Since it is a game, I suppose the devs are free to do whatever they want, including minefields. For practical purposes, both strategically and economically minefields are totally not useful in space despite science fiction films many examples. In fact, Ender's Shadow- the parallel sequel to Ender's Game- explains very clearly why outer space is entirely indefensible on the interplanetary scale to say nothing of the interstellar scale. Space is just too big. The larger the space the more the maneuver which makes a stationary mine ineffective. To limit maneuver within a single star system using only mines, would require far more mass than all the planets combined. Consider that astronomers have detected over 150,000 asteroids within our asteroid belt, and yet no two of them are ever likely to come within visual range of each other much less collide, and they are nearly all limited to within a few degrees of the ecliptic and sandwiched between Mars and Jupiter. There is a reason why in Ender's Game the only hope for humanity is to fully commit all Earth's forces to a counter-strike. Since defense is nearly impossible for either side, the only defense is a good offense.

I don't want it to seem like I am picking on you, but the idea of an undetectable but remotely controlled mine is also impossible. For it to be controlled by its owner and not by the enemy of its owner and possibly provide information on the movements of enemy ships nearby to provide for a meaningful detonation, the mines must maintain continuous contact with its owner. Millions of otherwise undetectable mines sending and receiving continuous transmissions would light up the entire area in the electromagnetic wavelengths.

There is a reason why mines were historically used in war in very specific and limit ways. WWI and WWII styled trench warfare where the contested space is usually measured in fractions of a mile are the best uses of a minefield. Of course, using them defensively in those conditions also prohibited offensive action as the mines were indiscriminate in their targets. But even if you had a smart mine, smart techs still malfunction, get tampered with or stolen by your enemies. 

But since this is a video game, the devs are free to do whatever they want, and if they want minefields, they can do it. But if they do, they will have to shrink the map so that they are more difficult to avoid and cheaper to deploy. Personally, I'd take a freighter full of C4 over a freighter full of mines. 

Well it all comes down to scale, doesn't it? How big the devs make the map, the distance between the stars, the distance between the planets all decides which of us is right. If we chose a realistic scale (and they won't because it wouldn't look pretty, require massive unending zooming etc), then mines wouldn't be feasible. Using back of the envelope calculations and Wikipedia, Low Earth Orbit (LEO) begins at 99 miles up. If you wanted to mine just that orbit one mine deep, you still have to mine a circumference of 25,509 miles! But since even random chance entry vector would render it useless in defending against blind asteroids, you had better finish off with mining the entire surface are at that altitude which is only 207,238,040 square miles. Long before you even finish building your minefield, the war would be over and frankly your economy would be ruined. To say nothing of the hundreds of warships you could have constructed to take the war to your enemy instead of building mines. 

You can even go all "nitpicking" on me , I'm not bleahware, I'm not going to blame you for "disrespect" - it's not GTA Edmonton, after all .

Probably I expressed myself incorrently, but when I listed different properities of mines, I never suggested them to be used simultaneously. Mines could be undetectable (within reason, as we know, there are no "silencers"), but they could only receive signals from ships, satellites, or drones patrolling nearby. You can consider them "space claymores" or any other "old mine" that has been repurposed under that hypocritical bill into "explosive device" and their trigger has been replaced with remotely trigged from target-triggered.

"Active" mines, that send signals could work either as hubs/relays, scanning area for enemies and acting accordingly. Even if enemy knows they are there, this could force him to divert his fleet away, changing course, given you some time. This way mines will complete their job. You can consider this versions of "active/passive" mines as sign "No tresspassing. Violators will be shot. Survivors will be shot again." Sentries never defended anything from well-planned attack, but it's never been their job. Their job was to scare random loiterers and serve as "early warning system". Geese has their own disadvantages, you know.

Priblems with space games that all theories are, well, theoretical and hypothetical. Even if our scientists say they know history proves they don't, I always remember poster we had in Uni - "according to aerodynamic laws bumblebee cannot fly, yet he had no idea and hence does". That was a joke (ha-ha, fat chance ).

But I digress. I do not propose to blanket whole orbit with mines, I may have problems with knowledge about space, but not with finances - I'm cost estimator after all. All I suggest is to place them tactically. If modern MLRS (by the way, what about blast waves' interference in space?) has cluster munition, what precludes our hypothetical fleets from using similar launchers or munition right before, during, or after the battle, to constrain enemy maneuvers?

And don't forget, I several times said you need to cover your mine fields, to prevent them, as you said, being stolen by your enemy (though our instructions consider every mine equipped with anti-withdrawal device, hereby rendering anything but destruction "outlawed").

Navigation-wise, well, I admit, I'm more or less skilled in land navigation only (air navigation is extremely limited, mostly in areas regarding joint operations), so I know you have to bypass, travel through, or encircle obstacles like draws, valles, mountains, rivers, swamps, etc. I have no idea what you have to do in space. So for me shortest and fastest route between two points is straight line. If enemies fleets could be detected in their movements, and they are not "zigzagging", their course could be approximated. And here you can either scatter your mines, or scatter decoys, posing as mines. Say corner reflectors that give same signature on long range scanner as mines, thus forcing opponent to divert, stop, or investigate. Regardless of action chosen, he'll probably lose time and/or few ships. Isn't that a nice trade for few pieces of metal and probably few barres of explosives? Besides, if you know you dropped decoys, what precludes you from salvaging them after need for them in area where they were dropped is gone? Going green with Volvo.

Moreover, how exactly sturdy ingame ships are? I mean remember all those stories that even if HE shell/bomb couldn't actually penetrate armour (or cause sympathetic detonation of ammunition stored), they could create such blast wave/concussion, so it would damage the target and render it inoperable, at least within tactical scale. In case of space ships, that could mean instant decompression. Unless crews acts like in "Mandate", they, of course, should seal different compartments of the ship, reducing risk of massive decompression. But what about shockwave that could dislodge certain systems, jam turrets or actuators or driveshafts?

Upd. By the way, had you played Space Rangers?

The thing with mines would easily be solved if you have fuel on your ships. Then the route taken would be very important. That would also mean that protecting fuel stations and ways of getting it would be very important. Also giving you a deeper economy.

I would love to see a deeper economy system in general. I dont know what types of resources will be in the game but i would hope more than credits. It would make defending, building and enhancing places in space more important. As it should be. Also the idea to have shipyards in space around mineral rich asteriods would be awesome. It would give the players an insentive to defend/attack such places instead of marching in with millions of troops into a planet wich could be attacked from behind and flaunt any plans of conquest. Strategic places is very important in warfare and in general. Economy places especially. 

Interesting ideas. In theory every turn costs upkeep, so if opponent was hoping for "blitzkrieg", because his economy is collapsing, then even few turns delay could be rather painful.But idea with supply lines (not just fuel) is even better.

As for economy, I think first Supreme Commander had something similar - cluster of industrial equipment, placed closely, would gave bonuses to production, yet they were more vulnerable.

Also, a very old Deadlock, if memory serves, had logistics chain - if your resources weren't increasing, that could mean you spent your existing resources simply to ferry them from one area to another, than meant your logistics chain wasn't optimal. I could be wrong, but Imperialism had something similar (yet different), where your logistics had throughput, that alone could create bottlenecks for your economy. Heh, even Cities XL has obvious bottlenecks - traffic congestion.

No, I never played space commanders. I did play the aforementioned Freelancer though- a kind of spacey dogfighting genre that was actually pretty good (still better than anything that has followed). Mines were the one weapon that was mostly useless. Unless your enemy was right on your tail and you dropped it without deviating course and the two of you were travelling too fast for him to take evasion action, the mine was useless. Try picturing WWI/II air battles but with the fighters occasionally dropping a mine or two- hovering I guess for them to be stationary. Not very useful. If your enemy is that close and on your tail, you don't have time to mess around with a mine, particularly when it requires that you keep your opponent lined up with the mine, which of course means resigning yourself to having his weapons trained on you and firing bits of your into space while you use the mine that he could still dodge.

As to forcing your enemy to "go around" you really must consider the size and emptiness of space. Asteroid near misses are usually still hundreds of thousands of miles away from Earth. A few minutes or hours could make the difference. Earth is a moving target too, so if your enemy is sitting still, the angle at which he may approach you changes every minute. That means your defenses must be either mobile or ubiquitous. Their best use would be around critical but small infrastructure (think shipyards as opposed to moons and planets) that your enemy would rather capture undamaged. The costs to deploy would be enormous, do little to defend against an all out assault, and pose future risks to your own if they ever malfunction; however, if your enemy thought he could capture it with a small force the mines just might do the trick. It is a gamble, and one that cannot be given a course correction if your enemy decides a different target is preferable to his purposes. If GalCiv ever did a prequel focusing on the era of stargates/tradelanes, mine fields could be used to devastating effect, but only because then your enemy's movements would be completely predictable. In essence, the more you can constrain maneuver, the more useful a mine will become. Space in general is limitless maneuver, so typically mines are useless. Create a situation like the trench warfare of the early 20th century where your troops cannot even maneuver two steps to take a dump and mines have a function. But unless you can make the mines smart, they will still constrain your movements the same as your enemy, and a wise opponent will use that fact against you.

What would be fun and practical is if they brought back the GalCivI long range nuclear missiles. My dad and I used to keep our capital ships back in defense of the homeland while raining wave after wave of hundreds of these missiles on our enemies. It was like missile defense, except we were the ones firing the missiles usually from the other end of the galaxy. That was fun... and a bit ridiculous.

Space mines, again? That's already been debunked, guys. Actually stopping ships would require so many mines to fill the space that it's actually *cheaper* to build ships, because ships can move to intercept the attacker and mines can't. On top of that, there's nowhere to hide them, which means my ships can simply shoot them at range and clear a path.

Mines only work if you can cover the approaches to something. They work on the ground because you have to go by ground, and they can be buried where you can't easily detect them. Mines floating in midair wouldn't deter aircraft at all, as they'd either go over them, under them, around them, or simply shoot them down because they're clearly visible.

On top of that, where are you going to use them? Trying to mine a planet blockades that planet from your own ships too. Mines are indiscriminate.

So now we need stealth smart mines in essentially infinite quantity in order to make this idea work. It'd make far more sense to build defense turrets that are like mini starbases and have guns, rather than mines. Those could shoot incoming ships at long range and you'd need far fewer of them to cover an area... but it's even better to just make a few ships and let their engines take them to where they need to go.

Space mines only ever make any kind of sense in games with space lane travel, because you can mine the space lane/wormhole/warp gate/whatever. Given that it's a fixed point you have to use, it actually makes some sense, particularly if you're blind coming fro one direction (ie: coming out of a wormhole) as you come out and hit the mines before you can react and take them out. Trying to mine a free travel galactic border is absurd.

Debunked? No. Outshouted? Yes. If you don't believe space mines won't add to the game, fine. Many of us do.

Well the map and travellane is flat so mines could work just fine? You dont actually travel "up or down" if there isnt a full fledged 3D map in GalCiv 3 

No, it's bee pretty debunked. The math was clear on just how totally insane this idea actually is. You need so many mines that it makes no sense to ever build them instead of building ships. On top of that, they flat out don't do their job unless you invent magic stealth mines that are also smart enough not to harm your own ships, somehow.

Now if you just want to throw up your hands and say "screw anything resembling internal coherence or logical consistency, we want space mines!", then I suppose it hasn't been debunked. But then, mines wouldn't be fun, either.

I know I can't wait for the AI to lay space mines absolutely everywhere and necessitate a ship designed to counter mines that has to be in the front of every fleet. That's going to add a lot of mindless tedium to the game, and we definitely need more of that.

No, they really can't. Take our solar system. The asteroid belt in it is pretty flat. It's made up of a huge number of asteroids. Yet they're so far apart that they aren't an effective barrier to anything. So to use something smaller (mines) to hit something small (ships), you're going to need astronomical numbers of mines. Numbers that are so huge that building them would take every resource in the solar system. If you leave out a part on that flat plane, I can use my hyperdrive and fly through that, making the rest of the mines you did lay totally useless. Remember just how fast hyperdrive lets me move. (And that's if I don't just make a hole by shooting your defenseless stationary mines with my lasers at long range.)

Or you build a couple of patrol ships with hyperdrive and cover the entire solar system.

The problem gets laughably hilarious in a 3d map, but it doesn't work on a 2d map either when I can come from every direction and you have to block me across an entire solar system. Oh yeah, and if you do, you've just blockaded yourself in.

There's a reason why even on Earth, mines aren't used to protect areas that can be accessed on land from every direction.

Mines work in a game like AI War because travel is through wormholes, which mean you can use them at one or two chokepoints and do real damage. With free movement in every direction and no terrain barriers, mines make no conceptual or gameplay sense whatsoever.

He-he. That’s the conversation I’ve been missing for!

Unfortunately I barely remember Freelancer (and I’m pretty sure I’m confusing it with something else), so I can’t discuss it.

But let me ask you – how those mines were deployed? Simply one dropped behind? And what if mines are scattered using device similar to chaff/flares launchers? Even now we have grenade launcher and targeting system, allowing your grenades to explode above the enemy in cover. Don’t you think that in future your ship’s targeting system would be able to measure distance to and size of enemy “craft” (or ship) pursuing you and launch those “mini-mines” in required pattern, to maximize hit probability? Squid can hide behind his ink’s cloud, why couldn’t you hide behind your mines “cloud”?

You probably wouldn’t believe, but similar systems existed. They weren’t dropping “mines”, they were dropping grenades (with time fuse), and dropped them only “gravitationally”, to cover lower rear, but they were there.

If memory serves, some, if not all modern tanks has something similar, to protect themselves in their “blind zone” (wave shooters’ style of destroying tanks, by placing explosives on them) via launching grenades.

Now combine those principles with hypothetical targeting system, add dispenser, capable to throw mines in required pattern, and, to reduce amount of mines needed to cover the same area, either use ship’s targeting system to control mines to explode them in the right moment, or (and) add “mines” with sensors, capable doing so, even such primitive as umbrella-patterned antennas. Those mines could have something like shaped charge to maximize damage. Or not.

You meant “asteroid near hit”, because near miss is a hit. Isn’t it?

Argument you use – vast size - is valid enough, but there are few other factors involved. For example, how ships will actually navigate?  Will it be something similar to space skeet, so all you need to do is to know your target planet’s orbit to calculate shortest route, which is straight line, or they going to take additional factors into consideration, like additional objects on their way (well, they should, otherwise they’ll crash), or they will be doing crazy maneuvers to complicated opponents’ calculation of their course? That should be wise too.

Other factors are ships’ speed, size, scanning range, sturdiness, armament’s characteristics, and how close ships’ formations are. Size is simultaneously is simplest and hardest question. If memory serves, in GC1 Transport had capacity of 5 billion people. Ship, capable to carry that amount of people and resources to sustain them (even if those are antibiosis chambers) cannot be small. Even GC2 ships could carry 0.5-1 billion are anything but small. But what about other ships, how big are they? For example, in Space Rangers, in game ships’ sizes, relatively to planets, were rather big. Yet, in intro movie, ships’ sizes relatively to human were much smaller. It is same simplification we have on maps, to be able to read them, otherwise, on some maps even big houses wouldn’t be larger than wasp’s stinger’s tip. Of course, we have some hints or “approximation”, but what about real data?

Regardless, those questions are related to ships’ sturdiness – how much damage they can withstand, and, how big (and powerful) is armament they can carry and needed to destroy or, at least, damage them.

Ships’ speed has several derivatives – reaction time on newly acquired data (say, report of obstacles ahead; this parameter is affected by detection range), thus avoidance time (and space required), and possible distance within formation, unless flight there controlled by computer of single ship, while others joined with it through some network. To allow such formation to maneuver, maximum speed should be reduced.

Combining all these together, we can ask next question – if ships course is straight line (at least on some section of their trip), what precludes you from playing space skeet yourself, should your weapon has firing range that surpasses your targets’ detection range, and projectiles can fly with certain accuracy?

As for smart mines, I think it wouldn’t be that difficult. Currently we have mines that controlled, so sappers could let friendly forces through them. And we have systems capable to recognize different vehicles. Given the progress, miniaturization, and costs decrease, are you sure there will be no mines capable to recognize different units from sides of war on their own, without guidance? They already can self-destruct, so it wouldn’t be too difficult to prevent your opponent using your mines against you.

Novalith cannon from SoaSE wasn't that bad either.

I seriously learned to mod games just to remove that damn thing from the game. The Deliverance engine and Kostura cannon also made me want to throw my computer out of the window, but not as much.

He-he.

That's why I like to play with people I can trust so we can have gentlemen agreement (even if one of us is woman), or prefer to play game with precise settings (thinking of Cossacks series), or miss "peaceful" mode in SoaSE when I was in the mood for contemplating.

You do know that this is a game right? And the map is a flat disk and not a full fledged 3D map. You go into a tile where mines are, you take a random ammount of damage. Stop being such a crybaby about it I know its unfeasible IRL but this is a scifi GAME. Anything is possible in sciFI and GAMES. There is so MANY other things in this game that is way more wacky than a frigging minefield if you are going for any form or realism... Get over it. Minefields are awesome even if they are unfeasible...

No, minefields are not awesome. They're boring and lame.  They don't add to the strategy of the game, all they do is try to let you create walls in space for some reason, unless you bring the ship that counters mines. So I just have to build somerhing to make the mines go away, which isn't at all interesting. 

in the case of Sins, mines are the thing I want to mod out. All they really accomplish is lagging the game.

Get the "Enhanced 4X Mod" and activate some of the mini-mods; they can remove or marginalize mines!

http://www.moddb.com/mods/enhanced-4x-mod

What is not boring and lame, building fleet capable to negate enemies' fleets, blockade them in their system, letting you build a lot of nukes and make it flashy?

No sarcasm, just curiosity.

So if enemy has cloaking ship, you build detector, if he got radar jammer you build better scanners, he goes for cannons you add armour, he adds lasers you add shields, he goes missiles you built point defense. For every move there is a counter move. Why would add modules to starbases that slows enemy movement? Why block enemy colony ships' movement with your scounts? For very same reasons you can add mines. They aren't ultimate weapon, they are just one of those tools you have, and your desire to remove them actually means they work.

Lagging? SoaSE isn't blitz oriented games, it's game of happy retirement, when you gather your family, get them on picnic and enjoy the play, sipping your favorite brew and snack. It's not for adrenaline-ridden youngsters who think starcraft of fast-forward is too slow.

Anything that does something other than sit still and act like a wall thrown up in the middle of space?

If the enemy has cloaking ships, I need to get detectors in the right place. Things move around.

I'm not a fan of the RPS weapon/armor style of the game either, so that doesn't help your point.

Mines just sit there being annoying, then you bring the mine removing ship and they go away. It's pointlessly binary.

Oh please.

Pick a huge map, throw a bunch of AI players in on one of the high difficulties, and see what happens to the game in a couple hours after the mines come out. The entire thing will slow down drastically once they start throwing mines everywhere, including the UI, at 1x speed. It's a known, acknowledged problem that they can't fix due to the game being single threaded, and it's existed since Entrenchment (in vanilla it was still possible to slow it down, but it took a lot more stuff to do it).

Mines are lag monsters. They're not even well implemented in the game either, and are the worst case of "micro a scout ship into them so other stuff can blow them up" annoyance. They add nothing of value to the game whatsoever.

People need to get over this foolishness that because we have mines on land on Earth, space mines are a worthwhile addition. They're not. They're total nonsense.

Huh, I always thought the biggest culprit was trade ships. On the biggest maps it slows down so bad I can see visible hesitation between updates and ships that just ignore or forget orders due to so much computational lag. Limiting trade ships seems to help, but not all that much.

When they were first implemented, the scout ships would auto engage mines in the same gravity well, so you could clear them after your main fleet moved on. Just park a scout and let them deal with it without having to micro. I'm still not sure why they removed that.

Trade ships are a problem too, but it got a lot worse in Entrenchment when mines made their appearance. The problem was the sheer quantity of them. The AI (particularly the Vasari AI) had a thing for blanketing systems with mines, in a lot of systems. Each individual mine isn't a big deal, but there was so many of them that it turned ugly.

Mines weren't annoying enough?

A whole metric ton of problems could have been solved by making the game take advantage of cores...

Every time I boot up the game, I open up task manager and look at three of my four cores sitting there with a firm grip on their junk, doing nothing. Then I slouch down and cry for a bit.

This one thing would make the entire game so much better, I can't believe Stardock and Ironclad have overlooked it so consistently.

The engine wasnt made to do it originally. That was a mistake (lack of foresight), but once done it can't be undone. Adding meaningful threading to a real time game would require so much work that it would be a new engine. 

If they ever make a sequel, that would be the time to do it. 

Well as far as stardock they have been trying to do something on a duel ar quad core with advanced algorithms.

Stay out of my space was what the thread was called that had the long argument about space mines. As far as mines go I don't care either way. About what the thread was about I don't mind you telling me to get out of my space. I would mind if I couldn't sneak into your territory without a right of passage agreement then I have a problem. If you are capable of catching me and overpowering me then do it. If you can't then I want to be able to run my ships through.

You can assume I'm on either side of the argument I don't care. from what I could see other than Lucky Jack people on either side of the argument couldn't be persua.ded. I think its time for Stardock to intervene like they did on tactical combat, and give an answer. I'm not seeing an end to this conversation.

I don't think mines should be made to easy. I think they should have to be maintaned. I don't think this game should be made that you are required to build mines to play it. Maybe you could make this an option that could be shut off. If we think of mines in the traditional sense like Ied's then their is no way they would be effective in space. It really doesn't matter if the map is 2d if real space is not, but it is actually closer to 2d solar systems in 3d space. Though this 2d line would have to be thousands of miles in diameter. 

I can visualize stealth or cloaked mines with fuel tanks and engines that creates a gravity well that can pull you out of hyperspace.

Mines would be ships without life support and provisions without people, Mines could be space platforms that could shoot lasers. here is two ways I think this could be done. I would not have any mine that could span two parsects this is why. 2 or 5 parsects is somewhere between 2 billion and 535  trillion miles to cover for one mine. Realistically if you want to cover a lot of space it would require a lot of resources inless your the Iconians who have replicators which require energy instead of resources.

If an area of space is mined it would affect the improvements that rely on other civilizations. I know in reality it doesn't work that way, but the description tells you which ones does. I think it would affect the tourism points given off by the planet. If I remember it right it would be 1/10 of the influence given off by the planets. Any trade routes going through the system that has been mined. The production and research points given off from the planet would be nulled until the system was cleared of mines.

There is an alternate way of doing this you could require the ships going through this to give off an beacon, so the mines wont attack. If you have advanced espionage you would know the beacon. I guess you could give the frequency to other races through trading that way the ships you want could pass through the system, but if someone has advanced espionage on you he would have your becon, so maybe having the option to build either mine is a good idea. In case the enemy has advanced espionage.

I think there should be countermeasures to anything that could be done on the game. There should be modules you could get to put on ships that could remove mines through research to remove mines. If you made these ships then it would slow you down instead of not letting you pass. I think since you start out the game with tiny hulls first. Their should be better mines for each kind of hulls. Yes I'm saying if you made a mine for a fighter it shouldn't be able to hurt my frigate. This also could be affected depending on what kind of mine by armor; shields, or point defense. Since not all ships has defense this would still work.

You could do that hull thing this way also bigger hulls take less damage; while, better mines do more damage for smaller ships. Yes I think how good espionage, and how advanced the civilization is makes a difference.

Most importantly I think that its time for stardock to rule if we should have mines or not. As far as where I stand don't care. U don't know what kind of technology is in the 23rd century.

P.s. I realized I made a mistake on the miles in a parsect so I recalculated the maximum distance on 5 parsects I did this in my head, and yes I'm bragging. Yes I find it hard to picture light years, so I prefer miles it is easier to work with since a mile is way smaller than a light year.

I am sorry I couldn't respond sooner to some of your comments in the past few days. I am working two jobs, so I've been busy. 

I am surprised to see how much discussion we've had on mines. Funny how one idea can take over a discussion. I thank all of you for your participation. It has been argued pretty conclusively by myself and others that in real life space is just too big to use mines effectively in any capacity. As some of your have pointed out; however, GalCivIII is not and will not be real life- I might add that even in real life the use of space mines for all their listed failings are still more doable than a traversable wormhole in that we don't have to re-write the laws of physics for the space mines. Being gamespace instead of real space, it will be two-dimensional. The question then is of scale. If the devs created gamespace to reflect the true distance scales of stars and planets it wouldn't be a very pretty game and you might need a supercomputer to play. Will the devs expand the scale, leave it the same, or shrink it? The smaller the scale, the more the stupid mines become a valid weapon. The larger the scale, the more your mines should suffer their real life failings. In GalCivII, the scale is adequate to make the attempt at using minefields. 

The second question is cost. In real life, it might be cheaper to tweak the laws of physics and build a traversable wormhole than it would be to mine just lunar orbit to say nothing of interstellar space. But again, it's gamespace not real space. Since the devs are free to set the costs wherever they like, mines could become feasible or even critical in any strategy, or they could be a fools errand. I feel sorry for the dev tasked with finding the right balance. Few of us would have any interest in mine-spamming, and given the option would turn it off during game set up.

That said, there may be a use for mines that does not present all the migraines discussed so far. Mines could be a standard module for military bases, and they could be deployed by your ships in fleet combat. 

Now to really go out on a limb here, I did take the time to try and imagine a way to integrate a mine-spamming strategy with the game mechanics that does not upset the balance of the game. So take a deep breath everybody, we're about to go off the deep end on this one.

For the broad use of space mines, we will need the game scale to remain relatively unchanged. It would already be a stretch to incorporate it into the existing scale unless you are playing on a small map. As for cost, mines should start out cheap. But like everything in the game, the early models would become obsolete later in the game requiring an upgrade to a more expensive model. Mines should have their own tech tree, be heavily dependent upon miniaturization techs, and face a minesweep tech tree that your opponents can use to deal with your mines.

As I see it, a basic minefield in space could be defeated with 1960's technology by detonating a nuclear warhead in the vicinity. The resulting EM pulse would disable the mines, or depending on the construction detonate the mines. In either case, a path would be cleared for your fleet. This makes a minefield vulnerable. There are only two counters to that. You can make them invisible/undetectable, or you can shield your mines. The tech tree for mines would split here into stealthed mines and shielded mines. Obviously, the counter is better sensors and bigger nukes. Or, one could use conventional weapons and merely improve targeting sensors to take out the mines. Depending on the weapon, you may need to give your mines armor and point defense. Otherwise, your investment in building the minefield is meaningless. Then there would be the smart mine tech that teaches the mines to differentiate between friend and foe. Of course, that would require sensors or communications, both of which may be deceived by enemy tech. Mines could be given propulsion and navigation so that fleets do not have the time to destroy the mines before the mines begin attacking them.

Mines should also have maintenance costs. While individual mines are far cheaper than a ship, a grid-sized minefield should be comparable as a minimum and so should the maintenance costs. Over time, minefields should grow old and begin wearing out. Cosmic radiation, limited power source, aging electronics should all constrain the lifespan of a mine that is not maintained. There should be random events like plasma storms or meteor showers or lost comets that can ruin your minefields, and mines that randomly blow up for no apparent reason, or pirates that show up and start stealing them (lol).    

Of course, every advance in mine tech makes the mines more expensive, bigger, more power-hungry, adds fuel costs and makes them harder and harder to hide. Ultimately, one must use a perfect cloak on the mines to keep the enemy from using their anti-mine techs before your mines are able to fulfill their purpose; however, the enemy may use the same ultimate cloak to pass right through your minefield unscathed. In short, if we are to make mines, let's make it an arms race between ships and mines, or merely constrain their influence strictly to fleet combat and military installations.