If I was to take a stab at what it might be like however.



Asteroid heatsinks and over the horizon based warfare.





Basically, you won't be fighting over literal space, because space is empty, but planets, moons and gas giants would have many valuables on them, enough possibly to fight over them when population levels get high enough that orbital real estate becomes costly.



Asteroid based energy weapons would be employed off of asteroids to adsorb the heat of combat, as asteroid bob above and below the horizon of their enemy around the same planetoid, firing missiles lasers and what ever else from long range, while trying to keep most of a planets atmosphere or surface between them and their enemy as to prevent annihilation outright.



Approaching an enemy world would be almost impossible without a beach head to allow safe approach to the planet.



But I'm no scientist, and such a space craft would likely be vulnerable to surface combatants, where a war of spotters and intelligence takes place, avoiding mass deployments that could be destroyed from orbit.

abmpicoli wrote:
The problem in having planets as ships is it's mass... and it's subsequent inertia... The earth's mass is ^6 × 10^24 kg ... There is too much "garbage" to much little usable mass... And we suppose that every way of travel will have to expend some energy correlated to the ship's mass...

Right-- what I'm saying is, don't even bother making a ship. Launch your missiles directly from Earth instead. Any launch platform you make is going to have crap in terms of delta-v anyways.



One of the questions that I always find interesting: what is the desired shape and guidance of ultra-long-range missiles traveling through a vacuum? The two questions are related.



End-stage guidance is certainly handy, but it means waiting until the last minute to use up part of your thrust. That means that delivery takes a lot longer than if you just used all of your reaction mass as fast as you could, immediately following launch. And it adds mass to your missiles in the form of gimbals, sensors, and computers. Since you're thrusting as you approach the target you limit your rotation to roll, leaving the missile more vulnerable to laser-based counter-measures. Maybe it might be better to just fire more missiles than to fire fewer guided missiles? A lot of it probably depends on your ability to hit your target and on your target's acceleration. You're not going to be able to hit a target capable of acceleration at any significant range without guidance. (But if you just want to rain nuclear hell on Europa, I don't think you're going to need much course correction.)



Rotation is a great way to maximize your armor vs laser-based point defense. Your spin is basically just limited by the structural integrity of your missile, it will never decay nor cost much energy, and it limits the amount of time that a laser can focus on any particular part of the hull-- or another way to put it is to say that the laser has to penetrate a larger area of the hull to get through. You can make long skinny missiles with a large roll and the smallest cross-section you can to maximize the number that get through point defenses. But it's not as efficient as just making a sphere.



Laser-based point defense is going to end up creating some rotation in targeted missiles-- in fact, your point defenses might not be about destroying missiles, but just hitting them for just long enough to send them off-target. I like the idea of a jack-shaped missile that uses this to create unpredictable acceleration and rotation in the targeted missile.



It's entirely conceivable that there might be chaff to confuse target point defense. To work effectively, point defense is going to have to acquire targets and shoot them down in microseconds. Low mass dummies don't have to fool anybody for long, just slow down point defense as much as a full mass missile would.

@Igncom1 ... Yes... but hey, interstellar travel right now *is* not so much about science, but about dreaming .... unless we are talking about generation ships... And even then... And nevermind space combat... And supercomputers don't guess anything *yet*... They run very complex models made by humans... So the "guess" part is still a matter of our imagination... And how we interpret the output data. For, now, let's settle for less ambitious projects, such as terraforming mars

These discussions never end up well.



Psudo-science discussions quickly turn into, who thinks they have the best approximate knowledge of subjects that supercomputers can only begin to guess at.

Well, this is my layman opinion, based on pontual knowledge of physics.



FTL The solution people have been using for FTL on hardcore science fiction is that you can have space folded in some way. I've heard somewhere that the current theory that fits the universe is the use of 11 dimensions.... So hiperdrive might not be FTL, but flight in a different set of coordinates. This is the "hiperspace" of Isaac Asimov in their Foundation series. It would kind of remind the Battlestar Galactica 2004 series , where ships appear out of thin air and then have combat at sublight speeds.



Without thinking on some cheat about having FTL travel, Time dilation and some fictional means to achieve close to light speeds can make it possible that war be waged in an individual lifetime... the problem is that , while for the astronauts only weeks or months have passed, there is no cheating the speed of light... in the slow universe thousands of years may have passed... https://en.wikipedia.org/wiki/Time_dilation . Joe Haldeman's "The Forever War" approaches brilliantly the subject. http://www.amazon.com/The-Forever-War-Joe-Haldeman/dp/0312536631/ref=pd_sim_sbs_14_1?ie=UTF8&refRID=1JGPHCHPTF5TARFPHEWV . Paul Anderson's "Tau Zero" have a similar approach not for a war subject... A malfunction in a spaceship make the crew accelerate more and more close to the speed of light, to the point they reach the end of the universe and it's rebirth...



Hulls The problem in having planets as ships is it's mass... and it's subsequent inertia... The earth's mass is ^6 × 10^24 kg ... There is too much "garbage" to much little usable mass... And we suppose that every way of travel will have to expend some energy correlated to the ship's mass...



The critical point of making interestellar travel possible is to have a compact power source... The most compact power supply that can be thought of in our current imagination in science is total conversion of matter to energy ( matter x antimatter reaction)... Long live the dilithium crystals!

This famous einstein's equation is the energy that would be equivalent to it's mass counterpart: e=mc[SUP]2[/SUP]... Thinking in a 100% efficient conversion of energy into kinectic energy, with relativistic physics, to move a mass m1 to half the speed of light would use 1.15 times the object's mass... http://spiff.rit.edu/classes/phys200/lectures/ke_rel/ke_rel.html... This is not something so extraordinary... well... yes, it is... it is totally utopic as well, because 100% conversion between different energy forms is , as we know now, an impossibility.



At 1/2 light speed we would be able to cross our solar system , to the two "edges" of the Kuiper Belt, in a little more than a day... We can start thinking about startrek here...



Even when we think in current air and naval combat, guns are not the most efficient weapons, even with our rudimentary missile vehicles. Certainly combat would be based in highly explosive, guided missiles. Currently we can make very complex calculations using a very simple PIC microcontroller... As technology evolves, it will become cheaper and cheaper to have missiles that will be able to correct trajectories so they can actually hit their targets...



Combat will certainly be automated. Even because right now people are automating war: drones, battle androids... This is technology we have been researching now... Chain of command would be inexistent, unless some type of Quantum-Entanglement communication is discovered, due to communications lag: our normal communications could take 1/2 a day to go through... And I agree that humans , if present at ships, would be mainly for very special diplomatic roles, and will be transported as a simple payload, with foldable environments. A diplomatic mission could take years to complete after completion... This if we don't reach the point where AI would be able to really replace humans at every mode... And we would become extint...