incoming projectile. And instead of making it out of some sort of fantasy shield material, just make it light and expendable and pack dozens of them.

Oops, your mobile shield has just turned into an anti-missile missile.

Then that's just an interceptor missile isn't it?

[magnemoe]

Shielding like this is pretty common, tanks has far heavier armor in front than from other directions, sides and back is thinner, top and bottom is far thinner.

WW2 tank destroyers took this to the extreme,

might be easier to just rotate the ship like you would point an tank towards the enemy. this avoids the vulnerable arm and will also reduce the silhouette of the ship as it would typically be much longer than wider.

The main downside of armoring just one side is also know today in top attack anti tank rockets, rocket fly over the tank, with an sharped charge blowing an projectile downward.

You would typically do something similar in space, both to get around armor and to do damage even if you miss,

And yes you will combine both active and passive measurements, this armor will be nice against energy weapons and kinetic hits, weaker against missiles who you use your own energy weapons against, this turn the missiles into dumb impactors or shrapnel who the armor protect against.

[vger]

Shielding like this is pretty common, tanks has far heavier armor in front than from other directions, sides and back is thinner, top and bottom is far thinner.

WW2 tank destroyers took this to the extreme,

might be easier to just rotate the ship like you would point an tank towards the enemy. this avoids the vulnerable arm and will also reduce the silhouette of the ship as it would typically be much longer than wider.

The main downside of armoring just one side is also know today in top attack anti tank rockets, rocket fly over the tank, with an sharped charge blowing an projectile downward.

You would typically do something similar in space, both to get around armor and to do damage even if you miss,

And yes you will combine both active and passive measurements, this armor will be nice against energy weapons and kinetic hits, weaker against missiles who you use your own energy weapons against, this turn the missiles into dumb impactors or shrapnel who the armor protect against.

Gosh, after reading this, the "buzz droid" missile concept in Star Wars Episode III (which I thought was almost the dumbest tech idea I had ever seen in the whole series), actually starts to make some sense.

[Seret]

Warheads in anti aircraft missiles aren't contact fused anyway, they're proximity weapons. They explode in proximity to the target and cause damage through fragmentation (typically they use an expanding rod type warhead). Since spacecraft are constructed the same as aircraft these warheads would be just as effective against them. So the aspect threatened by a missile wouldn't just be the side facing the enemy, it would also be all your flanks too.

I don't really think passive armour is a practical idea. Active counter-measures and defensive maneuvering would really be the way to go. Same as aircraft really. People seem to have this idea that space combat would resemble naval combat for some reason. It wouldn't, it would be far more like aerial combat.

[magnemoe]

Gosh, after reading this, the "buzz droid" missile concept in Star Wars Episode III (which I thought was almost the dumbest tech idea I had ever seen in the whole series), actually starts to make some sense.

The buzz droid don't make sense in combat as it has to match speed with the target, this take time and make it easy to shoot down, it makes sense as an sabotage tool around a neutral space station and similar places, more so as it can disable an ship later and can be non lethal.