Probing The Inaccuracies: Space Warfare

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RAKtheUndead
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Probing The Inaccuracies: Space Warfare

Postby RAKtheUndead » Sat Apr 04, 2009 11:29 pm UTC

This forum is not your blog. That said, this does look like an interesting discussion has resulted. No one need feel any strong need to read all of this OP, though, as it's a bit tl;dr.

(Suggested reading material during the article: Atomic Rocket.)

Recently, I decided to revisit one of my interests: Space warfare. It has been known to me for quite some time that most people don't really know that much about space combat, for the main metaphors for combat in space represent combat spacecraft in a fashion befitting ships on the sea. Now, I'm hardly an expert on these matters, but I would like to discuss the issue and possibly reinforce my own knowledge in the process. So, without further ado...

Probing The Inaccuracies: Space Warfare
a.k.a. Space Warfare: Almost Everything You Know Is (Probably) Wrong

Space warfare is one of the most popular settings for science fiction stories, with its near-endless expanses and its huge variety of different settings, but it's very difficult to find someone who depicts an accurate and plausible method of space fighting; who's done the requisite research. I'm here to deliver information on a few of the more egregious inaccuracies and some of the more common implausibilities in popular depictions of space combat, as well as discussing a few ideas which I see as plausible.

"The laws of physics strike again!"

Movement in Space: I begin with the source of some of the most egregious errors in space-based science fiction, the principles of moving through space. What makes this an especially irritating set of inaccuracies is the fact that any secondary-school physics student should be able to figure out these principles very easily and without much effort. Some of the knowledge about the movement of objects in space was devised by Isaac Newton, back to the 17th and 18th century, and is taught at primary school level.

So, firstly, there is no friction in space. Once you reach a specific velocity in open space, you're not going to slow down. This is elementary Newtonian physics, conforming to Newton's First Law of Motion, which states that any object in uniform motion tends to stay in that uniform motion until acted upon by a net external force - in other words, it conforms to inertia. Any molecules in space (because it's not completely empty) are going to be too diffuse to slow down the motion of a spacecraft.

The most obvious application of this law of motion would be the fact that once you get a spacecraft into motion in outer space, you're not going to need to use any more fuel to keep it at a specific velocity. Therefore, any depictions of spacecraft with engines flaring and the spacecraft remaining at a constant speed are already inaccurate. Missiles in space aren't going to need to burn fuel once they reach a certain velocity, so engines flaring from the back of those when they're remaining at a constant velocity causes another inaccuracy. (This rule also adds a practical benefit for missile design in space, which I'll address later.)

Secondly, spacecraft are often described as having a top speed, usually given in invented units. The speed limit of a spacecraft is actually going to be somewhere near light speed, short of limitations due to lack of fuel. A more apt measure to give would be maximum acceleration rates, as these would accurately depict how quickly a spacecraft could catch up to or run away from another.

"You know, you're going to have problems cooling that spacecraft...": I'm sure you've heard that space is cold many, many times over the course of your lives. Indeed, it is; about 3-4 Kelvin, I believe. But don't for a second think that, if you were to be ejected into space this instant, you'd freeze immediately. Remember what I was saying about diffuse particles under the last heading? That has its applications in terms of heat transfer as well.

You see, in order to transfer heat, you need particles to transfer it to. There simply isn't enough hydrogen in outer space to readily radiate heat to, and you'd die of asphyxiation long before you'd die of freezing. This also means that spacecraft are going to have lots of problems with dumping excess heat. Best not to use those fancy laser and plasma weapons, I suppose.

There is no such thing as "stealth in space"!: An unfortunate casualty to the laws of thermodynamics, due partially to the previous example, is the myth of "stealth in space". If you've devised a scenario where this happens, don't feel too ashamed: I've fallen victim to this inaccuracy myself. However, there is absolutely no way with real materials to devise a spacecraft which can hide in space.

The problem lies with the heat generated by a spacecraft. Even if you keep the spacecraft's engines off, you're going to have the 290+ Kelvin crew section lighting up against the background of space, and that's before you get to the heat given off by a power generator for that life support system that's keeping you alive. If you actually decide to fire up the engines, you'll flash up like a beacon.

And if you're thinking about losing yourself in the sheer volume of empty space, don't bother. Any prospective combat spacecraft is going to be picked up over the entire solar system, and thermal scans can be done in mere hours - with current equipment.

Explosions - They're Very Different: I'm going to guess now that one of your entrenched thoughts regarding space combat involves a lot of explosions. It's time to think again. Explosions work very differently in space to explosions in atmosphere.

You see, the atmosphere is precisely what allows the blast of an explosion to travel. In space, with its diffuse particles, there is no blast from an explosion. All you'll get is a very intense central point of light, followed by a very rapid spherical expansion and debris travelling out from the explosion. You're not going to be able to build a weapon from an explosive device, that's for sure.

Nuclear Weapons Don't Work Either: The nuclear weapon is probably the most feared device on Earth, capable of annihilating cities and leaving countries uninhabitable. In space, they're rather less intimidating. The lack of atmosphere means no blast, just as with a conventional missile, and they give off a pitiful amount of thermal radiation. Oh, and nuclear weapons don't produce EMP when you're in deep space.

However, there is one effect that remains: the large-scale emission of nuclear radiation, and without an atmosphere to degrade it, the level of radiation remains strong over a much longer distance. Even the smallest of nuclear weapons would leave a lethal radioactive cloud stretching for kilometres, and a strategic, ICBM-style nuclear device would remain lethal for more than 100 kilometres. There is, however, a simple shield against all of this radiation, and one that's probably going to be built into the spacecraft anyway: Lead. There's going to be a layer of lead for travelling through natural radiation belts, which limits the ability for radiation to penetrate.

Now, within about a kilometre, nuclear weapons will have effects. The radiation will be absorbed by the hull of the spacecraft, causing rapid and uneven heating, spallation of armour and impulse shock. These effects would seem to make a nuclear warhead on a missile a good idea. However, nuclear weapons are expensive, and degrade over time, and when you couple this to the likely propagation of anti-missile systems as standard armament, the number of nuclear warheads impacting the target reaches a low-enough ratio to make missiles with solid warheads and ultra-high speeds a far more affordable option. Therefore, I foresee the large-scale obsolescence of nuclear weapons in space.

Shiny Red Lasers? No.: You can't see lasers in space. Enough said. Most lasers used in space would be at infra-red frequencies anyway, so that would nullify that in any case.

Outer Space Ain't The Best Place To Practice The Guitar: One of the most well-known characteristics of space is its inability to transmit sound. As sound waves are longitudinal, they require a medium to pass through. The vacuum of space doesn't provide an environment conducive to transmission of sound, with the net result that you aren't going to hear a missile until it strikes you on the hull.

Combat Spacecraft Design, And Why Your Favourite Fictional Spacecraft Would Suck In Reality

"So, how much does it cost to maintain your massive spacecraft?": People like to appeal to insane size when inventing their fictional spacecraft and space stations. It's the reason why you hear so much talk of the Death Star and Super Star Destroyers from Star Wars, and why so many people describe their spacecraft with naval ship classes like "Battleship" and "Battlecruiser". As somebody who has (unfortunately) fallen into this trap before, and somebody who's seen the light, let me tell you that it's an utter pleasure to tell you that these spacecraft would be completely implausible.

I'll give you a few minutes to cry/shout obscenities at your screen. Basing your space navy around these is the first clue that you've forgotten, ignored or never properly learned the laws of inertia. First of all, how much fuel are you going to need to expend to get that much mass moving in the first place, and once you have it moving, how the hell are you supposed to stop it? Even if you do figure out a way to get it moving, good luck having a turning circle which isn't measured in astronomical units.

And that's before you get to the less obvious questions of upkeep. The crew size for the first, complete Death Star is somewhere in the region of 250,000, plus hundreds of thousands of auxiliary troops. So, where the hell are you going to keep the food for these 250,000+ personnel, not to mention dormitories, leisure areas, et cetera? A modern aircraft carrier has a series of ships devoted to feeding it, and they only have crews going up to about 10-15,000. Keeping more than a million people fed on a single space station would be a logistical nightmare that even the Empire couldn't fix. Oh, and don't forget the cooling systems, because space doesn't radiate that much heat easily. Hell, I can see why they left that vent open in A New Hope. How the hell else were they supposed to keep the Death Star cool enough to actually work in?

The same thing applies even to your garden-variety space battlecruiser. In fact, the logistical problems are going to be greater, because how the hell are you supposed to supply it when it's in hyperspace, let alone normal interplanetary patrolling? But perhaps there's a reason why most of you forget about these things, because if a lot of you had given this even the amount of consideration that I have, your heads would have exploded.

"No, space fighters aren't going to work either.":Again, I'm guilty of this inaccuracy, as indeed are a lot of writers who probably know a lot more about the ideas of space warfare than I do. The problem is that while the battlecruiser and ridiculously large space stations don't work because of an overly-large crew and requirements for huge amounts of food and cooling systems, the space fighter doesn't work because it has no place for anything more than a rudimentary life support system, and the lack of explosive weaponry in space means that it remains underarmed. Because space fighters can't engage large spacecraft, there's absolutely no point in maintaining them for fighting each other. They're just irrelevant, that's all.

So, no space dogfights for you.

"Space marines? No, not them either.": Yet another inaccuracy that I've been guilty of, but I've recently become convinced that the space marine as it's portrayed in science fiction is an implausibility. Robert A. Heinlein noted this in Starship Troopers, justifying his Mobile Infantry with the need for a "personal touch". However, when it comes to human-on-human space warfare, what's the point of having a personal touch when an overbearing presence in space, complete with city-annihilating weapons, frightens people that much more? Perhaps some sort of space-bound infantry will survive, policing space stations and maintaining order on planetary surfaces. However, this will remain more of a paramilitary force than any force specifically designed to attack.

Despite its irrelevance in a traditional spacecraft warfare context, it seems that the space marine may be relevant at some point in the future. Until using giant space stations loaded with weaponry becomes cheaper and logistically superior to using infantry, the space-bound infantryman need not fear for his job.

"So, what the hell is going to work?" - Some Plausible Designs?

Spacecraft Design: While your crazy, ornate spacecraft designs are doomed to failure from the start, there are a few types of spacecraft design which might work for combat purposes. These designs conform to one of two basic shapes: The cylinder and the sphere. There are advantages and disadvantages to either design, but I'll be presuming that most combat spacecraft will conform to the cylinder shape rather than the sphere.

Now, once you have your cylinder, you're going to have to develop crew sections for it, which will have to be inside the cylinder to take advantage of shielding. Here, we come to a little problem: Generation of artificial gravity, which is essential because long-term exposure to zero-gravity is going to cause significant physiological effects. The most plausible way of generating artificial gravity is to use centripetal acceleration to your advantage, and to place the crew inside a rotating centrifugal cylinder.

Now, this guy maintains that spacecraft should always have their crew sections laid out like a skyscraper, rather than an aircraft, but I'm inclined to disagree slightly, because of the need to encase a combat spacecraft's crew sections inside the spacecraft itself, maintaining an integrated design. Centripetal acceleration always acts in on the centre of a circle, and therefore, the crew members will be forced out onto the outer side of the sphere by inertial forces. Maintaining a cockpit which conforms to an "up" being the direction of movement would be reasonable, but I'm not convinced that it works so well for passenger sections, unless the centrifuge is lined longitudinally, which limits the amount of space available to the crew members.

There is a lower limit on the size of a centrifugal cylinder, based on the effects of the Coriolis effect on many would-be space travellers. Discovery One from 2001: A Space Odyssey had a centrifugal cylinder with a 11.6m diameter and a 3RPM spin rate, which would generate an artificial gravity with significantly less than 1G. Therefore, any combat spacecraft intending to generate 1G of artificial gravity would be approximately about the size of a naval battleship, with a rotational cylinder at a rate of about 7-10RPM.

Luckily, you're not going to have that many crew members to worry about. The thousands of personnel of many people's combat spacecraft designs (including some of my older ones, unfortunately) are a fiction. By the time that space travel becomes plausible, computing technology will be advanced enough to run nearly all of the spacecraft's systems, and automation will be king. I predict that combat spacecraft will require a crew up to about 20 personnel - on the largest combat spacecraft.

One of the most reasonable designs for an engine for an interplanetary spacecraft would use nuclear pulse propulsion from a fusion rocket, like the studies conducted by the British Interplanetary Society and NASA in their respective projects, Project Daedalus and Project Longshot. The Longshot design, with its separate engine and nuclear reactor, would be superior for a design carrying human personnel, and therefore shall be taken as the basis for my own designs.

Weapons Systems: You know that naval metaphor that you're thinking of? Forget about it. Close-range space combat just isn't going to happen. Sensor technology that can pick up spacecraft across the whole solar system, and the complete lack of shielding able to protect against long-range blasts, maintains that space combat will be fought over a very long distance, measured in hundreds or thousands of kilometres. This is the most difficult part of space warfare to predict, but I'll take a stab at it based on what I've read before.

Now, at those distances, a light-speed weapon such as a laser would seem like the most logical choice, but there may be issues which limit the usefulness of lasers in space. You see, lasers are prone to producing a lot of heat, which is something which isn't exactly a good thing on a spacecraft which might already be having difficulties with dumping excess heat. However, they don't require any ammunition, which makes them ideal point-defence weapons against missiles, et cetera.

Because of the heat problems with any sort of energy weapon, the most plausible main weapon systems of a prospective future spacecraft appear to be missiles and mass drivers. Out of these two choices, missiles are likely to be used the most often, as they have the ability to correct themselves in mid-flight. Because there are no acting forces in space to slow a missile's flight (back to the First Law of Motion again!), a certain amount of fuel is going to go much further, and the missile is going to be able to accelerate to much higher velocities, which will be important, because without an explosive warhead to count on, it's going to have to crash through the opposing spacecraft.

Mass drivers, usually magnetic accelerators in the form of the coilgun or the railgun, will likely be the other popular choice of armament for a spacecraft. Unlike missiles, their projectiles will remain mostly unharmed by laser point-defence systems, but unlike missiles, the projectiles would likely be unable to correct their direction in mid-air, meaning that computer systems will have to actively predict the relative velocity of an opposing spacecraft and correct its aim accordingly. Like the space missile, the mass driver's projectiles are designed to use high amounts of kinetic energy to smash through an opposing spacecraft, travelling at a high enough velocity to hit before the enemy can oppose inertia enough to move out of the way of the incoming projectile. Clouds of shot may be useful for this purpose; a spacecraft moving at a high velocity relative to your spacecraft is going to be stopped by a surprisingly light projectile - maybe even with as much mass as an empty beer can. Therefore, you may see kinetic shells loaded with kilograms of buckshot, ball bearings or even sand and gravel.

Apart from these weapons, there will likely be a number of new weapons that would be harder to predict. While most types of nuclear weapon will likely become obsolete for use in space, because of the requirement for it to hit the target directly, there is one sort of nuclear weapon which may be useful. The neutron bomb generates high-energy neutrons as a byproduct of its detonation, which are more difficult to shield against than the gamma rays of the majority of nuclear weapons.

As well as that, there are ways of generating EMP using a non-nuclear device, and while I would expect spacecraft to be heavily shielded against EMP and have plenty of redundant systems, a sufficiently large EMP is going to fry any transistor-based computer systems, rendering a spacecraft almost useless, and often rendering it as a big, metal, space-bound coffin for any personnel left inside.

* * *

So, almost 3,000 words later, and I haven't even discussed everything I've learned about space warfare, let alone what somebody with more experience with this subject and the physics behind it would be able to recall. This site is full of reading material on the subject, dealing with just about everything you'd ever want to know - and a lot of things you probably wouldn't.

If you made it to the end, well done. If you made it to the end without crying or cursing at the screen for me destroying your fantasies, greater commendations are due. As I've noted several times over the course of the article, I've fallen into several of these inaccuracy traps myself, so it isn't uncommon. There's actually a secondary reason for doing all of this research - as difficult as it appears to be to write a hard science-fiction story based around space warfare, I'm trying to give it a go right now, after some embarrassing failures with previous stories.
Last edited by RAKtheUndead on Tue Apr 07, 2009 3:09 pm UTC, edited 1 time in total.
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heyitsguay
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Re: Probing The Inaccuracies: Space Warfare

Postby heyitsguay » Sat Apr 04, 2009 11:45 pm UTC

Are we... supposed to thank you now?

Movies take creative license. They're under no obligation to be scientifically accurate and frankly it doesn't really effect the enjoyment (or lack thereof) of a movie. Except for you, apparently.

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Re: Probing The Inaccuracies: Space Warfare

Postby Sir_Elderberry » Sat Apr 04, 2009 11:50 pm UTC

heyitsguay wrote:Are we... supposed to thank you now?

Movies take creative license. They're under no obligation to be scientifically accurate and frankly it doesn't really effect the enjoyment (or lack thereof) of a movie. Except for you, apparently.

Well, within reason. I couldn't enjoy a movie if the climactic scene relied on the protagonist turning off a spaceship engines so it'll come to halt swiftly. On the other hand, I have no problem excusing the Romulans for being invisible in space, as it makes for good drama.

But, a lot of space combat sci-fi has handwaves available for lots of this stuff. Sure, you keep going in space without engines. But can you keep going at warp speed? (Extra note: If your series has FTL travel, you're already violating some deep physical laws. Visible lasers are nothing in comparison.)

In short, scifi quality does not necessarily scale with hardness. At its absolute hardest, after all, it's just realistic fiction.

EDIT: Also, while I won't go so far as to "thank" you, good job on assembling this. It was an interesting read.
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Re: Probing The Inaccuracies: Space Warfare

Postby Zeroignite » Sun Apr 05, 2009 12:47 am UTC

Uh, you should write a blog, not a forum?
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Re: Probing The Inaccuracies: Space Warfare

Postby quintopia » Sun Apr 05, 2009 1:07 am UTC

So what would you say are the major flaws in Niven and Pournelle's "Footfall"?

Would venting lots of steam into space be a good cooling system? Would it provide enough maneuverability for such a large ship?
Would exploding a nuclear bomb in the middle of your steam trail provide sufficient forward acceleration?
Would a high powered gamma laser energized by that nuclear bomb be sufficient to penetrate light shielding like the Snouts' designed-for-atmosphere digit ships would have?
Would a half-mile thick steel plate make a good defense against kinetic energy weapons?

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Re: Probing The Inaccuracies: Space Warfare

Postby Vieto » Sun Apr 05, 2009 2:04 am UTC

One way to solve the heat dissipation problem could be to increase the surface area of a ship. This, of course, goes against the cylinder/sphere ship design for structural stability.

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Re: Probing The Inaccuracies: Space Warfare

Postby Sir_Elderberry » Sun Apr 05, 2009 2:33 am UTC

Vieto wrote:One way to solve the heat dissipation problem could be to increase the surface area of a ship. This, of course, goes against the cylinder/sphere ship design for structural stability.

We have analyzed your heat-dissipation faculties and found them unable to withstand our power output.

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Re: Probing The Inaccuracies: Space Warfare

Postby Carnildo » Sun Apr 05, 2009 3:25 am UTC

Vieto wrote:One way to solve the heat dissipation problem could be to increase the surface area of a ship. This, of course, goes against the cylinder/sphere ship design for structural stability.

Any spaceship with an engine powerful enough to be interesting is going to have enormous cooling fins that are glowing either red-hot or white-hot, depending on what they're made of.

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Re: Probing The Inaccuracies: Space Warfare

Postby Diadem » Sun Apr 05, 2009 3:29 am UTC

You should read some Peter F. Hamilton. His space combat scenes are awesome. Sure he takes some creative license, but still very good, and pretty realistic.

For a start he gets the mechanics right. It's acceleration that matters, not velocity, and he gets this right. Where spacecrafts without humans in them can accelerate a lot faster, and missiles accelerate fastest of all. His combat is also all automated. None of this shooting with lasers and missing bullshit. You can't miss with a laser. It goes with the speed of light, even in space combat where you can be hundreds of km apart, that means you still hit instantanious for all practical purposes. Any targetting computer with more processing power than a 286 simply can not miss. His combats consist of both spacehips launching swarms of fully automated combat drones - and then hoping your swarm wins.

Compared with star trek or star wars or bsg, that is very refreshing.
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Re: Probing The Inaccuracies: Space Warfare

Postby frezik » Sun Apr 05, 2009 4:18 am UTC

It's hard to predict what will and will not be accurate in space warfare, because nobody's given it a serious go yet. It'll take at least one good war before anyone figures out the basic strategies and tactics. Pilots in WWI basically had to make it all up as they went, and are considered to have little effect on the outcome of the war. The first real space war can be expected to go the same way.

There are, of course, some things we can say for sure right away, like the importance acceleration vs velocity. There are other things I'm not so sure on, like the usefulness of close range fighters. Consider a fighter that takes out larger ships by delivering a magnetic bottle of antimatter to the target. Such a fighter may provide more smarts than a missle in order to evade enemy fire (provided the pilot can survive the G-forces), but still deal a pretty big punch. I'll also leave open the possibility of developing some other compact and highly destructive weapon, but obviously that leaves the realm of hard SF.

As for nukes, they have to provide some kind of explosive force, or else something like Project Orion wouldn't work. True, you don't get the atmospheric shockwave, but you'll get some kind of explosion. It'll just mean a renewed race to scale up the megatons. Research into increasing yield size stopped in the early '60s with Tzar Bomba, at 50MT (theoretically could have reached 100MT). Everyone on both sides agreed that it was far more power than even General Ripper could justify in a war, and instead focused mostly on compactness and delivery methods. But space nukes could easily be useful at 10 times that force.

I'd recommend looking at Gundam Century, a tech book explaining some of the mecha from UC Gundam. It's not always spot on, but it at least trys to justify itself pretty well. For instance, AMBAC uses conservation of momentum to spin a suit around by moving its arms, thus (thinly) justifying human-form giant robots. The Dom unit uses a nuclear thermal jet that sucks in air and superheats it to provide thrust (the Rick Dom being the space version, which provides all its own air). Coolent tanks have to be swapped out on space-based units (which causes one side to lose a lot of otherwise good pilots). It also has a very vivid description of dropping an O'Neill Cylinder on Sydney.
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Re: Probing The Inaccuracies: Space Warfare

Postby Sockmonkey » Sun Apr 05, 2009 8:12 am UTC

While the atomic rocket page is a great resource I must warn anyone thinking of reading it that it will do a pretty good job of killing the fun most sci-fi. I've read it pretty thuroughly and only my superhuman powers of denial have allowed me to still like the original star wars films. That being said, I do feel that sci-fi space fighters should obey at least the more obvious laws of physics like inertia and being able to spin on your own axis to shoot someone behind you.

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Re: Probing The Inaccuracies: Space Warfare

Postby RAKtheUndead » Sun Apr 05, 2009 10:59 am UTC

heyitsguay wrote:Movies take creative license. They're under no obligation to be scientifically accurate and frankly it doesn't really effect the enjoyment (or lack thereof) of a movie. Except for you, apparently.


I think it really depends on the medium. A movie in the "proper" Star Wars trilogy probably gets away from it based on the audacity of everything and the fact that it doesn't take itself too seriously. However, I don't enjoy something that tries to do things with scientific inaccuracy with a straight face. I suppose I either like ridiculously soft science-fiction, such as Doctor Who, or particularly scientifically accurate SF.

I'm also the sort of person who plays realistic simulation driving games, "realism" mods in military simulator games, et cetera. Indeed, I think I may write a series of "Probing The Inaccuracies" articles, concentrating on modern naval combat, possibly gunfighting and certainly one on automotive inaccuracies. Car inaccuracies are particularly egregious, and I'll certainly have to conquer those.

Zeroignite wrote:Uh, you should write a blog, not a forum?


Ah, but I've considered this before. I don't write a blog, precisely because nobody would ever read it. More importantly, I'd never get proper, well-considered responses, which are pretty important to me.

quintopia wrote:Would venting lots of steam into space be a good cooling system?


I'd say it would be a good cooling system, but an impractical one. Remember that you have to carry plenty of water for every unit volume of steam that you expel, which adds mass. That mass increases your inertia, and while you might have a secondary cooling system which uses steam, or some sort of coolant vapour, I doubt it would be the primary system for cooling. You might use a system like that during combat itself.

quintopia wrote:Would exploding a nuclear bomb in the middle of your steam trail provide sufficient forward acceleration?


In order to use a nuclear bomb as a propulsion system, as in the Project Orion system, you have to use a pusher plate for whatever explosion that you have to push yourself forward. The Orion system is definitely feasible, and is definitely a reasonable sort of hard science-fiction propulsion system. You may be exploding a nuclear weapon in the middle of your steam trail, but you'll be catching it on a pusher plate anyway, and considering that you'd have to carry huge amounts of coolant to use it as a propulsion system, you're probably not going to be using it for that in any case.

quintopia wrote:Would a high powered gamma laser energized by that nuclear bomb be sufficient to penetrate light shielding like the Snouts' designed-for-atmosphere digit ships would have?


I'd say that the weapons systems would probably be powered by an on-board nuclear reactor, as the developers of Project Longshot felt that powering the on-board systems with the propulsion reactor, as in Project Daedalus, was a rather impractical way of doing things, but I suppose there might be ways of harnessing the energy from the nuclear weapon in any case.

quintopia wrote:Would a half-mile thick steel plate make a good defense against kinetic energy weapons?


That all depends on the velocity of the kinetic projectiles, but I'd say that it most likely would. It would be incredibly heavy, though, and that increases inertia greatly.

Diadem wrote:You should read some Peter F. Hamilton. His space combat scenes are awesome. Sure he takes some creative license, but still very good, and pretty realistic.


I've heard good things about his work, and I'll have to check it out. Now, the whole dispersal of unmanned combat drones is probably a reasonable way of fighting, but in the near-future, I'd be inclined to think that space warfare would all be about trying to take out targets of opportunity - industrial facilities, space stations, fuel gathering stations, et cetera - because spacecraft are going to be expensive enough to not want to risk them on crazy endeavours.
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Re: Probing The Inaccuracies: Space Warfare

Postby Avian » Sun Apr 05, 2009 11:28 am UTC

RAKtheUndead wrote:There is no such thing as "stealth in space"!

...

The problem lies with the heat generated by a spacecraft. Even if you keep the spacecraft's engines off, you're going to have the 290+ Kelvin crew section lighting up against the background of space, and that's before you get to the heat given off by a power generator for that life support system that's keeping you alive. If you actually decide to fire up the engines, you'll flash up like a beacon.


Well, you could actively cool the side of your craft that's facing the enemy and have radiators on the other side. Of course that would mean you would have to know where they are in the first place (usable for a surprise attack on a planet for instance).

On the other hand I can imagine you could store the heat somewhere inside for a limited time. Imagine heat pumps that cool the hull at the expense of heating up a tank of some substance with a high heat capacity.

Actually, I don't see why this problem only applies to space. Stealth aircraft have the exactly same problem.

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Re: Probing The Inaccuracies: Space Warfare

Postby Woofsie » Sun Apr 05, 2009 1:58 pm UTC

That was a very fun and informative read, thanks. If you do go ahead and write more, I'd love to see them. :)

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Re: Probing The Inaccuracies: Space Warfare

Postby achan1058 » Sun Apr 05, 2009 2:48 pm UTC

I recalled hearing someone in a video gaming company said a particularly enlightening phrase to me, something along these lines:

We don't do physics here, we do fysics, with an "F".

The same clearly applies to Sci-Fi warfare.

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Re: Probing The Inaccuracies: Space Warfare

Postby BlackSails » Sun Apr 05, 2009 3:05 pm UTC

I dont see why you cant have stealth in space.

Whenever you want stealth, you just surround your ship in a perfect black body/IR mirror.

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Re: Probing The Inaccuracies: Space Warfare

Postby MarshyMarsh » Sun Apr 05, 2009 4:22 pm UTC

Something people always miss is that ship's will also need self-awareness technology. The ability to identify the reflection of ones own ship is key to fighting any enemy with big ass mirrors.

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Re: Probing The Inaccuracies: Space Warfare

Postby Iv » Sun Apr 05, 2009 8:12 pm UTC

So I guess the question is : please tell me what is wrong in what I wrote ? ;-)
I only read part of it but I got a counterexample on one thing:
RAKtheUndead wrote:Keeping more than a million people fed on a single space station would be a logistical nightmare that even the Empire couldn't fix.

What the Empire can't do, the proud America did :
http://en.wikipedia.org/wiki/Berlin_Blockade

5000 tons of food per day at its peak, about 2 millions people fed by the aerial bridge. And provided with coal. Heinlein would be ashamed to see that you underestimate militaries logistics :-p

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Re: Probing The Inaccuracies: Space Warfare

Postby SummerGlauFan » Sun Apr 05, 2009 8:38 pm UTC

I have a question about explosives.

While I know that triggering an explosive device (with the exception of a rediculously large nuke) in "proximity" to a spacecraft would have an effect somewhere between nothing and a mouse fart, wouldn't an explosive detonated directly on your target still transfer the kinetic shock into the target? For example, those space fighters you hate so much firing tactical nuclear missiles into the enemy ship should be able to do a very respectable amount of damage. Let alone even a conventional missile scoring a direct strike on a starfighter or other small vessel.

Edited because my keyboard has a problem with the S button.
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Re: Probing The Inaccuracies: Space Warfare

Postby Wiglaf » Sun Apr 05, 2009 9:01 pm UTC

First,
Spoiler:
I'm going to guess now that one of your entrenched thoughts regarding space combat involves a lot of explosions.
I'll give you a few minutes to cry/shout obscenities at your screen.
But perhaps there's a reason why most of you forget about these things, because if a lot of you had given this even the amount of consideration that I have, your heads would have exploded.
If you made it to the end without crying or cursing at the screen for me destroying your fantasies
Stow it.


You see, in order to transfer heat, you need particles to transfer it to.
Wrong. Radiation works perfectly fine in space.

On nuclear weapons: But perhaps a strategy of missiles will be to penetrate at high speed and then explode once in an atmosphere. A nuke could make that situation very hairy for the target. But, by the time space combat comes around, nukes will probably be boring. Large-scale weapons might not have anything to do with nuclei, and thus would not be called nuclear.
Even if you do figure out a way to get it moving, good luck having a turning circle which isn't measured in astronomical units.
Very large space ships would probably not be able to move without significant plans they can't stray from much. Their movements would probably be aided by the gravity of planets. If they encounter an enemy, they probably won't have much a choice other than shoot while flying on course.

Keeping more than a million people fed on a single space station would be a logistical nightmare that even the Empire couldn't fix. Oh, and don't forget the cooling systems, because space doesn't radiate that much heat easily. Hell, I can see why they left that vent open in A New Hope. How the hell else were they supposed to keep the Death Star cool enough to actually work in?
How does the Earth do it then?

Because space fighters can't engage large spacecraft, there's absolutely no point in maintaining them for fighting each other. They're just irrelevant, that's all.
Really? You mean to tell me you haven't watched Star Wars?

Now, at those distances, an instantaneous weapon such as a laser would seem like the most logical choice, but there may be issues which limit the usefulness of lasers in space.
Lasers are not instantaneous. At the ranges spaceships can engage, they may be light-minutes apart. If the ships are maneuverable, you wouldn't be able to hit at those long ranges. If the ships are not, they would be daft to not armor themselves properly. 286's may be able to project a ships motion, but they do not predict the future. Lasers would be useful in anti-missile defense systems. Missiles would indeed be the most practical long-distance weaponry, but don't expect them to work. Spaceships would indeed enter closer range combat, to the point where lasers and dumb projectiles could land on target.

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Re: Probing The Inaccuracies: Space Warfare

Postby EdgarJPublius » Sun Apr 05, 2009 9:16 pm UTC

A few things:

Stealth In Space

Man people take the axiom of 'there is no stealth in space' way to far and start assuming that all combatants will have near omniscience only limited by light speed lag.

Unfortunately, while stealth in space is highly limited, there is still such a thing as Electronic Warfare in space. Oftentimes I've seen people point to NSIS as justification for being able to provide highly accurate spectrographic analysis of small, fast moving spacecraft and/or missile exhaust to determine the targets mass and velocity with near-arbitrary precision.
This is highly implausible, it requires ridiculously sensitive instruments which would be highly vulnerable to even basic countermeasures, a sensor that can perform this kind of analysis on an inbound missile could be blinded by a laser pointer.
The rule will be ECM, ECCM, ECCCM... and etc. this is one thing the star wars universe gets mostly right, Everybody is jamming everybody else, amongst radar jamming, optical and IR laser dazzlers and all sorts of decoys, spotting and accurately engaging a target will be a lot harder than figuring out they're out there. In this situation, you may be able to move around with minimal notice just by keeping quiet and not spraying jamming signals everywhere, as long as you have an ally willing to keep local space polluted you may be able to have some measure of stealth.

Lasers in Space

They'll be invisible, there's very little mass to get in the way and cause diffraction, but they won't be infrared. Ultraviolet and other short wavelength/high energy beams are able to have much smaller spot sizes at much larger distances with smaller focusing assemblies than longer wavelength/low energy beams such as infrared. projectrho (the one stop info depot for everything you never wanted to know about space) posits an X-ray laser that melts steel at ranges of several light seconds, A feat an IR laser would be hard fought to accomplish within similar dimensions.

Also, Laser's aren't 'instantaneous' they are constrained, like everything else, by the speed of light, at ranges of only a single lightsecond, your beam will hit where your opponent /was/ two seconds ago (one second for light to go from the ship to your sensor, another for the laser to go from your ship to where you saw the enemy last. Depending on how fast you can accomplish the command/execution cycle, you may be even farther out of date than that)
This makes missiles an invaluable weapon for long distance engagements, the ability to change course in mid flight, and the ability to carry their own sensors (or to be accompanied by purpose built sensor craft, which could also provide local jamming and decoys to help defeat point defenses) means that though a missile will take longer to reach the target, it is far more likely to stand a chance of hitting it.

Of course, laser's aren't completely useless at range, using predictive targeting, it's possible to score an occasional hit at ranges of a few light seconds, but if the enemy is intelligent they will be maneuvering randomly to prevent that from occurring, and heat constraints mean that contant laser barrages to try to get those lucky hits will be an expensive proposition.

Linear Accelerators

Rail Guns, Coil Guns, MAC Guns, Mass Drivers, what have you, are all basically the same in terms of capabilities and role, and all have th same basic problems. While a large Mass Driver gun may be able to accelerate a projectile faster than your missiles can achieve, and do so to a larger mass, they'll still be limited to short range engagements for pretty much the same reason as lasers, but more so, because even a relativistic mass accelerator round will be far slower than a laser, som form of course correction would be essential for scoring a hit.

However, small mass drivers can serve as efficient missile point defense weapons, being able to take out armorer missiles faster than laser point defenses. And even large MAC guns have their uses, such as giving an initial speed boost to missile strikes, or as a last ditch kamikaze weapon when your radiators have been cut to ribbons and you're out of missiles.

Space War Theory:
History has shown, especially in naval warfare, but also in other areas of warfare, that engagements will tend to occur at the longest plausible ranges, In WW1 and II, naval engagements started at the extreme ranges of naval gunnery, where it took hundreds of shots to land a hit, and moved /out/ to where fighters had to be at the edge of their range to hit the enemy fleet and battleship engagements became rare, only occurring when carriers either weren't present, were occupied fighting other carriers, or were out of planes. Ground warfare is the same way, tanks fight at the very extremities of their accurate range no matter how much easier it would be to score direct hits by getting closer. Although aerial warfare in the age of the guided missile is extremely rare, the tendency there too is to begin the engagement as far out as possible (the so called first look, first shot, first kill doctrine) limited only by the range at which airborne radar can accurately differentiate friend from foe.

This tendency leads me to believe that combat will occur at ranges of light seconds, where lasers will be able to score occasional, random hits, but where missiles will be the real stars.
Of course, modern air combat has also taught us that sometimes, you just gotta knife fight, and so close range weapons will always be an important part of a space warships arsenal, espescially in electronic-warfare rich environments where getting close may be the only way to score a hit.

Space Marines

If you want something, then you're gonna have to send somebody to take it, whether it's robots or power armored infantry or something else entirely, there will always be a need for boots on the ground. If you wanna get a look inside your enemies space ship? Space marines are gonna have to capture it for you (space warfare doesn't tend to leave very intact hulks)
If you wanna capture a planet for your own, or just a part of it, or just get something that's on the surface, at some point space marines are gonna have to land and start subduing the population, defeating insurgents and winning hearts and minds. Nothing holds ground like a soldier. If you restrict yourself to achieving orbital dominance, then you leave yourself vulnerable to improvised or hidden weapons, ambushes, and, in a larger campaign across multiple worlds, hedgehog planets capable of sprouting spines once you've moved on and hitting you from behind (I.E. hidden space craft or weapons that wouldn't really work if you take the time to take the ground with space marines)


ProjectRho is a great resource, but it's still only a part of the story, It's being compiled by one guy and while he's usually spot on about the subjects he covers, there's still a lot of stuff that get's left out.
If you're specifically interested in space warfare, I'd also suggest looking into military theory and history, there's lots of great information available on Naval (I know, cliched analogy for space combat, but it works on a few important levels, such as point defenses, counter measures, missiles and fighters) air and ground warfare which are all applicable to space warfare.
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Re: Probing The Inaccuracies: Space Warfare

Postby Bears! » Sun Apr 05, 2009 9:18 pm UTC

RAKtheUndead says:
You see, in order to transfer heat, you need particles to transfer it to.

Wiglaf says:
Wrong. Radiation works perfectly fine in space.


This is something I've been considering after reading the original post. While I do agree that the OP seemingly forgot (or perhaps intentionally left out after proper rationalization) the subject of thermal radiation, he may be right in saying that asphyxiation happens before freezing to death, the reason being that the suit the astronaut is using probably functions as a very good insulator preventing the radiation from leaving at a sufficient rate to kill the astronaut. There are a lot of things to consider to produce a definitive answer on this one, but asphyxiation may very well come before freezing. You would have to look at the rate of heat transfer between the suit and space against the total heat emitted from the body over time, taking into consideration the reduction in heat emission as body temperature decreases as well as the amount of energy emission required for the body to cool to a sufficient temperature for death to occur. You'd have to compare this against the total available oxygen and the amount of oxygen intake that occurs over time. There are a lot of variables to consider in this one.
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Re: Probing The Inaccuracies: Space Warfare

Postby RAKtheUndead » Sun Apr 05, 2009 9:37 pm UTC

BlackSails wrote:I dont see why you cant have stealth in space.

Whenever you want stealth, you just surround your ship in a perfect black body/IR mirror.


Yes, that would be great - if:

- Black body materials weren't merely theoretical,
- You didn't have to dump heat in order to keep the insides of your spacecraft from melting.

You see, the very reason why a black body won't do a thing is because you actually have to dump heat from your engines, life support systems, et cetera, and that heat is going to show up on a thermal scan like a beacon. In fact, when it comes to the engines, if you want to move anywhere, you're going to be producing enough heat to be spotted anywhere in the Solar System - with today's chemical rockets as well. That's not even getting into nuclear pulse propulsion.

SummerGlauFan wrote:While I know that triggering an explosive device (with the exception of a rediculously large nuke) in "proximity" to a spacecraft would have an effect somewhere between nothing and a mouse fart, wouldn't an explosive detonated directly on your target still transfer the kinetic shock into the target? For example, those space fighters you hate so much firing tactical nuclear missiles into the enemy ship should be able to do a very respectable amount of damage. Let alone even a conventional missile scoring a direct strike on a starfighter or other small vessel.


Again, a good plan, if there weren't other practical issues with using a space fighter - you need a gigantic delta-v to make them work, and even then, they're extremely susceptible to point-defence systems... among other issues. Now, some sort of suicidal unmanned combat drone bristling with missiles that could be fired at close range may work, but that's hardly a space fighter, is it? It's not expected to come back.

Wiglaf wrote:
RAKtheUndead wrote:Because space fighters can't engage large spacecraft, there's absolutely no point in maintaining them for fighting each other. They're just irrelevant, that's all.


Really? You mean to tell me you haven't watched Star Wars?


Au contraire. I have watched Star Wars: A New Hope, which is precisely why I know why the series is unrealistic. The whole thing is based off a naval metaphor from World War II. Space is not an ocean, and you cannot seriously suggest that a series like Star Wars should actually be taken to try to justify elements of space warfare.

So yeah, what part of the space warfare in Star Wars did you like the most? The limited sub-luminal speeds? The shiny red lasers? The fact that the point-defence systems of the Death Star couldn't take down a series of space fighters before they got anywhere near the surface? I mean, it's a fun series to watch, but physically, it's mostly wrong.

Wiglaf wrote:Lasers are not instantaneous. At the ranges spaceships can engage, they may be light-minutes apart. If the ships are maneuverable, you wouldn't be able to hit at those long ranges. If the ships are not, they would be daft to not armor themselves properly. 286's may be able to project a ships motion, but they do not predict the future. Lasers would be useful in anti-missile defense systems. Missiles would indeed be the most practical long-distance weaponry, but don't expect them to work. Spaceships would indeed enter closer range combat, to the point where lasers and dumb projectiles could land on target.


You got me there - I didn't actually intend to suggest that it was an instantaneous weapon, because I had realised that it very much wasn't. But do you seriously mean to suggest that spacecraft are actually going to move into broadside range? As loath as I am to make naval metaphors, you may be forgetting the lessons that the entire world learned at the hands of one HMS Dreadnought, a ship which managed to push forwards development of naval vessels so much as to make every other battleship in the world obsolete by the time it got back to port - and then, made the entire battleship concept obsolete by introducing a massive arms race in naval combat. I'm going to guess that combat spacecraft are going to be a sufficiently difficult industrial task so that they wouldn't be mass-produced, and therefore, used more as a form of posturing in most scenarios than a practical weapon.
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Re: Probing The Inaccuracies: Space Warfare

Postby Sir_Elderberry » Sun Apr 05, 2009 9:39 pm UTC

Radiation works in space, but not as quickly. Hence, most death due to vacuum are not due to freezing, and the question of dissipating heat on a spaceship is actually pretty valid. (City-planets have similar issues.)
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Re: Probing The Inaccuracies: Space Warfare

Postby BlackSails » Sun Apr 05, 2009 10:04 pm UTC

RAKtheUndead wrote:
BlackSails wrote:I dont see why you cant have stealth in space.

Whenever you want stealth, you just surround your ship in a perfect black body/IR mirror.


Yes, that would be great - if:

- Black body materials weren't merely theoretical,
- You didn't have to dump heat in order to keep the insides of your spacecraft from melting.

You see, the very reason why a black body won't do a thing is because you actually have to dump heat from your engines, life support systems, et cetera, and that heat is going to show up on a thermal scan like a beacon. In fact, when it comes to the engines, if you want to move anywhere, you're going to be producing enough heat to be spotted anywhere in the Solar System - with today's chemical rockets as well. That's not even getting into nuclear pulse propulsion.


I never said that you could have stealth for indefinite periods, just that stealth is possible. You can be stealthed for as long as you can withstand the heat of your own emissions. Heck, you dont even need a perfect spherical mirror. A "good enough" mirror on the side facing the enemy would be enough to be undetectable.

In fact, when it comes to the engines, if you want to move anywhere, you're going to be producing enough heat to be spotted anywhere in the Solar System - with today's chemical rockets as well


Absolutely not. Once you have the desired heading, there is no reason for your engines to be firing. Furthermore, your exhaust doesnt have to be hot. It just has to be fast. Throwing rocks out the back of your ship at relativstic speeds would work nicely as a stealth engine.

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Re: Probing The Inaccuracies: Space Warfare

Postby RAKtheUndead » Sun Apr 05, 2009 10:23 pm UTC

EdgarJPublius wrote:Stealth In Space

The rule will be ECM, ECCM, ECCCM... and etc. this is one thing the star wars universe gets mostly right, Everybody is jamming everybody else, amongst radar jamming, optical and IR laser dazzlers and all sorts of decoys, spotting and accurately engaging a target will be a lot harder than figuring out they're out there. In this situation, you may be able to move around with minimal notice just by keeping quiet and not spraying jamming signals everywhere, as long as you have an ally willing to keep local space polluted you may be able to have some measure of stealth.


Certainly true, although you're likely to see as much development in more accurate tracking systems, less likely to be interfered with as a sort of limited arms race, along with redundant systems. Electronic warfare, even large-scale EMP devices using means other than nuclear detonation, are likely to be one of those sorts of warfare which will become common, but which I haven't been able to conceive of properly.

EdgarJPublius wrote:Lasers in Space

They'll be invisible, there's very little mass to get in the way and cause diffraction, but they won't be infrared. Ultraviolet and other short wavelength/high energy beams are able to have much smaller spot sizes at much larger distances with smaller focusing assemblies than longer wavelength/low energy beams such as infrared.


That makes sense - thinking about Blu-ray and HD-DVD, particularly. I was working with knowledge that I'd acquired from a mid-1980s book on the impracticalities of the SDI project and earlier attempts at anti-satellite weapons and BMD weapons. I believe that current ultraviolet lasers are considerably less powerful and less efficient than infra-red lasers, and have a pulsed output, but that is something where technology is bound to improve. Sometimes, I might cripple my creativity by relying on current restrictions, rather than restrictions in the timescales of practical space warfare.

[quote=EdgarJPublius"]Also, Laser's aren't 'instantaneous' they are constrained, like everything else, by the speed of light, at ranges of only a single lightsecond, your beam will hit where your opponent /was/ two seconds ago (one second for light to go from the ship to your sensor, another for the laser to go from your ship to where you saw the enemy last. Depending on how fast you can accomplish the command/execution cycle, you may be even farther out of date than that)[/quote]

True, and that's something I've definitely considered, but depending on their velocities and inertia, they may not actually be able to change course enough in two seconds to avoid a hit. I see lasers more as being point-defence systems against missiles, but I'm not completely sold on the fact that they'd be absolutely useless for long-range engagement, even if they were severely constrained - as you mention later.

EdgarJPublius wrote:This makes missiles an invaluable weapon for long distance engagements, the ability to change course in mid flight, and the ability to carry their own sensors (or to be accompanied by purpose built sensor craft, which could also provide local jamming and decoys to help defeat point defenses) means that though a missile will take longer to reach the target, it is far more likely to stand a chance of hitting it.


Indeed.

EdgarJPublius wrote:Linear Accelerators

Rail Guns, Coil Guns, MAC Guns, Mass Drivers, what have you, are all basically the same in terms of capabilities and role, and all have th same basic problems. While a large Mass Driver gun may be able to accelerate a projectile faster than your missiles can achieve, and do so to a larger mass, they'll still be limited to short range engagements for pretty much the same reason as lasers, but more so, because even a relativistic mass accelerator round will be far slower than a laser, som form of course correction would be essential for scoring a hit.


The most practical thing you can do, as far as I can see, with a linear accelerator is to load it with the equivalent of canister shot, effectively turning it into a massive shotgun with projectiles with velocities well past hypersonic. Here's where predictive targeting may come in handy - you calculate where the opponent may manoeuvre in the period that it's going to take to reach a certain destination, and fire a lot of shot towards him at such a velocity that it would be extremely difficult to manoeuvre past all of it. Each individual projectile will do only a small amount of damage, unless the opponent hits it head on at a high relative velocity, but you have the distinct advantage of not requiring the sort of incredible accuracy that you'd need for a laser or a solid linear accelerator projectile at those ranges.

These clouds of shot could also work particularly well when it comes to point-defence systems, making it quite a bit more difficult for a missile to evade being shot down.

EdgarJPublius wrote:Space Marines

If you want something, then you're gonna have to send somebody to take it, whether it's robots or power armored infantry or something else entirely, there will always be a need for boots on the ground. If you wanna get a look inside your enemies space ship? Space marines are gonna have to capture it for you (space warfare doesn't tend to leave very intact hulks)
If you wanna capture a planet for your own, or just a part of it, or just get something that's on the surface, at some point space marines are gonna have to land and start subduing the population, defeating insurgents and winning hearts and minds. Nothing holds ground like a soldier. If you restrict yourself to achieving orbital dominance, then you leave yourself vulnerable to improvised or hidden weapons, ambushes, and, in a larger campaign across multiple worlds, hedgehog planets capable of sprouting spines once you've moved on and hitting you from behind (I.E. hidden space craft or weapons that wouldn't really work if you take the time to take the ground with space marines)


Now, I recognise that an infantry presence will always be required in some form, but I don't necessarily think, after racking my brains about this specific issue, that it will take the form of space marines.

You see, the jobs you suggested could be done by other sorts of personnel. The espionage could be done by intelligence officers, as it is done currently. As for the subduing of a population, I was thinking that the infantry presence would take the form of some sort of armed militia, a paramilitary force as such, which would police an area and probably win hearts and minds more effectively than a bunch of helmeted invaders. Overwhelming firepower didn't exactly help the Americans in Vietnam, did it?

EdgarJPublius wrote:ProjectRho is a great resource, but it's still only a part of the story, It's being compiled by one guy and while he's usually spot on about the subjects he covers, there's still a lot of stuff that get's left out.
If you're specifically interested in space warfare, I'd also suggest looking into military theory and history, there's lots of great information available on Naval (I know, cliched analogy for space combat, but it works on a few important levels, such as point defenses, counter measures, missiles and fighters) air and ground warfare which are all applicable to space warfare.


I think I've regrettably given people the impression that I have just been relying on a single site, and even paraphrasing everything straight from that. This is an issue that I've given a lot of thought to, and I've read quite a few materials on the issue of space travel and space warfare, not to mention other forms of warfare. Let's just say that I've been addressing this issue long before I ever knew about Atomic Rocket, and I've made a lot of mistakes on the issue as well. I have a specific piece of old shame which relied on completely inaccurate information, and eventually, led to a complete degradation of my confidence regarding fictional writing - it was a simply atrocious and horrifically written story.
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Re: Probing The Inaccuracies: Space Warfare

Postby MarshyMarsh » Sun Apr 05, 2009 10:55 pm UTC

True, and that's something I've definitely considered, but depending on their velocities and inertia, they may not actually be able to change course enough in two seconds to avoid a hit. I see lasers more as being point-defence systems against missiles, but I'm not completely sold on the fact that they'd be absolutely useless for long-range engagement, even if they were severely constrained - as you mention later.


2 seconds seems like an extrodinairly long time in space combat. These ships won't be slowly manouving short distances to avoid fire. They would instead fly through at incredably fast speeds unleashing a barrage of fire whilst moving off again. Surely rather than sending out a missle at Mach 7, it is better off to send it off at Mach 7 from a ship travelling Mach 5 in the same direction?

Also an effective way to combat manouvering, would be to surround the given ship in 3 dimensions, with more of your ships and fire inwards with a 'rail gun' However numbers would be needed to do this effectively.

I also fail to see how fighters would be in-effective, delivering a tactical missle up close to an enemy (possibly firing it from the rear, catapulting the fighter in the opposite direction). 10 small ships could surround 1 large ship with missiles from various directions easier, than 2 large ships could attempt to out-manouver each other.

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Re: Probing The Inaccuracies: Space Warfare

Postby BlackSails » Sun Apr 05, 2009 11:38 pm UTC

MarshyMarsh wrote:
I also fail to see how fighters would be in-effective, delivering a tactical missle up close to an enemy (possibly firing it from the rear, catapulting the fighter in the opposite direction). 10 small ships could surround 1 large ship with missiles from various directions easier, than 2 large ships could attempt to out-manouver each other.


Yeah, the more powerful the weapons, the better fighters get. A nuke launched from a tiny fighter has the same bang as one launched from a massive capital ship.

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Re: Probing The Inaccuracies: Space Warfare

Postby SummerGlauFan » Sun Apr 05, 2009 11:45 pm UTC

RAKtheUndead wrote:
SummerGlauFan wrote:While I know that triggering an explosive device (with the exception of a rediculously large nuke) in "proximity" to a spacecraft would have an effect somewhere between nothing and a mouse fart, wouldn't an explosive detonated directly on your target still transfer the kinetic shock into the target? For example, those space fighters you hate so much firing tactical nuclear missiles into the enemy ship should be able to do a very respectable amount of damage. Let alone even a conventional missile scoring a direct strike on a starfighter or other small vessel.


Again, a good plan, if there weren't other practical issues with using a space fighter - you need a gigantic delta-v to make them work, and even then, they're extremely susceptible to point-defence systems... among other issues. Now, some sort of suicidal unmanned combat drone bristling with missiles that could be fired at close range may work, but that's hardly a space fighter, is it? It's not expected to come back.


Forgive me, but I have to ask what you mean by a delta v? Do you mean the structure of the starfighter has to be one? Why? If you mean that they'd have to be to carry tactical nukes, you are mistaken; tactical nuclear weapons can be surprisingly small.

Do you mean that they have to fly in that formation? Again, why?

Also, it's still correct that an explosive will transfer its kinetic shock if detonated directly on a target, yes? Which means missiles won't have to be limited to glorified, self-propelled bullets.
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Re: Probing The Inaccuracies: Space Warfare

Postby Sir_Elderberry » Sun Apr 05, 2009 11:52 pm UTC

Delta-V = Change in Velocity. He means that the space fighter would have to be speeding up, slowing down, turning, etc, in an environment where fuel is at a premium.
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Re: Probing The Inaccuracies: Space Warfare

Postby SummerGlauFan » Sun Apr 05, 2009 11:58 pm UTC

Ah, ok, I can see that.

However, remember that you won't be needing that fuel to constantly maintain your speed like you do with current aircraft, either. Plus, I was only using a starfighter as an example of a way to deliver missiles to a target, drones or even long-range missiles or other systems are still a viable option as well.
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Re: Probing The Inaccuracies: Space Warfare

Postby quintopia » Mon Apr 06, 2009 12:05 am UTC

MarshyMarsh wrote:I also fail to see how fighters would be in-effective, delivering a tactical missle up close to an enemy (possibly firing it from the rear, catapulting the fighter in the opposite direction). 10 small ships could surround 1 large ship with missiles from various directions easier, than 2 large ships could attempt to out-manouver each other.


Having enough numbers to completely surround a ship is another good argument for light, compact, maneuverable unmanned ships.

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Re: Probing The Inaccuracies: Space Warfare

Postby gmalivuk » Mon Apr 06, 2009 12:17 am UTC

Zeroignite wrote:Uh, you should write a blog, not a forum?

Yes, that is absolutely true. These forums are not your personal blog, and so wall-of-text posts that huge are generally considered bad form.

However, this does look like people are finding it a worthwhile discussion, so I'll leave it as is for now. Feel free to ignore most of the OP, though, as I think tl;dr is a perfectly fine response to something like that...
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Re: Probing The Inaccuracies: Space Warfare

Postby mooglinux » Mon Apr 06, 2009 12:19 am UTC

I think lasers could still work rather well. Even if it takes 3, 5 or maybe even 10 seconds, you are going to have a hack of a time changing the course of a massive spaceship to evade something going that fast. The UAVs in use in iraq right now have 2-4 seconds of lag (straight from the mouth of a fellow who pilots them remotly) but can still hit moving targets very nicely. Granted, these targets are much much slower than those in space combat, but space combat would ushually take place over a much greater range. Only moving your laser a fraction of a degree could be enough to properly lead a target.

Why cant ships just evade lasers? Its a thrust to weight ratio issue really. To change your velocity fast enough that someone could not figure out where you are going to be in 5 or 10 seconds would require massive amounts of thrust. Current fighter jets, for example, are little more than a cockpit strapped to an engine (the fins were an afterthought). Take the f-22 engines, for example. combined, the engines put out about 70,000 lb of thrust. however, the entire plane, fully loaded, weights 64,460 (ish) lbs. So the thrust to weight ratio is going to be about 1.08 (again, thats fully loaded)

reaching a 1.08 thrust to weight ratio in a large ship would be very difficult, espectially loaded up with lasers and missiles and humans (and all the baggage they require like food and life support). you would need absolutly massive engines. So that makes very large ships fairly easy to hit with a laser, even at very high speeds. Yet again, its not the speeds but the acceleration that makes the difference. The high acceleration and thrust to weight ratios of small fighters would be what makes them practical against the much larger ships with the big guns.

Then again, missiles trump fighters with regards to accelleration.

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Re: Probing The Inaccuracies: Space Warfare

Postby Vieto » Mon Apr 06, 2009 12:56 am UTC

I would think that the best type of ship for space combat would be something the size of a frigate or corvette. These ships would be fairly maneuverable, make dumb-fire and laser weapons almost completely inaccurate, be able to hold hundreds of missiles, and life support systems, as well as up to a dozen crewmen. There would be room for many engines for propulsion, as well as enough heating fins and even an anti-missile laser system. Rail Guns, however, would have too much inertia for a ship of this size.

The problem with fighters is that, in space, you can't bank your aircraft. They would have to be jam-packed with thrusters to even begin to simulate fighter movement in the atmosphere. Also, they would be fairly limited in weaponry and life-support, although an oxygen tank is usually all that would be needed for the short durations a fighter spends in space. You would only have a few missiles on board, or a projectile weapon/laser, but missiles would have to be able to determine a good guy from a bad guy in the heat of battle, targeting would be a nightmare,

I would think that larger ships would keep their distance, and serve as supply depots for the frigate-sized ships. Missiles would have to be used against enemy frigates, as straight-fire weapons would be logistically a nightmare to fight something that has almost unpredictable movement. Also, docking ports would have yo be convenient, and quick to use for your ships, but inconvenient (but not impossible, for prisoners) for the enemy ships, to allow for quick resupply and repair, and to limit possible marine parties.

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Re: Probing The Inaccuracies: Space Warfare

Postby Carnildo » Mon Apr 06, 2009 1:14 am UTC

RAKtheUndead wrote:These clouds of shot could also work particularly well when it comes to point-defence systems, making it quite a bit more difficult for a missile to evade being shot down.

What does "shot down" mean in this context? At the speeds involved in space combat, 50 pounds of lead makes for a decent missile warhead. Once it's on course for you, there's not much you can do to stop it: there are no guidance systems to disrupt, no fuses to destroy, no explosives to prematurely detonate, and lead just kind of "smooshes" when you hit it with a solid object.

mooglinux wrote:I think lasers could still work rather well. Even if it takes 3, 5 or maybe even 10 seconds, you are going to have a hack of a time changing the course of a massive spaceship to evade something going that fast. The UAVs in use in iraq right now have 2-4 seconds of lag (straight from the mouth of a fellow who pilots them remotly) but can still hit moving targets very nicely. Granted, these targets are much much slower than those in space combat, but space combat would ushually take place over a much greater range. Only moving your laser a fraction of a degree could be enough to properly lead a target.

Consider an engagement between two ships each a kilometer in diameter, at a range of five light-seconds (1,500,000 kilometers). Five light-seconds means that the targeting computer needs to project ship trajectories ten seconds ahead: five to account for the delay in getting sensor data from the target, and five to give the laser time to arrive. In order to generate a miss with 50% probability, the targeted ship needs to move half a kilometer in those ten seconds.

The formula for how far you move under constant acceleration is d = 1/2 a * t^2. Plugging in 500 meters for distance and 10 seconds for time gives an acceleration of 10 meters per second per second (one gravity) to generate a 50% miss (any shot fired at the center of mass or guessing wrong at which way you will dodge). Increasing the engagement range to 10 light-seconds (20 seconds prediction) means that the ship only needs to accelerate at a quarter-gravity. The required acceleration increases linearly with ship diameter, and decreases as the square of the distance.

A thrust-to-weight ratio greater than 1 (1 gravity of acceleration) might be difficult for an airplane, but bettering that is mandatory for any rocket that is going to take off from the surface of the Earth. Current man-rated rockets are generally between 3 and 5. As noted above, a one-kilometer spaceship at five light-seconds only needs a ratio of 1; something like the Apollo command module (4 meters) can dodge with a ratio of only 0.004.

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Re: Probing The Inaccuracies: Space Warfare

Postby mooglinux » Mon Apr 06, 2009 1:39 am UTC

But changing your acceleration is the real issue. if you are moving at either a constant speed or constant acceleration, accounting for that is trivial. Which comes back to the thrust-to-weight thing: how much would the accelleration of a particularly large ship like that have to change to dodge a laser? and how much fuel would they expend doing so?

just seems to me that constantly changing your velocity like that would be very difficult. for large ships anyway. smaller ones would have a much easier time dodging lasers, because it takes less change in acceleration (or Delta-V, my new vocab word for today! thanks Sir_Elderberry) to get out of the way of the laser, and its quite a bit easier to get that delta-v with a higher thrust-to-weight ratio.

Such meneauvering would require a lot of fuel tho. maybe some easier source of energy will be in use to power ships by then. like a fusion power plant, or antimatter (maybe someday many generations from now at least)
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Re: Probing The Inaccuracies: Space Warfare

Postby Indon » Mon Apr 06, 2009 1:44 am UTC

I'm not sure about the feasibility of laser fire at all.

Say we have a spaceship that's generating artificial gravity. It's probably spinning, and pretty quickly, to do so.

This means that even if a laser hits, it would have to be incredibly powerful to be able to actually melt anything, as between its' own movement (to try to evade more dangerous weapons such as missiles) and its' spinning to generate artificial gravity even a very short-duration laser would still end up hitting a wide area of the ship, and do little more than distribute some heat that would need to be dispersed - which is little more than what the firing ship would have to deal with, as last I checked, lasers themselves operate pretty hot.

'But a targeting computer can compensate, at least for the spinning' you say. And they could, until you take into account that orientation need not be related to velocity or acceleration. A tiny adjustment in yaw/pitch (Let's pretend the spin is a roll movement, I'm not sure there's much difference in space, honestly) causes huge shifts in the effect of the ship's rotation in terms of presenting the hull as a laser target.

Edit: Just to be clear, this isn't my idea I'm presenting, I grifted it from the Gap novels (which I love the combat in).
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Re: Probing The Inaccuracies: Space Warfare

Postby Diadem » Mon Apr 06, 2009 1:58 am UTC

The OPs arrogance and natural assumption that everybody else here is retarded and has not thought about anything is a bit annoying. But ok. The discussion is interesting.


I'm not sold on stealth being impossible. There are a great many ways to be stealthy. If your propulsion system is good enough (Or you invent wormhole technology or somesuch) you could fly at near light speed, meaning that anybody who detects you will only do so a splitsecond before you arrive. That sounds quite stealthy. You could also use the terrain to hide you. We can't scan through the moon, and if you're directly in front of the sun your thermal output certainly won't be detected.

Other people have already shown that it is not impossible to hide your thermal output for a limited amount of time, or in a specific direction. If you switch off your engines and minimize all other activity your power output will be minimal. And then isolating your spaceship well will in fact work both ways - you're less likely to be detected and you need less power to keep yourself warm. A spaceship cruising towards a target can effectively use zero energy. Life support can be switched off for a long time - use stored oxygen for a while and isolate yourself well so you won't get cold. Engines can be off. Everything else can be passive too. You need a few hundred watt to keep your central computer running, but that is about it. So I really don't see why stealth would not be feasible.



As for battle. I think combat drones will be the way to go. Why use an expensive manned ship if you can send a few hundred unmanned drones for the same price? Plus they can accelerate much, much faster and you don't have to worry about keeping your crew alive. How effective drones will be depends on how good our AIs get. But a manned spacecraft approaching a target up to a reasonably safe distance (which depends on technology and availibity of wormholes or ftl, etc, etc), preferably without being detected, and then launching a swarm of combat drones seems the most effective strategy.

As for what kind of weapons. Kinetic missiles (aka: bullets) are obvious. Lasers might play a limited role. And I wouldn't write off nukes either. But it all depends on technology. If you're writing scifi, it all depends on what kind of artistic freedoms you've taken. If you've invented FTL, then spacecombat will change a lot. I think the most important thing is for the story to make internal sense. You should think about where you take artistic license with the laws of physics, and where you don't. Then you should carefully think of the consequences this has, and make a story that makes sense giving these conditions.
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Re: Probing The Inaccuracies: Space Warfare

Postby Sir_Elderberry » Mon Apr 06, 2009 2:03 am UTC

Clearly, we just need to invent heat-seeking lasers that can bend themselves around to track down their targets. At that point, the war is won.
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