What future space combat would really look like • Hacker News Board

Re: What future space combat would really look like

#191

Post by vidarh » Wed, Dec 28, 2011, 11:11 AM UTC

nl wrote: post #167

zeteo wrote: post #128

Earlier quoted context omitted.

The point is that the 10-20 seconds latency that was mentioned is not even close to covering the next planet, much less the entire solar system. Yes, you can send off a bunch of heat-seeking missiles, but, as I mentioned in my original post way up this thread, these missiles are routinely defeated by counter-measures even when seconds away from the target. So, in the absence of strong AI, it's vastly more efficient t…

So, in the absence of strong AI, it's vastly more efficient to actually have a few humans on board the ships. Have you done the math on that? Humans (and more importantly their life-support systems) are hugely, hugely expensive in terms of the carrying capacity of a space ship.

There's also the rather large cost in reduced maneuverability when you want your on board humans to be able to survive.

Re: What future space combat would really look like

#192

Post by dalke » Wed, Dec 28, 2011, 11:26 AM UTC

Splines wrote: post #57

As mentioned in the post, David Weber's Honor Harrington series operates very much like this. I've read a few of them and enjoyed it. Nuances in space combat in his stories tend to be important. http://en.wikipedia.org/wiki/David_Weber#Honor_Harrington_se... Also, it's worth watching this scene from Mass Effect 2. It's amusing :) http://www.youtube.com/watch?v=7GqqDCe4Yrs

Assuming a ship of 500 m in length, and weighing 10,000,000 tons (100 times heavier than the largest aircraft carrier), the firing of a 20kg shell at 1.3% of the speed of light requires a momentum transfer of 0.008 m/s from the ship. Assuming constant acceleration, the firing requires a shell acceleration of 1.5E10 g, which is done in 130 microseconds.

A velocity change of 0.008 m/s in 130 microseconds means the ship itself has an average acceleration of about 60m/s/s or about 6 g. However, this assumes the entire ship is rigidly coupled to the firing system. If held together by normal structural forces, which propagate at best at multiples of the speed of sound, then no more than 1/2 meter of other structure can be involved. It's more likely the equipment itself will have 100s of g of stress.

The acceleration requires 1.5E14 Joules, or 35 kT of TNT, which is what the clip said.

Re: What future space combat would really look like

#193

Post by absentbird » Wed, Dec 28, 2011, 11:43 AM UTC

jrockway wrote: post #142

troels wrote: post #115

Earlier quoted context omitted.

Why would that ever be a goal?

Because people are irrational. Why did Hitler try to kill all the Jews? Because he felt like it and had the means to do something about it.

It was for racial purity. At the time eugenics was a big deal, it stated that some genes which were exhibited as external traits were superior. Hitler was attempting to create a better world by performing artificial selection.

As much as his ideas and methods were bonkers and would never work the fact that humans have stopped evolving naturally is something that some people still want to change.

More information: http://en.wikipedia.org/wiki/The_Holocaust#Development_and_e...

Re: What future space combat would really look like

#194

Post by skore » Wed, Dec 28, 2011, 11:50 AM UTC

JDulin wrote: post #187

sliverstorm wrote: post #129

Earlier quoted context omitted.

You can argue this over in your head a lot, but it's really quite simple in my mind. If we assume space travel becomes relatively easy (that is to say it is used for more than initial colonization) there will be interstellar commerce. If there is unprotected commerce, there will be pirates. Any time there are pirates, protection will develop. Let us call these peace-keepers the Navy. If you engage in commerce and you…

I think your argument is aiming at the right target, but is using the wrong ammo. The essay outlines why piracy is not possible (or at least practical) for space commerce. However, it is very plausible that nations will fight over shipping routes and try to destroy each other's freighters and merchant ships. Like you said "Anywhere you have commerce, you are liable to develop conflict." This will be true, but probabl…

True, but probably only until space flight becomes less prohibitively expensive, or the commerce that happens in space becomes more "interesting", to pirates.

Re: What future space combat would really look like

#195

Post by electromagnetic » Wed, Dec 28, 2011, 12:29 PM UTC

JonnieCache wrote: post #188

nl wrote: post #174

Earlier quoted context omitted.

most matter is easy to come by Endless wars over oil, rare earth metals in Africa and the ever increasing price of iron ore would tend to indicate you might be wrong about that. Just because a single 3D printer won't use much won't magically make resource constraints disappear.

I guess he's imagining some cheap way to rearrange subatomic particles.

The logical steps in 3D printing is to increase the number of molecules the printer can print with. There's almost an infinite number of molecules you have to deal with, so it's a very logical step that once 3D printing becomes a commercial endeavour then there'll be quick steps made towards an atomic printer.

91 regularly occurring natural elements is a much shorter order than tens of thousands of common molecules. Considering there are over forty simple hydrocarbons and molecular printers start looking bulky, granted you might only ever use a maximum of 5 hydrocarbons, but that day you need a 6th you'll be cursing your shitty base model printer.

Re: What future space combat would really look like

#196

Post by electromagnetic » Wed, Dec 28, 2011, 12:44 PM UTC

nl wrote: post #174

electromagnetic wrote: post #170

Earlier quoted context omitted.

Agreed. Piracy denotes the theft of goods or money. When you can print goods, money is worthless. Your soul resources become matter and energy, and most matter is easy to come by. Piracy would likely extend solely to the theft of energy resources. Similarly, so would war but on a bigger scale. Piracy of goods would only extend to things not easily replicable by the present technology, or not easily replicable on many…

most matter is easy to come by Endless wars over oil, rare earth metals in Africa and the ever increasing price of iron ore would tend to indicate you might be wrong about that. Just because a single 3D printer won't use much won't magically make resource constraints disappear.

As I said, piracy will eventually extend to the theft of energy or raw matter.

Carbon, silicone and iron are easy to come by in space. Actually, given that olivine may be a common material in asteroids you're looking at abundant magnesium, iron, silicone and oxygen right there. However things like rare earth metals may be less easy to come by and if 3D printing jumps to molecular printing, then there'll be ships carrying pure metals as goods. Consider Neodymium cost averages $350/kg, a ship hauling it out to Neptune will be worth a lot of money stolen. Especially when the pirates would be selling for If piracy happens over raw materials, eventually so will war even if it's just to stop the pirates. However there'll be asteroids found with thousands of tonnes of easily mineable rare metals, and then we'll see space battles.

Re: What future space combat would really look like

#197

Post by wisty » Wed, Dec 28, 2011, 1:53 PM UTC

zeteo wrote: post #130

ohyes wrote: post #88

Space combat seems pointless to me. What exactly would they be fighting over? Presumably you want to reach space for resources, so asteroids, planets and moons with minerals, stuff like that. You might also want planets/asteroids/moons that are 'good' for colonization (easily terra formed or already life sustaining). You probably wouldn't see many fights where you are firing at the resource itself. No one with the mo…

People have been making the argument that war makes no economic sense, and therefore won't happen, since at least 1898: http://en.wikipedia.org/wiki/Jan_Gotlib_Bloch#Research_and_a... Sixteen years later, they had the first world war.

It didn't really make much sense, either. Nor the next one.

Re: What future space combat would really look like

#198

Post by electromagnetic » Wed, Dec 28, 2011, 2:06 PM UTC

saulrh wrote: post #183

electromagnetic wrote: post #162

The OPs problem here is that in the attempt to change the analogy from naval combat to aerial warfare is that he fails to grasp the medium again. Space is big, space is empty. FTA this means everything is easily trackable, not only are thrusters visible from across the solar system (except perhaps if you're headed directly for someone, but the thrust required there would be insane), but even every object in the solar…

Mines are just as detectable as anything else. Problem: how does your mine know when to go off? If it has sensors, it has electronics; if it has electronics, those electronics are running at something above 3 Kelvin; if you're running anywhere above 3 Kelvin, you can be seen against the cosmic background. Also, asteroids are incredibly vulnerable, because they can't move. You don't even need to get into range; just b…

I don't disagree, but remember the number of asteroids over 100km is around 200. The number of asteroids over 1km is between 700,000 and 1.7 million. That means the very big asteroids are between 0.0003% and 0.0001% of the objects in the asteroid belt. Given that the smallest known Aten asteroid is ~5m in diameter, then it's an easy conjecture that the asteroid belt is likely to have tens if not hundreds of million asteroids They're going to have enough mass that blasting them is going to be impractical. It's going to be a waste attacking a mining asteroid if you're dumping hundreds of munitions at every nearby rock.

> If it has sensors, it has electronics; if it has electronics, those electronics are running at something above 3 Kelvin; if you're running anywhere above 3 Kelvin, you can be seen against the cosmic background.

This is very true, however given the variation in albedo's of asteroids and meteoroids then there's going to be a wide range of 'normal' temperatures for asteroids. With enough processing power you could assume that people would eventually start calculating asteroid albedo vs distance from sun vs apparent temperature. If you've got a light rock that's hot as all hell, then you might be best to shoot it just in case. Probably not likely for civilians at least, even the military might not want to be running too much processing power as they'd have greater heat sinking issues to worry about.

The real thing that will determine how hard or easy to find mines will be is human mining. How much dirt and debris are we going to be producing, or even purposefully producing. If we're mining bigger asteroids are we going to require ships to land, or simply dump payloads into orbit for ships to snag. If we're doing the latter, then we're talking about hundreds of objects running well above background levels. How much rock are we going to strip off an asteroid and leave nearby?

If piracy or warfare becomes real, then mining companies will likely want to limit the approach vectors for incoming ships. What better way than dumping copious amounts of junk in your orbit. Given that a cubic meter of silica weighs around 2500kg, then you're not likely to crash your ship into it at any speed. Put thousands of these in orbit, and people are only going to approach from the clear paths.

Again, all these rocks would be hotter than background, and you only have to mine 1% for it to be a solid defence. Making someone take 100 shots in 1-hit wins warfare is a very effective defence.

Re: What future space combat would really look like

#199

Post by onemoreact » Wed, Dec 28, 2011, 2:51 PM UTC

absentbird wrote: post #193

jrockway wrote: post #142

Earlier quoted context omitted.

Because people are irrational. Why did Hitler try to kill all the Jews? Because he felt like it and had the means to do something about it.

It was for racial purity. At the time eugenics was a big deal, it stated that some genes which were exhibited as external traits were superior. Hitler was attempting to create a better world by performing artificial selection. As much as his ideas and methods were bonkers and would never work the fact that humans have stopped evolving naturally is something that some people still want to change. More information: htt…

People are still evolving. Evolution is adaption to existing conditions and is basically impossible to stop. In fact dispute billions of years of multicellular evolution the cells 'in your body' and given time will develop into cancer, then portable cancer inside your body, and given the right conditions portable cancer outside your body.

PS: Humans closet genetic relative is a single celled organism whose species started from cultures of a woman's cancer cells. http://en.wikipedia.org/wiki/HeLa Tasmanian devils suffer from a similar disease of more natural oragin. http://animals.nationalgeographic.com/animals/mammals/tasman...

Re: What future space combat would really look like

#200

Post by jermy » Wed, Dec 28, 2011, 2:53 PM UTC

orenmazor wrote: post #3

I think Hamilton nailed it when he talked about kinetic weapons and 'wasps' (aka small bots that can move in ways a human occupied ship can't)

Indeed - in this particular series (The Night's Dawn Trilogy) space warfare was conducted at very long range by kinetic drones, fired from spherical ships.