Whay would real-life war spacecraft look like?

[Jouni]

Yep, I agree with you, and I add that space battle ship will be huge (well not that huge... just as big as an aircraft carrier) not because it will be bad-ass (but still) but it will be required for heat sink purpose. A huge vessel with a lot of radiator can bear more guns than as smaller compact craft that will overheat after using it main guns, assuming the gun will produce a lot of heat.

If the principal weapons are frequently firing direct-fire weapons, such as guns or lasers, ships should be cheap and small. Lanchester's square law applies in such combat: an n-fold advantage in quantity is equivalent to an n²-fold advantage in quality, with 'quality' meaning the rate at which a ship can destroy or disable enemy firepower.

[Hary R]

If the principal weapons are frequently firing direct-fire weapons, such as guns or lasers, ships should be cheap and small. Lanchester's square law applies in such combat: an n-fold advantage in quantity is equivalent to an n²-fold advantage in quality, with 'quality' meaning the rate at which a ship can destroy or disable enemy firepower.

It's not only about the gun but all the system behind, the generator (probably a nuclear one), the computers, life support for the crew,etc... so an efficient craft that not only can have good weaponry but also have the heat sink to maintain all the waste heat at an acceptable level during engagement will have some size to contain all those radiators according to our current technology.

[magnemoe]

It is easy to make a human like AI. The problem is just that we need dozens of supercomputers to let an AI think as fast as a human does. An artificial neuronal network works basically the same as a human brain. They already use them today for OCR and image analyzing because neuronal networks are very good at pattern recognition.

Mix it with a semantic web (structured knowledge database) and an suitable ontology (for processing the knowledge database) and it will eben be able to draw conclusions out of data and gather new knowledge.

Finally add a rule engine & rules or a Bayesian network or an evolutionary algorithm (or all of them) to lay out tactics and strategies.

We already have what it takes to make an AI. Even human like. But do we really want a human like AI? A human has flaws.

Computers and hardware can be hardened. Jamming and hacking won't be a problem.

If it really is a serious problem a hacker would already launched a nuke by now.

None has ever coming close to make an human like AI, as I understand they aim for something like an mouse brain.

Insects can do image analyzing pretty well.

However something like an mouse brain connected to an expert system should work pretty well. Main problem is to avoid your AI system to be outsmarted on the strategical level, secondary if you want it to do political level decisions, its an question about light speed delay really, inside an solar system you could probably do with AI outside of main base even if an closer base might be practical anyway.

Agree that hacking is not an serious issue, jamming can be avoided with directional signals something you have to use anyway outside of short range.

[kerbiloid]

[Guest]

Human mind = versatile but slow to react

Programmed AI = quick and lightweight

not even talking about all the different tasks an ai can do at the same time..

Having a fleet has no purpose, except making your belongings easy target for a big nuke. The only meaningful case is to defend an asteroid mining facility or the earth itself ^^,

but even then you don't need to stack them side by side like boats.

Keep in mind laser weapons even missiles can hit from huge range in space very accurately

But the real question is why bring war to space??? That's a very bad idea

[KerikBalm]

X ray lasers....

Soft x ray lasers with grazing incidence mirrors, and a 20 meter focussing array.

Firing multiple gigajoule pulses..... deadly out to several AU.

With an IR telescope that can detect the heat/blackbody radiation given off by ships.

How is your slug thrower going to compete about that?

Once battle is engaged, you have to contend with lightspeed delay, your target can randomly manuever to dodge, as can you.

The first ship to exhaust its reaction mass or heat sink loses.

[kerbiloid]

Having a fleet has no purpose, except making your belongings easy target for a big nuke.

From another side  not having a fleet means you can use 1-2 ships of all your navy at once (as the rest of them will be to far away from the action place.)

And if an opponent has 5 of them, he'll eliminate such fleet ship by ship.

Another point: how 100 ships could orbit a planet if their orbits are thousand kilometers one from another (i.e. absolutely no synchro).

I.e. any space navy would be:

1) either a chaotic cloud of ships around a planet being eliminated one-by-one by a small pack of brave space pirates;

2) or a single compact target for a big bada-boom.

Generally, I think that any space warship will be operating in low orbit. There's no point operating in empty space, and interception in a transfer orbit is hard

Except of any air (even not space) nuke under it would immediately get it.

Launched from a farmer's garage.

I imagine that "space fighters" would actually be orbital spaceplanes, capable of fighting in space, but primarily optimized for atmospheric combat.

As "flying submarine" projects of eartly 20th century. With the same result.

Soft x ray lasers with grazing incidence mirrors, and a 20 meter focussing array.

Xray lasers don't use mirrors.

20m mirror would be a lovely target for a little but smart anti-mirror cannon.

Edited November 25, 2014 by kerbiloid
corrected due to multiple quotes

[prophet_01]

Depends on the purpuse. Aside from engineering and logistic challenged, it's not going to be all that different from naval warfare and the changes that are happening there today. From a tactic/strategic point of view you would mostly rely on drones and missiles. Those will have a limited range and/or need refueling and maintenance. In earh orbit it's likely to be somewhat similar to the current X 37B.

But once you leave earth orbit you will run into big problems. The signal delay would force you to either make your systems more autonmus than usual (which is not going to be easy to sell to the public nor is it easy to set up) or use crews on site which rediculusly expensive. But if you would actually want to perform military missions outside of earth's orbit you are very limited anyway. What is the use of a system that has a deployment time of years or months at best for the most basic capabilities? Long duration miliary operations also tends to damage or destroy assets and if the replacement and resuply (materials/ammo) has to be planned months ahead it's easyer to just destroy the enemy launch facilties instead of a combat in deep space. As long as humanity is mostly living on earth and also most economic activities are taking place there this is not going to happen.

At least for the next decades it's unlikely that there will be more than a couple of unmaned military toys in space. A cold war scenario with the deployment of weapons of mass destruction in space is the only plausible scenario I see that might result in larger scale miliary activity.

If you are talking about distant future war after colonising planets etc., you can't do much more than guessing. Since it's not even clear that ftl is possible at all. Stuff like the possibilty or impossibility of ftl communications or engines would significantly affect the subject. I'm not even talking about the question"what exactly are the operations goals?". Peacekeeping or a simple destroy enemy targets are 2 very different areas

Edited November 25, 2014 by prophet_01

[*Aqua*]

Main problem is to avoid your AI system to be outsmarted on the strategical level, secondary if you want it to do political level decisions, its an question about light speed delay really, inside an solar system you could probably do with AI outside of main base even if an closer base might be practical anyway.

You want to let a computer work out strategies? I think no army general would allow that.

Keep in mind laser weapons even missiles can hit from huge range in space very accurately

That's what I think, too. Want to destroy satellites orbiting Mars? Scan it's orbit, shoot a few lasers and within 20 minutes or so everything will be toasted. Defending against that isn't possible. The moment you detect the lasers shooting they already heat up everything which is flying there. And then it is too late. We all know the

of the US Army in which they destroyed a drone within seconds with a laser. That's only the beginning.

You may need missles to bombard the surface. But they will take a much longer time to reach the planet (weeks? months?). I don't expect them to reach their targets as I'm sure there are some ground based lasers (or something other) which can shoot them down in time.

That means a stalemate after the first attack. Nothing will hit the Mars ground and lasers from Earth will probably dissipate in the Mars atmosphere doing no damage (if there will be no obscene overpowered laser).

Edited November 25, 2014 by *Aqua*

[Frozen_Heart]

Well I'm going to assume you mean something with current technology that could be built in the next 10 years.

In reality this is going to simply be a satellite with a few missiles attached. It will also have a decent amount of dV to maneuverer into the correct orbit to destroy enemy satellites.

A few years on from that things get tricky. I'd assume that spacecraft like the x-37 could be useful as they could launch, fire, and return to minimise how long they can be shot at themselves.

However laser weaponry is also coming along quite nicely so one a weapon satellite with one of those goes up the X-37 tactic becomes useless. As the laser travels so quickly and isn't subject to orbital mechanics, it would be shot out the sky before it had time to return.

After that development its anyone's guess how things would go.

I imagine that "space fighters" would actually be orbital spaceplanes, capable of fighting in space, but primarily optimized for atmospheric combat.

Just nope. That would be like designing a tank that operates as a submarine, or a battleship that operates as a fighter jet.

You might get some attempts at first but it would be doomed to failure. A dedicated space fighter or a dedicated atmospheric fighter would beat it.

Edited November 25, 2014 by Frozen_Heart

[shynung]

Well I'm going to assume you mean something with current technology that could be built in the next 10 years.

In reality this is going to simply be a satellite with a few missiles attached. It will also have a decent amount of dV to maneuverer into the correct orbit to destroy enemy satellites.

A few years on from that things get tricky. I'd assume that spacecraft like the x-37 could be useful as they could launch, fire, and return to minimise how long they can be shot at themselves.

However laser weaponry is also coming along quite nicely so one a weapon satellite with one of those goes up the X-37 tactic becomes useless. As the laser travels so quickly and isn't subject to orbital mechanics, it would be shot out the sky before it had time to return.

After that development its anyone's guess how things would go.

Depends on how far the power generation developments go. If the laser is limited to tactical (short range) engagements due to lack of power generation capability, someone will build a missile with enough heat shielding to shrug off whatever heat the laser is able to impinge on it.

[Frozen_Heart]

Depends on how far the power generation developments go. If the laser is limited to tactical (short range) engagements due to lack of power generation capability, someone will build a missile with enough heat shielding to shrug off whatever heat the laser is able to impinge on it.

Doesn't matter how weak the laser is. In space it doesn't lose power with distance. It could hit a missile launched from the moon in about a second if it was orbiting the earth. Maybe a missile could be designed with a system of heat sinks and radiators though.

[shynung]

Doesn't matter how weak the laser is. In space it doesn't lose power with distance. It could hit a missile launched from the moon in about a second if it was orbiting the earth. Maybe a missile could be designed with a system of heat sinks and radiators though.

A laser weapon works by heating the surface of whatever it hits until it disintegrates. This heating capacity directly corresponds from the power generation capability of the laser weapon itself. If a missile could be designed so that it has an extremely-heat-resistant outer skin similar to a manned spacecraft's heatshield, the laser cannot damage the missile itself until this outer layer is burnt or ablated off.

For a fair comparison, you can hardly harm somebody by shining a 1 mW laser pointer at his chest. You will, however, make a lasting wound by shining a 1 kW laser in the same spot.

Basically, for a laser weapon, it depends entirely on how much energy one can efficiently pump into the laser emitter, and how much heat dissipation capability you have.

Edited November 25, 2014 by shynung

[Kryten]

Doesn't matter how weak the laser is. In space it doesn't lose power with distance. It could hit a missile launched from the moon in about a second if it was orbiting the earth. Maybe a missile could be designed with a system of heat sinks and radiators though.

Lasers beams do diverge with distance; e.g, the lasers used in the lunar ranging experiments illuminate an area on the moon about 7km across.

[Dodgey]

A laser weapon works by heating the surface of whatever it hits until it disintegrates. This heating capacity directly corresponds from the power generation capability of the laser weapon itself. If a missile could be designed so that it has an extremely-heat-resistant outer skin similar to a manned spacecraft's heatshield, the laser cannot damage the missile itself until this outer layer is burnt or ablated off.

Or until the heat seeps through. Remember we are in space, there is no atmosphere to carry away the heat. Unless you are at rediciously close ranges there will be plenty of time for a laser or other radiation based weapon to bathe a target. The rate at which you can radiate heat is limited, more so on a small target such as a missle. Besides you don't have to disintegrate something to render it inoperable. Electronics have a limited working temperature range. Heat your missle above that and you turn it into a big slug which is one small thrust away from being avoided.

[cicatrix]

Any space combat in LEO will be the first and probably the last due to large amounts of space debris it produces. Disregarding that, I think AI wins here. Imagine a fight 200 drones vs. 200 drones each acting as a part of a network, acquiring targets, detecting attacks, calculating orbits, intercept courses, etc, performing evasive maneuvers, deploying decoys, jamming the signals, and more. All of that happens in seconds if not fraction of seconds. No human can control that. Everything will be controlled by a program that operates the network and the best program wins. So it would be a fight more between software engineers rather than between metal or humans.

As I see it, a basic drone should be a disposable low-cost machine having:

* a basic propulsion system that allows several hours of active maneuvering (say, 1000-2000 dV);

* an active/passive detection system (Radar, IR, Radio-triangulation, etc)

* a comm jamming device

* communication device

* computer system

* power source (accumulator or radioisotope power cell)

Weapon systems:

* a missile launcher (5-10 missiles)

* laser (for blinding the optics/sensors and destroying solar panels)

* several canisters with lead pellets to be shot at incoming missiles/enemy drones in immediate proximity

* a self-destruct charge

Edited November 25, 2014 by cicatrix

[shynung]

Or until the heat seeps through. Remember we are in space, there is no atmosphere to carry away the heat. Unless you are at rediciously close ranges there will be plenty of time for a laser or other radiation based weapon to bathe a target. The rate at which you can radiate heat is limited, more so on a small target such as a missle. Besides you don't have to disintegrate something to render it inoperable. Electronics have a limited working temperature range. Heat your missle above that and you turn it into a big slug which is one small thrust away from being avoided.

Heatshield materials (some mixture of polymers and, curiously, coke) are designed to be practically non-heat-conductive. One side can be exposed to hundreds of degrees celsius and the otherside remaining merely warm to the touch (about 40-50 degrees). They are also designed to ablate away when heated; the heat is carried away by this ablated material.

[KerikBalm]

Xray lasers don't use mirrors.

20m mirror would be a lovely target for a little but smart anti-mirror cannon.

What else would they use if not mirrors? they can't use lenses. They'd have to use grazing incidence mirrors.

So the X ray laser is firing from dozens of light minutes away... and you want to use a slug thrower to put it out of action....

Riiiiiigggggghhhhhttttt.................

http://panoptesv.com/SciFi/LaserDeathRay/SoftX.html

Everyone knows x-rays are highly penetrating, right? Not necessarily. As the graph below shows, the low energy x-rays (so called soft x-rays) can't even go through a meter of air without being attenuated away.

They are also rapidly absorbed by all other matter.

It is difficult to focus soft x-rays. Since they will not pass through matter, you can't use lenses. Mirrors will only work at grazing angles, so you need complicated grazing incidence mirrors. Furthermore, to get diffraction limited performance, the mirrors will need to be smooth and perfectly shaped down to about 1/3 of a wavelength. This means you would need to have a mirror without any imperfactions larger than about 1 to 10 atoms across (depending on the wavelength). If you can get these, however, soft x-rays would make an excellent wavelength for space combat, since they could be focused to high intensities at very long ranges.

Conventional lasers can generate soft x-rays, but with extremely low efficiencies. You need to turn a bit of matter ito a highly ionized plasma with a powerful laser pulse in order to get a weak x-ray beam out. However, there are free elelctron lasers that generate beams of soft x-rays for scientifc research. These beams are produced in extremely powerful pulses. Scientists love the high brighness, but get annoyed because a single pulse will vaporize their sample. As death ray designers, however, this is exactly what we want. X-ray free electron lasers may be the weapons of choice for future spacecraft.

Its of note that we do have soft X ray lasers, and they can be focused.

We can even generate hard X ray lasers... but if you thought the mirror perfection requirements for those was difficult....

http://panoptesv.com/SciFi/LaserDeathRay/HardX.html

The more energetic x-rays are called hard x-rays. These are fairly penetrating, capapble of going through several meters or tens of meters of air, and going through some 30 cm of human tissue to produce medical images.

It is very difficult to focus a hard x-ray beam. To focus light, you need optics that are smooth down to lengths as short as 1/3 the wavelength of the light. Hard x-rays, however, have a wavelength smaller than an atom. All matter is rough on this distance scale. Mirrors simply will not work, since the x-rays scatter randomly off the atomic cores rather than reflecting off a smooth surface. One method that should work is to use x-ray crystal diffraction to make a diffractive resonant cavity. By straining the diffraction crystals, you can shape the beam to focus where you want it. Then send the beam through an amplifier to get the very high intensities needed for a death ray. If you can focus such a beam, hard x-rays are the ideal choice for space combat, because you can't get any shorter wavelength that you have any chance of focusing. A diffraction limited beam of hard x-rays could be focused to lethal intensities at distances of over a light second.

Because hard x-rays are penetrating ionizing radiation, they can be used to kill unshielded targets without burning or blassting them. The radiation can damage electronics and kill people without causing material harm. However, most spacecraft will be shielded against solar and cosmic radiation, limiting the usefulness of this damage mechanism. Still, you can use the x-ray death beam to drill holes through your target.

Note that they are only talking about a light second... but if you run the equations, you can get much much more than that with a bigger focusing array.

That page generally talks about fairly small focusing arrays, whereas I'm talking about ones tens of meters in diameter.

Sure, a smaller craft could carry a much smaller array (like... say... 1 meter)....

But there is no stealth in space....

Space is the ultimate sniper's playground.... range is king, and I would imagine that long range soft X ray lasers would be the dominant weapons, like seige weapons of old.

Anything that pokes its head above the atmosphere or surface of a planet may find itself being engaged within a few/several/dozenes of minutes from interplanetary distances.

Note that it doesn't have to be a single monolithic laser or craft.... I suspect phased arrays would see much use.

Formations of smaller craft aligning and synchronizing to form phased arrays could dramatically extend the effective range of their fire.

Also, it would be much better if there was a gaussian beam distribution across the focusing arrays.

See this page for why you'd want the highest frequency you could focus, why you'd want a gaussian distribution, and what a phased array would do:

http://panoptesv.com/SciFi/LaserDeathRay/Diffraction.html

but in short:

Case #1

A beam aperature that looks like this (left):

Will look like this at a distance (Right)

Case #2

A higher wavelength, an aperature that looks like this (left):

Will look like this at a distance (right)

Case #3

A larger aperature that looks like this:

Will look like this at a distance (right)

Case #4

Now put a pair of aperatures (like two ships in formation) that are synchronized/in phase,

the aperatures look like this:

The spot at a distance looks like this (right)

Note how the spot is less divergent than case 1

Case #5

Add even more aperatures, and the beam looks like:

Case #6

The pseudo-gaussian (since to have a true gaussian, you need an infinite diameter) at a distance looks like:

Edited November 25, 2014 by KerikBalm

[kerbiloid]

What else would they use if not mirrors? they can't use lenses. They'd have to use grazing incidence mirrors.

"X-Ray laser"  as it has been depicted in SDI project  was a nuke with steel sticks around it. When nuke booms, sticks vapourize and radiate X-Ray in their axii directions.

Optical methods do not work with such short wave length.

[KerikBalm]

Did you even read my post?

"X ray" describes a range of wavelengths.

"Hard" X rays cannot be focused by mirrors, "soft" ones can.

Soft ones do however need extreme precision for the mirrors, and the mirror array would be large and cumbersome for a 1 shot use like a nuke pumped laser...

But it is possible, and for a reusable FEL laser, on some fission/fusion powered space craft... why not?

[NASAFanboy]

I believe that missiles and lasers would be the weapons that would be used in space. A craft modeled off the X-20 Dynasoar could approach a enemy satellite for a extremely close rendezvous, open a cargo door, release a missile, then retreat out of the way as the missile used monopropellant to adjust its trajectory to a collision course and fires it's motor.

[Kryten]

I believe that missiles and lasers would be the weapons that would be used in space. A craft modeled off the X-20 Dynasoar could approach a enemy satellite for a extremely close rendezvous, open a cargo door, release a missile, then retreat out of the way as the missile used monopropellant to adjust its trajectory to a collision course and fires it's motor.

Why not just use a suborbital missile?

[Nibb31]

I believe that missiles and lasers would be the weapons that would be used in space. A craft modeled off the X-20 Dynasoar could approach a enemy satellite for a extremely close rendezvous, open a cargo door, release a missile, then retreat out of the way as the missile used monopropellant to adjust its trajectory to a collision course and fires it's motor.

Ignoring the fact that it makes no sense to launch an orbital spaceplane to launch a missile when you could simply launch a missile (or dozens of missiles for the same mass).

As with most of the suggestions on this thread, this one implies that the target is at least passively cooperating to allow its attacker to rendez-vous with it.

In case of a conflict, anything that is on an intercept course will be detectable hours before it reaches its target, which gives the target ample time to evade to a wildly different orbit. Two or three small random burns are enough to put the target hundreds of miles away from where the interceptor thought it would be.

As long as both craft have propellant, there is no way you can ever rendez-vous an orbital missile with a target that is actively trying to evade.

Edited November 25, 2014 by Nibb31

[Kryten]

Ignoring the fact that it makes no sense to launch an orbital spaceplane to launch a missile when you could simply launch a suborbital missile...As long as both craft have propellant, there is no way you can ever rendez-vous an orbital missile with a target that is actively trying to evade.

Unless you don't leave the enemy enough time to detect the missile; IS had first-orbit intercept capability in the 70s, we should be able to handle it now.

[kerbiloid]

"Hard" X rays cannot be focused by mirrors, "soft" ones can.

Before focusing smth you would generate it first, and in megawatt amounts. High-powered chemical lasers produce infrared or ultraviolet, and of course not X-ray.

Nuke produces hard X-Ray, a bit softer than gamma.

Buy what plant would you produce "soft" X-Ray not in laboratory quantities but in megawatts?

(Because of that, authors of SDI project overviewed 2 laser types: chemical infrared (those, with funny multi-mirror maze on several satellites) and nuke-powered stick-surrounded.

If they had any idea of producing "soft" X-Ray of megawatt range, they of course would tell the world about this. But as we can presume, they had none.)