Interstellar war without co-ordination, is fine timing important at these scales?

Question

I've been working, on and off, on a universe with limited FTL based on the "one big lie" principle of sci-fi writing; travel speed averages just a hair over 4 times the speed of light, travel is instantaneous for the ships and crews travelling faster than light. Some time travel is demonstrably possible, ships do occasionally arrive before they leave, but because decisional causality can't be violated you can't do anything interesting with it. But most importantly, to this question, jump times, as measured from a non-FTL reference frame, can be rather variable (Poisson-ish distribution around the expected average with roughly 90% of the ships arriving within plus or minus 10% of their expected transit time on "standard" jumps) some ships will arrive as soon as, or even before, they leave, but never before the decision was made to send them, while others may take several times longer than expected to arrive.

A touch of background to the conflict; Humanity have been very worried about their weird alien neighbours for some centuries because they think that they could be squashed flat at a moments notice, as such they've sunk enormous resources into a huge battlefleet, all of six fleet carrier class ships, each one capable of pacifying any one system. Their neighbours for their part have concerns of their own, not being able to squash the humans and Humanity having advanced technology in areas that makes the aliens very vulnerable to certain routes of attack. The two are at peace, sort of; the aliens don't let us anywhere near certain installations and otherwise almost ignore us. They have no specialised warships but do have vessels that can be used in the role in an emergency that has never come. Oh and a few millennia ago they fought another alien group, their own overlord caste, to extinction and/or exile.

Technical details: No-one has FTL communications except by courier all intel gathering and ships comms are strictly lightspeed minus processing. So all intelligence gathered will be light speed lagged by the time you get it. In-system big ships are slower than small ones but when it comes to FTL bigger is better for several reasons, not least of all being heat dissipation capability compared to the size of the powerplant for the jump drive. Most populations are planetary but most material extraction and manufacturing is done off-world.

The current conflict; now the masters are back and our alien neighbours have asked for our help, between us we control a loose cone-like area that at their far frontier is a hundred or so light years across, no-one's sure, there's a small zone that unknowingly overlaps the "masters" self-exile. At a minimum they'd like to create a buffer in that area but ideally they'd like to wipe these guys out for good. The combined fleet is over a dozen fleet carriers, huge FTL capable vessels that are, in the case of the humans, heavily armed and carry large numbers of interplanetary warships, most of which are usually FTL capable in their own right, as cargo.

The question proper: Given a narrow interstellar battlefront of say 30 Light Years only a few light years deep say 10-15 systems in all and assuming a single strike unit can reliably pacify a given star system, but not a reaction force if one shows up, within days, is the fact that the strike forces' arrivals in the different systems could spread across up to 10 years or so going to hurt their ability to win the war or does a strike dispersion that small make no difference at such a scale?

Answer 1

This is a fascinating question that will have a substantial impact on your story. I love it! Let's get some basic observations out of the way, which will include some restatement of your limitations.

• A group of individual ships launching in tandem always arrive at the same time, but within a +/- 10% variance of when they expected to arrive.

• Groups of ships or individual ships not launching in tandem arrive with no guarantee that the other ships won't arrive years apart. Consequently, it's impossible to coordinate attacks between multiple targets.

• The "field of battle" is 30x3x3 light years or 270 cubic light years. The amount of physical space this encompasses, compared to the galaxy, is trivial like a grain of sand — but from the perspective of interstellar space ships, it's an inconceivable amount of volume. Massive fleets can be hidden by jumping them into some middle-of-nowhere location. Consequently, battles never take place in the void (if you were lucky enough to detect their presence, by the time you landed ships there, they'd be long gone after years of R&R). Frankly, who cares if your enemy's fleet is sitting in the middle of nowhere thinking strong negative thoughts about you — you control everything of value, which means you're still building ships....

• This means your battles are taking place at resource points. A resource point can be anything from a star system to a rogue planet to a "meteor shower" (or, what would be a meteor shower once it hit a planetary atmosphere). Any object or group of objects with a movement vector that is mathematically predictable and has something of value (not to forget that being mathematically predictable is, itself, something of value).

• And this all means that a "win" is defined as "I control all the resource points" because there's nowhere else worth going.

Except for one thing... and I'll get to that in a moment...

For the most part, your wars are all about the siege: the process of overcoming the defenses around a resource point and/or holding that resource point. Battles in space will almost always be minimal as only those ships stationed at the resource point can be involved in defense. This begs the question, "how much of that resource point needs to remain to still be of value to anyone?" If the reason a habitable planet is valuable is its mineral makeup, then just nuke it. You don't need its habitability and mining generally takes place underground anyway. (If you can see what I mean....)

From this perspective, you don't have a 270 cubic light year front, you have 10-15 siege points. All the rest of it is dead space.

Kind of...

Your first reaction may be, "hey! I can use that nebula as cover! What do you mean no space battles?" Except that it takes years to get there with months-to-years in variability of arrival and if there's nothing useful to be extracted from the nebula then what value is it? Answer: none whatsoever.

BUT...

You could jump your fleet into the void near the target resource point (oh, let's call it "Earth") such that your last FTL jump is a month +/- 3 days. (And this assumes that your variance doesn't grow smaller with jump distance. If it does, that error might be +/- 3 hours.) So "near space" has value as staging areas to ensure the whole fleet is there and coordinated using the very latest intel. In fact, it allows you to gather the latest intel because...

You didn't say what your communication was like

And, therefore, I assume you do not have interstellar comms that are faster than your ships. This means that the chance to gather local intel is incredibly important and near-space battles suddenly become a costly but necessary fact of your war. How do you detect something so small as 1,000 ships of the enemy's line within a light-month of your star? You do have a window of opportunity, because they need at least two months just to send and return reconnaissance. That means if you can find them fast enough, you can land your ships in their midst. Or change your defenses. Or whimper in disbelief that they thought your planet was strategic enough to be controlled.

Like I said, I love this idea

This is the kind of limitation that makes stories really fun. It has a taste of realism while enjoying a bit of fantasy — all the while requiring you to use your imagination to wrap it in an infinite number of plots. Think about it! They can find me within a light-month! Just how far out must I be to be undetectable while I gather intel? Just how fast can I change defenses to obsolete the intel? How much must I bring to both subdue and fortify a resource point? And what if those sneaky bounders left everything behind but a super-nova-causing bomb just waiting for your spies to show up?

Cheers!

Answer 2

The variance of this "Poisson-ish distribution" makes the difference here. "10% of their expected transit time" means that on a 10 year trip, the bulk of the jumping force will be spread over 1-year period. Each jumping ship will be essentially on its own upon arrival.

There are two ways to mitigate this issue.

1. Set up a rally point. Establish a rally point just outside target system. this point should be just outside of defenders' scanning abilities (Kuiper belt? Oort cloud?) and should be targeted by jumping ships with precision. Attacking fleet will be regrouping at this rally point until sufficient force is reassembled, and then start the attack on the system.

2. Mother ships. Instead of building a fleet, build one huge ship. It can be a host for smaller fighters and bombers, or some kind of a "Death star". the point is to be able to transfer all of attacking force at once, without spreading out along the way.

Answer 3

The question can't really be answered without more information! Are the two sides in the war vast interstellar empires or are they relatively small? Are they relatively evenly balanced?

You're describing a situation where strength can't ever be concentrated, and that has major consequences.

If they're evenly balanced vast empires, all they can do is bleed each other to death -- no battle is more than a pinprick and no assault can me made on the enemy's main strength. If they're small polities or unbalanced enough, a war of attrition can be "won" with the winner almost as devastated as the loser.

So the lack of ability to concentrate forces makes a decisive war almost impossible. The optimal strategy may well turn out to be to fortify your systems with enough force to beat off an attack by a single ship -- which is all you are likely to ever see. Fortification is a risky strategy if a whole fleet can pick where to attack and then come after you -- think D-Day -- but not if it must come one ship at a time.

For a pretty good analogy, think of the era of fighting sail on Earth, but with the requirement that each ship travels alone and can't predict when it will arrive. No fleet actions are possible. So there are no Trafalgers and the war drags on and on.

Answer 4

Since there is a statistical variability in when ships arrive, the main effect will be to adjust the fighting platforms to be effective under these conditions. There are several ways to approach this (depending on other conventions you are using in your worldbuilding).

If you are a fan of the "Age of Fighting Sail", with individual ships largely alone in a vast ocean of space, you amy choose to emulate the American "44 gun" frigates, such as the USS Constitution.

"44 gun" Frigate USS Constitution under weigh

The premise behind the Constitution and her sister ships was to be individually more capable than any comparable European sailing ship of the same class, given the large disparity between the size of the USN and European navies of the day.

Joshua Humphreys' design was unusual for the time, being long on keel and narrow of beam (width) and mounting very heavy guns. The design called for a diagonal scantling (rib) scheme intended to restrict hogging while giving the ships extremely heavy planking. This design gave the hull a greater strength than a more lightly built frigate. Humphreys' design was based on his realization that the fledgling United States of the period could not match the European states in the size of their navies. This being so, the frigates were designed to be able to overpower any other frigate yet escape from a ship of the line.

However, other configurations are possible as well, although what you choose may have more to do with your personal preferences and what worldbuilding conventions you choose to go with. Massive "battleships" capable of carrying gigantic laser batteries or huge railguns capable of firing projectiles at interplanetary velocity (11km/sec+)are an option at on end, while aircraft carrier like ships deploying hundreds of small combat craft are at the other extreme (an old RPG called "Traveller" split the difference with a "carrier" capable of interstellar jumps carrying "Battle Riders"; warships in their own right).

Regardless of what conventions you choose, the key consideration is that ships must be individually capable of dealing with potential enemies without support. They must be fast or manoeuvrable enough to be able to accept or decline combat on their terms, and powerful enough to deal destruction to most likely opponents. In some regards this is more similar to an air superiority fighter like the F-22 (and also can be used to describe the difference between ships, the F-22 would represent a combat platform capable of taking the fight to interstellar space, while the home systems would of necessity be protected by more numerous but less capable platforms analogous to F-16's), but since the ships need to operate without support, the naval analogy is much more suitable.

So the true issue is to examine how the nature of your FTL system works, and derive the second and third order effects from that.

A previous WSE answer looked at some of these aspects: What shape of a ship would be most effective in real life space combat?

Answer 5

There are many earthbound armed forces that fight under similar conditions.

Start with subs. These operated (not sure anymore) with little to no intel, with a mission that is given at the start that may not be viable at the end of a journey, and are/were generally "local only" fighting and recon units.

For example, subs may be deployed to a region, but only have the intel available that existed when they left. They get to their destination and have to carry out orders based on their own discretion. They were usually tasked with things like "sink ships in this area" or "fire nukes if they fire first" etc, and would have to decide the best ways to go about it.

Another example would be the navies of the earth during the golden age of sail. They would frequently be deployed as a single, or small group of units with a task. They may have intel that existed when they were docked, but once out to sea, they were pretty much on their own. There are several examples of "fleets" of sail ships being deployed to the same region with the same goal, and very little communication between them.

You could also use land-based armies prior to the adoption of radio communication. They would be deployed with a goal and a target, but after that, the entire army was kind of a set and forget setup. Attack here! wait for word back of how that objective goes. Generals were given a lot a latitude in most cases to make huge changes to plans and expectations so long as the broader goal was met.

It may be unthinkable today where twitter is a source of intelligence gathering, but what you describe is essentially how war worked until very recently.

So sending out 6 forces with 6 different goals, and hoping for the best seems reasonable. Once they report back you can send out the next 6. Your war would look more like it did in our history, where goals were more disruption and less about holding land, but you could very easily make it work. Just from your description, I would send out my 6 fleets to attack resource gathering operations. Mostly those that produce fuel, ammo, metals (or whatever ships are made of), and of course water and food if applicable. Also, I would look at some less guarded resources, and try to send at least one fleet there. Something like attacking tobacco fields to disrupt the economy.

Answer 6

Small or Single Purpose Vessels are Doomed

Large Multi Purpose Vessels: In combat one has to assume that if something can go wrong it will, and then prepare a plan that allows you to succeed even if the very worst happens. In this case each and every single ship arrives by itself spread out over a long time period leaving each and every single vessel launched totally without support or able to give support to another. This means that each and every ship needs to be capable of being completely self-supporting in as close to every way possible as can be manufactured. I am envisioning mother ships with any smaller support vessels they need to have attached to them. These Mother Ships are part factory, part warehouse, part command and control, and equipped with a truly devastating amount of weaponry.

Smaller Battle-Riders Fighters don't really work in space, were talking about full sized combat vessels that arrive attached to the massive command ship. After it arrives outside the enemy's defensive envelope they detach and form a screen around the command vessel to increase defensive capability and prepare to launch sorties into enemy held territory while recon is gathered.

Drone Swarm Manufacturing Part of the command vessel's manufacturing capabilities involves creating vast fleets of autonomous drones which will be sent into enemy territory first in attack constellations. They are intended to draw fire from defensive emplacements and locate enemy combat assets and force disposition within the battle space. They are not fighter craft, again, because of physics fighters just don't work in space. These drones are armed, but they are not going to be jinking and dodging and swooping. They are intended to be scattered everywhere from hell to breakfast within the enemy battle space and detect and attack enemy defensive emplacements. These drones will be at least armed with nuclear weaponry and multi-megawatt lasers. If they are destroyed before firing its not a complete loss, the larger vessels watching from afar now know where one more enemy asset is located. If it can detect and fire before being detected and fired upon another chink in the enemies defenses has been opened up. Should any survive they can continue monitoring enemy positions and activity like spy satellites and act as an auxiliary com network if needed.

Assault Begins After all this has been accomplished the smaller vessels can begin moving into the system to assault enemy forces, exploit gaps in the defenses created by the initial drone activity, and generally make it safe enough for the command vessels to begin moving into the system to finalize the assault and consolidate their hold over the system. Ideally you would have all or most of the command vessels and their assets available to participate, but each command vessel acts as it's own fleet and is capable of independent operations. This is less than ideal however and the goal should always be to coordinate between these battle groups so that they can provide mutual support and cover, and so that reserves can be held in the "rear area" outside of the enemy defensive envelope should the need for reinforcements or to repel a counter attack arise.

Consolidation of Victory These command vessels are so monumentally powerful, large, and versatile that once a system has been conquered they can act as system defenses if arrayed about the system so that long-term expensive projects like building their own defenses. traditionally forces are most vulnerable when they have recently won an assault, being prepared to defend what you just took is just as important as being able to take it. The automated manufacturing facilities within these ships can begin mass producing the things needed to turn the system into a fully defended staging area for the assault on the next system. These factories can build other automated factories and collect resources to fuel this construction. By the time everything is said and done your ships are repaired, the conquered system is fully defended and you are ready to pass it off to arriving rear echelon defense forces as your newly repaired, refueled, and refitted command ships prepare to jump to the next system and do it all over again.

Answer 7

There's a potentially vital plot point that you kind of elided...the humans have purpose-built warships which, assuming some technological equivalence, are the superior fighting machines. The friendly aliens have impressive but more general purpose vehicles. It may be best to pair them, either using the same jump or staging action nearby, so that you deliver a premium weapon and are still prepared for any unexpected circumstances you might encounter. The forced interactions would unfold into the story.

Answer 8

The solution is simple: you build combinable fleets that detach on arrival.

Instead of constructing the ships as independent entities, you build them so that the entire fleet attaches into one "whole", performs the jump, and then detaches into its separate parts before mounting the attack. This ensures that the entire force arrives simultaneously. You might even include some parts that simply exist to provide jump capabilities to the rest of the fleet.

Answer 9

One of the big dangers for a war (for the participants at any rate) like this is that it devolves into a kind of Rocket-Tag. With a huge battle theatre that is mostly empty space, valuable resources and strategically viable locations are going to be at a premium. Add to that the logical consequence of space colonization and you end up with a handful worlds that are the core of a civilization, and several more that are developing colonies (be they singular research stations around a planet or cities with thousands or millions of inhabitants). These core worlds is where a good chunk of the population lives and, more importantly, where the industrial heart of the civilization rests.

Naturally, colonies are still valuable and must be defended, but in a scenario like this, the primary goal would be locating the enemy's homeworld or manufacturing base. As long as those remain, with these long travel times, you're going to be doing very little damage of consequence to the other party. Sure, you may destroy a fleet here or there, but with travel times in the range of 10 years, the enemy will have rebuilt that fleet by the time you get to the next system.

So a lot of the war would be small scouting fleets or single ships zipping across space with minimal support to find parts of the enemy empire that are valuable enough that crippling or capturing them actually means something. These would need to be ships with FTL capabilities, else your intel will be literally decades or centuries out of date and of such a low resolution as to be practically useless. As a result of how unpredictable FTL travel is, there may be a push for building a large amount of FTL capable scouting drones. This way you can send them all to the same system, have a look around and return, with the hope that some of them return in a matter of days (subjective time), to 'cheat' the time requiredments, as it were.

Once a system like this is located, it becomes a race between the aggressor and defender to get as many ships there to either capture or protect the system, turning the war into a series of very low intensity conflicts between scouting ships and picket ships followed by enormous slug-fests between massive fleets over critical resources. Whoever loses their manufacturing base first is the loser of this war. For a good example, look at a typical 4x game where you'll notice that an early resource advantage can rapidly snowball into a huge advantage later. Losing 5% of your annual ship production capability may not seem like a lot, but that means that your enemy will outnumber you by 5% in the first year, likely inflicting heavier casualties, resulting in a larger numerical advantage the next year and so on.

For these massive battles around critical locations, there are trade-offs to be made with regards to either bundling your fleet or sending it piecemeal. Bundling them, either by coordinating FTL jumps or using large motherships would concentrate your striking power. However, this has the disadvantage that if you're on the wrong end of the bell-curve with regards to timing, your enemy may have years to evacuate or ready their own fleet. Alternatively, all your ships may map the jump separately hoping some of them can "ride a good FTL current" as it were and arrive before the enemy has the chance to set up additional defenses.

Another thing to keep in mind is whether the FTL tech can be weaponized. In theory, if you can speed an object up to 4c, you have an absolutely killer weapon that will likely vaporize a planet if it has sufficient mass. Even if that isn't possible, with the energy output necessary to achieve FTL speeds, there's some fun to be had. It's not inconceivable that once a suitable target is located, the attacker may simply scrounge up several large asteroids, fit them with FTL engines and chuck them at an enemy planet. Jumping a 10-15km diameter asteroid into a planet's gravity well is a pretty good way to cause some major havoc. And because their initial travel is at FTL speeds, there's functionally nothing that can be done to stop them.

In terms of command and control, generals are going to have to keep worst-case scenarios in mind and will often be writing orders for soldiers with the idea in mind that they may not arrive until years after the general's retirement, requiring a whole new scale of planning that is profoundly different from what we are familiar with.