What shape of ship would be optimized for space combat in the context of a future space navy? What advantages and disadvantages would the shape you have chosen have and why is it the best for future space warfare?

Space warfare will be in a close to hard science scenario. Space is a 3D environment where no stealth is possible because since space is cold, the tiniest amount of heat would radiate like a beacon. Most combat would be based on bringing your weapons to bear on the enemy as fast as possible, maneuvering as fast as possible or simply having redundant systems and long range firepower capability.

Assume technology has advanced 500 to 1000 years from the modern day. There is limited FTL, low intensity artificial gravity, and most weapons would be relativistic direct fire or guided.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – James
    Apr 2 '18 at 17:28

31 Answers 31



Space is a 3D environment, and attacks can come from any direction. This suggests that a sphere might be the best shape, with weapons mounted across its surface, but that would both be inefficient (most weapons could not come to bear upon a single target), and present a large target.

A cigar-shaped object would allow weapons to target in all directions, particularly if turret-mounted, while vasty increasing the number that could bear on a single target and presenting a minimal cross section.

Of course, this assumes direct line-of-sight style weapons. If space combat is based on missiles, and these are fired at extreme distances, the most effective shape will probably be the one that can hold the most missiles, so we're back to a sphere again (missiles could be fired from any 'side' of a sphere, and be guided to the target).

Space combat might also be based on passive engagement - laying of 'mines' of some kind along desired (e.g. economical, efficient) routes. In this case, either technology - mine detectors/eliminators - will render the shape of the spacecraft moot, or, if we assume that these mines are difficult to detect/remove, then a cigar-shaped ship, propelled lengthways, would present a very limited cross section and so miss most mines (at least relative to other shapes). The 'nose' of such a ship might even be purely armour / disposable, to negate the impacts with mines that it doesn't miss.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – James
    Apr 2 '18 at 17:28

You have FTL and gravity control. Between the two, physics is completely different.

But I can try.

First, energy.

If we assume a 1% per year growth rate, 1000 years from now we have a 20000x higher energy budget (E4.5). We are currently a K-type 0.7 civilization; they would be a K-type 1.15 civilization.

A K-type 1.15 civilization has no sigificant portion of its economy on planets unless it is a gas giant; their energy budget is 30x larger than what an Earth-sized planet can radiate without boiling its oceans.

If we assume a 3% growth rate, they are a K-type 1.9 civilization (ie, within rounding error of 2). This has either swallowed an entire star in energy-consuming structures, or have lower density (say ringworld size) structures over a good chunk of the local galaxy.

If we assume a 5% growth rate, they are a K-type 2.8 civilization (ie, within rounding error of 3). This civilization has swallowed every star in a galaxy in dyson-sphere like structures or found more efficient ways to use the energy of a star and are using it.

Gravity manipulation and FTL mean they have access to ways of manipulating the universe that are as alien to us as self flying jet planes are to a hunter gatherer society.

By occam's razor they are related: this civilization can manipulate the fabric of space time to cause it to bend in strange ways.

Together with the above energy budget, chemistry based matter as we know it is going to be as modern a material as bone is to us. You would no more build a tank out of carved mammoth bones than they would generate a space ship out of metal alloys.

Sure, it is elegant and beautiful and it is amazing what primitive people can pull off with such limited tools. But for serious engineering?

Finally, information. Human ability to process information has been growing at as exponential and as steady a rate as our ability to process energy. Arguably they are tied, as what we call energy is really energy arranged in a highly usable way, which is a question of entropy, which is information.

We have every reason to believe that we are close to being able to emulate a human intelligence. We have been able to emulate increasingly complex networks of nerves and replicate the behavior of relatively simple organisms. Barring a surprise (like, for example, we encode memories and information in DNA), scaling up to a human is a matter of marginal technical improvements in remote sensing and computing.

Even if we assume that making smarter than humans turns out to be hard, creating artificial human-scale intelligence isn't far off on the scales we are talking about. As humans are shockingly horribly suited to the environment of space, initial intelligent exportation will be with such beings, and such beings will out-compete water-bag humans at living in space.

The bandwidth to communicate a mind state from one location to another isn't going to be that high (again, assuming continued scaling of current technology). So warfare is going to involve intelligent munitions on suicde missions with backups and indoctrination that their sacrifice is worth it for their highly related "left behind" copies.

Life support won't be a question; just maintaining a computational platform. Hardening these against electrical weapons is going to be easier than keeping a biosphere around.

So, we are talking non-matter based distributed networks of the descendents of uploaded minds piloting exotic high-energy weapons.

Nothing is going to resemble a WW1 battleship or WW2 aircraft carrier. Those where designed based on the energy budgets and situations of a gravity-locked biological life form using 20th century technology, not a space-based intelligence using 30th century technology.

If there are civilizations using space battle ships that fire relativistic projectiles and guided missiles, they'll be the equivalent of US white supremists stockpiling assault rifles for the coming civil war. History has passed them by.

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    $\begingroup$ I think this, more than any of the other answers, attempts to grapple with the constraints of the problem as given. Very thoughtfully written, thanks! $\endgroup$
    – Charles
    Mar 27 '18 at 4:27
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    $\begingroup$ Thank you for the great answer, very poetic, sounds like it came out of a saga. Well if you could chance to maybe predict what this craft of super advanced futuristic nature would look like that'd be really cool. $\endgroup$
    – Efialtes
    Mar 27 '18 at 21:53
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    $\begingroup$ This is the most correct answer IMO. Humans have made such massive strides in the last century or so (first atmospheric powered flight: 1903, first man on the moon: 1969) that it's almost impossible to conceive what the end result of another ten centuries of almost exponential growth would be. $\endgroup$
    – Ian Kemp
    Mar 27 '18 at 22:52
  • $\begingroup$ @mark Strange? A constillation of neutron stars dancing in exotic fields. Dust scattered over parsecs. Nothing but a distortion in the distant stars. Lines of spin 1/2 nova-bright cords swirling chaotically. A small silver sphere. An asteroid with an hole in one side of infinite depth. $\endgroup$
    – Yakk
    Mar 27 '18 at 22:56
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    $\begingroup$ I hate to point it out, but this answer does not fall within the limits specified: "There is limited FTL, low intensity artificial gravity, and most weapons would be relativistic direct fire or guided." $\endgroup$
    – rek
    Mar 28 '18 at 22:34

I think a more important factor than the shape of any individual ship is the relationship of ships in the fleet to each-other.

A primary challenge of war craft in space would be that, due to inertia, the path of a ship would be easily predictable by the enemy (just goes in a straight line at constant velocity). Hence, it can easily shoot a missile from a long distance away and guarantee it will hit. This could be somewhat avoided by the ship accelerating or decelerating, but this is costly--not only does it use up energy to expel a projectile, but it also means that the ship has to part with some mass each time it does this.

A better solution to this challenge would be to have the ships connected to each-other by elastic strings. For simplicity, let us say that there are 2 ships rotating around a center of mass, which are prevented from flying off in different directions by an elastic string. The ships can communicate to each other to pull on or to slack out the string during battle, in some sequence that is indecipherable to the enemy ships. This will change the rotational acceleration of the ships, making it very hard for the enemy to predict where each ship will be in the future. Furthermore, all mass remains in the system and, assuming there is a good way to recollect energy when the rope is slacked out, it uses relatively little energy.

On the ships themselves, this would simply be perceived by small variations in the apparent gravity on the ships (higher apparent gravity when the elastic string is pulled, lower when it is released). This could be compensated by, for instance, adjusting the small level of artificial gravity.

  • $\begingroup$ Welcome to WorldBuilding! If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$
    – Secespitus
    Mar 26 '18 at 16:49
  • $\begingroup$ I like this idea as a varriant was used in Star Fleet Battles with tractor beams. $\endgroup$
    – PCSgtL
    Mar 26 '18 at 17:15
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    $\begingroup$ I remember an old arcade game, variant of Asteroids I think, that had things set up this way. Worked great until you used the engines :) $\endgroup$
    – ivanivan
    Mar 26 '18 at 18:55
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    $\begingroup$ @ivanivan Space Duel $\endgroup$ Mar 26 '18 at 22:38
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    $\begingroup$ If I observed this tactic in use I would immediately fire at the barycenter to sever the strings. $\endgroup$ Mar 27 '18 at 15:25

Depending on what offensive and defensive technology is used in your universe, different shapes would have different benefits.

Relevant factors are:

  • Minimize or maximize surface area to volume ratio: A smaller surface/volume ratio allows you to add thicker armor to your ship without adding more mass to it. On the other hand, if waste heat is a problem in your universe, you might want to maximize surface area in order to improve cooling through radiation.
  • Minimize or maximize profile, in one, two or three dimensions: A small profile makes you harder to hit and allows you to use even more armor for less mass in that particular direction. But on the other hand, you also have less space for placing your own weapons. You also need to keep the enemie's maneuvering capabilities in mind. If they can outmaneuver you or attack from multiple angles at once, you might not be able to show them your "best side" at all times.

    If you require solar power, then you need a large surface area in at least one direction.

  • Structural integrity: If you take hits, you want to avoid breaking apart.

  • Engineering concerns: Your ship design might be heavily influenced by a primary system which requires a certain shape. If one specific component (propulsion, weapon, etc.) is the main contributor to the volume of your ship, then that component's ideal shape will be a major influence on your overall design.


Death Star

The best way to concentrate all your mass in the least amount of space and under the minimal amount of surface area.

If armor technology is relevant in your universe and if your enemies are fast but have trouble aiming, then you want a sphere. They won't find your weak side, because all your sides are the same.

But keep in mind that if the enemy does land a good hit with a penetrating weapon which can pierce through your whole ship, they will do the maximum amount of damage to your internal systems. Also, with such little surface area, getting rid of waste heat could become a problem.


Battlestar Galactica The shape you imagine when you imagine a space ship.

When you can manage to always point the bow towards the attacker, you have a very tiny profile. Adding some thick armor to the bow gets you a lot of resilience for very little mass. But even if the enemy manages to flank you, you still show comparably little profile. And you still got a good surface/volume ratio.

A structural weakness is that a powerful hit from the side might easily cut your ship in half, which will likely disable it completely.

If your design is dominated by systems which are long and thin (like linear accelerator weaponry or certain propulsion technologies) then this shape will be the most natural one.


Independence Day UFOs

The classic UFO shape is very flexible when it comes to profile. Depending on situation you can minimize it by showing the edge to the enemy or you can maximize it by showing them your face.

A direct hit on your face will easily pierce it, but the damage will be localized. If you have lots of redundancies in your primary systems, it will take several hits to take you down. Hits from the edge will easily miss and will only damage the outer sections. If the enemy can outmaneuver you that they can face your edge if they want to and has a weapon which is capable of piercing your ship edgewise and is accurate enough to do so... well, then you are pretty screwed no matter what shape your ship has.


Crystaline Entity If you need to maximize surface area for some reason, then this is the shape to go. But keep in mind that it will likely be very fragile. A fractal shape could also be useful if you want to maximize the occupied volume of your ship. The enemy might be able to hit you, but they will have trouble doing any actual damage, because there is just so much ship to hit.

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    $\begingroup$ I was going for the fractal/modular shape. Toss in all or nothing armor and/or make the parts as independent as possible to minimize damage, maybe even to the point of being capable of some independent operation. $\endgroup$
    – SJuan76
    Mar 27 '18 at 21:57
  • $\begingroup$ With @SJuan76 on this. I think it actually helps with the "structural integrity" angle to have that kind of forest of disposable protrusions to take hits for you. With a sphere you'd have to worry about your ability to seal off hull breaches pretty much anywhere. $\endgroup$
    – T.E.D.
    Mar 28 '18 at 14:27
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    $\begingroup$ IIRC, this was how the Spathi in Star Control II designed their ships, with all the personnel hiding in bunkers inside the main ship. They also made their good gun rear-firing, so they could do the most damage while running away. $\endgroup$
    – T.E.D.
    Mar 28 '18 at 14:48
  • $\begingroup$ Good examples of different classic (famous) configurations and their pros and cons. Reminds me of a question I've never gotten around to looking into though - why does Galactica have retractable landing bays? They are only retracted once (in the 2004 series), and nothing had to be moved out of the way first, so the area behind them must be empty - seems like a huge waste of internal space in light of this question. Edit: addressed tangentially on this SciFi SE answer. $\endgroup$
    – brichins
    Mar 28 '18 at 17:35

Ship combat is about much firepower you can effectively bring to bear on your opponent while reducing your own exposure to their weapons.

Basing this on the known factors of ship to ship warfare during the age of empires, it's all about how many guns you have. That requires you to have a shape that maximises the surface area to give you enough space to mount all those weapons.

The sphere is well known to minimise the surface area to volume ratio, what we need is the opposite, we need to maximise the surface area to volume ratio. This will reduce the mass while allowing us to mount more guns.

I was going to suggest Gabriel's Horn, but it is a rather impractical shape to build. So I shall instead suggest a Menger Sponge

Menger Sponge

This gives a considerably larger surface area for your mass so you can mount more guns, and allow you to launch indirect firing weapons such as missiles and fighter craft from protected internal openings.

Any resemblance to a Borg cube is entirely co-incidental. You will be assimilated.

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    $\begingroup$ I strongly disagree with your premise that surface area=more guns. Guns need specific hard points, energy, ammo feeds. They are not a one molecule thick liquid to surround the ship $\endgroup$
    – Andrey
    Mar 26 '18 at 14:26
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    $\begingroup$ My point is that any gun requires surface area X, internal volume Y to operate. So infinite X with 0 Y = 0 guns. For instance look at his much internals a battleship turret has i.pinimg.com/originals/42/04/55/… $\endgroup$
    – Andrey
    Mar 26 '18 at 15:10
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    $\begingroup$ What good is surface area that is not oriented towards the target with unobstructed view? $\endgroup$
    – mart
    Mar 26 '18 at 15:14
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    $\begingroup$ @mart, did you read the last paragraph? $\endgroup$
    – Separatrix
    Mar 26 '18 at 16:04
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    $\begingroup$ @user121330, well you don't want some punk kid flying down a channel somewhere you can't shoot at him and bombing your exhaust port. $\endgroup$
    – Separatrix
    Mar 28 '18 at 11:26

Obviously this is a subject of substantial debate, and there isn't really one "right" answer. But I would like to make some additional points not mentioned in the other answers here.

Fundamentally, this question depends on two things:

  • What is your state-of-the-art in weapons and propulsion technology, and;
  • What kind of combat do you want?

As an avid player of space RTS games, a designer of combat ships in Newtonian physics simulators, and an aerospace engineer for the US Navy, my philosophy on starship combat is to avoid close-in engagements at all costs. In my experience, if you get close enough to your enemy for a slug fest, you're both going to come away in bad shape. And spaceships are inherently bad combat platforms for a lot of reasons:

  • It's very difficult to maneuver in space, and the more massive your ship, the harder and more expensive it becomes
  • By their very nature, guidance and propulsion systems cannot be shielded from damage and will be the first things you'd lose in a fight
  • Unless you're using some kind of reactionless drive, every engine and thruster on your ship will present a large, soft target
  • For every action (fire a gun, take a hit) there is an equal and opposite reaction (you get pushed away, undesired rotation, harmful vibrations or accelerations, etc.)
  • A solid object about the size of a BB traveling at orbital speeds can make a hole several inches wide and deep
  • Holes in your spaceship are generally worse than for any other vehicle (even submarines) unless your ship is unmanned

I much prefer long-range engagements, preferably with the advantage of surprise. It's much safer for you, and you're much more likely to win. For this approach to work, agility and stealth are your major design drivers. If, however, you want epic close-quarters slugfests, your architecture will need to be fundamentally different. Speed and agility will still be essential, but you'll trade stealth for heavy armor and layered weapons.

Keep in mind that providing lots of surface area to mount lots of guns is not the best strategy! More surface area means more mass, and more area for the enemy to hit. Complex shapes are hard to build, harder to repair, and very bad for attitude control systems in space due to irregular CG, resonance frequencies, flexibility in the structure, and weird effects from battle damage. Less is more in this scenario: you want just enough weapons to kill your opponent, and just enough area/mass/systems to support them, no more. Space them out so that one good shot by your opponent won't knock out multiple weapons or vital systems at once. Redundancy will be particularly vital in a close-quarters battle, because you will take lots of damage, and armor alone won't protect you.

If you have your eye on CQB, do you envision frontal assaults or classic broadsides? Frontal assaults would compel a wide, flat ship with most of its weapons on the front for maximum damage output. Broadsides would emphasize symmetry about the long axis with mirrored weapons on either side.

Perfectly symmetric ships are not a great idea here because of the amount of duplication. For example, take a sphere: the weapons on the rear are useless if confronting an adversary at the front, and all they're doing is slowing you down. Engines on the sides or front are dead weight and added vulnerability unless they're actively being used.

If you favor long-range combat, do you want conventional or directed-energy weapons? Torpedoes have great damage ouput, but suffer from limited speed, maneuverability, and vulnerability to countermeasures. Lasers would be superior with near-instantaneous damage on target, are scalable to whatever your power source can handle, and impossible to effectively counter, but have relatively low damage output. (And no, you can't just coat your ship in mirrors -space is dirty, and those mirrors won't stay clean enough to protect you from a big laser.)

Will your ship be fighting alone, or with support? Combat support or logistics? A ship with combat support won't need as many weapons or firing arcs, because it'll have buddies which can fill the gaps. A ship with logistics support (think oilers in the US Navy) won't need lots of onboard fuel, munitions, or maybe even crew spaces, so it can be smaller and lighter than a lone-wolf ship.

Finally, stealth isn't as impossible as you might think. Space is vast, and finding one little glowing pip of thermal energy in a sea of stars is no easy task. Take this interstellar asteroid which passed through our system just a few months ago: we didn't see it until it had already passed and was on its way out. If you place your heat-rejecting components and radiators in one protected spot on your ship and cover the rest with thermal coatings, you'll look just like the background.

Lastly, I'd suggest you look closely at modern naval warfare and ship design, because although it's (mostly) 2-dimensional, it really is a good analog for space combat considerations.

  • $\begingroup$ Wow I really liked your post thanks for the input. $\endgroup$
    – Efialtes
    Mar 27 '18 at 21:57

It depends on your science. The most likely is that they will look very similar to modern rockets and spaceships - basically like a tower. There are solid, basic engineering reasons for those designs that aren't going to change easily.

There are a bunch of little reasons. Heat dissipation is likely important and is harder the more spherical you get. Efficiency of design - only having one engine (or bank of engines), power flowing along one direction, etc. Having a variable cross-section might be important - the ability to point your "nose" into enemy fire to reduce the chance that relativistic weapons hit you. But all of those are relatively minor.

The biggest reason is structural. A tower-type design means that thrust is 1) always primarily in one direction, and 2) the materials of your ship are aligned with that thrust. A sphere or cube would need to be massively over-engineered, in comparison. You might be able to do a sphere with engines all along one hemisphere, but that doesn't scale as well as you try to make the ships bigger.

You can solve this by adding more power and AG, but that means more heat, and that's not easy to get rid of. Additionally, there's no such thing as a free lunch. That power your spherical ship is using on AG could be put to better use in a tower-based ship. Because of the extra engineering, it also means that you can build more tower ships for each sphere, even given the same materials. Even if spheres are better 1 to 1, that's not going to be the case - someone who sticks with tower ships will end up with a tonnage advantage, even if everything else is equal.

To get away from tower ships you need some sort of overriding reason to build a less efficient ship. It could be a requirement of your FTL engines, or even your normal-space engines if you get creative enough. But basic technology advancements aren't likely to take us away from a tower/cigar design.

  • $\begingroup$ Could you explain heat dispersion issue? I get it in any terrestrial craft but in space, with vacuum being such a good insulator wouldn't you want giant heat sinks in the sphere that then radiate heat? $\endgroup$
    – Andrey
    Mar 26 '18 at 16:40
  • $\begingroup$ Also wouldn't a tower structure be the weakest if the ship ever needs to turn? $\endgroup$
    – Andrey
    Mar 26 '18 at 16:41
  • $\begingroup$ @Andrey Depends on the exact technology, but likely you'd want heat sinks in addition regardless. But the more spherical you are, the higher your volume-to-surface area ratio, so the more you need additional heat dispersion. So that complicates your build, those heat sinks are larger and more vulnerable, etc. $\endgroup$ Mar 26 '18 at 16:50
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    $\begingroup$ @Andrey You still engineer your tower to take lateral maneuvering thrust. But your main engine firing is going to be - by far - the largest stress on your ship, so that's where the biggest support needs to be. You turn by moving the nose of the ship and keeping your main engine going. You can also "dodge" by varying your acceleration randomly (within some bounds of what you want), which in a relativistic battle will vary your location significantly. $\endgroup$ Mar 26 '18 at 16:55
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    $\begingroup$ I like that none of the reasons for retaining the tower-like shape depend on lifting off from a planet or atmospheric reentry - with an additional 500 years of tech development, it's likely that many ships would be built in an orbital shipyard and not be expected to ever land on a planet. $\endgroup$
    – Rob Watts
    Mar 26 '18 at 17:48

The "Children of a Dead Earth" video game has basically solved this for hard science. This link backs up most of the science behind the game. Basically Kerbal Space Program with guns and missiles, his cone shaped armored warships are probably the closest to potential reality given that he has virtually no hand-waved science so the ships and weapons have to actually work.

enter image description here

You can see the sloped armor to deflect impacts from ahead while allowing sensors and weapons to fire ahead as well. Engines are at the rear where the nozzles are protected, since without controlled thrust you are adrift.

enter image description here

The interior is mostly fuel/remass tanks, coolant so radiators can be stowed if necessary while in combat, and the crew living module. The layout is like a very narrow tower rather than a horizontal hallway since under thrust "down" will be towards the engines.

enter image description here

Obviously the aesthetics are lacking compared to the aerodynamic ships in media, and civilian, non-combat ships would look quite different (more like lollipops with a bulbous habitation module with internal rotation or a ring so the ship can be spun for gravity when not under thrust and a long column of tanks and radiators with an engine at the rear).

You can go to Atomic Rockets if you want to read up on all sorts of very realistic, practical ship designs. Essentially, your engines determine the ship shape.

Here are some examples (all shamelessly lifted from Atomic Rockets). First is a classic Heinlein torchship, basically a sphere with a fusion rocket at the end.

enter image description here

Very practical, but probably not what a dedicated combat vessel would look like since it offers a huge profile in every direction. But great for optimizing internal volume and keeping everything away from that super radioactive drive.

A more aerodynamic version with some concession to atmospheric stability.

enter image description here

Finally, a more likely shape, which is the lollipop design from Attack Vector:Tactical where the engine is as far from the people as possible.

enter image description here

The spikes on the rear are radiators for the engines, designed to stay in their own shadow to limit the neutron damage. Again, high performance engines have HUGE radiation emissions, so there are a lot of design constraints. The ship also has to support itself when under thrust, so everything tends to be stacked over the engine which reduces the total weight of the superstructure (towing a ship is even more weight reducing since pulling requires less strength in support structure than pushing) like the Avatar movie Venture Star

enter image description here

Where the big thing to the left is the engine that tows the smaller cargo/crew module to the right. But having your engines up front probably isn't the best for combat, so we are back to the CoaDE cone shape which offers some protection to the engines.

If you sort of handwave away the radiation from the engine, you can get stuff like the Rocinate from "The Expanse"

enter image description here

which has an engine with less shielding for the crew, some aerodynamic atmospheric capability, the tower design, sloped armor, and quite frankly, a more pleasing aesthetic appearance than the CoaDE cones.

Even with FTL (how exactly does that work? Wormholes, warp drive, jump gates, etc) the "real space" combat would still dictate the cone shape, unless you are using some sort of magic engine that doesn't require remass and doesn't emit lots of nasty radiation/toxic byproducts you don't want washing all over your ship and living areas. Most sci-fi ships have MASSIVE engines, but almost no fuel! This is the opposite to reality.

Limited artificial gravity could limit the need for ships to spin when not under thrust, but what does "low intensity" mean? It is weak, only in parts of the ship? Because while under thrust there will definitely be a pull opposite the direction of thrust, so either you are counteracting that so you can have a horizontal "ocean liner in spaaace" layout or just compensating for not having thrust during the long periods of weightless drifting between destinations (unless you have something like the Epstein drive in "The Expanse" series, which can thrust almost indefinitely on very little remass).

Relativistic weapons means either lasers, which diffuse at relatively short ranges AND generate as much heat in your ship as they do on the target ship, or super rail guns which still deliver as much kinetic energy to your ship as the target (but hopefully you have recoil compensators to spread it out). Point being, a near light speed kinetic impact will destroy ANY ship, no matter how armored, so no point in armor in that case (rather better to let the projectile zip right through your ship). But you have to decide on how heat will be handled (since almost no modern sci-fi media depicts radiators they just ignore it), do you have some sort of energy/gravity shield, and how do ships maneuver in real space (i.e. how hot [radioactive] are their engines and how much remass/fuel do they need to carry). This will dictate a lot of the practical ship design. Is there an aerodynamic re-entry requirement? If so, then a streamlined hull is necessary. Otherwise you can have almost any shape you want, just realize that it all has to be supported while under thrust, unless your antigravity can compensate.

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    $\begingroup$ very detiled I like it... $\endgroup$
    – Efialtes
    Mar 27 '18 at 22:03
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    $\begingroup$ You got here before me for this one. Since the game is very Hard Scifi looking at forums dedicated to the game for successful designs should be informative since it tends to include the little details like where you might want to put your power sources and radiators etc. $\endgroup$
    – Murphy
    Mar 28 '18 at 13:19

Given there is no stealth in space and you can aim and fire at long distances, there are a few different ways you can go.

  1. If weapons are relatively short ranged. If ships weapons are relatively low powered, then the issue might be to be able to manoeuvre when in relatively close proximity (relative may still mean hundreds of kilometres away). The "Star Fury" fighter of the TV series Babylon 5 provides a possible answer.

The ship's reaction motors are mounted at the ends of the long booms, providing a great deal of leverage to move the ship about all three axes. If you watch carefully, the ship can be orientated to point in any direction to track, acquire and fire on any target, but may continue on the same orbital path, unless the engines fire long enough to impart a change in velocity different from the initial path. While never actually mentioned in the show, the rectangular booms housing the engines could serve as heat exchangers or radiators as well.

enter image description here

The adaptable Starfury design

This design can scale very well, with the caveat that larger ships will tend to turn more slowly since they have greater mass, thus more inertia to overcome before pointing the main battery at the target.

  1. Space combat takes place at long ranges (10's of thousands of kilometres).This isn't the sort of space battle seen in movies (evidently inspired by the age of sail wooden ships pounding each other with muzzle loading cannons). Ships are far enough away the are not visible to all but the most powerful sensors, and except for laser weapons, there is significant time between shots being fired (out of electromagnetic railguns or coilguns) or missiles arriving on target. While turreted battleships might seem to be the solution, the sheer length of electromagnetic weapons firing at orbital or interplanetary velocity precludes this.

Instead, the ship might resemble a sea urchin, with long spines corresponding to rail or coilgun barrels extending in all directions. When targets are detected, the appropriate barrels are energized and fired. Either fine control can be applied directly to each barrel (say a small 2 degree of freedom ball mount) or the ship itself makes fine control movements. After the long journey, the projectiles might also have small rocket motors to make final adjustments to strike the target as well. Like a real sea urchin, this ship could also be "grounded" on a small asteroid and still present a bristling array of weapons.

enter image description here

Sea urchin based coilgun ships would resemble this

If missiles are the primary weapons system, they will be quite large. The New Horizons spaceship took only 9 hours to cross the distance between the Earth and the Moon, but it was launched on an Atlas rocket derived from an early Cold War ICBM

enter image description here

If this is your anti ship missile, your launch platform is going to be huge

This suggests that a similar dynamic will be in play, the ship will essentially be a mobile ICBM field, and the final product may resemble "corncob", with each "kernel" being the cover of a launch tube.

enter image description here

Not so tasty when it's shooting at you

  1. Ultra long range weapons (out to one light second). Since the space environment allows you to build huge structures in zero gravity, there are few limits as to what you can actually build. The Atomic Rockets "Conventional weapons" page has a long section on lasers, and the ultimate laser weapon is an X-Ray FEL driven by an electron beam accelerator a kilometer in diameter. At one light second (300,000km, slightly less than the distance between the Earth and the Moon), it has enough power to slice through metal, ceramic and carbon fibre in milliseconds. The one light second rule is rather arbitrary, based on the notion that you want no more than two seconds to elapse between the time you fire the beam and the time you see the results of the shot.

At one light minute, it is still powerful enough to melt materials, and is a dangerous radiation source to unshielded sensors (or people) a light hour away.

enter image description here

The Ravening Beam of Death (RBoD) X-ray laser

At that point, the shape of the ship is largely irrelevant, since you can be theoretically slice an enemy ship into small pieces from incredible distances. The RBoD will be an unlovely assembly of girders, power modules and radiators. It will likely be surrounded by a cloud of small drones with provide sensor data, giving a finely detailed 3D view of the surrounding volume of space.

  • $\begingroup$ The sea urchin ship is awesome!!! Your idea? Can I steal that? lol $\endgroup$
    – Len
    Mar 28 '18 at 19:50
  • 1
    $\begingroup$ While I don't think I've ever seen that anywhere else, I won't lay claim to it. If it works in your story, enjoy! $\endgroup$
    – Thucydides
    Mar 28 '18 at 20:00

When you consider The Kzinti Lesson (the more efficient a reaction drive is, the better a weapon it makes). Any civilization that can produce the energy to travel between worlds can also produce a weapon that can turn pretty much any solid matter into plasma making armor irrelevant.

This means the quality of your ship's defence is exactly proportional to its ability to avoid damage altogether. If we assume two ships have good enough of sensors to see and target each other at any given range, damage avoidance becomes a function of how narrow your profile is vs your maximum acceleration in relationship to that axis.

For example, if your ship has a 10x10 unit front profile, and you can accelerate 10 units in any direction in the time it take an enemy missile to compensate to hit you, that means through randomizing your strafing acceleration, an enemy missile has a 1:2 chance to predict your X profile and a 1:2 chance to predict your Y profile for a total chance to hit of 1:4. If you extrude that ship's profile to be 1x100 units (same area but thinned out), then an enemy missile has a 1:20 chance to predict your profile on the X axis and a 1:1 chance to predict your profile on the Y increasing your overall chance to evade a shot 5 times over the squared out ship.

Logically, the more you can stringify your ship, the more effective that randomized strafe can be to reduce your odds of being hit, but you you can only min-max you ship's thinness to a point before you risk it breaking under its own inertia. Also, when a stringified ship does get hit, it is cut completely in half separating vital systems from one another. Since a stringified ship is so fragile, this means an enemy ship can just compensate for your evasiveness by firing a lot of weaker shots instead of one big ship vaporizing one.

The Solution: A Spherical Hex Lattice

![enter image description here

By modifying these principles and turning your ship to a spherical lattice, you maximize how "thin" you can make any one surface of your ship while also maximizing its overall structural integrity. It also breaks up lines along any single vector so a targeting system can't take one cardigan component for granted like it can with the stringified ship. Even if you fire a bunch of shots into the "hitbox" of the ship, 99% of them will just pass harmlessly through the lattice without hitting anything at all. It will also propagate damage way less than a solid design. If a weapon designed to vaporize an equally massive solid ship scores a lucky hit, it will only vaporize a few nodes, while leaving most of the ship in-tact.

With each node containing systems that can't just be cut off in bulk like on a stringified ship. Firing at it is a lot like trying to kill a swarm of bees with a handgun. However, it does have 1 advantage over a swarm which is that certain systems don't need to be in every node. In a swarm of smaller ships, each ship needs thrusters, senors, weapons, computers, etc. which all need to be miniaturized enough to fit on each swarm ship and powerful enough to target larger ships at range. This means most of the mass of your swarm is just expensive, redundant support systems whereas a larger ship might have less redundancy but more powerful systems. In a lattice ship, the engineers control the level of redundancy; so, you might have 30 nodes allocated to propulsion, 20 to weapons, 6 to sensors, etc. This way you get all of the advantages of integrated systems you see on a big ship with all of the difficulty to fully wipe out like a swarm

(Note: This idea is an adaptation of the "spaghetti" ship exploit from the MMO spaceship building game, Starmade, which demonstrated that such ships could take on "traditional" ship designs of similar tech 50 times their mass and win. This game also demonstrated that high density spherical/cubic ships performed the worst out of any ship design shapes because they are easier to hit from all directions, and always have plenty of vital systems to punch through no matter what damage propagation profile your weapons have.)

  • 1
    $\begingroup$ Additionally this ship design would be exceptional at radiating heat away from its components. Also spreading out it's sensors takes advantage of the "bigger telescope" effect astronomers use when they coordinate multiple sensors around the world to observe far off objects. $\endgroup$
    – Muuski
    Aug 14 '19 at 17:03
  • $\begingroup$ This is a concept I've been thinking about for a while too, but this is a smarter execution of the concept than I'd been able to come up with. I feel like IDEALLY you'd want the ship to be able to 'de-stringify' itself to allow higher G-forces when you need to alter your orbit or trajectory, and then expand into the low-density form when you need to optimize sensor, weapons, and defensive performance. This is very clever. $\endgroup$ Aug 14 '19 at 18:40
  • $\begingroup$ A folding lattice ship would certainly be cinematically cool, but it would add so much complexity with all those servos and joints, that by the time you are done, it would probably be more structurally sound to just try to turn it at full volume. $\endgroup$
    – Nosajimiki
    Aug 14 '19 at 20:05
  • $\begingroup$ Frankly, I believe people WAY over emphasis the importance of how fast a ship can turn in space. Even if your enemy ship is evasively strafing at 10Gs, you'd still need to be hundreds of thousands of km away for dodging to work against beam weapons. Matter does not maintain cohesion at speeds fast enough to close that gap to dog-fighting range before the battle is over. $\endgroup$
    – Nosajimiki
    Aug 14 '19 at 20:05
  • $\begingroup$ Also there is the limit of every gram counts, I mean propulsion systems are really heavy and usually take up a good 10% of the ship's overall mass, with 50% or more of the rest being fuel tankage. I mean this sort of ship would need some crazy engines that are short of unobtanium. $\endgroup$
    – Efialtes
    Aug 19 '19 at 11:07

If you’ve ever read Arthur C. Clarke’s “Hide and Seek,” you know how important it is to be able to maneuver. A ship with spherical symmetry, and especially with vectored thrust, can turn on a dime.

If you need more surface area rather than less (which I imagine is more likely to be because of heat dissipation when you only have radiation, not convection, to remove heat than to have more space to stick weapons), you could make the sphere a hollow lattice, maybe with some internal struts.

The engineering of different spaceship components might give you more interesting shapes. If you need to generate a shield in the form of an ellipsoid, you want two separated foci for it, so maybe you have a beam with those on either end. Maybe the engines have to be kept apart from the crew. Maybe spikes radiate excess heat. Something like that is what retroactively explained the iconic shape of the USS Enterprise and why other ships in the same universe have the same recognizable style based on it. If the spaceships need to enter atmosphere, it makes sense for them to be aerodynamic. If they need a bay or a hangar, that changes the design.

  • $\begingroup$ +1 for addressing heat dissipation, which is doubly important for anything using hot weapons (ie pretty much any weapons) $\endgroup$
    – user70585
    Mar 26 '18 at 23:22

I think that the shape is basically irrilevant, but you should add some details about the technology level (Is there FTL ? What weapons ? Artificial gravity ? Are there something like an actual fighters ? )

True, space is a 3D environment, but at the same time you can deploy your fleet in a 3D formation.

Making an analogy with the current fleets, the attack can arrive from every direction (let's forget the submarine for now) and you deploy the ships to cover this (roughly in a circualr shape).
There is no reason why in space you cannot do something along the same logic: the attack can arrive from every direction, so you deploy your ships in a sphere (or cilindrical) shape, with the advandage that, without a strong gravitational force given by the Earth, every ship can aim its weapon towards the outside of the sphere and be oriented accordingly so that it need to cover only its top.

Assuming this, the shape of the ship became pratically irrilevant and you can use whatever shape make sense or is more efficient for the ship type, but you don't need some particularly exotic shape.
Bonus point, you still operate a ship where, from a human point of view, there is a top and a bottom, which is the natural situation for the crew.

  • $\begingroup$ It's up to your structural engineer because it doesn't matter, +1 $\endgroup$
    – Mazura
    Mar 26 '18 at 17:03

Disk or Saucer Shaped

Probably with a structure like several movable concentric rings joined together to form a saucer shaped ship. The outer larger rings are to be joined edgewise with the next smaller ring inside them

It is quite efficient for a Space Battleship-

  • It has the benefit of 2 large surface area faces, providing room for a large number of retractable turret based weaponry.

  • The shape provides the maximum maneuvrability ,after the sphere, for 3 dimensional space travel. Multitude of small engines along the rim, for quick burst of speed, and a main engine near the centre for long travel. The movable concentric ring design allows the main engine to be fixed in place. The easy movement would lead to greater rates of evasion or escape.

  • The ability to move in any direction in a plane in an instant, gives it the advantage of unpredictability, with no chance of path prediction attacks.

  • Concentric ring design allows the turret basea weaponry to be aimed and oriented in a large number of ways, leading to higher flexibility in combat, and significantly higher accuracy. The rings could be aligned to increase or decrease the rate of fire by allowing or not allowing the inner ring turrets to get a line of fire on the target. The angle of the ship, with respect to the plane of the assailant, could regulate the rate of fire by allowing more turrets to fire simultaneously.

  • The shape itself is very hard to hit when seen edgewise. With all the turrets retractable, the ship basically becomes a line in space from the side, and the damage dealt to the ship ( if any) would be minimal due to the direction of the attack. Adding armour to the ship only along the rim would add minimal bulk and make the ship practicality impenetrable from the edge, giving an insurmountable tactical advantage.

So all in all the concentric saucer is a very balanced shape of ship to have. It boasts the title of the shape most difficult to hit (after the rod shape) and the highest concentration of fire (after the sphere). Its maneuvrability is second only to to the sphere but with the distinction of having significantly less mass, causing less fuel consumption.

Overall, it appears to be the best shape for a space Battleship

  • $\begingroup$ I think this ones starting to be my fave shape ... $\endgroup$
    – Efialtes
    Mar 27 '18 at 22:00

There is no reason to assume that space ships will look anything like ships at all. The shape of a ship is driven by environmental constraints - water most importantly. The desire to keep it out, the need to cut through it efficiently.

In space, none of that is true. The ISS is probably a much better model of a future space ship than all the SciFi movies. Even your average oil platform is closer than the Enterprise or the Death Star.

Especially a war ship is quite likely to be made up of frames and struts and a lot of its enclosed area will actually just be the empty space between the structural components. This way, any individual part can be hit, destroyed or discarded as necessary without impacting the stability of the structure.

The need for an actually enclosed area, with atmosphere and (preferably) gravity, would be a tiny part of the whole thing. The crew quarters and control areas. Want to repair the laser array? Don a space suit.

A war ship would be built with redundancy in mind, so it can sustain a couple hits without losing vital parts. It would try to put the hottest parts (engines, some weapon systems) at the edges so an enemy targetting them doesn't hit the control or central parts.

Must-read: http://www.projectrho.com/public_html/rocket/

It's a massive website, but it tackles all of these questions in as much detail as you can stand. Don't write SciFi without reading Atomic Rocket first. ;-)


One that looks exactly like an asteroid? To expand slightly: Any spaceship that looks like a spaceship and is detectable will be space dust in the first few hours of a space war. The most effective spaceship has these characteristics:

  • Does not look like a spaceship
  • Does not emit anything detectable
  • Does not move in a way unlike other space objects
  • Has weapons that cannot be tracked back to the spaceship

So, a hollowed-out asteroid, with nukes that drift at low speed in a random direction for a few hours before firing, using fake "outgassings" or EMP propulsion for movement, staffed by a computer.


  • $\begingroup$ Welcome to Worldbuilding SE! Generally speaking, an answer to a question should contain more than just a single line. As it stands, I think your answer might be in jeopardy of being deleted as poor quality. You can easily avoid this by explaining why an asteroid shaped starship would be the most effective, what the design pros are, how design cons can be avoided a/o mitigated and so forth. $\endgroup$
    – elemtilas
    Mar 28 '18 at 23:24
  • $\begingroup$ Thanks. I was literally adding lines as you commented. Mind removing the downvote? $\endgroup$
    – Dan
    Mar 28 '18 at 23:25
  • $\begingroup$ I didn't leave a downvote. I had kind of figured you were heading in the direction of such stealth as would be possible in space, but am glad you clarified your answer! $\endgroup$
    – elemtilas
    Mar 29 '18 at 0:27
  • $\begingroup$ Yes, stealth is the way to go. I see spaceships that look like spaceships the same way I see any above-water naval force: useful for projecting soft power and for parades, and useful against opponents who have no missiles, but useless (and a deathtrap) in any equal-vs-equal war. Missiles are cheap, ships are expensive, missiles only have to hit once, counter-missiles have to hit every time. $\endgroup$
    – Dan
    Mar 29 '18 at 0:36
  • $\begingroup$ Also, a starship buried deep within an asteroid has instant armour plating and little need for "shields". I think good in reality, but asteroid-ships sure make for horrible movies! So, what ship will you be serving on? Oh, the USS Randomly-Shaped-Space-Rock-Number-1701. Ya. Real romantic that! $\endgroup$
    – elemtilas
    Mar 29 '18 at 1:51

As a aerospace engineer, here are my thoughts on this question:

In space (unlike in a planet's atmosphere), there is nothing comparable to air resistance. So protuberances, booms, antennae, photovoltaic arrays (a.k.a., solar panels), etc., don't have any negative effects on a spacecraft's ability to travel through space. Therefore, spacecraft can be virtually any shape.

All spacecraft need to be built as light-weight as possible, because the more massive the spacecraft, the bigger the 'engines' would need to be, which would require more 'fuel' (whatever type of fuel it might use). In fact, the energy required to accelerate a mass can specifically be calculated using Einstein's General Theory of Relativity -- as velocity gets closer to the speed of light, mass goes to infinity, and the energy needed to accelerate that mass also goes to infinity. Now you might say then that the mass is irrelevant, but that would be a mistake -- any 'work-arounds' that allow for FTL travel do not negate fundamental laws of Physics, and wouldn't apply to sublight speeds. So the design of the spacecraft's structure would have to be light-weight, which would make any protuberances, booms, antennae, PV arrays, etc. rather flexible.

However, a vehicle with FTL capabilities would also experience tremendous rates of acceleration, or at least would experience considerable gradients of acceleration, when jumping to FTL speeds, or even at sub-light speeds. In other words, different parts of the spacecraft would be accelerated differently. Think of it as the equivalent of your head snapping back when you slam on the gas pedal in your car. These acceleration gradients would make it undesirable to have any long flexible structures sticking out of the main body of the spacecraft, since they could more easily break off.

Also, from a structural efficiency standpoint -- getting the most volume for the least mass -- a sphere would be the best choice. So the closest to a sphere that you could keep the spacecraft, the better from the basis of minimizing mass. Also, it would minimize the cross-sectional area in all directions, making the ship a smaller target.

Another consideration is that the crew compartment (and anything else where the crew needs to access from inside the ship) is essentially a pressure vessel -- normal atmospheric pressure internally, and zero pressure outside. In order to withstand the pressure differential and not create unnecessary stress concentrations in the hull, a sphere or cylinder (with rounded ends, like a SCUBA tank, Propane tank, etc.) would also be the most desirable.

But you're talking about a war ship, meaning it will be equipped with weapons to fend off enemy ships. In order to be effective in a combat situation, the gun emplacements need a wide range of motion to have as wide a field of fire as possible. Think about the turrets of a castle or other fortification (e.g., Fort Ticonderoga), of the shape & location of the gun turrets on a B-29 or the tail gunner of a B-52 -- they stick out to create as wide a field of view as possible.

So IMHO, I think a sphere with gun turrets that stick out (a shape something like "Bumble Balls") would be the most effective. Alternatively, a cube with the turrets at the corners could also work pretty well.

  • 1
    $\begingroup$ Great answer except for one thinking mistake: The ship is not a pressure vessel. Only the crew compartments are. Large parts of the ship would just be exposed, not just antennas, but also reactors, engines - anything that does not have to be accessed during flight. Most likely that will include the weapons as well. $\endgroup$
    – Tom
    Mar 29 '18 at 12:32
  • 2
    $\begingroup$ @Tom - Yes, the crew compartment is what needs to be pressurized, but spacecraft designed for combat need shielding to withstand enemy fire, which must cover other parts of the ship beyond just the crew compartment. Such shielding would make accessing anything beneath it more difficult & time-consuming. Therefore, as many of those components as possible need to be accessible from inside the shielding (i.e., from the crew compartment), meaning those areas where the crew gains access need to be pressurized too. Also, you don't want to have to make a spacewalk during a battle to make repairs. $\endgroup$
    – Big_Al_Tx
    Mar 29 '18 at 15:03
  • 1
    $\begingroup$ The shielding needs to be only from the outside, you can leave the inside open and accessible, but making it pressurized is an order of magnitude more effort. Plus if you look at the ISS, pressurized != armored. In fact, the shell of the crew compartment could be much weaker than the structural frames that other stuff is attached to. $\endgroup$
    – Tom
    Mar 29 '18 at 18:13

Frankly, it's easy to be caught up in the "configure my weapons" issue and forget the "physics of reality" issue.

If you have the tech to fight a serious battle, then the only shape you'll be using is a sphere.

Remember, unless you're going to stand-too (hard to do in space!) and lob stuff at each other, you're going to need to turn. The early U.S. space program used a very short cylinder, but it was short enough to manipulate with four evenly-spaced thrusters.

If you're big enough to handle munitions, you don't have that privilege anymore. Physics will force you to efficiency.

So, a sphere with (ignoring strength) six thruster emplacements and a single engine set pushing it forward. Weapons bristling in all directions so that you minimize the need to spin, pivot, and turn — because that all takes time (unless you have some Clarkean Magic to absorb inertial energy...).

This solution has other benefits, it's least likely to break in half, least likely to have chunks (like corners) blown off, most likely to have an evenly dispersed magnetic shield (magnetics like spheres, think "planet"), and least likely to be snuck up on (no corners, angles, or shapes to look around, just "out" from the center).

It also has the cool ability to gently spin during an attack to bring more weapons to bear "broadside." Try that with another shape!


Shape is irrelevant unless said ship enters atmosphere. The best design is a mobile factory that pumps out drones. The capital ship hides while the drones fight it out.

Considered a ship is full of people and life support equipment, you really don't want people shooting at you if you can help it.

  • $\begingroup$ I would actually disagree slightly here about the "shape is irrelevant" part. To borrow Star Trek, the out-Of-Universe reason all the fed ships have these graceful curves is because it makes them look pretty on camera. The in-universe reason is that the curves and shapes are designed to help with warp flow. Compare the borg, who use squat, ugly flying bricks, but are implied to have a much higher mastery of engineering so the ineffiecient and non-aesthetic design just works for them. Essentially the question is "does ship hull shape affect your limited FTL/propulsion characteristics?" $\endgroup$
    – Wenlocke
    Mar 27 '18 at 11:32
  • $\begingroup$ So your argument is the shape only matters for cosmetic reasons? In space there is no drag so ships can be any shape they want thus shape really doesn't matter. $\endgroup$
    – Thorne
    Mar 27 '18 at 22:58
  • $\begingroup$ Not quite. Shape can matter if your ftl system relies on it (example: in the Lensman series, they use an inertialess drive where superluminal velocity is only limited by the friction through the interstellar medium, so they developed teardrop shapes. In Star Trek, the ship curves help with warp field flow efficiency, ostensibly (in universe, at least.) The borg get around it by being that much more advanced.The argument is, at base, not just what factors affect combat movement, but also what affects general ship operations, unless your ship is dropped off in the combat zone and picked up. $\endgroup$
    – Wenlocke
    Mar 28 '18 at 9:29
  • $\begingroup$ So you're saying that the shapes depends on the rules of fictional technology? Unless you impose rules that require a certain shape then you don't actually need that shape? Still proves my point. Shape is still irrelevant. There is no real reason beyond self imposed restrictions for fictional technology as imagined by the author.. $\endgroup$
    – Thorne
    Mar 28 '18 at 11:15
  • $\begingroup$ I think we're just arguing around what we consider as "irrelevant." Essentially yes, informed by the restrictions of the technology in play, the shape can be anything within those criteria. What you can't do is set a restriction on how the technology works and then say "the shape can be anything" if the shape is affected by those restrictions. $\endgroup$
    – Wenlocke
    Mar 28 '18 at 12:36

The ship and warfare are designed within your world and therefore it must obey the rules you created.

  • Where the ship take its power from and how?
  • Where are the ships supposed to maneuvre and how?
  • What are the systems it is carrying?
  • What weapons it is using and what weapons it is exposed to?
  • What defences the ship have?
  • What is the ship's estimated survival time within the battle?
  • What is the technological evolution of the spacecrafts?
  • Are you building a world for a book (series), computer game, RPG sessions? Do you expect to need a photodocumentation of your ships?

All points above limit the ship design to a degree regardless it is personal or cargo carrier, civillian or military. Now, you have a set of possible shapes. For military uses there are two types of equipment: Fighter and Support.

  • Fighter is designed to be as lethal as possible and as tough as possible. The actual design differs from the means how the figther strikes (Death Star-like range attack, X-wing dogfight) and how much it is affordable and expendable to the fleet.
  • Support is optimised to carry/provide as much as possible. Again, the actual purpose of the vessel defines the actual design.

Last but not least, if you need a graphics for a cover, illustrations, game visuals and "the community", the good-guys' ships must look sharp and sexy and the bad-guys' appropriately badass.

  • $\begingroup$ Very informative I will keep it in mind... $\endgroup$
    – Efialtes
    Mar 27 '18 at 22:07

I'd have to say long rod/cigar shape for flexibility.

What I haven't seen mentioned--it would pivot better than any other shape, allowing you to get any part (Except the dead center) out of the way of an incoming attack almost instantly. With a little extra fuel you could pivot on a point besides the center. Note that this pivot can take place in any axis.

Longest distance of acceleration for cheap guns like rail guns where you are just flinging inert matter. This can also be used to drive the ship (Accelerating hydrogen, for instance, to near the speed of light would be a great drive).

Large surface area for mounting external "smart" weapons like rockets.

Smallest profile if the combat is one on one since you can point right at your enemy and he would have to hit you head-on. Also smallest profile in flight so you are less likely to hit space junk--only one small end section of the ship needs to be hardened against abrasion from interstellar hydrogen/micro meteors.

Could spin for gravity if you like when outside of combat. Inside combat I think the spinning for gravity would negate nearly every combat advantage though--but the change might make for some interesting story devices.

  • $\begingroup$ "(Except the dead center)" assumes the centre of mass is also the centre of the ship. It needn't be. $\endgroup$
    – rek
    Mar 28 '18 at 22:42
  • $\begingroup$ True, you could also use more thrust on one end or the other to cause the pivot to be more or less anywhere, it would just be quickest/most effective to pivot somewhere between the center of mass and the center of the ship by providing max thrust from the opposite sides of the opposite ends. $\endgroup$
    – Bill K
    Mar 28 '18 at 22:45

The shape best suited to secure your faction's strategic objectives.

The other posters have provided an excellent scientific foundation for your designs, but consider alloying it with your navy's strategic goals. Weapon design tends to follow the mission objective, whether that be the seizure of a valuable resources, suppression of opposing forces, or the destruction of strategic assets.

What shape of ship would be optimized for space combat in the context of a future space navy?

First, disregard the notion that the Millennium Falcon could survive a high speed flight through the interior of an Imperial Star Destroyer. Or a Death Star.

(I don't see any flaps!) I don't see any flaps!

Atmospheric Re-entry

As Ian Kemp and Rob Watts pointed out, spacefaring vessels don't like air. If your navy's in the business of subjugating planetary colonists, then the engineering department would temper the abstract geometries of its products with some aerodynamic capabilities. This gives you the artistic license to design different classes of vessels with each suited to the task for which it was built.

Most importantly, this creates an asymmetric combat environment in which a purpose-built atmospheric fighter in it's own territory will be able to outmaneuver an unwelcome interplanetary visitor with ease. The same goes goes for combat against "amphibious" (transatmospheric) spacecraft, though the advantage would be less pronounced.

1588: Spanish Armada Defeated

The Spanish ships were slower and less well armed than their English counterparts, but they planned to force boarding actions if the English offered battle, and the superior Spanish infantry would undoubtedly prevail.

Motherships might be look like this: My allegiances are beginning to show...

While transatmospheric varieties will start to look like space shuttles and planes will look like planes (albeit optimized for atmospheric specifics like air density).

Construction and Resupplying

Getting fuel and repair materials into space isn't easy, so maybe the most effective unit would be the one that sacrifices some combat effectiveness for the ability to be replenished at any outpost. Many battles have been lost by generals who neglected their supply lines.

Why was Rommel defeated at El Alamein?

The Allies were close to their supply bases in Egypt and the Axis forces supply lines had become stretched in contrast.

What advantages and disadvantages would the shape you have chosen have and why is it the best for future space warfare?

Motherships would be flimsy "bags of air" that warehouse supplies for refitting smaller craft.

Security craft are usually cheap, sturdy, and fuel efficient for running patrols (e.g. cop cars). I'd go with a universal frame that can be fit with modular components that can be replaced as they break or the objective changes.

Vessels that assault asteroid colonies might be tough little spike potatoes with omnidirectional maneuvering.

Space station assault craft would be quick transporters with a variety of docking ports and a few forced entry options that won't cause decompression. A tube covered in ports seems likely.

Additional Considerations

Space warfare will be in a close to hard science scenario...no stealth is possible because since space is cold, the tiniest amount of heat would radiate like a beacon... combat would be based on bringing your weapons to bear on the enemy as fast as possible...most weapons would be relativistic direct fire or guided...

You just described a video game called Elite: Dangerous, which focuses heavily on delivering a hard science experience. Check out the interviews of David Braben, who can go on for hours about transatmospheric flight and combat in gas giants.

P.S. E:D says that you can go stealth in space, but only if you close your heat vents, which starts to melt your ship. :) enter image description here

The general who is skilled in defense hides in the most secret recesses of the earth; he who is skilled in attack flashes forth from the topmost heights of heaven.

-The Art of War - 4.7 Tactical Dispositions


The ship would have:

  • A large circle facing the attacker with small holes for the guns to fire through.
  • Behind the circle a set of guns, sensors, engines, and the cockpit all a long way from each other able to move around when needed.

The circle would be big enough so that your cockpit weapons and engines can be hidden from view behind it. The circle would allow your critical systems to be hidden from the enemy sensors while still firing.

An enemy would in effect have to play battleships to destroy your crafts critical systems, methodically working through every part of the circle where your systems could be hidden.

  • $\begingroup$ As soon as you have technology to accelerate something to even 1% the speed of light (and if you have FTL, I'd assume that is fair game), no amount of physical shield will protect you from a rock thrown at that speed. $\endgroup$
    – Tom
    Mar 28 '18 at 11:38
  • $\begingroup$ @Tom Yes, but it would still protect you since the rock will pass through the shield alone and hit nothing else. The same way hiding in bushes protects someone from a bullet. $\endgroup$
    – PStag
    Mar 28 '18 at 18:17
  • $\begingroup$ You assume that the critical systems need to be hit. I assume that the impact will transfer enough energy to not only shatter you, but apply enough force to your ship to send it spinning. $\endgroup$
    – Tom
    Mar 28 '18 at 21:43
  • $\begingroup$ @Tom It is easy to produce a material that does not shatter, most materials do not. But if you were to be sent spinning then that isn't being destroyed that is just being pushed away. $\endgroup$
    – PStag
    Mar 29 '18 at 12:01
  • $\begingroup$ You are right that a good choice of material could make this work, at least for the first few shots. However, unlike battleships, any sufficiently large hit and the force it applies to you will add some kind of rotation and from the observed impact point and rotation axis and speed I can calculate the mass distribution behind the shield, giving me a reasonably good idea where you are hiding. $\endgroup$
    – Tom
    Mar 29 '18 at 12:29

There was a big discussion on the Aurora forum a few years ago about realistic space combat.

Here are some takeaways from that:

Except for knife fighting ranges you need seeking weapons (missiles). The reason is that detection ranges are very long due to the limitations of stealth in space.

The reason is that you cannot target the ship. Light speed communication and detection means that you are seeing where the ship was. Also your weapon takes time to arrive. Lasers travel at c. Most anything else travels significantly slower. You have to target the probability bubble of where that ship might be when your beam/projectile/etc. arrives.

The probability bubble gets bigger with the combination of acceleration available to the ship and the combined travel time of the detection radiation and the weapon's travel speed. You can shrink the probability bubble two ways: better processing power to rule out unlikely outcomes faster than the bubble grows due to the time of calculating that and giving up damage to attack an area.

Missiles shrink that bubble by course correcting as they travel.

Missiles can be better than fighters because they can apply more acceleration to "dodging" (making their probability bubble bigger) on approach since humans tend to squish if you get too energetic. Also, missiles don't mind going on a one way mission. Some are actually eager for it: "Bomb #2, get back in your bay."

That leads to a doctrine of missile vs anti-missile weapons with variations. Anti-missiles can be either small missiles or direct fire weapons.

So the strategies are:

  1. Long range missile slugging match: Throw out as many missiles as you can as fast as you can since any ship you eliminate is one less ship firing on you and less defensive firepower. The side that runs out of ships, assault missiles or defensive missiles first loses. Variations revolve around different mixes of offensive and defensive output and a decision between mass devoted to launchers vs mass devoted to missile storage.
  2. Turtle with a knife: Have enough speed, defensive firepower, armor and shields (if they are a thing in your universe) to wade through the missile storm to get into knife fighting range.
  3. Combination fleet: A usually non-optimal combination of the two.

Also note that I mentioned that there are limitation on stealth; not that it was impossible. The more efficient your systems are ad doing what they need to do, the less heat you will radiate. Also, you can concentrate some of the radiated heat away from your target (if you know where that target is).

Also, ship stealth is helped by the fact that space is big and there is a lot in it. Detection capabilities (a combination of receivers and computing power) determine how bright relative to a distant star a ship has to appear to be spotted in a short time. That will determine how far away the ship will be before you spot it.

Shape can help with the cross section but you have to give up storage volume to do that. You also have to decide between storage and launchers. Given the distances involved, you can likely put most of your launchers on one side of the ship or you can spin she ship. That is a factor of other world considerations.


The only thing that would matter is the moment of inertia tensor.

(Which physicists and engineers often just call the "moment" usually.)


There's no other consideration, at all: since there is no air resistance.

(It's surprising nobody else has pointed this out.)

Note the excellent example animated-gif of four rolling objects on that wikipedia page.

Depending on your desired strategic approach, your engineers would create objects with different moments of inertia. (Each would have different advantages - consider an ice skater pulling in her arms during a spin.)

In space nobody can hear you scream, there is no surface effect physics, no viscosity physics (aerodynamics, etc) - but there is your moment tensor. Which changes everything and is the "whole" design.

BTW note that even more-so, if you have "inertia control" (just as in Star Trek and most scifi ships) - then, the design of moment of inertia is all-important.

Indeed: just one example, you could have a ship that deliberately is long and slender with huge weights concentrated on each end...

Then by using your "inertia dampers" on just one end you could create astoundingly fast (sci-fi) combat movements - spins, "dodges", and so on.


We can't really give any clear answers to this because of the first rules of warfare:

  1. Build your tools in the best way to deal with the environment you will fight in.
  2. The enemy is part of the environment you will fight in.

The correct shape for warfare is always completely and utterly dependent on what you need to do with it, and that includes surviving enemy attacks. So what sorts of attacks are they using?

If they have laser based attacks, ships which can maintain integrity while rolling (like cigar or spherical ships) will have a huge advantage by making it difficult or even impossible to target a single point for a long period of time.

If they have kinetic weapons, shapes which are effective at taking hits from kinetic weapons would be valuable. I could see a structure which is little more than a thin shell with the actual body of the craft inside on mobile girders. If you can't see where the "heart" is, it's hard to hit it, so all of your hits on such a craft become glancing blows.

If they are using nuclear weapons, then it might become effective to use a spider like structure. Have a large number of dumb objects spread far enough apart to make it hard to hit all of them with a nuclear strike. Even the mighty Tsar bomba was not lethal at 45km. Put wires between them, and your spider can flit along them to escape any particular attack. This would force them to fire quite a large number of weapons at you to trap the spider -- and hopefully you're shooting back at the same time.

Likewise, your environment includes FTL. What does that do to to your design. One of the comments on another answer pointed out that there's an in-world explanation in Star Trek that the ships are all smooth and curved to cut down on warp drag. If your FTL works like Star Trek's does, you may need to take that into consideration.


To borrow from a comment I left elsewhere, you really have to look at exactly hat the characteristics of your ships propulsion are in order to know what the best shape is: You have limited FTL and limited Artificial gravity. The implicatons of having those depend on how good they are, as limited AG could go right out to inertial damping, which means your turn characteristics could be significantly different. Are you using reaction drives for sublight thrust/manouver, or are they reactionless? Again, a factor.

The timescale involved puts us into and beyond Trek era, where we have inertial damping, force fields to help with structural integrity (all based on the same space-bending effects that make FTL travel possible) and spaceship hull designs that, out of universe, are desgined on aesthetics and looking good on camera, but in universe, are based on warp field physics so are more efficient than a flying brick (see also the Borg, who are supposed to be so good at warp physics that they can make their non-aesthetic flying bricks travel faster than everyone elses anyway.)

Arguably, your technology level and the underlying nature of it will inform your ship design as much as your tactics.


The shape of a ship is determined as much by other factors as by optimal fighting capability.

Manoeuvrability is important; your ship needs engines and thrusters and whatever else in order to be able to simply get from one place to another. It also likely needs some way for crew to embark/disembark: airlocks, docking ports, escape craft, etc. These requirement will all have more effect on the final shape of the design than its offensive or defensive capabilities.

To be sure, for a warship, shape is important. But it is not the first factor driving the design.



In space, I don't think shape matters at all. I think its all about speed.

Imagine a ship that is faster in every way to all the ships around it, flies faster, shoots faster, and computes faster with onboard super (quantum?) computers.

In short, you couldn't shoot it down because its faster than your ship and faster than anything that you can shoot at it. But it could still blow the heck out of yours because it shoots faster too.

Whenever I see a movie where aliens attack Earth (Independence Day) and alien fighters shoot it out with human jets (Independence Day) it always seems like the two types of craft are on equal or close to equal footing (Independence Day). NONSENSE! The alien ships would run circles around ours. With their greater tech they would totally obliterate our jet fighters and not even take one loss. It would be a total and complete slaughter! No offense to any fighter pilots.

And its not because of the shape. Its because of the speed. So all things being equal, except for the speed, the much faster ship would absolutely win.

Better yet, imagine a ship that could teleport? One second its there, it shoots the snot out of you, and then poof, before you even know it laser blasts are rocking your ship and you never even saw your enemy.

Whichever side achieves either or both of these technologies first will have the upper hand as long as the other side doesn't achieve the same or equivalent tech.

Even force shields wouldn't help because those can only take so much damage before they go down too. Sooner or later speed wins.

And if you really want to go way out... how about a ship that is made out of energy? Or a ship that can "phase through" objects? Or a ship whose body resides in an alternate dimension?! You cant hit it, but it can hit you, regardless of shape. Those are more hand wavey, but we've all seen worse in sci-fi.

Don't just think outside of the box... forget there's a box altogether!


I think it all boils down to how realistic do you want to emulate real physics. No matter the shape of the ship, if you want to be able turn and fight is not simple at all. For instance, your ship is travelling along at 0.2c at heading 180.0 and you've done a pass-by shot at your enemy, even if you rotated your ship to keep the primary weapons on the enemy, you are pretty much on the same heading of 180.0, and you will need a tremendous amount of energy to change your course to come around for another pass, and you can only expel so much thrust to do so or you'll smear all life on the bulkheads... unless you have inertia dampers.

So to have combat, your pretty much have to slow down to a point that it becomes a slug fest, or it becomes an orbital conflict and you can use the planets gravity and atmosphere to bring your ship around. Other than that, it long range weapons that accelerate very rapidly at first, then use cold rcs systems to align on target so detection is darn near impossible.

Watching a ship on TV turn like an airplane is not even close to reality.

Just saying. Frit

  • $\begingroup$ This is interesting information, but it does not answer the question. In a condensed form, it would have been a good comment. Take our tour, do a few things to earn 10 rep, and you can post comments. $\endgroup$ Mar 28 '18 at 21:11

Any shape that can hold your FTL drive.

If your FTL technology allows ships to accelerate faster than light in realspace and not by taking a shortcut through some other dimension (hyperspace, thirdspace, the Warp etc.) then any FTL-capable ship - literally every one - is a potential weapon of mass destruction on a hereby unprecedented scale.

Take, for example, the Space Shuttle orbiter. Assume we've replaced the Space Shuttle Main Engine assembly with FTL drives and filled it with ballast to increase its mass to its maximum takeoff weight of 109000 kilograms for a higher impact energy. Assuming a velocity of 1 C (which is great for a weapon but still not that useful for interstellar travel), it would impart over a million megatonnes of impact energy on a target. That's enough to crack a planet in half.

Your space war would be a cold war, as literally anyone with minimal FTL capability could reduce a planet to a debris field orbiting a star. The very threat of it would be enough either bring someone to the negotiating table or cause your civilisation to be annihilated in a "get them before they get us" scenario.

  • $\begingroup$ Your light-speed orbiter would probably do a heck of a lot more than just crack the planet in half (and here's where I'd put a link to the XKCD "Relativistic Baseball" What-If, if I had one). Anyway, welcome to WorldBuilding.SE! Take the tour and visit the help center to learn more about the site, and enjoy your stay! $\endgroup$
    – F1Krazy
    Mar 29 '18 at 14:33
  • $\begingroup$ This is a good answer to, regrettably, the wrong question. The OP is asking about ship-to-ship combat, not planetary bombardment. $\endgroup$ Mar 29 '18 at 16:03

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