Factual space fleet composition

[spartasman]

I've been wondering what a realistic space-navy would be composed of, without the use of any of the 'magic' technologies that seems to pervade science fiction (I.E. Inertial dampeners).

What would a space fleets composition look like based simply on the extrapolation of currently existing technology? that means no anti-matter engines or the like, artificial gravity (at least without centrifugal force), or energy shielding.

Without those things, what sort of doctrine and what types of ships would be most effective in space combat?

[Eleventh Century Remnant]

In addition to physical realism, a sensible answer to that question is also going to have to deal with political realism. Probably even more so. What purpose is the fleet intended to serve- what is the strategic objective, what is the threat, what are the legal considerations, how many cubic miles of paper will it be necessary to wade through to screw the money for something so fantastically expensive out of Congress or the Treasury? The actual hardware is likely to be the simple, fun part.

At the moment, and until something thoroughly extraordinary happens- like every nonproliferation treaty ever spontaneously combusting and nuclear surface to orbit becoming legally and politically feasible again- space hardware is even more ridiculously costly than military hardware in general, and there is a very, very low level of genericity to be had. Everything is a one off, a bleeding edge prototype. (a slight overstatement, maybe, but close enough for jazz.)

You can count on one thumb the number of spacecraft designs that have flown often enough for it to be possible to consider them out of the experimental stage- Soyuz, and that's it.

Although, space robotics is fairly far advanced- we've sent robots to a damn' sight more places than we (humanity as a whole, of course) have sent people- ah. What types of ship would be most effective in space combat? Unmanned ones. No complicated plumbing to lug along, lighter, cheaper, can safely be sent into harm's way or on one way missions, can be made advanced enough to follow a plan a lot more easily than a ship could be built to send a thinking, on the spot human.


Assuming there isn't a massive non sequitur in the phrase "realistic space-navy". There's a fair chance we (again, the human race) simply aren't going to make it, there will never- not until the fall of the present and the rise of a new set of civilisations, anyway- be enough of a human presence beyond the atmosphere that interplanetary power projection even becomes anything more than daydreams.

Of course, there is the situation where orbital space is controlled/threatened by air and surface launched ASAT missiles- could be done now, has been. Debris is a wonderful thing, yes? This is really just an extension of business as usual.

Next most probable case; robotic lunar and asteroid resource extraction, robotic orbiting solar power, none of it armed, and no space navies, only armies of diplomats and space lawyers.

Then we get down to power- projection probes, probably ion drive or something similarly efficient and high delta- V, simply armed- modern day aircraft cannon should be enough, we're not looking at fantastic manoeuvrability here.

Manned, combat, spacecraft? Ask me again fifty years ago. Or in five hundred years' time.

[spartasman]

I didn't ask what conditions a space fleet was feasible, I asked what a realistic space fleet would be composed of. If the United States built a big moon-base or started colonizing mars, and China or Russia or whoever was trying to do the same, what types of ships would be useful in space?

[GrandMasterTerwynn]

I didn't ask what conditions a space fleet was feasible, I asked what a realistic space fleet would be composed of. If the United States built a big moon-base or started colonizing mars, and China or Russia or whoever was trying to do the same, what types of ships would be useful in space?

In order to answer the latter, you have to answer the former, you pedantic twit. Those conditions dictate what sort of space fleet is going to be built. And even then, building a spaceship whose sole purpose in life is to go and kill other spaceships . . . makes little sense. It's extremely expensive to move things around if you're in a hurry, and your definition of "hurry" may not coincide with the definition of "hurry" you could afford under the laws of physics.

To whit, a realistic space military power projection force will consist of unmanned drones. Small unmanned drones. Since you don't really care if you get them back, you can put all of the drone's available delta-V into making haste. Each encounter with whatever you plan to shoot at will be a flyby, but the drone will dispense a number of guided sub-munitions at some predetermined point. These will impact the target, and rely on kinetic energy, and the fact that space structures will be built light, to get the job done. That's assuming you don't find some cyberwarfare exploit in your target's systems and take control of their life support, or something like that.

Since, realistically, space travel will be a leisurely affair, your opponent will know that your drones are coming for weeks or months in advance. They can try to shoot them down with railguns, but that's why you dispatch a whole swarm of them. Then, during transit, you try other methods . . . like cyberwarfare. Or negotiations with the drones serving as your threat. You won't send the troops in until after your first few waves of drones have had a chance to smash as much of their shit as possible. And the troops will come in a ship that isn't really all that different from a "civilian" passenger-carrying spaceship. Only this one might have some modules docked to shoot missiles, or possibly a high-energy laser to be used to defend against any incoming projectiles.

[Purple]

The issue is that you can not separate the two questions.
In order to determine what the composition would be you have to first find the conditions under whom it was made.
The conditions directly dictate the composition of the fleets.

Also, under the conditions you mentioned just now I doubth there would be a space fleet at all. Mars or even the moon are large enough to share for the forseable future and a joint venture would be far more likely than a space war.

Furthermore, as long as you are dealing with nations from earth alone, any conflict would not be decided in space but on earth.
Hence, you would not need a space fleet at all since no one would dare to go to war like they don't now. And there is no need for force projection in space since there are no space terrorists and the like.

[Connor MacLeod]

I'm not sure we can decide what "realistic" is, since we have not actually built any space ships in the context that the question requires (when and if we do is another matter entirely.) I know there are people (or entire groups of people) who devote time to this question the same way I do to 40k (Or Mike/Curtis used to Star Wars) but the arguments over what "space war" will be have yet ot be satisfactorily resolved (I dont think they have even decided the "lasers vs missiles" bit, and the fighter issue has been revisited more than once.)

What it will amount to is "plausible", and that is entirely a function of internal consistency and what sort of tech base you want to give the universe in question. Efficiencies, engine types and power, the kinds of powerplants and weapons you use, etc. will all affect how warfare is going to be, nevermind the aforementioned political or other "human" factors (EG irrational ones like "honor bound warrior culture" or "religion" or "ideological purity" or something else silly.)

[Eleventh Century Remnant]

I know, but unfortunately it really is the same question. Feasibility determines composition. For instance, for that hypothetical moon base (and you know that's not going to happen before 2050, if it happens at all)- unless it's completely self sustaining, it has a very obvious vulnerability.
Why build a multi- billion dollar warship that might not even succeed, when you could fire a relatively simple probe- style missile, a Cassini with a warhead instead of a lander, for less than a hundred million? No less obvious, and probably no less effective.
Or spend a mere million or two, and nail the supply ferry with a simple, practicable-now ASAT missile before it leaves earth orbit.

Oh, and don't forget starting World War Three into the bargain. One thing space warships are not, are never going to be, is deniable. Any open use of force is going to be a shout-it-to-the-world obvious act of war, against someone who by definition is also a spacegoing power and almost certainly nuclear. "Accidents" and brinkmanship may happen, certainly will (if anything happens at all), but there is a line.

Robots are cheaper than astronauts, and depending on how the law shakes out, killing them might still be the right side of the line- property damage, no casualties. So, yes, something like a Cassini probe with an excimer laser- or at the least some kind of weapon pod- in place of the lander and scientific instruments is likely to be the long range backbone of the United States Space Navy. Within the earth-moon system, missiles fired from the planetary surface should be enough for power projection.


I know that's not the answer you wanted to hear, but when it comes to realistic space, there has been so much dead time, there were so many missed opportunities, there are so hopelessly many glorious possibilities foregone and bypassed and lawyered-out and turned to shit that I've just got no optimism left anymore.

[keen320]

To the best of my knowledge the only armed spacecraft/station was Salyut 3.
http://en.wikipedia.org/wiki/Salyut_Program
Apparently they put a small 23 to 30 mm cannon on it and test fired it a few of times before de-orbiting. It's claimed to have had success shooting down a satellite.
I don't think it could possibly qualify as a warship by any stretch of the imagination, however.

[Eleventh Century Remnant]

Even funnier than that, http://www.astronautix.com/craft/polyus.htm- a complete failure of an (automated) orbiting battle station launched by Energia, ended up assbackwards in orbit, the sensor supposed to tell it that had never been tested, so the first automatic correction burn intended to stabilise it's orbit re-entered it instead. Oops.

[spartasman]

well, I suppose my question has been answered then. I suppose there is a reason then that a sci-fi story has to pull things like 'inertial dampeners' and such out of its ass. Good to know.

[Simon_Jester]

The problem with the question is that it can't be answered in the "in the foreseeable future" sense because no one has a clear picture of what a "foreseeable future" space presence large enough to merit dedicated military tools for attacking it would look like; ECR is right on this point.

If we posit a more distant future where the political and technological context allow significant exploitation of space, such that armed platforms become useful... well, at that point there will inevitably be now-unknown technologies thrown into the mix even if they're not outright magic like "inertial dampeners."

I mean sure, someone could design a 'space battleship' on paper; it's actually been done on some level. But there's no way to predict the context in which such a thing would be useful, and the sheer cost of building the thing now makes the idea that anyone would do it now laughable, given that there's nothing up there for it to shoot at or fight.

So you could describe "realistic" space warships that use only technology we know can be created. They'd probably look like very sophisticated missiles, because crew capacity is a waste of tonnage on any militarized platform smaller than an Orion drive... and because at the rate computers are developing, the gap between a human brain on the spot and a robot on the spot is liable to close faster than the expansion of space infrastructure.

[lucretiabrutus]

I suggest Atomic Rocket as good reading for a starting point, since most of the site is dedicated towards realism. Added to that it's a very entertaining read.

Quite apart from political necessity, technology is an important ingredient to consider for your composition. Do you have lasers that can remain tightly collimated for an AU? What kind of fuel do you use? How much fuel does the fleet carry (which determines what its delta-V is)? Are your battlefleets entirely robotic drones with sophisticated AI, or do you need a manned control ship to guide them? How cheap are ships in this universe? How cheap is energy? Do you have mass antimatter production, or is this not used? Does your fleet attack planets or other fleets? Do planets utilise ASat weapons? Is it a peacekeeping fleet, or a full-blown military endeavour? Is it a police force? Did you recently encounter an opposition, or has there been time to build a lavish fleet?

Every single one of these question will influence fleet composition.

[GrandMasterTerwynn]

well, I suppose my question has been answered then. I suppose there is a reason then that a sci-fi story has to pull things like 'inertial dampeners' and such out of its ass. Good to know.

Handwaving isn't strictly necessary. One could write a political thriller where you have a couple of orbital habitats feuding over something or another. Say a political marriage between two ruling oligarchies has failed (since democracy in SPAAACE is not guaranteed.) Since you could have any manner of cybernetic and genetic alterations done, and with friendly AIs wandering the solar system, these agents could slip into the opposing orbital habitat posing as someone from a neutral power. And then they try to break into the habitat's central systems and hijack the life support, or the pointing systems that keep the habitat's solar arrays aimed at the sun. Or, even more sinister, they're trying to disable or reprogram the mirror or laser array used to deflect large space debris/runaway barges/potentially hostile drones in preparation for a drone attack. And on the other side, you could have the habitat's own internal police force trying to stop the sabotage. Or perhaps there's a loose coalition of powers that has a Space Patrol, and the Space Patrol's agents are the ones trying to stop the saboteurs.

Or you could write a story revolving around the tense negotiations between two opposed space powers, who are trying to hammer out an agreement, while under threat of incoming drones. Either they agree on something and remote-kill their own drones, or they face MAD.

You could even have stories of space piracy in a hard ultra-plausible sci-fi setting. Only instead of Space Pirates with PEW-PEW laser beams, you have pirates who wait until important passengers or crew from a transport liner leave the secure area of a spaceport. Then they abduct them and hold them for ransom. Or they have crackers who break into the ship's computers, shackle the AI and threaten to set the nuclear reactors into open-loop if the ship's owners don't pay their extortion fee. Or else, they're working on the inside, draining company funds through traditional embezzling. And you could have locals, or a Space Patrol who has agents on the ground, trying to break the piracy ring.

None of this requires writing stories with PEW-PEW laser beams and gravitonic super-tachyon subspace neutronium-annihilation gamma-handwavium plants.

[Simon_Jester]

Yeah. As I said, you can design combat spacecraft using realistic technology (which, for the sake of argument, I'm going to say excludes anything we couldn't design starting right this minute, so fusion reactors are right out). It's not impossible to design such a thing. The problem is that we are so far from the kind of interplanetary civilization that would need such things that the social context can't be projected forward: we can't guess what they'd be for and why we'd be using them.

That's not a problem that goes away when you posit handwave technology, really; it's just that we can't easily predict a path from the present we know to a future of Space Wars.

[spartasman]

From what I can glean from all of this, the most probable space warship even relatively possible in the near future would pretty much just be a space station with point defense lasers, missiles, and perhaps a few drones. Is that correct?

[sirocco]

Or a weapon platform with plenty of drones followed by a transport ship. You may add some support ships for maintenance, growing food or mining materials from asteroids, etc.

This is basically a self-sufficient fleet for long term missions.

[TOSDOC]

well, I suppose my question has been answered then. I suppose there is a reason then that a sci-fi story has to pull things like 'inertial dampeners' and such out of its ass. Good to know.

There are plenty of stories out there that do great without inertial dampeners--they're a magic gimmick so TV Sci Fi never has to paint their actors' outlines as red smears on the wall when things go wrong. It just all depends on the setting you're looking for:

Present day Earth trying to meet an alien invasion in orbit? Give Footfall by Larry Niven and Jerry Pournelle a try. Although the Michael might now be more automated in today's age than outfitted with a manned crew, like a big Predator aircraft. The advantage of Michael's crew was onsite human reaction to changing situations, and dealing with damage control.

Not having magic shields or inertial dampeners makes even warships vulnerable in space combat to things that are merely moving very rapidly towards it. You might enjoy the Aliens: Colonial Marines Technical Manual for a military doctrine that takes limits of technology into account when dictating space combat. Without shields, and limited by fuel and committment to a vector once begun, warships take on an assassin mentality different to Star Wars' carriers and fighters. Ships lie in wait for an enemy, giving nothing away until the last minute when their missles or kinetic weapons can be fired without missing, not just because it's expensive but because resources are limited and even a small strike can cause catastrophic damage.

[hongi]

Present day Earth trying to meet an alien invasion in orbit? Give Footfall by Larry Niven and Jerry Pournelle a try. Although the Michael might now be more automated in today's age than outfitted with a manned crew, like a big Predator aircraft. The advantage of Michael's crew was onsite human reaction to changing situations, and dealing with damage control.

Is an Orion feasible in the first place?

[TOSDOC]

Is an Orion feasible in the first place?

That's a good question. If you mean technologically, I'll leave that to the engineers, but this article and its links made for very interesting reading. It's true this is one of Eleventh Century Remnant's untried space vehicles, due to the Atmospheric Test Ban Treaty among other obstacles, but the premise was tested successfully using conventional explosives:

http://en.wikipedia.org/wiki/Project_Or ... ropulsion)

If you mean politically, socially, and economically, I'd say not at our current state of world affairs. Footfall's state of affairs was much more extreme, and the situation in that story called for getting a battleship in orbit by any means necessary as soon as possible to regain air and space superiority. In that case only the technological limits had to be overcome, and they did so with remarkable ingenuity.

[Eleventh Century Remnant]

Oi! Don't blame me for the failure of Project Orion...

For as close as the internet is likely to get to the Encyclopeda of the Real, there's http://astronautix.com/index.html- the main entry on the Orion confirms that while the physicists thought it was great, the project manager wasn't predicting flyable hardware before 2010-2030, and at least one person- a mathematician- thought "Zis is not nuts, ziz is super-nuts". There are numerous entries on various aspects of the project- use the alphabetical index, the search function doesn't work- as well as various other projects and articles that have gone by the name.

Personally, comparison with various other projects suggests it would not have been easy, apart from anything else the designers saying 1964 and the project engineer saying 2010 does not sound like a well integrated program, but the propulsion physics were sound, there's no cheaper method of getting mass off earth; the legal concerns, the test ban treaties ultimately being intended to preserve MAD, the private legal concerns in particular- Orion was much less of a rad- spewing monster than usually represented, cleaner than most atmospheric tests, but that's still a hell of a lot more than none.

There were many different sizes of Orion design, ranging from endoatmospheric explosive powered testbed past could have been got off the ground by the first stage of a Saturn V, through fifty men to Pluto (and think of the age this would have been happening in before quibbling with "men")- up to twenty million ton starship. Basically, they would not have been plain sailing but they were well within the realm of the physically practical, international law prevented them happening, and in a metaphorical way they were shot down by the oldest and probably most effective strategic weapon of all, Fear.

For that reason, and for the purposes of the thread, Orion fails the practicality test, as do most nuclear rockets.

Chemical propulsion, sheer cost holds practical size and reach back to the realm of the armed probe/drone ships already discussed, and dirty work becomes a much cheaper alternative.

Then there are further out possibilities like the ideas NASA's Propulsion Research Laboratory get paid to think about, electric ion and plasma drives that could be real- could have been real a hell of a lot sooner- if actual time and money were invested in them, and maybe ideas like Mach- Lorenz Thrusters, Heim- Droscher Theory- which may actually be testable, and if true will make space a very different and much more accessible place; all that is probably too far out on the fringe to consider factual, though.


There's an idea we've been missing; solar sails. They have been inching micrometrically towards the practical since the late sixties, deserve to be real, and pose interesting challenges. For one, the sail might be the weapon, if it can be made to flex enough to focus on a small area. Magnetic wire with thin reflective material laid over it, an interesting plot could be made out of that.

[Eleventh Century Remnant]

The economics of chemical launch are easier to find than things like the production cost of bombs; try http://www.theculture.org/rich/sharpblu ... 00066.html- not sure if the picture will import, but

The cost of "interface" transportation between the surface of the Earth and low orbit is the determining factor in the feasibility of many schemes for space industrialisation. If access to space is sufficiently cheap, then not just mining operations (as described in part one of this series), but solar power satellites, scientific outposts on the Moon, voyages to Mars and even cities in orbit would become affordable. Unfortunately, very little progress has been made in the development of cheap launchers. In 1996, it cost $11.8m (2002 dollars) to put a tonne of payload into low Earth orbit using an Ariane 5 rocket. In 1962, it would have cost $13.3m (2002 dollars) to launch a similar payload with a Titan 2 rocket. Decades of technology and billions of dollars of development costs separate the rockets we use in the twenty-first century from the workhorses of the early years of the Space Age, and launch vehicles are no more cost effective than they were.

Some features of the history of launch vehicles are readily apparent:

•The price of launches has only rarely fallen below $10 million per tonne (the low stated price of the Proton 8K82K is most likely an artefact of the Soviet system rather accurately reflecting the high value offered by that vehicle).
•There are relatively few heavy lift vehicles (the now obsolete Saturn V and Energia, the Shuttle, the various Titan variants), and a large number of launcher types adapted to more moderate payloads (in the region of ten to twenty tonnes).
•Since the early 1980s, there has been a steady fall in the price of launches towards prices reminiscent of the Titan boosters used for moderately massive payloads in the 1960s and early 1970s.

On the other side, http://www.islandone.org/Propulsion/ProjectOrion.html, from which

Does it make any sense to even think of reviving the nuclear-pulse concept? Economically the answer is yes. Pedersen (55) says that 10,000-ton spaceships with 10,000-ton payloads are feasible. Spaceships like this could be relatively cheap compared to Shuttle-like vehicles due to their heavyweight construction. One tends to think of shipyards with heavy plates being lowered into place by cranes. How much would the pulse units cost? Pedersen gives the amazingly low figure of $10,000 to $40,000 per unit for the early Martin design (56); there is reason to think that $1 million is an upper limit (57). Primarily from strength of materials considerations, Dyson (58) argues that 30 meters/second (about 100 feet/second) is the maximum velocity increment that could be obtained from a single pulse. Given that low-altitude orbital velocity is about 26,000 feet/second, around 350 pulses would be required (59). Using $500,000 as a reasonable pulse-unit cost, this implies a "fuel cost" of $175 million, cheaper than a Shuttle launch. Whereas the Shuttle might carry thirty tons of payload, the pulse vehicle would carry thousands. If one uses the extreme example of spending $5 billion to build a vehicle to lift 10,000 tons (or 20 million pounds) to orbit, the cost if spread over a single flight is $250 per pound, far cheaper than the accepted figure of $5,000 to $6,000 per pound for a Shuttle flight.

Going by the best numbers available, you're flat out wrong. Pulse units are much cheaper than you seem to think, and not having to design down to the extreme limits of precision and weight- saving required by conventional aerospace is cheaper still- by at least a factor of twenty-five.

[TOSDOC]

Oi! Don't blame me for the failure of Project Orion...

Wouldn't think of it! Please don't misconstrue!

No, sir. Is it Jane Fonda I'm thinking of instead?

[TOSDOC]

On the other side, http://www.islandone.org/Propulsion/ProjectOrion.html, from which

Thank you for those figures, that was some article. It's gratifying to see they were attempting orbital rendezvous via Saturn V's as well as working out launches from the ground. But the cost analyses are amazing--I wonder what they would be after adjusting for inflation.

[Eleventh Century Remnant]

Well, I can see that D13's obviously a fan of Valentin Glushko- the engines strapped to that goalpost must have developed at least 330 seconds Isp.

Going from

Eleventh Century Remnant wrote:
there's no cheaper method of getting mass off earth

That's insane. The only way it could be cheaper than the plain alternatives is if you either don't count the cost of the bombs or use cheaper material figuring its negligible mass anyway.

to

Stop right there, we're talking about different settings. I'm assuming space to space transport, which is a whole different beast than Earth launch.

is at the very least slipshod and a failure of comprehension.

Reinforced by failure to read the title of the linked paper- "Project Orion; Its Life, Death, and Possible Rebirth"- mistaking an apple for an orange, or possibly the other way around, the paper is present tense, intended to convince that Orion is worth doing now, and the references are to current (at the time of writing) costs for both, and actually a worst- case for bombs. Not a valid objection.

As far as the book "Atomic Audit; the costs and consequences of US nuclear weapons since 1940" goes,

First, what did nuclear weapons cost the United States? From 1940 through 1996, we spent nearly $5.5 trillion on nuclear weapons and weapons-related programs, in constant 1996 dollars.

, but

In fact, when we add the cost of deploying offensive delivery systems to those of defensive weapons, along with the costs associated with targeting and controlling the arsenal, we find that 86 percent of what was spent was spent on building a variety of launch systems and ensuring that not only could they be fired when ordered to do so but, more important, that they would not go off unless valid launch orders were issued.

Which goes some way to set

57. Kenneth A Bertsch and Linda S. Shaw, The Nuclear Weapons Industry
(Washington D.C.: Investor Responsibility Research Center, 1984),
on p. 55 state that warheads for 560 ground-launched cruise missiles
were expected to cost $630 million. Not only were these military
weapons but they were quite likely fusion devices as well and so would
be significantly more expensive than simple fission bombs.

in context.

And for chemical rockets, pray tell; how? Exactly how do you reduce the cost of chemical surface to orbit by a factor of twenty-five or more? Given that the ten thousand dollar to orbit figure is the nearest rough estimate of a historical average of what turned out to be practical- for this to be true and more than wild assertion, three thousand (the likely Isp of an Orion rocket) has to be the same as 476 (hydrogen-oxygen chemical). Two plus two still doesn't equal five.

[spartasman]

Here's a question. How expensive would it be to transport manufacturies to a base located on the Moon (Moonbase construction not included) and assemble a ship there? Surely the lower gravity would require less fuel to launch?