On earth where we puny humans fight each other on land air and sea we have of a concept of strategic points which are

  • oil fields
  • trade choke points
  • islands in the sea
  • mountains on land
  • places where countries bully each other

All of these features are present on earth and we know are good strategic points but given the vastness of space what can be a good strategic stronghold for an interstellar species.

For the civilisation (A) their technological prowess is much like:

  • FTL travel is not allowed FTL communication is

  • they spawn a massive civilisation across the galactic arms and control like 2/3 of the galaxy .

The civilisation A is blissfully unaware of another smaller but advanced civilisation B. A war breaks out when a scout of A is destroyed by B in what B perceives as a threat to their sovereignty. Now what places in such a war would be a good strategic point offering decent tactical advantage

  • $\begingroup$ Well, you should think of what is strategically good on earth, but on a giant scale. If there is a small area where an asteroid field that leads to a large amount of resource-rich planets is significantly thinner, than that would be a very optimal place to set up a choke point. $\endgroup$ Apr 28, 2017 at 20:15
  • $\begingroup$ How can they be a galactic civ if they have no FTL travel? $\endgroup$
    – ShadoCat
    Apr 29, 2017 at 9:30
  • $\begingroup$ @ShadoCat They would have to inexpensive relativistic interstellar travel. They do have FTL communications that would help bind their civilizations together. $\endgroup$
    – a4android
    Apr 29, 2017 at 11:19
  • $\begingroup$ @SuhridMulay Your last sentence of the question reads " Now what in this wade would be a good strategic point". What is a "wade"? Please either clarify or correct. Thank you. $\endgroup$
    – a4android
    Apr 29, 2017 at 11:32
  • $\begingroup$ Question edited. The typo in the last line has been removed. Thanks @a4android for pointing it out $\endgroup$ Apr 29, 2017 at 14:50

10 Answers 10


Since interstellar travel seems hideously expensive, even a galactic empire might have trouble mustering the resources (in a timely manner) for invasion and defeat of a defended planet deep in a system gravity well.

But, then, it really doesn't need to...when bombardment using any old space debris will do most of the job.

For the attacker, this makes four types of key terrain:

  1. A convenient debris field (asteroids, comets, moonlets) that can be steered toward the defender's planet/habitat/orbital/whatever.

  2. A concealed location for the attacker to gather local resources and manufacture the robots and engines of the bombardment attack.

  3. A forward observation location, from which the atacker can gauge the effect of the bombardment, spot defenses, and command final adjustments to the bombardment robots.

  4. Arrival orbit for the mopping-up troop ships after the bombardment is complete. This orbit should allow for ready close observation and access to the planet, moons, and stuff in orbit. It should, however, be far enough out that any remaining defenses cannot easily snipe at transports and cargo resupply.

Using the Sol system as an example, an interstellar attacker might arrive and hide in the kuiper belt, harvesting matter and materials. Then storm into the Asteriod Belt with a swarm of newly constructed robots, attaching to myriad asteriods and beginning the bombardment of Earth and Luna. A forward observation sneakship moves to a few million km away from Earth, and directs the bombardment. A few weeks after bombardment is complete, the mop-up fleet arrives in an eccentric orbit well outside geostationary, and starts sending assault shuttled down to Luna and Earth.

The type of attack determines several possible lines of effort for the defender.

  1. Spot the inbound attack fleet(s) early, and deny them their concealed assembly point

  2. Use deception and decoys to fool the attacker into wasting their resources attacking the wrong planet/habitat/orbital/whatever. Make the defender's real civilization appear to be waste to the attacking observers. Make attacks look more effective than they really are.

  3. Disrupt the attacker's communications and observations. Prevent undetected forward observation. Destroy forward observers.

  4. Redirect the bombarding robots using hacking, misdirection, etc.

  5. Mine the likely mopping-up fleet orbits.

  6. Fight them on the beaches, fight them in the streets, etc.

If the attacker succeeds, the defender's planet is laid waste. It might still be habitable after all the dust settles (literally). The attacker gains no real benefit from occupying the wasteland. They can't use it to build another invasion fleet - it lacks population and industry.

If the defender succeeds, the attackers are similarly likely to be wiped out.

But there's another important element: Time.

Without FTL, each planetary attack, from receipt of order ("build a fleet, raise an army, and invade X") to final result ("Yay, we won!") will take a decade or more. Support from down-arm will take centuries --millenia!-- to arrive, so there's not much point waiting for them.

Defenders, upon detecting inbound invasion fleet years before arrival, seem likely to shift to total-war footing, using all possible resources of the economy and population to prepare their all-out defense. They are, after all, facing annihilation. It's certainly in the defender's best interest to invest in earliest detection of inbound invaders.

Each side is likely to place observers in the many otherwise-irrelevant border systems. Since a base cannot build and man an invasion fleet, nor defend against a full invasion, like an inhabited and developed system can, the strategic value of these observers is minimal.

However, if your space travel requires, say, intermediate fueling or power stations to justify bases, such infrastructure would have strategic value...though limited. While it's possible to build and defend a chain of supply bases to support massive invasion fleets, the defender will certainly be observing, and gets additional years (decades) of warning to prepare for the onslaught. Remember the time effect - by the time a defender's raid reaches the supply base, the attacker's fleet has already passed through and resupplied years before.

Big fleets are unlikely to sit around for decades awaiting some other fleet to fight. Invasion fleets will be in motion. Defenders will be constantly building and stockpiling system-specific weapons and monitors rather than general-purpose ships. Fleet battles with big ships full of sapients are likely to be rare, but fleet battles with tiny robot ships are likely to be frequent.

Since this sort of warfare destroys inhabitants and industry without gaining control of territory or space, eventually a dead-zone a decade or two across will separate A and B. Along the edge of the dead zone, heavily-fortified systems swarming with decades of layered defenses will overwhelm the longest-range attackers. Any new colonies within the dead zone will likely be spotted by monitors from the other side and wiped out...eventually. Stalemate.

  • $\begingroup$ Plus one for time. It will be THE major strategic factor in a sublight galactic war. Although I think you have somewhat underestimated its impact. $\endgroup$
    – a4android
    Apr 29, 2017 at 11:28

With civilization at a galactic scale, you probably ask about entire strategic systems and not strategic points within a systems. I'm assuming that the sublight interstellar technology also allows ground to orbit transfers.

  • The presence of a world where one or both species can work in "shirtsleeves". Worlds are useful because they provide cover and concealment, heat dumps, raw materials, etc. If the world has an ecosphere that is compatible with the species, it is more valuable than a barren rock.
  • The presence of asteroids rich in metals, ice, and other raw materials.

Any system which combines the two will be valuable.

  • If there is an established infrastructure of dockyards, factories, refineries, and smelters, even better. Decide if one or both species would follow a "scorched Earth" policy or if factories can change their ownership. (Perhaps even several times? What happens to the workers?)

Within a strategic system, strategic points are:

Follow-Up: STL interstellar travel requires either lots of time or an awesome delta-V. This suggests the existence of powerful sublight drives. It would be possible that those drives are not suitable for insystem travel, shuttle landings and station stationkeeping, but the best guess is that those will be "easy" (low engine mass/cost, low fuel requirement, high delta-V).

Getting close to lightspeed might be more difficult. You will have to decide how often a typical ship can accelerate-and-decelerate before it has to refuel.

  • If the answer is only once, then refueling stops are pointless. The ship would have to spend as much fuel to stop, refuel, and accelerate again as it gains by refueling. So the best idea would be to fly directly to the destination.
  • Prepositioning forces are a slightly different concept. You hold fully equipped and fueled ships in a forward staging area in case they are needed. But with flight times measured decades or centuries, that sounds silly, too.
  • $\begingroup$ The OP explicitly says that FTL isn't allowed $\endgroup$
    – sphennings
    Apr 28, 2017 at 16:33
  • $\begingroup$ @o.m. FTL communication is allowed but FTL travel is not $\endgroup$ Apr 28, 2017 at 16:35
  • $\begingroup$ oops, sorry, I read that the other way around. $\endgroup$
    – o.m.
    Apr 28, 2017 at 16:37
  • 1
    $\begingroup$ +1 was also thinking Lagrange points, for position holding efficiency. NASA likes to put observatory craft at the Earth-Sun Lagrange points for that reason. There's a nice diagram here (same idea for planet/moon points). The DSCOVR is currently hanging out at L1 (and took this awesome image set recently, btw). $\endgroup$
    – Jason C
    Apr 28, 2017 at 19:16

Since FTL travel is not allowed, but FTL communications is, how is interstellar travel handled? If such travel is via wormholes or gates, those naturally become choke points, and by extension a strategically important point for defense. They would make great places for ambushes.

Additionally, fuel sources are critical. If your civilization A uses gas giants as fuel sources, those are strategic points. Without fuel, the interstellar commerce would not flow.

Lagrange points are critical as well. These are gravitationaly stable points in an orbital system. L1 is between a planet and the sun of that solar system. Imagine a stealthed capital ship at L1 ready to make an attack on a colony planet. It would expend almost no energy for station keeping and could quickly power up for a quick strike mission.

Outside of the inhabited areas of the solar system, resources are important strategically. The asteroid belt and Oort cloud would important sources of elements, both heavy and light. The Oort cloud could also supply complex hydrocarbons if the civilization still needed them.

All of this said, anything can be made into a strategically important resource by creating a need.


The primary points of contention would be areas of high resource worth. A civilization's ability to wage war would be directly related to the quantity of fuel, metals, and foods.

  • Solar systems with stars that have gone supernova could be major sources of valuable resources, as the elements produced in the star will have been ejected into the system. The "r-process" that occurs in collapsed supernovae produces many elements beyond iron, such as uranium and thorium.
  • Planets with a powerful agricultural base would be needed to provide a civilization food, as a huge civilization has an enormous number of civilians and soldiers alike to feed. And if a civilization failed to do that, they would effectively lose a war, due to internal conflict.
  • large, rich asteroid belts would provide many resources.
  • Planets with strong technology or production bases are needed to produce goods, and thus make important targets.

In a galactic conflict at sub-light speeds. It might be very easy for ships to infiltrate the other army's territory, as the distance between stars is incredibly vast, it would be virtually impossible to intercept a ship that passes your lines at a large distance from your border stars. And your civilization might not even notice the breaching of the line if they aren't specifically scanning that part of the sky. Because of this you might not fight from barren planet to the next, but instead choose targets deep in enemy space, balancing potential tech advances the targeted planet can make by the time a ship arrives.

In battles taking place in a solar system, A position further from the systems star would be preferred to an internal position, because it uses less fuel to transfer orbits. Also infiltrating through areas of low visibility like nebulas would be important.

These infiltrating ships could go around disrupting important supplies because hitting a lone trade ship would be fairly easy, and the odds of having a military ship intercepting the attacking ship as it escaped would be very low.

They could also be used for military intelligence. Since light takes thousands of years to travel from a planet in the center of one of these civilizations to the nearest viewing post in another you could not easily see what was going on with telescopes. it would be useful to send a ship behind enemy lines then transfer the more recent info to central through FTL communication.

You should also decide on what starship weapons you have. If they are long ranged, like a missile with interstellar range, than the dominant strategy would probably be mostly defensive, since planets would just sit tight and target distant ships that would get hit years later.

If the range is short enough, the dominant strategy would be almost 100% for all out attack, like in "Enders Shadow" by Orson Scott Card. The logic behind this is that defending an important planet would not be possible, because if you grouped your forces in one area, the enemy could just attack somewhere else, or on multiple sides at once. With limited resources, and short range weapons, you need a huge number ships to defend a single planet. The enemy would also be able to use less fuel to move around, because the nature orbital mechanics makes it so that a ship in an orbit that is farther away from a planet expends less fuel in orbital shifts.

You should also decide how your soldiers are transported for so long a distance. It could be Cryogenics so that the soldiers would wake up whenever they where needed for battle, or it could be generation ships, where they train each sequential generation for the battle they will fight.

I hope this helps,

  • 1
    $\begingroup$ Hi Widea, and welcome to Worldbuilding and Stack Exchange. You should note that a supernova would eject matter far outside what used to be its planetary system (assuming that the star formation process left sufficient matter in the accretion disk for a planetary system to form in the first place). Nebulae, which can be remnants from supernova explosions, can be millions of light years in diameter (though thousands of light years just might be a more reasonable first-order approximation for size). $\endgroup$
    – user
    Apr 28, 2017 at 20:11
  1. Border systems (as staging points for incursions or defense fleets)
  2. Resource-rich systems. (Not all stars / star systems are equal, though this depends on resource needs vs. resource availability. With the ability to travel and colonize the stars comes near limitless resources, with transport of said resources being the larger limiting factor; how much can you move from resource-rich systems to resource-poor systems, and how quickly, and "why are we needing this resource-poor system." IE. if space infrastructure is needed in those systems, then transporting stuff to them becomes relevant. If no such infrastructure is needed, it is a waste of effort / time to do so.)
  3. Habitable planets (depending on how common those are, and if the two warring species have the same idea of what a habitable planet is.)

Let's do an as exaustive as possible list of what do you need in Space and during a war?

Vital need: The most obvious to begin. I suppose even if you have FTL communication, you won't use only unmaned craft. You will need to provide food and water to your troops. And your ennemy will need supplies to sustain planetary siege you will maybe provoke. Water and food sources as well trade routes (you will probably always use the shortest path, because the voyage without FTL to the closest star is at least 4 years long, see Proxima Centauri) will be real strategic points, if you don't want your troops and population to starve.

Example of water sources: water rich asteroids, frozen moon (like Europa)...

Example of food sources: habitable planet with vegetation and maybe animals, farm spacestation (like in the video game serie X), nebulae (some are believed to contain organic molecules, you could manage to synthetise food with them)...

Military ressources: A bit more specific to war: ammo, spacecraft and fuel. Ammo will be plasma for plasma weapon, ion for ion cannon... Only laser will not need ammo (maybe replacement lens?). You will need to control ammunition factories and be able to supply them (trade routes, again and mines for metals, and various ressources you could need, you will found them in all kind of stellar object, it depend of the nature of the ressources). Same purpose for spacecraft, you need to control "spacedockyard" to be able to repair existing spaceship and building new ones. To fuel for vessels, assuming they are powered by fusion reactor, and not old fashion hydrazine (not efficient enough, too explosive and heavy), you will need hydrogen, to fuel the fusion reaction.

Economy and communication: Money is the sinews of war (and intel too). You will need to control trade routes and "space docks" to destroy the ennemy economy and prevent him to build new spaceship, enroll new troops... To gather intel, controlling ennemy communication and command centers is a good start. They will contain informations and will help you to decypher ennemy code (like with the Enigma machine). It will prevent your ennemy to correctly communicate too, and disorganise his military organisation.

Space specific strategic point: Since the begining, this is the same kind of strategic point than on Earth. Now let's talk about space specific one. A spaceship is really greatly insulate (see vacuum insulated panel). It means your ship will generate many static electricity. It could be dangerous for the ship electronics (and the crew, maybe). You will need to discharge it sometimes if you don't want to be thunderstruck the next time you approach a planet (fun fact, you will be the source of the lightning). You can find this kind of issue with ion thruster (not at the same scale but I assume the activity on your warship will generate static electrecity, firing a ion cannon for example). Heat will be an other problem. You can't dissipate much heat in void, beacause of it's poor thermal conduction (see the begining of the paragraph). You will need to enter a fluid to dissipate heat quickly (a really low temperature liquid is the best of the best). You could dissipate the heat by irradiation to, but you will be really visible (and this is not a good during a war).

Point to discharge static electricity: point with opposite charge like planets or asteroid (if you're lucky)

Point to dissipate heat:where you can find fluids colder than your ship. Ocean on a planet, atmospher of a planet, nebulae...

But on this time and distance scale, war is close to be a none-sense. You could find all the place/ressource you need in another place, closer and more important safer.

I hope you like my list! Thanks for the reading.


All of points you described could be splitted in options:

  • sources of resources
    • energy is most important resource
  • key points on a route
    • trade route
    • army's potential route
    • resource delivery route: from a mine to the a factory

I would add

  • military bases
    • especially military production bases
  • centers of political and/or technological life (one of them is the capital)

But with FTL communication and FTL travel absence both species have an issue. Any galaxy has size of thousands of light years. Army become obsolete in dozens of years and when it reach the destination, it would be met with some spaceships which are better by 2-3 generations. Only minor battles are possible and war will long for ages without some way to travel FTL (as teleport or moving with FTL).

In your world you could put resources and routes as you wish to create some tension in the war. For example, create teleport (as space gate or wormhole or whatever) which is key point of any route, and put this teleport close enough to both species.


As o.m. noted, I suppose that a strategic point could be a whole key system or area.


To wage a war in space you need 3 important resources

  • technology
  • matter
  • energy

Thus sources of those resources can be strategical points.


A star system

A star system with Dyson swarm will supply with energy fairly well, and contains matter for millions of years if you rely on the star energy output. Million years mostly because one can mine the star itself and it is usually deep gravity well compared to the energies it produces and energies needed to lift the matter from the star.

Planets are obvious sources of different matter, especially Gas giants, as an example

So, in fact, any star system can and will be a strategical location just by itself. But stars have different energy output, and in that regard choosing stars with higher energy output might be preferable.

A supernova and supernova remnant

Less obvious choice, but in fact, it might be a very valuable resource.

It provides with energy and matter, and if one is capable of harvesting it(which needs a good technology, but still seems to be in realm of known to us physics)

The energy of a supernova blast is about 1044J (up to 1046J) which is equivalent to the energy produced by 8300992 stars like our Sun in 1000 years time.

A lot of the energy is stored in the kinetic energy of the star matter which is heading outwards.

That can be used in multiple ways, including launching your fleet to all stars of your enemies which is the most primitive thing you can do with it because the energy has way richer uses.

Not only ready to blast supernova is valuable, its remnant a black hole or neutron stars are also very valuable objects.

They are valuable at least for 2 reasons - energy, and matter. You can use their gravitational potential to convert available to you matter to the energy (both for BS and NS), or you can use NS as a neutron source for transmutation of the elements you have into elements you would like to have.

some thoughts about supernova as a useful resource in the answer My star will explode as a supernova. What can I do in order to ensure that my planet survives that?

A supermassive black hole

Mostly the same as with usual black holes or neutron stars - but at way much greater scale. Way much greater scale.

Basically, if you have the technology, which is still in the realm of known physics and known materials, by securing the SMBH you secure the galaxy.

You can throw stars into the SMBH to generate energy and energy extracted just from a single star like our sun thrown in SMBH will produce about 894 foe (1 foe = 1044 J)

A bit more why the SMBH are useful as energy producing places in the answer Why would a civilization choose to inhabit a single enormous vessel instead of maintaining interstellar colonies?


It is important to understand that scale of action and technologies aren't that heavily connected with each other, and it is in that way since we invented computers.

I mean, if you can operate on the scale of a single star system or even a planet - only physics stops you from scaling the technology to use it on 1000 star systems, or million star systems, or the galaxy.

The physics in terms of availability of matter for your devices and energy for them to work and energy needed to launch them to the target.

Defense is more or less the same it is a matter of how much you have both resources and energy.

Energy utilization efficiency of the technology, materials demands for the technology it affects the capabilities of those who use them, but in a lesser way that ability to get the access to an energy source which boosts you capabilities 6-10-20 order of magnitude compared to your enemy.

The gap between technologies of both parties might be significant in terms of how advanced it is, but the difference can be compensated by energies available to those parties. And to wage galaxy wars the technologies have to be above a certain level.

At least is seems that way at our current level of understanding of the physics, significant break trough may change equilibrium of involved parties And thus megastructures like matryoshka brains might be strategical points too as they generate science for your enemy. And it is in your best interests to have them and prevent your enemy to have them.

The technology used in the answer is sufficient to wage wars at stars/galaxy level(K1, K2 civilizations).


  • Have read the answers, and it seems many do not understand which practical implications FTL communication have, by saying the ships will be older and technologically less advanced than enemies ships.

    You have to understand the scale of such thing as attacking a star system. A system where you enemy can control everything, where it sees the attack is coming, it sees its size, where he has time to prepare for counterstrike using the whole resources of the star system.

    Your attack can be successful if none of that matters when all the preparations of the defending side are totally useless. When he has no chances to defend himself using all resources he has in the system when they are against an overwhelming force heading to their system.

    No matter in which technology do you believe, what you think is possible or not, but taking manufacturing capabilities in the case is the must for the attacker. You live in the time when all Intel facilities technologies could be sent to you with one mouse click, same can be done for the attacker fleet, they can improve themselves on the way to the target according to the technologies available to those who sent them.

    With some technologies, it can be easier with other more of a hassle but it definitely possible.

  • I recommend Isaac Arthur Megastructures playlist, all.

    To grasp the scale of what can be possible I highly recommend to watch his The Kardashev Scale - it is not about technology but about of scale of things how big they might be and some practical implications of the scale.

  • areas with needed resources i.e. garden worlds, fuel extractors, asteroid/comet mines.
  • asteroid fields (ambush, hazards, etc.).
  • Very important people/places (hostages, culture centers)
  • Nebulae (resources, low visibility, potential technological interference)
  • High/exotic gravity areas
  • Research and development centers

To list a few and relate them to the Earth ones, I would think that asteroid fields that contain some kind of special element (think Star Trek Dilithium crystals), areas of stable gravity not being close to black holes or crazy suns, planets that are extremely habitable. Stuff like that.

I see an issue, with space being so vast that you could move around a lot without ever meeting someone else.

  • $\begingroup$ FYI, areas of stable gravity describes the vast majority of space. $\endgroup$
    – Gryphon
    Apr 28, 2017 at 16:34

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