Would bigger space war ships be actually better or not?

It depends what technology you are using.

For example, a ship big enough to carry a nuclear reactor in the 100+ MW range and railguns/beam weapons powered by it is going to have a minimum size. If this weaponry can counter multiple missiles - or whatever the small ships were carrying - then the 'big ship' approach works best.

Look at it this way, from naval history..

• In 1800, a 'big' 3-decker ship of the line could take on smaller ships with a very high chance of success - no asymmetric warfare.

• By ~1850, a smaller ship with explosive shells could obliterate such a ship.

• By ~1870, steel armor and big guns gave battleships advantages over smaller ships in almost any number.

• By ~1880, quick-firing guns on small ships gave 'small' ships the advantage (in theory, never tested..)

• By 1890, quick firing guns and better accuracy on the battleships swung the advantage back (but torpedoes.. The torpedo was the first true asymmetric weapon)

• In WWI, big ships were mostly kept in port by the threat of submarines with torpedoes, only venturing out under heavy escort.

• By WWII, big battleships were practically obsolete in the face of both submarines and aircraft. The new capital ships - Aircraft carriers - could only survive by virtue of their own 'small ships' (aircraft) in protection.

There have been very few naval engagements since. The Falklands suggested that missiles from 'small ships (planes)' could beat 'big ships'.. but anti-missile technology has come on since then.

So you have a fundamental problem. Can your swarm of small craft - in realistic numbers - land a fatal punch on the big ship before the superior firepower of the big ship takes them all down? Remember that in space, it's really hard to hide. You can't have a submarine, obviously, but also there is no horizon, no atmospheric distortion.. your big ship can spot incoming ships and ordinance from a huge distance.

Every such decision is a combination of two factors, the effectiveness of the ship in combat and the vanity of the admirals in charge of ordering the vessels.

During the age of ship to ship combat, a bigger ship with bigger guns, more range, more armour was an advantage. In the age of carriers, a bigger ship was a bigger more expensive target. The building of the Yamato was an exercise in vanity, and its demise showed the futility of that exercise.

Big aircraft carriers are now an exercise in vanity. They're about projecting power over the little people, not about symmetrical warfare. It's well known that a good submarine can easily knock out a carrier, but both such submarines and the big carriers are currently controlled by the same powers. Should symmetrical warfare break out between the submarine powers you're not going to see any carriers getting involved. Just as the Yamato didn't put to sea until the end of the war because she was too expensive to lose, the carriers would be kept well away from places the submarines could get to them. It's not so much about the cost of the vessel as the loss of prestige that goes with it.

Your fleet admirals would be making very similar decisions; how expensive is the ship; how vulnerable is it to the latest technologies; how good does it look on my resume to have commanded it; how bad is it going to look if we lose it; is my career over if I prang it in spacedock; does it actually carry enough firepower to be worth it.

There's no glamour in a missile boat, there's no pride in a kid sitting in a tent a thousand miles away with a joystick controlling a drone. Consider your technologies when you build your space battles, but also consider the vanity of the old guard. They want to see dogfights, they want to be launching manned fighters, they want to see the whites of the enemies' eyes, they want acts of romantic heroism. They don't want to be pushing buttons from a distance.

Bigger ships are better in some areas, and worse in some others. They are, however, so ludicrously impractical to build that the bulk of any space fleet will be made out of smaller ships for sheer convenience. Consider a modern army: a tank is better than a soldier in every combat metric, but for every tank, there are probably about 1,000 soldiers, because people are so much cheaper.

Pros of a larger ship:

• Intimidation factor. This is never to be underestimated when it comes to warfare. A squadron of fighters coming towards you = meh. An Imperial Star Destroyer coming towards you = oh crap.
• You can fit bigger weapons/more weapons on it.
• It can carry more cargo, be it food, fuel, troops, smaller spaceships...
• Potentially greater durability - for example, if the hull is breached, then the larger the internal volume, the more air there is, and the longer it'll take before you're all suffocating
• It's a status symbol. It says, "Look how rich and technologically-advanced we are!" It makes you look cool.

Cons of a larger ship:

• Exponential increase in cost (raw materials, construction time, number of required crew members, fuel, maintenance...)
• Exponential increase in power consumption (see: square-cube law, tyranny of rocket equation)
• Much larger target
• Much larger "space dock" required to hold it
• You probably wouldn't be able to enter planetary atmospheres with it, whereas a smaller, more aerodynamic ship might be able to fight in the atmosphere as well as in space (I say "might" because you might not need or want that functionality at all)

So a space army will want at least one large ship, to act as a flagship and status symbol, but any significant number would be wholly impractical.

Would future space admirals favor huge ships, or smaller ones?

I tend to think for warfare, large swarms of smaller ships would be better. There are many advantages to many smaller ships. For the sake of comparison; let us say we are talking about the same total tonnage of hardware; say a battleship or a fleet of 100 smaller ships that collectively weigh the same as the battleship. Note first, this can be more expensive, but the expenses add redundancies that are an advantage.

For example, you now have 100 engines, and 100 armament systems. You have infinitely more options in battle: A battleship is in one place; you have 100 ships you can arrange however you want. A battleship is hard and slow to move; 100 ships can be reconfigures into a front, a spear, with a mile between them (very easy communications distance even in poor weather) they can present a 100 mile wide search front. Unlike the battleship, you can sacrifice 10% of your ships to eliminate an enemy. A single torpedo, missile or Kamikaze bomber could sink (and has sunk) a battleship, or loaded with appropriate incendiaries start an inferno deck fire that disables the ship. But a Kamikaze doesn't sink a fleet, at best it sinks 1% of it: You have resilience.

Finally, big ships tend to have centralized resources and supplies of food, fuel, communications support, etc. A fleet of smaller ships will tend to result in decentralization of these resources and supplies, which is a good thing: You have backups, and therefore (again) resilience.

There are parallels IRL; in my field the modern supercomputer is actually a network of tens (or hundreds) of thousands of off-the-shelf Intel processors, the same ones you can put in a desktop or laptop machine. The chips themselves are typically up to 64 independent processors. If any fail to function, the controlling software can just not use that chip, we mark it as offline and get on with the day's work. The servers hosting this site are probably working exactly the same way: If a node fails, it is marked as offline and not used until a tech repairs it. A swarm of "small" ships (processors in a supercomputer) can do things impossible to do with a single large ship.

I haven't forgotten we are talking about space; all of these translate, with a few substitutions, to the space scenario.

There are some practical disadvantages; it is slightly more difficult to transfer personnel, move supplies and fuel around, etc. It probably requires more fuel. Storms that a big ship could ride out could sink some smaller ships (less of a problem in space; but translate perhaps to space debris).

Overall, by having 100 hulls, 100 engines, etc, the interior livable space could be much tighter than if all that material was used to enclose one giant space. The small ship fleet is not for the claustrophobic! But we are still talking about, say, 400 ton ships, so it isn't just a pilot's seat and a few jump seats. Think more like Submarine quarters; the crew can still sit around a table to eat or play cards; you still have a galley to cook in. A battleship has a crew of 2700, so the small ship crew is on the order of a squad of 27 or so people. Of course you can have highly trained specialists scattered throughout the fleet, electrical and mechanical engineers for example; you don't have to provide one for every ship.

I wouldn't rule out very strong network communications throughout the fleet and virtual reality or virtual presence. Small does not have to mean primitive.

Although each ship should probably have a ship-runner (person in charge), the chain of command doesn't have to be self-contained; e.g. personnel can report to both their ship-runner and a fleet-wide executive that is on another ship, and take their orders from that executive. A ship-runner may only be in charge in situations where the fleet-wide executive is offline, dead, or the ship's comm systems are disabled.

I think there are far more advantages to a fleet than there are to a monolithic ship, and the disadvantages of a fleet are manageable. Rationally speaking, I think I'd opt for the small ship fleet and the resilience it offers: If 50% of my big ass ship is blown to smithereens, I am probably dead. If 50% of my fleet is blown to smithereens, I can still win this thing.

One important thing to consider is travel time - you can't fight a battle if you can't get there. If you're on a small ship, it's going to be much harder to include all the resources you need for more than just a short trip. So if you don't have FTL, large ships will be an absolute necessity - you'd have a large carrier that houses the fighters as well as the food production, etc. necessary in order to travel a meaningful distance.

If you have FTL, then small vs. large ships is going to depend a lot the nature of the FTL drive. You could have a form that requires more and more energy the larger the ship, in which case large ships would be infeasible (I believe Alcubierre drives fall in this category). You could also have a form that is more efficient at larger scales (I want to say wormholes would fall in this category), which would naturally lead to larger ships being used at least for transport.

The problem with this kind of space opera (I should note that I am a fan of this type of military sci-fi) is that it makes no sense.

First and most obvious: we're not ever going to have a space navy where sailors spend months or years in interplanetary space. A robot will be exponentially cheaper, safer, and more effective.

Second, dropping a rock onto your enemy (kinetic kill) is easy, if you have the propulsion technology which is assumed in the typical space battle. The only way (aside from magic force fields, tractor beams, teleportation gates, etc.) you can stop a rock is to detect it in sufficient time to change its momentum vector. Detection is nearly always assumed to be easy in space battles, while in the real world It. Is. Not.

Anyway, the assumption "Oh! They've got a spaceship! I should attack it!" is just plain silly. The typical reason given to attack an enemy ship is to gain control of a volume of space (especially a volume of space which includes a planet, or other large resource). What I'm saying is you can't "control" a volume of space: you can't defend it from a targeted attack.

The only realistic scenario is:

1. To restrict access to space to a small group of superpowers (by definition) so that there will never be any question about who attacked you.
2. Use a hidden network of doomsday devices, which will automatically attack the resources of the attacker, making the cost of any attack too expensive to contemplate (mutual assured destruction, MAD).

This is the only realistic scenario I can think of, given the most realistic situation where volume defense is generally impossible (with the possible exception of planets, which may have enough economic power to support orbiting (A.I. robotic) forts and defense systems).

Everything is going to boil down to a battle. But the war will be won with the supply chain. You simply can't resupply or replace lost units without big ships. You also can't effectively attack an enemy big ship from all sides without little ships. Supply and manufacturing depots will also need to be attacked. The power demand for large munitions and the agility provided by small crafts will be required.

To answer the question, A wise admiral will neither favor large or small ships but will use both strategically to achieve her/his current goal. Given all the excellent points in other answers, I believe you can easily deduce that neither ship type can be excluded.

Well, let's take a look at the scaling of a few vital numbers. If we grow the length (and width, and height) of a space ship by a factor of N, we grow

by a factor of N^3

• its volume
• its mass
• its emergency energy production (energy production by heating some entropy containers)
• its top laser based firepower

by a factor of N^2

• its surface
• its long term energy production (because this is connected to surface as we need to radiate away the entropy)
• its propulsion force (bounded by energy production and exhaust area)

by a factor of N

• its shield thickness

not increased at all

• its top non-laser missile power, assuming the missiles are nuclear anyway

by a factor of 1/N

• acceleration

Now, powerful lasers are certainly one of the best counters against incoming missiles, thus a really big spaceship can be expected to be able to defend itself against large missiles. The additional shield thickness also works to help it defend against smaller ammo. So, talking offensive vs. defensive, I believe that the big ship is better.

However, the size has the cost of reduced maneuverability due to the reduced acceleration.

A strategy a fleet of small ships could try against a single large space ship would be to try to exhaust their emergency energy production by launching a big number of nuclear looking missiles against them, forcing them to use their lasers to destroy the missiles, overheating their reactors. A last round of actually nuclear missiles could subsequently overwhelm the big ships defenses. This puts an upper limit on the usable size of space ships. So, sorry, no death star class ships...

Due to the laws of physics, my instinct is that the destructive power of weapons will always exceed the defensive potential of armour and other defensive technologies. Therefore the escalation towards bigger, tougher ships is avoided and instead the priority is on nimbleness for evasion over tanking the damage.

However, on the flip-side of this is the problem of speed. FTL travel or no, you will likely require a much larger vessel for logistics and viable long-distance travel. More generally, there will always be tasks that favour one property over another, so it's difficult to favour one specific attribute as the one 'future' of space war. It's far more likely to develop a combined arms approach that uses a variety of archetypes.

The simplest one would be a combination of carriers/hive ships that provide all the qualities that favour larger sizes, combined with unmanned drones or nano-ships that encapsulate what's desired from smaller vessels.

There is an incredible website somewhere out there dealing with all aspects of space travel, battle etc. in stupifying detail - sadly I lost the URL. From what I can recall, one thing about space battle is that many movies, books, etc. simply transport the concept of a ship to space - but that is the wrong concept.

A space ship does not need an outer hull. It would most likely consist of modules chained together by some skeleton structure. As such, the very idea of size begins to break down. The ship might have a length x width x height that is considerable, but most of the space inside that area is just empty space.

This design would also be advantageous in battle, because travelling at space speeds does not exactly allow for much maneouverability. Not being hit can more easily be accomplished by not having much to hit, while evasive action is largely impossible. Additionally, a modular structure will keep any damage local, maybe even allowing you to drop away a destroyed element of the ship.

Mass will be a much more important factor than size. Most likely, tons or kilotons or something like it will be the better measurement for the size of space ships.

That said, the answer to your actual question depends on other factors, namely size/mass restrictions of core components. In many stories, movies, etc. the capital ships are so big because, for example, warp drives are by necessity massive. This leads to the carrier design - capital warp-capable ships with smaller non-FTL crafts that dock with the capital ship for FTL travel.

If you want big ships in your story, all you need is to come up with a convincing restriction that makes their size necessary or advantageous in certain conditions. Maybe the most powerful weapons in your world cannot be miniaturized?

There are a couple of issues with combat in space:

1. Doing anything in space is expensive.
2. Armor/shielding, as we currently understand it, is ineffective against military grade weapons.

So, you don't want to invest a ton of money into a large ship, because smaller ships will, if they ever get close enough, be able to destroy them with not much effort (even modern day bombers are able to carry nukes).

However, with 10 years or so, our laser technology will be so effective that we will be using them on surface navies to combat other ships/incoming missiles (there are already some systems like this in place, such as this). However, such a device requires a lot of power. Thus, you lean again toward larger ships with bigger power generation capabilities.

Ultimately, I think space combat will boil down to this: large ships with highly sophisticated sensors, covered in an array of point defense systems that can detect and eliminate small ships and missiles before they can even get close enough to pose a threat. The only reason energy weapons don't rule the day now is because of the energy requirements and the fact that atmosphere distorts the laser beam, robbing it of some of its energy. In space, that isn't an issue.

However, when you start talking battles between two large ships, directed energy weapons won't work as well. It takes a long time to melt through thick armor plating just with lasers, and energy shielding against pure laser attacks is already somewhat feasible. These larger ships might act as carriers for AI or remote piloted drones in an attempt to overwhelm the other's point defense/laser systems, but that probably isn't practical.

You would probably end up with large mass-driver weapons like railguns. If you accelerate a big piece of metal to a fraction of the speed of light and then successfully hit the other ship, it's going to cause very significant damage and will be almost impossible to stop with lasers.

So that's my prediction on what type of military ships we will likely end up with in space, given our current technological limitations. Obviously some of that technology needs to mature a bit, but we aren't too far off.

The use of small fighter craft in some space operas like Star Wars is based on the use of carrier and land based airplanes in naval combat in World War II.

A big part of the advantage of airplanes in naval combat is that they travel in a different medium which has less resistance and thus requires less fuel to travel fast in. Also the airplanes can vary their altitude while the surface ships cannot.

Thus carrier and land based planes can locate and attack surface ships while the surface ships are too far away from land or the carriers to attack them. The planes can attack from too high for the weapons of the surface ships to reach them, while gravity helps their weapons reach the surface ships. And the airplanes can travel several times as fast as the surface ships.

These advantages don't exist in space where every vehicle travels in the same medium or vacuum.

Thus space fighter craft and space carriers for them are unlikely. Space warships may range from space torpedo boats to space missile frigates to space destroyers to space cruisers to space battleships. And different technologies and sociological factors will determine what types a fictional space navy will build more of.

The main issue with large spacecraft using Plausible Mid Future levels of technology is everything is constrained by the rocket equation. Essentially every gram counts, so increasing the mass of the spacecraft comes at an ever increasing performance penalty. The ability to do tactical manoeuvre in the combat zone like instantaneous acceleration or "jinking" out of the way of oncoming missiles.

On the other hand, spaceships do need to carry massive shielding to protect the delicate humans aboard, not to mention the electronics and other systems which will be affected by exposure to radiation. Heavy armour also provides protection against laser and particle beam weapons, although not so much against hypervelocity kinetic energy weapons.

So perhaps the best solution would be to combine the two ideas. En route, the spacecraft are encased in a large honeycomb like hanger structure, which provides protection against radiation and small impacts (flecks of dust, small particles of gravel floating in space), while in the combat zone, swarms of small, manoeuvrable ships are released to create a spherical zone bristling with sensors and weapons.

The final factor to think about is what, exactly the premier weapons system is that you are fighting against. Massive Ravening Beam of Death (RBoD) lasers could theoretically be deadly out to a light second away (just under the distance from the Earth to the Moon) and escaping from that would be problematic with any sort of ship. Kinetic energy weapons like missiles or railgun projectiles generally would need larger vessels or installations to launch, but there should be sufficient time to detect oncoming rounds and evade at a light second. Nuclear driven weapons like CASABA Howitzers are an intermediate case, since they can project effects from 100km/sec (pellets from nuclear "shotgun rounds", to nuclear driven HEAT rounds projecting metal jets at 3% of c, to using the nuclear charge to crate a focused plasma jet moving at 10% of c. More information can be found here, and at the Atomic Rockets site in the section here.

Of course, being hit in either a large or a small ship is bad news, even something orbiting the Earth is already moving at more than 7km/sec, and objects moving at interplanetary speeds are moving far faster, so the kinetic energy of a strike could rival a nuclear explosion, even if the impactor is made of wadded up kleenex tissues. You will need to make the determination if it is more feasible to try to dodge the strike, or to be massive enough to absorb it.

I think the analogy from naval warfare to space warfare has several issues:

1. Actual naval warfare is constrained by a curved earth, air resistance, and the asymmetry of water and air. So aircraft carriers have a huge advantage over battleships, not because of swarms of small vehicles, per se, but because the small vehicles travel over the horizon. Similarly, submarines lurk under the surface and fire torpedoes that you can't really hit from a surface vessel.

   On the other hand, a laser in space can hit a distant target far faster than a physical projectile.

   Not to mention that carriers may become obsolete as hypersonic missiles and torpedoes are finally perfected. So maybe future battleships will launch these -- or maybe they'll all be launched from land bases and targeted via satellites.

2. The ultimate space weapons are launched from enormous "vessels", where we might loosely define a huge device and an entire solar system as a "vessel". Look up Relativistic Weapons in the fascinating Exotic Weapons page. (The exotic weapons page is absolutely worth a read... be prepared to spend some time there.) These are the ultimate, unstoppable weapons for destroying entire planets. Small targets would be hard to hit with one, of course, so a swarm of small spaceships might take out your launcher, but if you get a first shot you'll destroy their planets with no chance of them defending. Lots of luck with them surviving in a bunch of little ships with their home planet(s) gone.

3. Space is larger than the ocean. Even at some FTL speeds, it'll take you longer to get to a battle than the days or even weeks it takes a ship to cross the Pacific. Which tilts things towards larger ships, I would say.

Would future space admirals favor huge ships, or smaller ones?

Huge ships obviously. It's not a strategic choice but an ego thing. A huge ship is a massive show of power.

Now in space, huge ship would be preferable (like an aircraft carrier). The ship would actually be a giant factory, building and repairing drones. In battle the ship would hide and send the drones out on automated missions.

The only weapons the ship would have is anti drone weapons for last ditch defense. The ship in all likelihood would flee if attacked, leaving behind drones to aid the escape. Losing a capital ship is too expensive to risk it.

They wouldn't bother with giant space lasers like the Deathstar because destroying a planet doesn't require massive weapons. A simple vial of a lethal virus or self replicating nanites could destroy a planet. It's much cheaper and easier. The drones could also be used to accelerate and protect an asteroid to create an extinction level event.

As for where the battles are held, they will never be in wide open space. They will always be near planets because there is too much open space to ever be able to protect it.

The only way battles could be held in open space is if both sides agreed to the terms and created rules for warfare because damaging a planet was too risky and inhabitable planets were too valuable. The problem with this is if the sides are not equally matched, nobody will ever agree to rules that might hold them back.

Just for kicks, let's consider a fairly extreme spaceship size... The Earth. Then, you can scale back and see if there's a good balance for your universe.

Advantages-

• so large, it would be difficult to destroy with any kind of laser tech. Physical attacks would need to be massive, like tossing large asteroids
• atmosphere and magnetosphere shield Earth from a lot of energy and physical damage "attacks".
• underground / underwater bunkers and cities would exist for added protection during wartime, and travel.
• enormous energy store, in the form of geothermal energy.
• in carefully-regulated solar proximity, it sustains its own atmosphere, oxygen production, and water stores, pretty much indefinitely [though rebooting this after extra-solar travel would be quite a challenge]

Overall, the sheer size make it easy to attack, but difficult to damage significantly.

Disadvantages-

• although the Earth is moving a high velocity through space, its mass and the laws of Inertia make any kind of steering or stopping nearly impossible.
• the only way to achieve FTL would likely be a technology that enables re-positioning without the need for propulsion. Possibly some means to surround Earth with a field that "drops is into hyperspace", and then emerge elsewhere.
• any travel anywhere away from our precise solar conditions would mean destruction of Earth's surface water, surface atmosphere, & surface life. It would still work as a vessel, but would have to be re-engineered for such conditions (subsurface reservoirs, oxygen production, etc)
• so large, it would be difficult to defend without massively automated, widespread systems. Even with all inhabitants underground, a coordinated attack of landed vessels would be difficult to repel.

That example is a bit extreme but highlights some interesting possibilities and vulnerabilities of very large ship design.

Another possibility would be a ship that has different modes of operation. In travel mode, it's lightweight, fast, and decently cloaked - but vulnerable. In battle mode, it could fly into an asteroid belt and essentially construct a defensive shield. In that mode it's not mobile, but has camouflage and a heavy layer of physical shielding.

A combination of different kinds units is always better than a single kind, so I guess you'd have both. Large ships are efficient carriers, so these would be useful to supply smaller ships with fuel and ammo, perhaps even carry them during long marches. Smaller ships are definitely better for scouting and surprise attacks.

It's worth noting that size is usually not a constraint for spaceships (only mass is), so truly huge ships could be build if needed. For example, a ship equipped with a huge radar locator would provide a noticeable advantage in reconnaissance without slowing down the army it supports.