Space warfare

[Ex-User (9086)]

There are more efficient ways to store energy than batteries: chemical energy.

I know, my point was there are no theoretical or factual ways to store it more or equally efficiently than to spend it the moment you collect energy.

Also what about infinite energy and the ability to deliver it in an extremely low amount of time?

If this is going to be so far fetched then I'd say no space exploration would happen and people build virtual universes with near limitless energy and become gods inside of simulated realities.

Why care about what's outside if you can simulate it whenever you like.

 

[Teax]

Actually, I started to question this part:

To defend a planet you would have to spend an equal amount of energy to stop those objects.

It seemed so plausible because, what could possibly withstand a kinetic bomb except another kinetic bomb...... but why do we have to completely stop it?

Assuming the previous scenario, an incoming projectile of 95% light-speed, aimed at the planet. If the enemy can launch large projectiles with these kind of speeds, then we should be able to do this in those early-warning 16 days you mentioned:

I present: defense plan "Speed Bump":

We take a pebble, comparable in size to the incoming projectile and place it in its path.

This will not simply kick the pebble away. From the perspective of the incoming projectile, the pebble is the one flying with 95% light-speed crashing into the projectile:

This plan uses the same principle as the attack itself: How would the explosion be caused on the surface of the planet? It's not a bomb, but all of the kinetic energy is converted into heat at the impact point, and the resulting expansion creates the explosion.

The collision of the pebble into the projectile is the same. A lead pebble will create an explosion inside the projectile, and tear the projectile apart. If that is not enough, we can make the pebble out of uranium for a thermonuclear explosion.

Of course we haven't actually stopped the incoming mass. Inertia dictates that the resulting explosion will continue moving with at least half the initial speed. Instead, we managed to distribute the mass/energy that was initially concentrated into 1 very small point (the projectile), across an extremely wide area.

In other words, it's not the energy of the incoming attack that is dangerous, it's the energy-density. This plan gets rid of it.

By the time this wave hits earth, the energy-density of the attack has dropped so considerably, that it should be barely noticeable. However if we use Uranium pebbles, or worse, if the enemy uses Plutonium projectiles, one such attack still might kill every living creature on the surface of the planet. (Plutonium + ecosystem = bad)

So, the second stage of this plan is:
to place a shield right after the initial pebble. This shield might be just a big rock, or a thin metal plate, I'll let the INTJ scientists figure that out. Like any explosion, the matter of this explosion is constantly expanding. The shield takes out a piece in the middle creating a hole that is also constantly expanding.

So of course this shield cannot be placed too close to the speed-bump-pebble, or the energy-density will still blow it away. The aim is to place it close enough so that all the damaging plutonium would be collected at the shield, instead of being distributed across the planet.

This plan does not require nearly as much energy to defend the planet, as the attacking side wastes to accelerate the projectile. Where there's a will to live, there's a way

 

[Terran]

Teax how do you make those gifs? I want to learn.

Also you're a tactical genius! Although I would have suggested anchoring (with a very large and strong metal wire I guess) another body of mass to the projectile 90 degrees to the side while it is still a large distance away from the planet, so for a small amount of time when the wire comes under tension and the second mass is still ideally at least 80 degrees to the side, the centre of mass would change and go to the side, changing the velocity of the projectile so its course would stray a few degrees to the side.

That would really have to be a very large distance from the planet though, and wouldn't account for acceleration if the projectile was in fact a missile (plus gravity of the earth, although that is made insubordinate by the extreme speed of the object in this case) . BUT would theoretically work for an asteroid in a collision course.

Plus your model does not account for gravity, the 'shrapnel' may be curved toward the planet if their speed is too low, or if the shield is too far away.

 

[Teax]

Thx Actually, I'm too lazy to do the math on whether half the speed of light is enough to escape earth's gravity hehe.

The problem with wires is: how to attach it? If we just place it in the projectile's path, it will be obliterated on impact. We're talking about speeds here that instantly transform all matter in it's path into gas/plasma.

 

[Pyropyro]

Diplomacy, disable the necessary infrastructure, surrender, shot the satellite down, diplomacy, hack it, surrender.

Or more likely, deal with it until it's out of ammo, a bunker buster missile is probably cheaper than it.

I was expecting you to have an expanded strategy in mind... I know kinetic mass isn't sexy as Starcraft but it's in the realm of possibility.

Anyways, I guess Teax and Terran's conversations are a bit more interesting.

 

[Pyropyro]

Actually, I started to question this part:It seemed so plausible because, what could possibly withstand a kinetic bomb except another kinetic bomb...... but why do we have to completely stop it?

Assuming the previous scenario, an incoming projectile of 95% light-speed, aimed at the planet. If the enemy can launch large projectiles with these kind of speeds, then we should be able to do this in those early-warning 16 days you mentioned:

I present: defense plan "Speed Bump":

We take a pebble, comparable in size to the incoming projectile and place it in it's path.

This will not simply kick the pebble away. From the perspective of the incoming projectile, the pebble is the one flying with 95% light-speed crashing into the projectile:

This plan uses the same principle as the attack itself: How would the explosion be caused on the surface of the planet? It's not a bomb, but all of the kinetic energy is converted into heat at the impact point, and the resulting expansion creates the explosion.

The collision of the pebble into the projectile is the same. A lead pebble will create an explosion inside the projectile, and tear the projectile apart. If that is not enough, we can make the pebble out of uranium for a thermonuclear explosion.

Of course we haven't actually stopped the incoming mass. Inertia dictates that the resulting explosion will continue moving with at least half the initial speed. Instead, we managed to distribute the mass/energy that was initially concentrated into 1 very small point (the projectile), across an extremely wide area.

In other words, it's not the energy of the incoming attack that is dangerous, it's the energy-density. This plan gets rid of it.

By the time this wave hits earth, the energy-density of the attack has dropped so considerably, that it should be barely noticeable. However if we use Uranium pebbles, or worse, if the enemy uses Plutonium projectiles, one such attack still might kill every living creature on the surface of the planet. (Plutonium + ecosystem = bad)

So, the second stage of this plan is:
to place a shield right after the initial pebble. This shield might be just a big rock, or a thin metal plate, I'll let the INTJ scientists figure that out. Like any explosion, the matter of this explosion is constantly expanding. The shield takes out a piece in the middle creating a hole that is also constantly expanding.

So of course this shield cannot be placed too close to the speed-bump-pebble, or the energy-density will still blow it away. The aim is to place it close enough so that all the damaging plutonium would be collected at the shield, instead of being distributed across the planet.

This plan does not require nearly as much energy to defend the planet, as the attacking side wastes to accelerate the projectile. Where there's a will to live, there's a way

Teax, can we spam the deployment of solar sails via satellites/space drones(?) as a means of delivering those defensive "pebbles"? It's cheap fuel and material wise and a sail will cover more area just in case the target projectiles can be navigated manually by the enemy.

 

[420MuNkEy]

Without making any assumptions of future technology, the current possibilities for "space warfare" are fucking terrifying. There's a reason we stopped doing high altitude nuclear testing. Honestly, if North Korea wants to kick any country in its metaphorical balls, a high altitude nuclear detonation would be the way to do it.

 

[Ex-User (9086)]

Actually, I started to question this part:It seemed so plausible because, what could possibly withstand a kinetic bomb except another kinetic bomb...... but why do we have to completely stop it?

Assuming the previous scenario, an incoming projectile of 95% light-speed, aimed at the planet. If the enemy can launch large projectiles with these kind of speeds, then we should be able to do this in those early-warning 16 days you mentioned:


We take a pebble, comparable in size to the incoming projectile and place it in it's path.

Your plan appears impossible. First it assumes you have more resources than the attacking side and that you can maneuver them around in 15 days. If so the opposing side can send more stuff your way than you can deal with.

Matter is not important here, it's pretty much equal to energy in its use.

The time it takes to place your defences in the right location is days, which brings the dispersion very close to the planet. Not to mention that littering your solar system with rocks and shields would require constant energetic output to keep where it needs to be.

Then it assumes we are dealing with rigid bodies, which we aren't, bombs would be clouds of dust held together by microgravity mixed with a few larger rocks. Any attempts at dispersing it or blowing it up would be ineffective.

Thermonuclear is very energy inefficient and can't blow up dusty asteroids, instead it would leave a tiny hole inside and allow most of the mass to move through.

What happens when this dust reaches the atmosphere? It doesn't make spectacular explosions but that's not the point.

It heats the atmosphere and increases the global temperature due to friction, it also strips off some of the atmosphere and ionizes it while burning and polluting the environment plus starting a runaway greenhouse reaction. If the heating is sufficient the planet's oceans boil off and temperatures are enough to destroy all life and industry, much like on venus.

The more habitable the planet the more dust in the mixture, for sparsely populated worlds without atmospheres greater amounts of big rocks prove more effective.

I like your gifs and ideas, kudos.

 

[Pyropyro]

Without making any assumptions of future technology, the current possibilities for "space warfare" are fucking terrifying. There's a reason we stopped doing high altitude nuclear testing. Honestly, if North Korea wants to kick any country in its metaphorical balls, a high altitude nuclear detonation would be the way to do it.

As Project Starfish showed us, kicking Van Allen in the 'nads might affect not one but all countries that have satellites up there.

Taepodong-2 (hehehe) might scratch the bottom of the belts but I'm not sure if said missile has enough umph to carry a sizable bomb at the same time.

 

[Teax]

Teax, can we spam the deployment of solar sails via satellites/space drones(?) as a means of delivering those defensive "pebbles"? It's cheap fuel and material wise and a sail will cover more area just in case the target projectiles can be navigated manually by the enemy.

I imagine every pebble and shield being fixed to one space-craft carrying said item. But using sails as a means of delivery to the impact point doesn't make sense. We shouldn't try to cut costs here, in that hypothetical scenario of planet defense we only have less than 16 days to get a pebble and shield to their destination points.

Pebble is a bit of a misnomer, it can be quite big. And since we're also transporting a giant shield anyway, might as well use actual fuel for both. It's going to be a one-way trip for the craft anyhow. (poor thing)

But this is the perfect idea for stand-by. Sails are a zero cost means of maintaining the high-orbit of the defense system.

First it assumes you have more resources than the attacking side and that you can maneuver them around in 15 days. If so the opposing side can send more stuff your way than you can deal with.

Assuming that the plan works for 1 attack, I don't think it's possible to be overwhelmed by multiple attacks: Using this formula and this chart I calculate that to accelerate only one watermelon to 95% speed-of-light requires 5 billion liters of diesel fuel, which is about how much diesel our entire planet consumes in 60 years. This is just an approximate figure.

But it's clear that using a "rock" for defensive purposes would require several magnitudes less energy and resources than accelerating such a rock to use it for offensive purposes. This strongly offsets the resource balance in favor of the defendant.

So yeah, I guess we can say we have much more resources-per-attack, such that we could afford to be generous in other areas, like littering a ton of pebble-carrying craft some useful distance around the planet. Maybe this type of "sphere shell" pattern:

The time it takes to place your defences in the right location is days, which brings the dispersion very close to the planet. Not to mention that littering your solar system with rocks and shields would require constant energetic output to keep where it needs to be.

Using Pyropyro's idea, we can hold these craft in place with solar sails. When appropriate, a stand-by craft could use the sun to nudge itself back into stable high-orbit. Or alternatively, it could signal back home and the planet could send a friendly laser beam to nudge the craft. In either case, the craft would be so far away from the earth's and the moon's gravity as to spend most of its time just chilling.

Then it assumes we are dealing with rigid bodies, which we aren't, bombs would be clouds of dust held together by microgravity mixed with a few larger rocks. Any attempts at dispersing it or blowing it up would be ineffective.

Thermonuclear is very energy inefficient and can't blow up dusty asteroids, instead it would leave a tiny hole inside and allow most of the mass to move through.

A dust-shot! This is a most interesting idea. If we're talking about a dust-ball flying at your regular comet speeds, a small rigid body might just punch through it. But here, we're talking about something that hits the pebble with 95% speed of light. So this is speculative, but I'd say this is basically a particle accelerator experiment played out in space. Those first atoms of the pebble and dust-shot that collide, even if they survive, will heat up to such a degree that they would stop being solids, and become gaseous. The rapid expansion of the gas and release of energy should be sufficient to break apart any form of incoming projectile. The result is more like an expanding gas-cloud than a dust-cloud (Again this is the kind of thing best left to the INTJs to find out)

And even if it doesn't work well enough we could just make the defense pebbles much bigger. After all, we already know that we have the energy advantage, so shielding ourselves with large rocks is not a big deal. Depending on the speed on the incoming attack, we could just choose the size of the pebble to match.

But dust is an interesting weapon. If the enemy somehow... though I can't figure out how atm, sends a wide tube of dust in the direction of the planet, I can't see a way to collect it all.

 

[Ex-User (9086)]

But dust is an interesting weapon. If the enemy somehow... though I can't figure out how atm, sends a wide tube of dust in the direction of the planet, I can't see a way to collect it all.

There are many dusty asteroids held by microgravity. I think it would be as simple as casting nets and gathering tiny fragments and then accelerating those within a net, or in a more solid tube that would later disassemble.

The opponent doesn't need multiple attacks, even if you defend from 1 solid rock, your pebble will be moving towards your planet at the 50% of the collision speed and won't be there to stop a rock that's just right after it. And each attack would involve multiple rocks and possibly at varying angles depending on the stellar neighbourhood situation.

Also, for objects moving at 95% of c, no explosions do much to them, explosions move at 100% c so they don't have the time to take full effect.

Your method isn't several orders of magnitude more efficient if you factor in that you need twice as much mass to save half the energy. Because you need a pebble of equal mass and then you need a deflecting plate of reasonable size. And there's a potential risk that all these scatterings collide with more incoming material and start moving towards the planet regardless.

I'm not sure how that gaseous dispersion would work, doesn't seem likely because then the defences would need to cover a large area and would be destroyed while the attack would continue and there would be no time to replace them.

If you have 15 days and you place deflection 7 days away (you need some time to do it) and with 14 days left you get information that the rocks and dust continue to fly towards you then you only have time to place defences 6 days away. This is all assuming you can detect further attacks at all and your sensors haven't been destroyed. It would be good practice to mix a few energy sensitive drones with the rocks that would eliminate your sensors to make you unaware of the scale of attack. If the defences are too close then deflection becomes impossible, excluding dust that can't be avoided.

 

[JimJambones]

*in the meantime, target practices on giant asteroids while waiting for a suitable foe*

 

[Seteleechete]

I was expecting you to have an expanded strategy in mind... I know kinetic mass isn't sexy as Starcraft but it's in the realm of possibility.

Anyways, I guess Teax and Terran's conversations are a bit more interesting.

Those are the only strategies I can think of, either disable a key thing that is required for it to fire like communications/radar or shot it down, there really aren't many options to deal with such a weapon. And if you can't you have to minimize the damage by not giving it good targets and going guerilla warfare. If you can't shot it down and it's not too expensive to fire it becomes a deliberating weapon.

In many space operas space dominance is everything that matters because you can't effectively defend agianst weapons in space from the ground.

 

[Teax]

Disregarding dust attacks for now:

The opponent doesn't need multiple attacks, even if you defend from 1 solid rock, your pebble will be moving towards your planet at the 50% of the collision speed and won't be there to stop a rock that's just right after it.

It's unlikely that the center of mass of the pebble gets propelled towards the protected planet, even if we tried to place it perfectly centered:

For obvious reasons we will avoid placing the pebble centered, and even if it were, the slightest deviation will cause it to miss the planet. On top of that, we're not talking about billiard here

The impact explosion would likely not happen centered, and likely not leave the pebble intact.

And each attack would involve multiple rocks and possibly at varying angles depending on the stellar neighbourhood situation.

Isn't varying angles much easier to defend than same angle? We already assume we have a defense setup, just move the closest pebble into position.

Anyway, when the two sides are unfairly unequal, overwhelming the opponent is always an effective strategy. So I didn't even mention it. I am basically making the same argument the OP and post #49 made about defense technology never matching offense technology during ship vs. ship battles. The reasoning being, that given equal technological progress, one is always more powerful than the other. If the attacker has the means to throw 100 giant rocks with 95% light speed, the defenders have the means to place 10000 giant rocks in their defense.

Also, for objects moving at 95% of c, no explosions do much to them, explosions move at 100% c so they don't have the time to take full effect.

We're not talking about Newtonian physics here. Relativistically speaking, the incoming projectile is standing perfectly still, while the explosion moves with 100% c.

The only relevant approximate number I know is that the resulting expansion will be far above 10km/s. We have to take into account time dilation. At 95% c the explosion will unfold 3x slower than normal, but after the speed-bump, it will be less than 2x (γ). Placing the pebble only 20 light seconds away, the explosion will approximately cover a planet the size of earth:

Placing it 1 light-minute away, results in only 1/9 of the explosion hitting earth.
1/36 for 2 light-minutes away. 1/81 for 3.

Your method isn't several orders of magnitude more efficient if you factor in that you need twice as much mass to save half the energy. Because you need a pebble of equal mass and then you need a deflecting plate of reasonable size.

I don't understand what you mean. We don't accelerate these rocks to anywhere even close to speeds of light to move them. And the shield object can be just 2x or 3x bigger than the projectile, if it's placed far enough from the planet.

I'm not sure how that gaseous dispersion would work, doesn't seem likely because then the defences would need to cover a large area and would be destroyed while the attack would continue and there would be no time to replace them.

Any solid or liquid material, sufficiently heated, will evaporate into a gas or even plasma, that's all I meant. The cause of the heat-up in this situation is the collision(destruction?) of atoms at near-light speed with all sorts of exotic particles, weird effects and uncontrolled energy releases.

 

[Ex-User (9086)]

We're not talking about Newtonian physics here. Relativistically speaking, the incoming projectile is standing perfectly still, while the explosion moves with 100% c.

I don't think that's how it works. C is the maximum causal dispersion speed of events, so this follows that most energetic events expand at c, but this doesn't freeze objects moving at 95% in time. Then again, you could adjust for it by simply matching the speed and direction of the targeted object so it's unimportant.

My main idea included overwhelming because I was comparing how to make very small scale observations work defensively, which they wouldn't.

There's too much detail that can't be verified so there's little reason to continue this comparison. I see an inherent inefficiency of defence assuming the opponent initiates the planetary strike and that's about it.

 

[Teax]

Ups sorry I meant the radiation moves at 100% c. The actual explosion is as fast as the expansion, and that's in the area above 10km/s. But that's more than enough, because relativistically speaking, the explosion happens inside the moving coordinate system viewed from the perspective of the incoming projectile. What we see from our perspective is really irrelevant and, unless you studied physics, will sound quite counter-intuitive, so I'd rather not try to explain. (here's an article with pictures for those who are unfamiliar with this)

Fair enough I'll leave it be.

Someone in the future, having old backups of the Internet on their hard-drive somewhere, might use this thread to get inspiration for their attack....

 

[Ex-User (9086)]

The actual explosion is as fast as the expansion, and that's in the area above 10km/s. But that's more than enough, because relativistically speaking, the explosion happens inside the moving coordinate system viewed from the perspective of the incoming projectile. What we see from our perspective is really irrelevant and unless you studied physics, will sound quite counter-intuitive, so I'm not going to explain. (here's an article with pictures for those who are unfamiliar with this)

I know about time dilation and length contraction, I'm not talking about our perspective, you still have to account for two separate reference frames so time becomes relevant as does the distance.

Studying physics isn't required to understand relativity.

I mean, it works if you match the projectile's frame by attaching to it so there's no problem there. But it wouldn't work by simply exploding in front of it or trying to deflect. (Faster objects would be much more difficult to stop this way)

Where did you get the 10 km/s from?

 

[Teax]

I mean no offense *hug*

Where did you get the 10 km/s from?

Just stuck with me as a rule of thumb expansion speed inside earth's atmosphere pressure. I don't have a memory for concrete figures, nor which book/site I seen them in so don't take my word for it, please

 

[Pyropyro]

I mean no offense *hug*

Just stuck with me as a rule of thumb expansion speed inside earth's atmosphere pressure. I don't have a memory for concrete figures, nor which book/site I seen them in so don't take my word for it, please

Did you mean g or 9.8 m/s2? I can't remember any 10 km/s during college physics

 

[Ex-User (9086)]

Just stuck with me as a rule of thumb expansion speed inside earth's atmosphere pressure. I don't have a memory for concrete figures, nor which book/site I seen them in so don't take my word for it, please

I think you are conflating the fusion/fission energy release with the shock wave, which only occurs in atmospheric detonations. Neutron release is near-light speed accompanied by radiation but there are no shockwaves in space, so the damage potential is greatly lowered. There's no medium to carry the shock, just as there is no sound in space.

As to the shock wave itself:
http://fas.org/nuke/intro/nuke/blast.htm

During the time the blast wave is passing through the superheated atmosphere in the fireball, it travels at supersonic velocities. After it leaves the vicinity of the fireball, it slows down to the normal speed of sound in the atmosphere. As long as the blast wave is expanding radially, its intensity decreases approximately as the square of the distance. When the expanding blast wave from a nuclear air burst strikes the surface of the earth, however, it is reflected, and the reflected wave reinforces and intensifies the primary wave.

So the velocities are super and then sonic. Around the 340 m/s mark.

 

[Teax]

Makes sense.

I think I severely underestimated the explosion, here's another way to look at the experiment:

Consider an incoming attack at 80%c. We already agreed that propelling a counter-projectile with also 80%c towards the incoming projectile would neutralize the attack:

The collision would happen at 95%c (because), and even in the most timid of cases, if no atoms get destroyed, the energy released during impact is (by definition) sufficient to propel all matter to 80% c. So even a tiny fraction of that energy is enough to exceed 10km/s.

And even assuming if matter doesn't get pushed away, each kilogram releases something in the order of a Giga-Joule, while it only takes a Mega Joule to evaporate that kilogram into gas. And since temperature=kinetic energy, such gas would still disperse/expand at those insane-speeds.

The speed-bump is the same experiment viewed from the perspective of one of the projectiles:

The resulting explosion will continue on with 80% c on average , so from the perspective of the planet, the explosion/expansion still unfolds (in slow motion) with a whopping 60% of its normal speed.

I forgot if I was going anywhere with this....

 

[Aviator8]

Space battles would have two sides. The sniper approach is impractical because the ships would move away, and not have any predictable trajectory, and the close in approach is impractical because you won't get close enough.

What you want is a joust, the battleships move as fast as they can at each other and shoot at each other. They can't hang around, but at least they were able to effectively engage each other. Then the sniper ships take their shots, all the enemy's attention focused on the biggest momentary threat, and are able to score hits.

With this method, you can use a defensive midfield as a weapon, dragging it along with you, and releasing it on the enemy.

Planets could be protected by their stars relaying it's power to prepositioned weapons, and drones would be used as escorts, decoys, and for general harassment duties.

Most space weapons would have to be automated, or lightly crewed, and nuclear weapons would be the primary explosive ordinance.


Another scenario is that all space warfare is as we suspected future nuclear ware fare would be, where we sit on our planets shooting misfiled at each other, until one side loses.