Essay on Realistic Space Combat
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forums.spacebattles.com
In general, we really can't discuss FTL options with the word "realistic" in mind, so we're discussing STL. I'd suggest that in a single system STL setting chances are people will accept slow travel because it's much easier to build a safe, inexpensive transport system that takes months to send people from place to place.
Here's the bottom line -- communications will be at lightspeed, travel will be automated. What do you care if you're sitting in a space capsule traveling to Mars at 300,000km/h (and thus taking quite some time to get there) if you can work, play, communicate with loved ones, and enjoy "feelies" while in transit.
The key takeaway from musings like this is that, at the extreme, Newtonian space combat is very very weird, and will probably be very different from what we might expect depending on the technical details -- which are unknowable. And bear in mind that the article simply assumes symmetrical combat. What if the two sides have different technology stacks?
I should note the article also assumes spaceships with crews launching missiles. Why bother? Your space fleet would simply comprise missiles.
I thoroughly recommend Arthur C. Clarke's Earthlight in terms of fictional treatment of futurist space warfare (but it's asymmetrical).
Before we discuss drive designs, we have to understand what the limitations on travel are for us. There is a very real sense in which we could send a million space ships and not care whether they make it or not, or whether our missiles are conscious and no different from space-ships and so on.
The mass and propellant stuff works out the same, but the practical consequences are so different that it's hard to think seriously about any of these problems, when the actual problem is mind and not rocketry.
Warfare has usually been asymmetrical. We're a bit biased because of emphasis on recent western wars, but historically most wars have been fought between different technologies and doctrines. And asymmetries are likely to be far greater in future.
Incidentally the US navy has been experimenting with drone submarines as torpedo launch platforms for decades, so it's underwater too.
To me the question of propulsion is most interesting, and specifically I wonder how feasible it would be to solve the problem of engine design by using two different engines. Nuclear propulsion looks good on paper, but a ready supply of fissile material is likely to be difficult to obtain.
Lastly we might consider whether or not space combat will happen at all. Spacecraft are very expensive, and the conditions which give rise to warfare on Earth seem unlikely. When your political entities are light-years away from each other, it's hard to have resource conflicts. Or, in a universe with FTL, it's probably hard to have conflicts when you don't have causality.
"The fighter is probably nothing more than a glorified chemical-fueled missile anyway, no more sophisticated in principle than the missiles you already expend by the dozen. You can at least double its effective range by replacing the pilot with a computer and turning it into a disposable missile bus (I say at least because the computer will probably mass a lot less than the pilot and the life support systems necessary to sustain him). It may be able to accelerate faster too, since it’s now freed from the restriction of having to not kill the pilot with bone-crushing sustained G forces."
Also this:
"This means that, unlike in many pop SF depictions, warship crews will probably be quite small. Human beings require a lot of supporting mass in supplies, life support, and crew quarters, so spacecraft in general will probably be heavily automated. A warship will probably basically be a can full of weaponry on top of a big fuel tank, with the crew controlling the thing from a small habitat module. The crew will effectively be command crew; there to tell the machines what to do, not to micromanage the operations of the ship. You’ll probably have a small core crew to fly the ship, a few damage control technicians, and maybe a medic or two. Serving on one will be more like serving on a WWII U-boat than anything else."
Makes me think you actually didn't read it.
Otherwise, a single outage could take the whole fleet down.
Combat like this was described in Joe Haldeman's 'Forever War'[0], IIRC.
Particularly sad are the descriptions of drones that follow a ship for months, years, and nail it right as it is pulling into port. :(
Most of the time I even read books good authors wrote in completely different genres just because they were good (Simmons for example). Even if I usually don't like the genre, the books are still good. On the bad side there is Neal Stephenson...I tried so hard to find the reason why so many like him...
On the other hand though, Heinlein makes a good case for interplanetary war never happening in Time Enough For Love. "The second best thing about space travel is that the distances involved make war very difficult, usually impractical, and almost always unnecessary. This is probably a loss for most people, since war is our race's most popular diversion, one which gives purpose and color to dull and stupid lives. But it is a great boon to the intelligent man who fights only when he must — never for sport."
An interesting digression, but he also makes the case for why a common currency between planets is completely impractical (like was mentioned in the news a year or so ago). The entire book is a great read, and it's probably tied for 1st in my list of favorites.
Dark on the visible light spectrum, sure. But if you have active engines or live crew (or both), you will be much warmer than space-at-large. Asteroids are tricky because they're dark AND cold.
It's a "stealth" ship because of two major things. Its hull's ability to deflect or absorb radar waves, and its heating/cooling exchange which was built in such a way that it can absorb heat into internal heat sinks for a limited amount of time, while cooling the exterior and engine emissions in order to reduce IR emissions.
With the stealth systems functional, you would have to find it by sight, which is hard to do.
They even discussed how the simplest way to disable many civilian craft was to disable their external emissive heat exchangers, since without them you couldn't run your engines for fear of cooking everyone inside. Warships had "tiger stripes" to limit the effect of losing one emissive surface would have on the ship's effectiveness. They also had methods of dumping massive loads of heat by ejecting molten salt (with an magic^w magnetic field collecting the cooled salt near the tail of the craft).
Such stealth ships couldn't maneuver much, but they could only be countered by other stealth platforms in a cat and mouse game reminiscent of Cold War submarine contests.
Maybe the "stealth" weapons of space combat look a lot like blimps.
They use big, cold, dark tanks of compressed gas for thrust. No combustion; just spraying compressed gas for propulsion/steering until they're close enough to the enemy target.
Then and only then, they activate active engines (or fire missiles with active engines) for the attack.
I'm not sure if those physics remotely work. I guess you could at least get up to a few thousand km/hour with a decently big enough tank of compressed gas in space, when you don't have friction or drag to worry about.
Now, keep in mind that any ship bearing humans is going to need to radiate infrared photons at about room temperature, around 300 kelvin.
What this implies is that you want to be using an infrared telescope and look for whatever lights up against the cosmic background. Spaceships would be easy to spot, at least inside of our solar system.
Me, I'm not a physicist and have no idea what I'm talking about, but I do know that if you're looking for a campfire in the desert and the desert is the size of Utah and Nevada, you're going to have a hard time.
Conclusion: you can have stealth ships, and will only be able to counter them by blanketing the volume you patrol with sensors or by deploying your own stealth platforms.
> You have a stealth ship, only detectable by occlusion
From every other angle, the gas/plasma/etc flying out of the cone would still contain the same amount of heat energy, just dispersed over a larger area. Anything more than a few degrees above absolute zero will stick out like a sore thumb, and you'd have to disperse the heat from a single thruster over thousands of square meters to get close to that.
That's where cheap remote sensor networks probably win. For the cost of your single "thermally stealth" warship, your enemy can likely afford thousands of cheap dumb probes that can spot you from many angles.
"Stealth" will probably staying cold as long as possible. An attack ship/missile could be launched on an initial trajectory from somewhere in space by kinetic (rail gun-like?) means. It then remains dark/cold for most of its journey, until it is extremely close to the target. At that point it could launch chaff/flares and close in for the kill.
Alternately (or complimentarilty? is that a word?) another effective strategy might be to park a bunch of dormant ships/weapons around the area you wish to attack/defend. Dark and cold, they'd be nearly undetectable... until they're needed.
You've jumped to conclusions about the kind of drive it would have. Once launched it would only use mass drivers for course correction. Remember: think ahead. Remember also, that these are only supposed to have limited maneuverability.
That's where cheap remote sensor networks probably win. For the cost of your single "thermally stealth" warship, your enemy can likely afford thousands of cheap dumb probes that can spot you from many angles.
If they are so cheap that they are easily detectable, then enemy HQ can calculate a geometry that would preclude your detecting the ship. Also, I'm not necessarily envisioning a full-on warship. Being unmanned, small, and low energy as possible is a win for craft such as these, so they would also tend towards being inexpensive. On the other hand, the "more, dispersed" counter-strategy is disadvantaged by a factor of N^3. An optimal strategy would consist of multiple stealthed units to achieve dispersal/coverage. This way, your enemy is always guessing whether all of their detection platforms have been located or compromised in some way, opening an attack vector to their vital in system transfer orbits. (Lines of commerce.)
"Stealth" will probably staying cold as long as possible. An attack ship/missile could be launched on an initial trajectory from somewhere in space by kinetic (rail gun-like?) means. It then remains dark/cold for most of its journey, until it is extremely close to the target. At that point it could launch chaff/flares and close in for the kill.
Indeed. But without special provisions, such an attack mothership would be highly visible from vast distances, so again there is a possible application of stealth.
> If [the sensors] are so cheap that they are easily detectable
I'm thinking there's no reason that the cheap sensors would be anything but tiny, dark, and cold.
Relatively speaking, this is true. But would basic physics render them tiny, dark, and cold enough in the face of a technological arms race? Remember: think ahead. The opposite side would counter by building IR telescopes with enough sensitivity to detect even the minimal differential in IR emissions and correlate that with other emissions and starlight occlusion. Thus the arms race begins.
Remember that we're dealing with societies with several decades of technological advancement over our own. They would have access to vastly greater computational resources and technological manufacturing. The most esoteric and sensitive sensors available to NASA now would be somehow outmoded by units that could be mass produced. Moore's Law and the like still obey basic physics, but there is nothing in basic physics that ultimately limits detection or stealth. (Maybe getting the blackbody emissions of a unit down to the same level as ambient gas in the solar system?) There would eventually be some balance reached between numbers and individual unit potency, subject to one horrendous cloud of war.
> But would basic physics render them tiny, dark, and cold
> enough in the face of a technological arms race? Remember:
> think ahead. The opposite side would counter by building
> IR telescopes with enough sensitivity to detect even the
> minimal differential in IR emissions and correlate that
> with other emissions and starlight occlusion. Thus the
> arms race begins.
As IR detection improves, it gets easier to detect tiny dark sensors - but the tiny sensors also get the improved IR detection ability, and it really, really gets easier to detect attack ships or missiles that are going to produce heat as a byproduct of acceleration.
Attack ships/missiles that need to carry a payload and/or accelerate will always be orders of magnitude more expensive and easier to detect than a sensor that essentially remains motionless.
And even if Side A knows where all 10,000 of Side B's sensors are located around the solar system, then what? It's a pretty expensive proposition to destroy them. One side could even bleed the other dry that way - for every $1 that Side B spends deploying sensor probes, Side A has to spend $10 or $100 or $1,000 to destroy it.
Ultimately, what the ease-of-detection means in space is that battles will much tougher to win for the underdogs, as it will be harder for them to overcome a deficit in resources with the use of stealth or surprise.
In general. I'm basically arguing that this can be subverted in limited geometric/temporal contexts. Given a sufficiently motivated arms race, it will be exploited.
And even if Side A knows where all 10,000 of Side B's sensors are located around the solar system, then what?
Then if Side B has completely discounted stealth, Side A has the opportunity to circumvent all of Side B's sensors and mount attacks with units that "stay quiet until nearby," as you outlined. Also, if Side B's sensors are so minimalist and cheap, what's to keep Side A from destroying them all, or enough of them to make them moot? If you've completely discounted stealth from a simplistic thermodynamic argument, you've not thought through the nuances.
Ultimately, what the ease-of-detection means in space is that battles will much tougher to win for the underdogs, as it will be harder for them to overcome a deficit in resources with the use of stealth or surprise.
Stealth as I've outlined it isn't going to benefit the underdog. It will benefit the side with the greater industrial and technological resources.
EDIT: Alternately (or complimentarilty? is that a word?) another effective strategy might be to park a bunch of dormant ships/weapons around the area you wish to attack/defend. Dark and cold, they'd be nearly undetectable... until they're needed.
It seems like we're thinking along the same lines. Only in space, there is no reason to limit yourself to distance proximity. There will also be proximity by delta-v. If you extrapolate improving detection technology, there will be a point at which a little bit of active effort will be required to maintain stealth in the face of enemy reconnaissance.
Er, and what does it do with the absorbed radiation? If you assume it can magically not re-radiate the absorbed EM radiation, then its heating up without limit, and so you also need to make it magically able to absorb limitless energy without failing.
Er, previous comment was written for people who think one or two steps ahead. A parabola is great for directing EM energy. (Think searchlight.) The rest was left as an exercise for the reader.
and so you also need to make it magically able to absorb limitless energy without failing.
There is indeed a fail, but not the one you envisioned. (EDIT: Don't feel too bad. That discussion on spacebattles was presaged by similar discussions on USENET in rec.arts.sf.science from over 25 years ago. I have a bit of a head start.)
So its a magic surface where the inside is a perfect reflector and emitter, the outside is a perfectly absorbent and transmitter (to the inside)? That (though it requires multiple levels of magic) solves one problem, but of course then its also a drive system you can't control or turn off that turns all of your internal energy use and all incoming EM energy into thrust in the direction opposite the outlet of the cone, in addition to creating a detectable (by reflection from anything that passes through it) plume of EM emissions from the back end of your ship that will expand in such a way as to be visible even in the area from which your ship itself is shielded from direct observation.
Not a surface. It's a paraboloid shaped machine. (With a "stamen" in the center.) It seems magical to us now, but within the realm of physical possibility, so it's fair game for science fiction speculation.
its also a drive system you can't control or turn off that turns all of your internal energy use and all incoming EM energy into thrust in the direction opposite the outlet of the cone
Yes. It will be tricky to use. Swarms of these units will be implementing strategies devised by AIs in cooperation with interfaced human geniuses, heuristically solving the horrendous geometric and continuous thrust trajectory puzzles formed by the partially and probabilistically known configuration of enemy units. (EDIT: There will also be some mass driver propulsion available, but this will also be limited.)
plume of EM emissions from the back end of your ship that will expand in such a way as to be visible even in the area from which your ship itself is shielded from direct observation.
I must admit I haven't worked out the numbers for how hot these things can get or how concentrated their waste EM plumes can be before it's counterproductive because the near-vacuum gas/plasma starts emitting too much. As mentioned elsewhere in these threads, I'm not envisioning a Star Trek or Star Wars style ship. These are clouds of small autonomous drones. Small size, unmanned operation, and larger numbers are going to be a big win for such technology. In other words, I'm not trying to stealth something big and hot in the first place. (Unless it's the "mother ship" and that will only operate far outside of enemy space.)
Start with clouds of small, dim, but potent drones, then take the arms race in a particular direction.
> objects that like a hostile ship are dark,
> drifting, and small.
The only thing I would add is that I'd presume that if space was popular enough to fight over, there would be several ships flying around on several different trajectories. Between the vastness of space and an abundance of hot targets, it would not be trivial to locate another ship, especially if warships were designed with this in mind.
We generally find near-Earth asteroids the day of their encounter with Earth. This would be all that's needed for a spacecraft to respond to a potential threat.
Image throwing a bag of sand at someone running at you. That sort of thing.
(I once discussed space terrorism with someone - they suggested a good way to hold the world to ransom would be to threaten to fly a spaceship full of sand out of the atmosphere, slingshot it around the moon, and slowly sprinkle the sand out the back effectively making it impossible to put anything in orbit again if the world didn't meet your demands.)
very imaginative and good series to read.
At that point it's a matter of maneuvering randomly to dodge the kinetic kill munitions. Which certainly involves some luck.
I think direct kinetic weapons only work at long ranges against targets with static movement patterns - ones in regular orbits.
Spaceships can easily dodge projectiles coming from long range, as long as they're looking for trouble.
I think the better option would be some sort of missile bus that released this cluster/shotgun munition at close range in order to ensure a hit.
Only outlaws (terrorists, rogue states) would use machine-guns in space.
nope. The perceived danger of dumb kinetic weapon is a relative speed to the target, ie. kinetic energy. It means that either target or shooter has technological ability to control the energy at respective level. Lets suppose both - i.e. symmetric situation of the same technological levels on both sides. Thus the opponent can deploy similar energy level devices as a defense. For example - today an anti-ship missile can be fought against by using anti-anti-ship missile or guns. New laser defense systems are able in realtime to defend against incoming mortar round today, etc... By the time somebody puts sand in space, an automated laser space junk frying Roombas would be just naturally flying around.
In that book, a colony on Mercury is attacked through the use of several billion pebbles that were flung into the solar system in a calculated way such that they all converge on the colony several years later and the kinetic energy they gained going down the gravity well combined with the sheer mass is a devastating attack and totally undetectable (a single pebble would just burn up in an atmosphere or be a consideration in colony design on an atmosphere-less planet like Mercury, so why monitor it? Billions of them would form a destructive plasma cloud if aimed at Earth or simply a kinetic energy weapon against Mercury).
Further, the author discounted kinetic energy weapons too easily. A rail gun in space would not have to worry about air resistance limiting the range or impact magnitude of the rail slug, and so would be a very effective weapon in ship-to-ship combat (or more likely, railgun installations on satellites aimed at the intruding ship).
Taken together, I think space warfare wouldn't involve ships as we know it at all. It would be planets firing at each other similar to ICBMs between countries today, with drone-like mobile weapons platforms with stealth that are launched as part of commercial launches and placed via gravity slingshots (and so can be as cold as space until an activation signal is sent to it, allowing stealth tech to actually work). These would be placed near potential enemies and probably allies alike, and would be used both offensively and defensively: if an enemy makes an open attack, they would target the attack itself, if they attack, it would reduce the potential response time, though it could not be as significant in magnitude as a massive attack launched from the planetary surface.
(Warning: The book is really not a good first one to read from Kim Stanley Robinson, as it explores some of the more esoteric elements of the Mars Trilogy even further, with a focus more on how technologies of all types, especially bioengineering and artificial intelligence, would affect societal norms, and is far enough away from our current norms that it'd probably "gross out" people ill-prepared for it. Better to read the Mars Trilogy first and follow the line of reasoning that produces the kind of society in 2312, I think.)
I thought of another attack vector: systems disruption - hacking, if you like. It has the advantage of working at the speed of light (so being easy to aim), energy efficient, and relatively hard to defend against.
At the crude end of the spectrum we have blanket 'denial' attacks: flooding the enemy ship with huge amounts of EM radiation aimed at knocking something important out. Idea here is that while lasers do much the same, they work simply by melting the hull. Using other frequencies may present the opportunity to selectively overload important systems, zap internal electronics, or disrupt sensitive and hard to shield components like targeting sensors.
More refined approaches might involve penetrating shipboard networks using the enemy space navy's command & control infrastructure. There's no need to describe the arms race of exploits & countermeasures which would result.
Interstellar travel implies access to plant-scorching amounts of energy, and that, again, puts warfare into MAD WMD territory right off the bat. War will be short, genocidal, and boring in a realistic vision of the future.
Hard science fiction inevitably leaves behind many aspects of today's life, including current and merely extrapolated ideas of warfare and military power. That's what makes it interesting and difficult. That's also what makes pseudo-hard science fiction unsatisfying.
Don't cross the street to get your ass kicked.
Well, each of those detectors is also a space mine and/or missile. Wrap them in black velvet. Make their power supply a dual-purpose radioisotope battery and nuclear bomb. Space combat essentially becomes swarms of exploding robots trying to destroy each other, such that the attacker can get a relativistic kinetic missile to the significant target without being intercepted and deflected.
There are no capital ships, no fighters, no scouts, or anything of the sort. You just have clouds of smart missiles trying to influence the targeting of the planet-killing rock.
Also, where were the "sand shotguns"? It's fine to consider missile swarms that overwhelm your target's missile defenses, but if you throw a trillion micrometeorites at your opponent, he's going to have a bad time. Besides that, it is also reaction mass, usable for maneuvering your own vessel.
In term of definition of objectives mainly. If the objective is to exterminate another civilization, why not just launch an infinite number of small vessels that will crash on planets, space station and space ships? If it's controlled by an IA, who cares? the only thing which will matter will be economical sustainability.
if the objective is to take control of a planet or a solar system, you are going to need big vessels, troops and other SF concepts. But I don't think anyone will care to take control of population. They might care about ressources and installation. Everything is so fragile, that it wont make any sense to try to gain control of it, the odds that every will be value-less at the end of the fight are simply to high!
Once is enough. The Soviets annexed Czechoslovakia with civilian airliners on scheduled flights full of heavily armed, bloodthirsty Spetsnaz. Once you get a foothold you can bring in reinforcements at your leisure.