Set in the distant future, two factions are engaged in bitter conflict spread across the solar system. The Earth Federation wants to deprive the rebels hiding among the moons of the gas giants of solar power by encasing the sun in a Dyson sphere.

However, we know space is vast and chances that a spacecraft could be caught up in the proximity of the shrapnel from explosion of a space-mine is simply negligible. What can be done to improve these space-mines, so they might be able to turn the tide of war?

Technology would be anything up to 1000 years from now. FTL is not yet realised.

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    $\begingroup$ You seem to have skipped a step from 'building Dyson sphere' to 'therefore space mines'. $\endgroup$
    – Halfthawed
    Commented Jun 3, 2020 at 5:05
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    $\begingroup$ I'm a little confused. A dyson sphere requires mining, as in material extraction, and a war can involve mining, as in placing bombs. Which uses are used throughout? $\endgroup$ Commented Jun 3, 2020 at 13:39
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    $\begingroup$ A civilization that can build a Dyson sphere in wartime as a strategic act has many other options to deal with those pesky gas giant moons, like throwing them at each other. $\endgroup$
    – notovny
    Commented Jun 3, 2020 at 17:37
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    $\begingroup$ I had a solution, but it was using technology developed 1003 years from now. Still pre-FTL though. $\endgroup$ Commented Jun 3, 2020 at 19:44
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    $\begingroup$ If your society can build a Dyson sphere merely to deprive the rebels of light, it isn't going to be bothered by rebels. $\endgroup$
    – NomadMaker
    Commented Jun 4, 2020 at 0:33

10 Answers 10


In naval warfare you don't mine the whole ocean, you just mine the waters next to your target, usually an harbor you want to limit (if it's enemy's) or protect (if it's yours).

Can you do that in space? Yes! Good old Kessler syndrome.

You don't mine space, since space is big. You mine the low orbits around the moons, or better saturate them with space garbage, so that any attempt to reach space will turn into a game a Russian roulette.

That has also the advantage of making unusable for you only a small fraction of space.

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    $\begingroup$ But I still want to make interplanetary wide pizza delivery... $\endgroup$
    – user6760
    Commented Jun 3, 2020 at 5:17
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    $\begingroup$ Just drop the pizza in drop-pods that can survive the collision. That way you can mine the target but also deliver goods on a one-way trip. $\endgroup$ Commented Jun 3, 2020 at 13:02
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    $\begingroup$ If you mine most orbits except for polar orbits then you'll be able to have 2 access points to a planet. Might require a ground array of lasers to clean up any debris that drifts into the clear zone? $\endgroup$
    – cobbal
    Commented Jun 3, 2020 at 14:43
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    $\begingroup$ @user6760 Then you don't want mines. You don't plant mines anywhere where your people will go, only where the enemy will go. $\endgroup$
    – Graham
    Commented Jun 4, 2020 at 12:41

Modern mines are target seeking. A space mine would be essentially a hunter-killer drone, possibly with a kamikaze warhead if you want it to look more like a traditionally dumb mine.

Secondly, shrapnel need not go off in all directions. Modern anti-aircraft weapons used focused shrapnel directed towards the target, a space weapon might only fire a few pieces (like EFP) and these might be guided. Range can be unlimited.

  • $\begingroup$ Yeah, and its a mine because it can be on standby in orbit for centuries, thereby functioning as a mine $\endgroup$
    – Hobbamok
    Commented Jun 4, 2020 at 22:42

Some basic problems with the concept I see are :

the Earth Federation wants to deprive the rebels hiding among the moons of the gas giants of solar power

It seems very unlikely that 1000 years from now they'll be relying on solar power (which is very weak anyway at that range). We expect to develop fusion power within the next 75 years or so and the "rebels" will be orbiting gas giants so no shortage of fuel.

Dyson Sphere to block out the sun for the gas giants

Ignoring the fact the won't need solar power in the first place ...

This does not require a Dyson Sphere. A Dyson sphere proper would require an insane amount of resources and it would be easier to build billions of robot warships to hunt the rebels down and wipe the rebel scum from existence.

Instead you "just" need build a few large shields that can shade the gas giants and their moons. You place them in powered "pseudo-orbits" (real orbits would have the wrong orbital period, you need to overcome this with active orbital maneuvering). These would require a lot of resources, but still a lot, lot, lot less than a Dyson Sphere.

At most you'd build a ring, although like a Dyson Shell these are unstable in orbital terms and not practical.

Dyson Sphere top completely block out the Sun.

That's a Dyson Shell. These are not stable in terms of orbits. The mechanical stresses are also enormous (even a ring has enormous forces on it, but a sphere is just a disaster). Modern interpretations of this tend to be Dyson Swarms and their variants.

The high ground

You don't need mines, you need something to protect you from the vast numbers of extremely high velocity, low mass kinetic weapons the rebels will be flinging at you from the high ground they occupy.

Gravity works in their favor and they will have fusion powered engines, so they can almost certainly fling relatively small mass items at you with extreme accuracy and enough energy so that any one of them would be enough to wipe out all life on e.g. Earth. They can just wander off to the Oort cloud or Kuiper belt and they've an endless supply of junk to send your way.

Again this makes building the billion ship robot fleets and hunting the rebel scum down that much more important !

Do it to them before they do it to you !

Waiting around trying to patiently build a defensive wall (your Dyson Sphere) is pointless as all it does is given the rebel scum (did I mention they're scum :-) ) time to attack you with kinetic weapons. Better to go on the offensive - and more fun anyway.

So you build vast robot fleets with the same tech you were going to use to build a Dyson Sphere. These patrol aggressively and in particular you saturate the gas giant systems with even higher numbers of these.

You build kinetic weapons that can do them damage, perhaps even wipe them out (lousy rebel scum) before they do damage to you.

You do not need to wipe them out, of course. You can just suppress them to the point that your robots fleets can keep them under control and slowly reduce them to nothing.

Now back to ...


Yep, after all that, there is a use for mines.

The rebels are going to use mines (of a sort) to defend against your vast robot fleets. These mines will need to be passive arrays triggered by the detection of nearby fleets. They're going to have to use weapons fire - so not a minefield in the sense you may have meant. They will have limited numbers of projectiles, but these can be autonomous missiles with high speed and targeting capabilities. They can employ very high yield thermonuclear warheads - there is no theoretical limit to this beyond the limited size of the warheads.

Mines won't eliminate a fleet, but they should reduce the numbers enough to allow your own smaller fleets to engage them successfully.

This would be a war of attrition between two forces. One has the mass of the inner solar system, but the rebels have the mass of the gas giants to work with. If the rebels can survive long enough to develop the required self-replicating robot factories and fleets, the inner solar system looses, as it cannot complete with the production potential it faces.

That's why the inner systems need to build those vast robots fleets ASAP and launch a first strike on the rebels to prevent them developing that capability.

But this is also why the rebel scum need to build vast semi-intelligent minefields. Not to guaranteed protection, but to remove the worse of the danger and let them develop their industrial base to the point it can win.


I would strongly encourage you to read The Short Victorious War (ahem: read the two preceding books first), by David Weber, as an example of well designed "space mines".

Hint: You don't want things that just blow up. What you want are actually Autonomous Weapons Platforms. As others have noted, you first have to realize that mines, even in terrestrial use, aren't used on a large scale, but to defend specific points that the enemy must pass through. In Honorverse, that means the egress lanes of wormholes. Other science fiction series (e.g. Starfire where FTL has such "choke points" have also used mines in this manner. (Note also the "mines" in TIE Fighter.)

This was already hinted at, but obviously, no matter how they work, your mines will incorporate IFF systems, so that your own ships can 'sail' right through them without setting them off.

Additionally, as I was saying about AWPs, mines in Honorverse aren't just bombs, they are ranged energy weapons. (I don't recall offhand if they are single-use or can keep firing over and over until the enemy blows them up. I want to say they come in both varieties.) They don't require the enemy to actually run into them, just to wander into their effective range. Ideally, that range is sufficient that a modest number of platforms can create a field of overlapping ranges such that even knowing they're there, the enemy has to stand clear and pick them off (possibly wasting munitions to do so, especially if the platforms' range is similar to the enemy's energy weapons range, such that they have to use expendable munitions for mine-clearing). Of course, if you're blockading a wormhole, the enemy has no choice but to emerge right in their midst.

Additionally, if you're using AWPs (and not just Kessler-style area denial), you want them to be as inconspicuous as possible. (This will depend, of course, on whether you allow Stealth in Space.) You also probably want to equip them with evasive systems so they aren't perfectly stationary (and thus subject to long range kinetic strikes), and maybe even point defense systems to make them harder targets to take out with missiles.

An alternative, as David Hambling noted, is for your "mines" to essentially be remotely-operated or autonomous missiles, that "lie doggo" until an enemy comes within range, at which point they light off and try to do what missiles do. The drawback of this is that they don't have an advantageous initial velocity, as they might when launched from a ship. You can partly overcome this by using larger platforms with internal launchers.

Summary / TL;DR: The key is to stop thinking of "mines" as floating bombs. What you want are AWPs.

  • $\begingroup$ Nearly all the torpedos in honourverse are explosively pumped single use lasers. The 'innovation' was in using FTL communication to trigger off remote launchers left in place by massive carriers, increasing the throw weight they had. $\endgroup$ Commented Jun 4, 2020 at 0:46
  • $\begingroup$ @JourneymanGeek, that depends on what "era" of Honorverse you're looking at. In the "Call to ..." series, we're long before that point; by "On Basilisk Station", the transition to "laserheads" from traditional nukes is still in progress. (Also, you meant "missiles". "Torpedos" in honorverse are something else entirely that don't show up until well into the series.) I don't recall if Manticore ever used Apollo to control "mines" rather than system-defense missiles. That sounds more like something Haven (Hi, Shannon!) would have done. $\endgroup$
    – Matthew
    Commented Jun 4, 2020 at 13:35
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    $\begingroup$ That tears it, that's next on my to read list. I do have a good chunk (all?) of the books as ebooks :D $\endgroup$ Commented Jun 4, 2020 at 13:49
  • $\begingroup$ @JourneymanGeek, right, I forgot about that... you can get the entire series up to "Mission of Honor" for free, with no DRM, legally, in electronic form. That includes the anthologies and the first few books of the two spin-off series. (Please support the author(s) by purchasing books if you enjoy them! I have ePub copies floating around, but I also have AFAIK every book to date in hardcover. Also, please support Baen for being awesome this way!) $\endgroup$
    – Matthew
    Commented Jun 4, 2020 at 13:57
  • $\begingroup$ Oh..I pick up the bundles for those, the vorkosirgan saga, RCN/Leary.... They're good value. I just need to sort them all $\endgroup$ Commented Jun 4, 2020 at 15:06

You plant bombs where you know your enemy is going to be.

If you're engaged in combat over a planet, presumably there are strategic objectives on or around it that both sides want to attack or defend. Things like major cities, orbital docks, military bases, that sort of thing. There will be locations from which it's energetically favorable to attack those targets - where you can get the best effect for the least efforts. These depend on the details of your weapons (some kind of laser? missiles? troop transports or drop pods? etc.) but as long as you know the enemy's capabilities, it's really just a matter of mathematics.

Since you know the positions the enemy will want to occupy to attack your objectives, you can lay mines near the most important positions, the ones with the most advantageous lines of fire. Then when the enemy tries to attack your ground bases, blam!


In order to be effective, mines should be:

  • cheap to produce and deploy (especially in the literally astronomical quantities required to cover volumes of space)
  • hard to detect
  • covered by fire (in order to impede enemy mine clearance activities)
  • sufficiently damaging to deter enemy movement
  • not a threat to friendly forces

My crystal ball foretelling technology advances for the next 1000 years is a bit faulty, but I see "hard to detect" as being near impossible to achieve for a contact mine. Just looking at mass detector technology, in 1000 years I would expect every ship to be able to detect any mass large enough to threaten its integrity. Even if mass detector technology falls down, I would expect active sensors plus thermal imaging to be able to detect any threatening objects - if it is not EM absorbent then it will give a reflection, if it is EM absorbent then the thermal sensor will detect the tiny increase in heat when it absorbs the energy from the active scanner. (Note that the active scanner is probably a drone rather than a ship to counter anti-radiation missiles.) So the standard idea that "space minefield equals millions of ball bearings occupying a volume of space" doesn't really fly in the realm of technology being considered.

Alternatives include self-activating "sprint" homing missiles floating through space and nuclear-pumped X-ray lasers / grasers. However, although these each threaten a much larger area than a ball bearing, they are many orders of magnitude more expensive, they rely on their expensive sensor suite to detect and correctly identify enemy targets and they become useless if the enemy get hold of the IFF codes for them. A decoy that will trigger one of these mines is probably much cheaper than the mine, defeating the entire economic rationale for deploying mines at all.

In short, the (very short to non-existent) era of the space mine will have passed, as reflected in conventional military wisdom of the era. Except...

Maybe one side pulls off an intelligence and special forces coup - they know where a significant target fleet is going to be and they are able to hack the programming of the target ships' sensors for a brief time window to completely ignore the incoming mines / ball bearings. The mines destroy the ships, the enemy do not get a chance to examine the ships' black boxes - then the mine-using side leak the sort-of-true fact that their victory was due to undetectable mines. Until the enemy figure out what is going on they will become exceptionally cautious in moving anywhere that might have been mined and will prioritise anti-mining technology over the stuff that actually will help them. This combination of espionage, sabotage and psychological ops may allow the ignoble mine to have a last moment of almost-glory before fading into obscurity again.


Mines are not primary weapons for launching attacks. They are an area denial weapon. And, as you've noted, the entire solar system is simply too big of an area for you to use mines to deny the enemy access to the whole thing.

But there are specific locations within the solar system where you specifically don't want the enemy to be able to go: Rich resource sites. Optimal locations to launch attacks on your cities or resource-producing installations. Possibly lagrange points, if those are used as staging areas or if high-value installations tend to be placed there.

So you identify those locations and mine only them. If your space travel method is one which causes them to have preferred approach vectors, then scatter some mines in those paths, too, to stop the enemy further out, but the general strategy remains the same: You don't rely on mines as a primary means to destroy all enemy forces, but only as a defensive tool to prevent the enemy from going to specific places where you don't want them.


In space you don't really need mines that explode. Any little piece of scrap can be accelerated to enormous velocities and be more destructive than any sea or land mine we have right now. (As an example, octanitrocubane has an explosion speed of 10100 m/s and NASA's Juno spacecraft was accelerated to over 100000 m/s.)

Mines that only get triggered when enemy spaceships are near don't make much sense, since the scrap of enemy ships is as deadly as mines to allied ships and I can't think of a good way to clear destroyed enemy ships off an orbit. I'd rather go with super fast, super small bullets instead of 'mine fields'. Sure, if the mines weren't really mines, but railguns that automatically fire on hostile ships, they'd of course be more efficient than a bullet field when it comes to covering a big area. Still, the bullet field would be harder to clear than the railguns and it couldn't be corrupted or tricked into not destroying an enemy.

It would be possible to spread bullet fields in a way only a small surface of a globe isn't covered by their trajectories, allowing spaceships to leave. All the defensive artillery could then be focused on that little surface, which would allow the defence of a gigantic planet with only a few canons.

Edit: I can't stop thinking about this idea of the perfect artificial scrap field. Some would try to build ships without humans in them that can dive quickly through the field, others will try to lead the scrap out if its trajectory with magnetism or super precise laser beams...

  • $\begingroup$ The scrap of enemy ships is as deadly to the minefield as the minefield is to other ships, too. $\endgroup$
    – T.J.L.
    Commented Jun 3, 2020 at 14:51

As said above yes I’d say either in orbit or around moons. If you wanted to place some in open space you’d be best off having a ‘rule’ in your story about space lanes. For example if ‘hyper space’ Or something is only accessible through certain lanes then mining said lanes would be tactically valid or if ships commonly follow a certain route for whatever reason leaving mines somewhere along those routes would make sense. Something to also consider is that your mines could be cheap or crudely made so just leaving them in places may not be that big of a deal to a faction that’s not too worried about losing the resources or ‘polluting’ space. It’s just like modern naval warfare at that point: the ocean is vast sure but there are places one can assume someone may pass through and you may as well leave a cheap but devastating mine there.


The major problem of mines in space is that space is ridiculous big, so stationary mines are out of the question.

One solution that keeps them operating like mines we know would be to equip them with propulsion, advanced sensory equipment and a microchip: If the mine detects a spacecraft that doesn't transmit a certain signal or doesn't fullfill certain characteristics, it activates, homes in on the spacecraft, accelerates towards it and crashes or detonates. Basically a long-range magnetic mine in space.

The problem I see with this concept however is that such a mine gives an enemy spacecraft ample time to react and that it is very wasteful to put all that technology into a device that will eventually selfdestruct.

For that reason I would argue that you wouldn't use mines for such a purpose but intelligent combat drones that are deployed in such a way that their cumulated effective operative range denies easy access to an area of space, just like an old school minefield.
The great advantage of drones is that they are compact, reusable and can be equipped with really advanced A.I. to employ tricks such as calling other drones in the vicinity for help, laying advanced ambushes et cetera...

In fact I would argue, that it won't be long until we can employ such systems in our real world. Once our neural networks are sophisticated enough to put them inside combat drones, you can easily use them to create death zones, in which they will open fire on everything that moves. Somewhat further in the future they might even be able to distinguish between targets.

Another great thing about drones is that you can pack really nasty weapons on really small devices when employing those weapons is their only job, which means that a bunch of small drones can easily pack enough punch to annihilate vastly bigger spacecraft.


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