Good analogies for space combat

[Bulhakov]

I've been browsing Atomic Rockets recently and I got into a discussion with a friend on how to best parallel spaceship combat on the ground. Naval combat is definitely not the best way to go, but if we do simplify things to 2D, we found that a "giant ice rink" seems an interesting parallel:
- everyone is riding crotch-rocket ice-capable motorcycles (you can go extremely fast, but slowing down or turning is limited so trajectories are somewhat predictable)
- there's no hiding - everyone is visible from miles away (assuming no special stealth technology)
- dips in the ice are gravity wells of planets (severely limiting movement if you go deep into one, but also one of the few places to hide)
- every motorcyclist can very precisely shoot sniper rifles (laser weapons)
- ... but it's very difficult to hit anything as everyone operates on a few seconds of lag unless they are really close (limits of speed of light at large distances)

Any comments on this parallel? Flaws? Additions? What strategies would stem from these assumptions? Would the motorcyclists simply head at each other trying to sniper-joust? Circle-strafe eachother? Try to lay traps/mines? Release self guiding drones/missiles?

[Calen]

I would expect to see a mixture of jousting and circle-strafing. If the fleets want to engage* they would charge each other, as the fleets got closer they would probably start some maneuvers to help throw off aim, misdirect shots. The emphasis would be how to best present more weapons of your side compared to the weapons of their side.


*Barring one side having radically better movement tech than another, forcing a battle would be extremely difficult. You would have to threaten a planet or station to force a fight.

I would recommend the Lost Fleet series of books as a good take on this kind of space combat.

[BayardSPSR]

It seems more similar to modern-day beyond-visual-range aerial warfare. That said, I don't know of any games (let alone RPGs) that implement modern day BVR air combat at all (let along well).

And yeah, the vast distance means that it would be comically easy to dodge or otherwise countermeasure incoming fire, unless that fire was somehow faster than light and maneuver and detection somehow weren't.

You might get a weird dogfight of extremely-long-range homing projectiles trying to hit their targets while maneuvering out of the way of countermeasures, but even then jamming would probably be the most weight-efficient countermeasure. That is, if a missile capable of reaching and hitting a target at space ranges weighs as much (or more) than a jammer capable of countering the missile, then just getting the number of weapons into space necessary to overcome predicted countermeasures is going to be cost-prohibitive relative to countering whatever the enemy throws at you. The tactical implications of this would be the opposite of present day air combat, though, where putting missiles in the air is far cheaper than putting maneuverable aircraft in the air.

Maybe this means we'll have eternal interstate galactic peace in the far future. That would be nice.

Or maybe this means that space combat would be more like WWI dogfights, relying on short-range kinetic or laser weapons due to the vanishingly low P(k) of long-range fire.

If communication is sufficiently fast relative to projectiles, you could also have comical situations where the first few salvoes of war are fired, and then peace is negotiated before they reach their targets. That would be weird diplomatically... and resemble some of the colonial wars between European countries prior to the telegraph (like how the War of 1812 ended before its last battles were fought).

EDIT: Also, the people in this thread might be able to feed you some more ammunition (pun very much intended).

[The Glyphstone]

It seems more similar to modern-day beyond-visual-range aerial warfare. That said, I don't know of any games (let alone RPGs) that implement modern day BVR air combat at all (let along well).

And yeah, the vast distance means that it would be comically easy to dodge or otherwise countermeasure incoming fire, unless that fire was somehow faster than light and maneuver and detection somehow weren't.

You might get a weird dogfight of extremely-long-range homing projectiles trying to hit their targets while maneuvering out of the way of countermeasures, but even then jamming would probably be the most weight-efficient countermeasure. That is, if a missile capable of reaching and hitting a target at space ranges weighs as much (or more) than a jammer capable of countering the missile, then just getting the number of weapons into space necessary to overcome predicted countermeasures is going to be cost-prohibitive relative to countering whatever the enemy throws at you. The tactical implications of this would be the opposite of present day air combat, though, where putting missiles in the air is far cheaper than putting maneuverable aircraft in the air.

Maybe this means we'll have eternal interstate galactic peace in the far future. That would be nice.

Or maybe this means that space combat would be more like WWI dogfights, relying on short-range kinetic or laser weapons due to the vanishingly low P(k) of long-range fire.

If communication is sufficiently fast relative to projectiles, you could also have comical situations where the first few salvoes of war are fired, and then peace is negotiated before they reach their targets. That would be weird diplomatically... and resemble some of the colonial wars between European countries prior to the telegraph (like how the War of 1812 ended before its last battles were fought).

More likely we'll have peace between fleets of interstellar ark ships harvesting asteroids, gas giants, and the remains of smashed planets. It was made as a very good point that to force a battle between fleets you'd generally have to threaten a high-value target like a planet, and the #1 tactical weakness of a planet is that unlike a ship, it cannot dodge. Its course is fixed, invariable, and predictable, so passive dumb projectiles can still hit it with 100% guaranteed accuracy if aimed properly.

[BayardSPSR]

Another thing: in the absence of faster-than-light weapons, if you fired at a planet, its population (were they able to detect it) would probably have years, if not decades, to develop countermeasures to the attack. The weapons could become obsolete before they hit the target, and the party that attacked would risk being counterattacked with weapons they couldn't imagine when they first fired. There could be a balance of deterrence based on the possibility of technological development alone, and there could in practice be no cost to disarmament.

Until you get faster-than-light weapons, that is.

[goto124]

That also depends on the distance between the planet and the weapon. I didn't think the weapon firing at the planet was THAT far away.

[The Glyphstone]

And the specifics of the weapon. The classic example is a rock with engines strapped to it, that you accelerate as close as you can to lightspeed while aimed at an intersection point. This is about as low-tech as a planetkiller wepaon can get, and its effectiveness is determined solely by how much acceleration your engine can put out. At near-C, a planet would have, at best, hours to try and intercept the projectile, so to have a hope of blocking it, you'd need a method of detecting it while it was much further away, and thus still gaining speed. As it grows faster, the time window between detection and impact shrinks, so the acceleration rare is the critical factor.

[Mando Knight]

- there's no hiding - everyone is visible from miles away (assuming no special stealth technology)

This is one thing that I think Atomic Rockets overthinks. Stealth isn't so much making yourself invisible to the opponent, but making them not realize that they're looking at an enemy. You're a tiny dot of heat among the background of a field of stars and planetary debris (particularly at the distances where the lightspeed lag is relevant), and it's very expensive (if at all possible) to run sensors that can deliver high resolution, wide viewing angle, and fast analysis all at the same time.

Now, once your opponent finds you, they can lock onto your trajectory and track you rather easily, but it's the "determine that this half-a-pixel dot is a target in the first place" bit that's the difficult part.

[Bulhakov]

This is one thing that I think Atomic Rockets overthinks. Stealth isn't so much making yourself invisible to the opponent, but making them not realize that they're looking at an enemy. You're a tiny dot of heat among the background of a field of stars and planetary debris (particularly at the distances where the lightspeed lag is relevant), and it's very expensive (if at all possible) to run sensors that can deliver high resolution, wide viewing angle, and fast analysis all at the same time.
Now, once your opponent finds you, they can lock onto your trajectory and track you rather easily, but it's the "determine that this half-a-pixel dot is a target in the first place" bit that's the difficult part.

I think the main assumption here is just that you can expect to spot (and be spotted by) the enemy way before you can effectively engage them. This is because senor tech will always work at light speeds (i.e. detecting some form of EM radiation coming from the ships), but weapons will always be either sub-light speed (missiles/drones/projectiles) or relatively near-range (lasers need to be focused on something).

[Strigon]

Depends largely on the path you're taking. "Hard" sci-fi would have one of two ways of doing things, in my book:
High-lethality, quick engagements with high casualty rates. This assumes ships are difficult to hide - missiles, mass-drivers and lasers tear opponents up very quickly, evasive maneuvers have little effectiveness. Even if you win, chances are your ship is heavily damaged. The jousting analogy seemed appropriate, and the term "rocket tag" has never been more so.

Slow, intense, stealthy engagements. This assumes ships are something like submarines; in the inky blackness of space, nigh-impossible to detect unless you either use active sensors, or it activates a radiation-emitting device, like its engines or active sensors of its own. Under these circumstances, 2 ships might be within kilometers of each other and never know; and often, the first sign of another ship is when you've got an incoming missile. Further reading

[Bulhakov]

Thanks for the submarine analogy, this might work out if some form of "space stealth tech" does become available (simulating dark matter?).

Maybe we could split this up into three possible scenarios:
- near present day tech - sensors > weapons, tracking drone missiles and lasers for both defense and offense, ships try to predict each-others trajectories and fire drones in the generic direction, lasers try to disable the drones

- future tech "stealth" - we might get the submarine analogy, even the most primitive weapons will be able to kill a ship that is unaware of enemy presence

- future tech "shields" - what then? stronger weapons need to be developed? radiation blasts? heavier missiles? even more "space jousting" but less lethal?

Any good books with a hard sci-fi approach to space combat?

[Mutazoia]

Any good books with a hard sci-fi approach to space combat?

Most hard sci-fi approach space combat as "DON'T". The cost of building the ships and training the crews, only to have it all thrown away after one small hit....it's not worth it.

[Firest Kathon]

And yeah, the vast distance means that it would be comically easy to dodge or otherwise countermeasure incoming fire, unless that fire was somehow faster than light and maneuver and detection somehow weren't.

Another thing: in the absence of faster-than-light weapons, if you fired at a planet, its population (were they able to detect it) would probably have years, if not decades, to develop countermeasures to the attack.

You do not need FTL weaponry, it would be enough if the weapon fires at the speed of light. For example, you have no way of detecting an incoming laser shot before it hits you (unless the weapon has a detectable "charging up" phase) because all the information about the shot (light, energy discharge, etc.) travels as fast as the shot itself.

Any good books with a hard sci-fi approach to space combat?

I really like the space combat as presented in the Honor Harrington series by David Weber. Spaceships in combat have to deal with all the problems physics present to you, including limited acceleration, deceleration and turning speed, limited detection ranges, max speeds far below c for ships (but not weapons) etc. The series has some elements which are not (yet) based in science (FTL travel, limited inertia reducers, gravity detectors and generators, [redacted for spoilers]), but I think the main factors are accounted for and (as far as I can tell) scientifically correct (except for gravity, which propagates instantaneously in-universe). For examples of single-ship engagements read The Honor of the Queen, for fleet engagements The Short Victorious War (even better: read it all from the beginning )

[CharonsHelper]

Its course is fixed, invariable, and predictable, so passive dumb projectiles can still hit it with 100% guaranteed accuracy if aimed properly.

I'm seen that before in fiction. I disagree entirely.

Yes, Fleet A can shoot a rock at planet B from extreme range. However, Fleet B could then easily poke it with another smaller rock to get it off course.

Active defenses would be the name of the game.

[CharonsHelper]

At the OP - it all depends upon the technology involved.

Are there shields?

How fast are the ships relative to the speed of weapons?

How are the ships propelled? It may be nothing like modern rockets. I doubt that physics as we know it would apply to FTL.

What range are weapons relative to ship speeds?

How accurate are the weapons relative to ship dodging ability? Even lasers could miss from a couple of light seconds away if the ship is dodging fast enough.

You could have anything from hugely distant shooting matches, to close range broadsides which go by in a split second as ships pass one another. If the speed of ships are close to that of weaponry, boarding other ships might even be a viable tactic.

In an RPG context, I'd start with the sort of combat you want, and then come up with the sorts of technology which justify it.

For example - in the game I'm working on (Space Dogs), ships have gravity drives to travel within systems because warp travel doesn't work anywhere near a star's gravity. This allows me to keep combat 2d because you need to stay within the plane of the star system in order to keep top speed. You can go one step above or below the plane of the system, but all movement costs are doubled there.

Because of the gravity drives, you can 'catch the wind' of other ships which makes boarding other ships relatively easy once they're at all damaged. (Which pushes combat back to the personal level where the game thrives.)

[ImNotTrevor]

I have been wondering about this for a few minutes and it strikes me that space combat would likely occur at distances no longer than a few hundred kilometers, at the furthest.

That, and combat ships would be as compact as possible, with the exception of maybe the bigger troop carriers. Which are your big meaty targets to go for.

I imagine that if I really wanted to cause trouble for the enemy, I would map their trajectory and launch my secret weapons:
FLYING ROBOT SPACE TORSOS
Well, basically a torso with arms and a sensor array head controlled by a person in an advanced VR setup. These little guys would be launched using magnetic rails or by emitting pressurized gas while turned off, after being well refrigerated to ambient space temp. Basically impossible to detect, moving quickly, and if they have little pressurized gas canisters they could even adjust their flight angles in case of enemy maneuvers. (And most likely the small fluctuation in temperature from the launch will go unnoticed)

They slow themselves down when they get close, latch on to the enemy ship, and just start tearing things apart. Throwing remote-detonation explosives into critical areas, actively shooting back at defenders, disabling guns, blowing holes in larger decks, etc.

That way you could disable without destroying and do so pretty reliably since the projectile is smart and human-controlled. Plus side, none of your own humans are put at risk.

Maybe it's just wishful thinking on my part and maybe I just secretly want to say that I created the idea of launching flying robotic torsos as a weapon. Maybe it's just a really cool idea.

[DigoDragon]

One thing about throwing large scale weapons around that I rarely see addressed (such as the large asteroid with engines) is that should the weapon miss its intended target, it does not simply stop and fade out of the picture. It'll continue sailing through space, drifting in trajectory as large gravity wells affect it until it hits something. Maybe not for years (or even centuries), but it'll eventually hit something and ruin that's target's day.

Mass Effect 2 had a great line about why aiming weapons was important:

Spoiler

Show

Gunnery Chief: This, recruits, is a 20-kilo ferrous slug. Feel the weight. Every five seconds, the main gun of an Everest-class dreadnought accelerates one to 1.3 percent of light speed. It impacts with the force of a 38-kilotomb bomb. That is three times the yield of the city buster dropped on Hiroshima back on Earth. That means Sir Isaac Newton is the deadliest son-of-a-*itch in space. Now! Serviceman Burnside! What is Newton's First Law?
First Recruit: Sir! A object in motion stays in motion, sir!
Gunnery Chief: No credit for partial answers, maggot!
First Recruit: Sir! Unless acted on by an outside force, sir!
Gunnery Chief: Damn straight! I dare to assume you ignorant jackasses know that space is empty. Once you fire this husk of metal, it keeps going till it hits something. That can be a ship, or the planet behind that ship. It might go off into deep space and hit somebody else in ten thousand years. If you pull the trigger on this, you're ruining someone's day, somewhere and sometime. That is why you check your damn targets! That is why you wait for the computer to give you a damn firing solution! That is why, Serviceman Chung, we do not "eyeball it!" This is a weapon of mass destruction. You are not a cowboy shooting from the hip!

[Strigon]

One thing about throwing large scale weapons around that I rarely see addressed (such as the large asteroid with engines) is that should the weapon miss its intended target, it does not simply stop and fade out of the picture. It'll continue sailing through space, drifting in trajectory as large gravity wells affect it until it hits something. Maybe not for years (or even centuries), but it'll eventually hit something and ruin that's target's day.

Mass Effect 2 had a great line about why aiming weapons was important:

Spoiler

Show

Gunnery Chief: This, recruits, is a 20-kilo ferrous slug. Feel the weight. Every five seconds, the main gun of an Everest-class dreadnought accelerates one to 1.3 percent of light speed. It impacts with the force of a 38-kilotomb bomb. That is three times the yield of the city buster dropped on Hiroshima back on Earth. That means Sir Isaac Newton is the deadliest son-of-a-*itch in space. Now! Serviceman Burnside! What is Newton's First Law?
First Recruit: Sir! A object in motion stays in motion, sir!
Gunnery Chief: No credit for partial answers, maggot!
First Recruit: Sir! Unless acted on by an outside force, sir!
Gunnery Chief: Damn straight! I dare to assume you ignorant jackasses know that space is empty. Once you fire this husk of metal, it keeps going till it hits something. That can be a ship, or the planet behind that ship. It might go off into deep space and hit somebody else in ten thousand years. If you pull the trigger on this, you're ruining someone's day, somewhere and sometime. That is why you check your damn targets! That is why you wait for the computer to give you a damn firing solution! That is why, Serviceman Chung, we do not "eyeball it!" This is a weapon of mass destruction. You are not a cowboy shooting from the hip!

As much as I love that quote, and the ME universe, and agree with the general principle, most of the time it's going to be wrong. Chances are, it'll hit a star and have no effect, or hit an asteroid and have no effect, or pass through enough space dust to slow itself down and have no effect

Doesn't change the basic principle that any missed round could, potentially, come back to bite you, though.

[mikeejimbo]

One thing I rarely see addressed is that weapons and countermeasures would be pretty much automated. Targets would be detected automatically, and once a human pushed that red button under the molly guard, the firing system would perform all the calculations and fire. Likewise, defenses would be pretty automated - anything large and travelling fast enough would get blasted by point-defense lasers, the maneuvering system would fire to change trajectory, etc. The arms race would become one of programming better firing algorithms vs better defense algorithms.

I don't think anyone would let another ship get close enough for lasers to have enough energy to be effective. If they did, those *would* be easy to hit, because as has been said upthread, you can't detect it in time, and since trajectories are predictable it'd be a relatively easy calculation. Maybe tiny drones armed with lasers could be programmed to fire from just beyond point-defense range, but again, that's just a further escalation in the arms race.

We're already approaching the point where cost of automation is cheaper than training humans. Depending on what's going on in space, there might not even *be* humans there. Automated asteroid mining, automated exploring/scouting, heck, probably even automated construction.

The only thing I can really even see having humans in spacecraft for is transport, and for that to be feasible you either need FTL technology (and I don't know enough physics to consider the implications of FTL weaponry), or possibly generation ships.

Edit: Yes, I realize that this makes for dull games, or at least not exciting dogfight space combat.

[CharonsHelper]

Edit: Yes, I realize that this makes for dull games, or at least not exciting dogfight space combat.

While perhaps not the most likely result in real life, for game purposes you could easily say that AIs are too susceptible to EMP and/or hacking to be used in combat.

Though, if you want to split the difference, you could go for Star Trek style combat where the computers do all of the targeting etc. but it's still humans who make the tactical decisions to avoid any hacking.

Edit: I know that the US army had drone issues because for quite some time they were (stupidly) using unencrypted channels, and the insurgents just watched where the drones were going on their laptops. And that's just remote controlled - not AI.

[goto124]

One thing about throwing large scale weapons around that I rarely see addressed (such as the large asteroid with engines) is that should the weapon miss its intended target, it does not simply stop and fade out of the picture. It'll continue sailing through space, drifting in trajectory as large gravity wells affect it until it hits something. Maybe not for years (or even centuries), but it'll eventually hit something and ruin that's target's day.

I wonder if a missed bullet (or laser, or equivalent) becomes a brick joke that returns to bite the PCs in the rear end later on... could be funny, or annoying, or both

[DigoDragon]

As much as I love that quote, and the ME universe, and agree with the general principle, most of the time it's going to be wrong. Chances are, it'll hit a star and have no effect, or hit an asteroid and have no effect, or pass through enough space dust to slow itself down and have no effect

Doesn't change the basic principle that any missed round could, potentially, come back to bite you, though.

You know, considering that all the mass an energy of the universe that can interact with us only accounts for about... 4% or so of the universe, actual chances of hitting something might be pretty small. :3

But then again, in a fictional setting that would be a bit boring.

[The Glyphstone]

I'm seen that before in fiction. I disagree entirely.

Yes, Fleet A can shoot a rock at planet B from extreme range. However, Fleet B could then easily poke it with another smaller rock to get it off course.

Active defenses would be the name of the game.

Hence why I mentioned the acceleration/speed being the crucial deciding factor. An active-defense projectile imparting detrimental dV is indeed the easiest way to deflect a killer asteroid, but that doesn't necessarily make it easy. The longer that rock has been accelerating, and the faster it's moving, the more counter-force is needed to deflect it onto a trajectory that won't still kill the planet/biosphere. So higher acceleration on your planetbusting KEW makes it harder to stop on two levels, the reduced time you have to mount a defense and the increased energy you need to throw at it to do anything.

But yes, you're correct that having a fleet (the most active of active defenses) is the only thing that'll protect a planet, since the planet cannot protect itself. The thing is, once you've got a fleet, why not just keep building that fleet until it's big enough to hold all your civilians too, rather than be tethered to a planet with no real value except sentimentality?

While perhaps not the most likely result in real life, for game purposes you could easily say that AIs are too susceptible to EMP and/or hacking to be used in combat.

Though, if you want to split the difference, you could go for Star Trek style combat where the computers do all of the targeting etc. but it's still humans who make the tactical decisions to avoid any hacking.

Edit: I know that the US army had drone issues because for quite some time they were (stupidly) using unencrypted channels, and the insurgents just watched where the drones were going on their laptops. And that's just remote controlled - not AI.

If your starships are being hacked, it's probably coming from inside the hull, so you have bigger problems. You'd have to let tactical computers/AIs do the actual fighting, because everything in space is moving immeasurably too fast for merely human reflexes to react to. Keeping humans in the loop for tactical decisions and target selection is just common sense to avoid friendly fire, but once battle is actually joined it'll be up to the combat algorithms.

[CharonsHelper]

Hence why I mentioned the acceleration/speed being the crucial deciding factor. An active-defense projectile imparting detrimental dV is indeed the easiest way to deflect a killer asteroid, but that doesn't necessarily make it easy. The longer that rock has been accelerating, and the faster it's moving, the more counter-force is needed to deflect it onto a trajectory that won't still kill the planet/biosphere. So higher acceleration on your planetbusting KEW makes it harder to stop on two levels, the reduced time you have to mount a defense and the increased energy you need to throw at it to do anything.

Why would it be accelerating much? A bit from gravity, but if you have interstellar propulsion, that's not very fast.

But yes, you're correct that having a fleet (the most active of active defenses) is the only thing that'll protect a planet, since the planet cannot protect itself.

A space station could, and that's pretty much the same thing, especially if you have a space elevator to get to orbit. (likely common when space travel is common)

The thing is, once you've got a fleet, why not just keep building that fleet until it's big enough to hold all your civilians too, rather than be tethered to a planet with no real value except sentimentality?

Plus the atmosphere. And natural resources. And gravity. And foodstuffs. And...

If your starships are being hacked, it's probably coming from inside the hull, so you have bigger problems. You'd have to let tactical computers/AIs do the actual fighting, because everything in space is moving immeasurably too fast for merely human reflexes to react to. Keeping humans in the loop for tactical decisions and target selection is just common sense to avoid friendly fire, but once battle is actually joined it'll be up to the combat algorithms.

Hacking would likely only apply if you had the ships/robots be entirely AI controlled, which some on here were suggesting. So long as people were on board making the tactical decisions & target selection it's a non-issue. (Though theoretically it might be easier to splice a probe/missile in to hack the ship physically than it is to actually destroy it.)

EMP or some other future technology might still be an issue though.

Frankly, there are far too many technological unknowns to make anything more than a best guess anyway. I was mostly just suggesting that, from an RPG/game perspective, shift all of the potential variables so that you end up with a fun game to play rather than necessarily the most likely option.

[Anonymouswizard]

Most hard sci-fi approach space combat as "DON'T". The cost of building the ships and training the crews, only to have it all thrown away after one small hit....it's not worth it.

Oh no, the logistics will stop it. Your ship likely isn't carrying much in the way of additional fuel, so you can't afford to waste any evading attacks. The most likely outcome is both ships get hit by missiles causing extensive damage and loss of life, possibly being outright destroyed, before both losers limp off. But that's if the ship gets there on time in the first place.

Now orbital combat does feature in the game I'm writing, Infinity Drive. Ships have the choice to either fight back, flee into the system, or attempt to activate their FTL drive (which is wormhole based and has to charge). Ships tend to include lots of bulkheads and redundant systems or very heavy armour plating, although the object of the fights are always over access to the planet.

[Mechalich]

Any good books with a hard sci-fi approach to space combat?

I like the Dread Empire's Fall series by Walter John Williams. It's reasonably hard: FTL exists only via wormholes that the people can't really actively control, ships have absurdly powerful anti-matter torchship drives but still have to find ways to handle acceleration, the primary kill weapons are anti-matter missiles and one hit = death in pretty much all cases, with even glancing detonations capable of crippling a vessel, there's no incredibly powerful computation devices, and the mechanics of things like time lag on detection, communication, and response are very important tactically (these torchships can build up to large percentages of c).

The thing is, Williams enforced his set of rules by making all the relevant factions splinter groups from beneath the heel of an incredibly dogmatic empire that had ruled them for millennia, thus insuring that everyone was playing by the same technological rules and that only minor variations in tactical approach would still matter. It's an important lesson is design for this sort of thing: you need to make sure of what technological capabilities you're playing with and then define what they'll do, because even seemingly subtle variations will chance the situation immensely.

[Telok]

The Yerkes Observatory in Chicago has an automated telescope that you can use to spot asteroids out past Mars orbit. It's internet controlled and schools or individuals can buy time on it, I got to use it recently for a class.

So a 100 cm telescope can pick out a 100 m dull grey rock at a range of 250 million km. Today. The computer compensates for the movement of the Earth so the background stars are stationary and takes a series of pictures. It stacks the pictures and you look for streaks or you can time-lapse the images and watch for movement.

For reference the Space Shuttle was 56 m long and the speed of light is 300,000 km/sec. So passive visual sensors can assume a minimum of locating a 100 m craft at 8 light seconds without much difficulty and with today's technology.

[The Glyphstone]

Plus the atmosphere. And natural resources. And gravity. And foodstuffs. And...

Atmosphere? Hydroponics generate breathable air from waste gas, and provide food to boot.
Natural resources? Asteroids, comets, and gas giants. Mine them suckers, cause 'aliens come to Earth to steal our liquid water' means those aliens are too dumb to close their airlock doors in the right order.
Gravity? Centrifugal spin. Wheeeeeee.
Foodstuffs? Hydroponics again. Om nom nom delicious space veggies.

Really, there is nothing a planet offers that you cannot duplicate if you've got the technology to build interstellar ships to begin with. Granted, it'll have some rather drastic effects on your species after a number of generations, but it's perfectly survivable and functional in theory.

Hacking would likely only apply if you had the ships/robots be entirely AI controlled, which some on here were suggesting. So long as people were on board making the tactical decisions & target selection it's a non-issue. (Though theoretically it might be easier to splice a probe/missile in to hack the ship physically than it is to actually destroy it.)

EMP or some other future technology might still be an issue though.

Frankly, there are far too many technological unknowns to make anything more than a best guess anyway. I was mostly just suggesting that, from an RPG/game perspective, shift all of the potential variables so that you end up with a fun game to play rather than necessarily the most likely option.

Yeah, I missed that was a response to other people in-thread. Though if hacking is a thing, counter-hacking protocols would be the appropriate defense, and it just becomes another layer of weapon vs. armor - I read an interesting essay by, I think, Orson Scott Card on this topic, regarding the evolution of weapons vs. "armor" all the way from clubs and animal hides up to modern-day drones and jammers, and presumably beyond into AI vs. EMPs and hack-borne viruses. Plenty of potential to keep the player characters of the game in question the most-relevant figures; using AI-driven drones to do their fighting is just a more distant or abstract version of using guns/swords/etc. - their role in combat becomes directing the drones and protecting them from interference by the other side's hackers, while the drones themselves go about the actual fighting.

[CharonsHelper]

Atmosphere? Hydroponics generate breathable air from waste gas, and provide food to boot.
Natural resources? Asteroids, comets, and gas giants. Mine them suckers, cause 'aliens come to Earth to steal our liquid water' means those aliens are too dumb to close their airlock doors in the right order.
Gravity? Centrifugal spin. Wheeeeeee.
Foodstuffs? Hydroponics again. Om nom nom delicious space veggies.

Really, there is nothing a planet offers that you cannot duplicate if you've got the technology to build interstellar ships to begin with. Granted, it'll have some rather drastic effects on your species after a number of generations, but it's perfectly survivable and functional in theory.

You could, but not for free.

How much of your population are you going to have doing all of those things which are automatic on a planet? If 3/4 of your population is busy doing all that and maintaining the gear for it, wouldn't you be better off on a planet where basic needs are covered by 3-5% instead? Not to mention the initial costs involved.

It all depends on how the tech works and how much maintenance they take.

And that's ignoring all of the psychological issues of being cooped up on a ship 24/7 365.

And on a planet you could put some massive active defense weaponry, so it's not necessarily even safer to be on a ship.

[Strigon]

You could, but not for free.

How much of your population are you going to have doing all of those things which are automatic on a planet? If 3/4 of your population is busy doing all that and maintaining the gear for it, wouldn't you be better off on a planet where basic needs are covered by 3-5% instead? Not to mention the initial costs involved.

It all depends on how the tech works and how much maintenance they take.

And that's ignoring all of the psychological issues of being cooped up on a ship 24/7 365.

And on a planet you could put some massive active defense weaponry, so it's not necessarily even safer to be on a ship.

All this, plus one little thing.
Your planet gets hit by a weapon, and everything's fine. Worst-case, it's a particularly large asteroid, and you have a few years to evacuate before the mass extinctions make it uninhabitable for humans.
Your spaceship gets hit by a weapon, and you die.

I think it's safe to say that a planet is more robust than a ship.^{[citation needed]}