Space Warfare - How would the ships be built/designed?

[cantab]

You can't look in the direction of the Sun

Specialised equipment can, but simpler is to put some equipment away from Earth. In any case the "blind spot" will be relatively small and difficult if not impossible for an enemy to really exploit.

[Kibble]

In any case the "blind spot" will be relatively small and difficult if not impossible for an enemy to really exploit.

Au contraire! This is the reason we have only ever detected 16 minor planets with orbits entirely inferior to Earth's.

[KSK]

Yup. And each one of them costs money and resources to build. Forcing the enemy to overspend on defensive measures is a great way to win a war (Reagan did it with SDI; the cost to keep up was a big contribution to the collapse of the Soviet Union).

This. Assuming we're not in total sci-fi territory then I'd argue that firstly, the amount of effort it takes put a large weapons platform into space is disproportionately higher than the effort it would take to destroy it with a cheap and cheerful chunk of metal moving at sufficient velocity. Secondly, all the really important stuff that the combatants would be fighting over is likely to be planetside.

I don't think a space battle would even get as far as a siege - it would be MAD all over again but with swarms of kinetic impactors produced as cheaply as possible, with just enough onboard guidance to aim at a planet and a solid rocket motor to hurl it at said planet as fast as possible. Shoot one down and there's another half dozen coming in right behind it. If you're lucky they're aimed at your military infrastructure, if you're not, then your major population centres are about to have a very bad day.

Sure, it might be possible to defend against that sort of threat but it would be enormously expensive, to the point where the best defense is making sure that you have an equally good offense. At which point those who have the biggest economy will 'win'.

[Superfluous J]

Au contraire! This is the reason we have only ever detected 16 minor planets with orbits entirely inferior to Earth's.

Comparing what we can do now and what a spacefaring civilization with the capability and infrastructure to wage war can do is like saying Pacific islanders can't row to Los Angeles, so it must be impossible.

[Kibble]

Comparing what we can do now and what a spacefaring civilization with the capability and infrastructure to wage war can do is like saying Pacific islanders can't row to Los Angeles, so it must be impossible.

What's the use in speculating over nonexistant technology? Our civilization goes to outer space too, and in a thousand years, the technology and methodology used to do so will almost certainly resemble how we do it.

[shynung]

What's the use in speculating over nonexistant technology? Our civilization goes to outer space too, and in a thousand years, the technology and methodology used to do so will almost certainly resemble how we do it.

People of the past centuries used to speculate about travelling to the Moon and Mars using rockets, something we can do today with some effort. It's not a stretch for us to speculate high-tech futuristic sensors that can see what we can't see today, using mechanisms we haven't figured out yet.

[Kibble]

But the limitations to what we can do is what makes things interesting - assuming 100% sky coverage by thousands of space telescopes that don't miss a single thing, even near the glaring brightness of the Sun isn't just inaccurate, its boring!

[Superfluous J]

But the limitations to what we can do is what makes things interesting - assuming 100% sky coverage by thousands of space telescopes that don't miss a single thing, even near the glaring brightness of the Sun isn't just inaccurate, its boring!

Which is why writing about that isn't the best idea, unless your story is about something else and that's not central to it.

But real life tends to be boring.

[Kibble]

But real life tends to be boring.

I disagree but that's just my opinion ^w^

[Superfluous J]

I disagree but that's just my opinion ^w^

Well not "boring," but 99% of people's lives wouldn't make an enjoyable read.

[cantab]

Au contraire! This is the reason we have only ever detected 16 minor planets with orbits entirely inferior to Earth's.

To clarify, then, I'm confident the blind spot can be made small with equipment designed and operated to reduce it. With our current telescopes we're super-cautious, not pointing them anywhere remotely near the Sun just in case something goes wrong and they get destroyed. A system with the specific goal of surveying the whole solar system would be pointed much closer to the Sun (though probably not at it).

This. Assuming we're not in total sci-fi territory then I'd argue that firstly, the amount of effort it takes put a large weapons platform into space is disproportionately higher than the effort it would take to destroy it with a cheap and cheerful chunk of metal moving at sufficient velocity.

Getting that hunk of metal moving might not be so cheap. If it's been mined on a large planet or moon then it has to get from the surface to orbital or escape speed. If it's mined on a small asteroid then that mining operation is automatically a large militarily-relevant installation in space, it might as well be armed itself or otherwise protected.

Secondly, all the really important stuff that the combatants would be fighting over is likely to be planetside.

Maybe, maybe not. There's an argument that once you're in space it's stupid to plonk yourself back down in some deep gravity well, and space habitats built from material mined from smaller asteroids are better than trying to colonise large planets or moons. I think whether such habitats become widespread will depend on how interest and investment in space colonisation compares to developments in space launch technology. If getting off the surface of Mars is cheap and easy by the time colonisation is a big thing then there might be no space habitats, if it's expensive and hard there might be no Mars colonies.

assuming 100% sky coverage by thousands of space telescopes that don't miss a single thing, even near the glaring brightness of the Sun isn't just inaccurate, its boring!

Reality is under no obligation to be interesting. Stories are though; if you're writing hard sci-fi you might reasonably opt for observation of the solar system to be spotty to allow threats to be missed.

EDIT: Once a war is underway, it's plausible that sensors will be the early targets. Take out your enemy's telescopes and it becomes easier to hide bigger threats from them.

Edited September 7, 2015 by cantab

[cryogen]

I can't remember the name of the space telescope that accidentally jettisoned its cover too early, while it was still pointed at Earth, and went thru its entire helium coolant supply in seconds.

Solid hydrogen, actually.

A design flaw in the spacecraft control electronics caused the telescope dust cover to eject prematurely in its first few hours on-orbit, exposing the telescope to the Earth. In normal operations the telescope would avoid pointing at the Earth as well as the Sun because the heat load was too high for the cryogenic cooling. At this early stage in the mission, the telescope was deliberately pointed at the Earth for safety under the assumption that the dust cover was present. The influx of power into the telescope caused the solid hydrogen cryostat to boil off all of its cryogen. As a result, the cryostat vent, now expelling gas at rates orders of magnitude higher than designed, acted as a tiny thruster rocket overwhelming the attitude control system and ultimately spinning the spacecraft up as high as 60 rpm. After the hydrogen was exhausted, spacecraft engineers were able to re-establish attitude control. However, with the cryogen gone, the science instrument was no longer functional and the original science mission ended.

https://en.wikipedia.org/wiki/Wide_Field_Infrared_Explorer

Wide Field Infrared Explorer (WIRE)

Edited September 7, 2015 by cryogen

[Kibble]

Solid hydrogen, actually.

Oh, thanks.

Your username is really relevant!

[shynung]

EDIT: Once a war is underway, it's plausible that sensors will be the early targets. Take out your enemy's telescopes and it becomes easier to hide bigger threats from them.

Most if it, yes. There's bound to be a few sensor sats overseeing important areas that happen to have some sort of CIWS installed.

[RizzoTheRat]

If lasers can be got working, then kinetic become pretty much obsolete. A laser weapon can shoot down an incoming kinetic shot in seconds, and used offensively can't be blocked. Sensitive parts of a spacecraft could be fried very quickly.

However in space they would need bulky power generation and large radiators to remove excess heat.

Laser weaponry is still in very early development so far, so kinetic is really the only current option.

Current attempts at laser weapons are intended to either fry/blind sensors, or cause a small damage to sophisticated systems to stop them working properly. Firing a laser against an incoming missile or drone is cheap and doesn't need to do a lot of damage as aerodynamics or gravity will do the rest of the work. However against a ballistic weapon they're useless, instead of a 40kg lump of metal hitting you at 500m/s (155mm shell), you get a 40km lump of warm metal hitting you at 500m/s.

The LaWS on USS Ponce is supposedly fully working and they've demonstrated it taking out an outboard motor on a small boat, so the technology's there.

[SargeRho]

Current attempts at laser weapons are intended to detonate missiles and shells, or otherwise break them up. This also works against an ICBM in the boost phase.

That being said, if you want to blind someone, without allowing for anti-radiation targeting in return, how about launching a number of small drones, all equipped with lasers of varying frequencies, firing at the target to overwhelm its sensors, and also completely eliminate the risk of them using sensors built to home in on these being used to target the ship, rather than mounting the lasers on the ship itself?

[shynung]

That being said, if you want to blind someone, without allowing for anti-radiation targeting in return, how about launching a number of small drones, all equipped with lasers of varying frequencies, firing at the target to overwhelm its sensors, and also completely eliminate the risk of them using sensors built to home in on these being used to target the ship, rather than mounting the lasers on the ship itself?

Go one step better: have the drones instead carry a nuclear warhead designed to work as bomb-pumped lasers.

[SargeRho]

That'll do, but in Space, if you can see them, they can most likely see you too, so it's probably worth blinding their sensors to avoid return fire.

[Frozen_Heart]

However against a ballistic weapon they're useless, instead of a 40kg lump of metal hitting you at 500m/s (155mm shell), you get a 40km lump of warm metal hitting you at 500m/s.

However, across the huge distances in space, weapons like gun are to slow to work. A ship could easily avoid anything fired at it while using lasers to fry all the sensors of the other satellite.

a number of small drones, all equipped with lasers of varying frequencies

current laser weapons need a large and expensive power supply. I doubt that they could fit on a small drone.

You would need a decent sized satellite with large solar panels and radiators to use a laser.

[SargeRho]

You don't need a large, powerful laser. Just one strong enough to overwhelm the sensors, the goal of these isn't do melt the sensors, or the hull of the ship. Think of it as a space-flashbang rather than a space-Predator.

[Rune]

Solid hydrogen, actually.

I don't think that "solid" refers to the hydrogen. Namely, because I don't think the tank could handle the millions of atmospheres of pressure metallic hydrogen takes to form.

Current attempts at laser weapons are intended to either fry/blind sensors, or cause a small damage to sophisticated systems to stop them working properly. Firing a laser against an incoming missile or drone is cheap and doesn't need to do a lot of damage as aerodynamics or gravity will do the rest of the work. However against a ballistic weapon they're useless, instead of a 40kg lump of metal hitting you at 500m/s (155mm shell), you get a 40km lump of warm metal hitting you at 500m/s.

The LaWS on USS Ponce is supposedly fully working and they've demonstrated it taking out an outboard motor on a small boat, so the technology's there.

Or Rocket, Artillery and Mortar (RAM) point defense. The HEL TD and other prototype laser systems have already shot down incoming mortar shells at representative ranges. Don't forget, that lump of metal is encasing several kilograms of high explosive, which becomes rather hum, shall we say, "interesting" when you warm it up.

Dumb kinetics could sound like the answer, and certainly space-borne rounds don't need high explosive, until you run numbers on it: with a measly 0.1g and a hundred-km head start, you can be 50m and 10m/s away from your supposed position by the time the 10km/s railgun round gets there. In the meantime, you can be depositing kWs on their sensors and weapons thousands of kms away, without any lag or possibility of dodging, and no horizon to hide behind. And a 10km/s railgun is more sci-fi than a MW-class laser, and in a similar power range.

Rune. So yeah, currently kinetics is the only game in town. But that's because the first 'laserstar' hasn't been built... yet.

Edited September 7, 2015 by Rune

[tater]

You can point an array of infrared scanners at every point in the sky at once, you know?

Back in the early 90s, we were writing rules for semi-realistic space combat for traveller (rpg) and of the 2 astronomers among the "gear heads," one was an IR astronomer who worked on the IR telescope at Mauna Kea. He said that equipment he had (diameter of telescopes, and required integration times (assuming it was in orbit instead of on a mtn) he could scan the entire volume of sky in several hours able to detect a crew cabin at 293K out pretty far (many light minutes as I recall). Not a SF warship radiating gigawatts, a player ship being dead quiet except that they are in shirtsleeves.

Obviously a small region around the sun would be excluded. As a reality check, from the Earth the sun is about 30 seconds of arc wide. The excluded solid angle is pretty tiny, so to be useful you need to have a precise sort of warp/jump drive that drops you within that solid angle of all detectors, then you need to accelerate radially.

Virtually any "stealth" case anyone can come up with is a special case. Remember, if you posit a universe where directional radiators are perfect, etc, such that stealth is a thing... then those societies will have many more sensors spread everywhere to compensate. In a realistic universe where stealth just isn't a thing, then they might only have a few sensors, making special cases sometimes possible.

This is why I said that questions like this cannot be generalized, you need to state your SF universe. If you are claiming the real world, then no stealth.

[cryogen]

I don't think that "solid" refers to the hydrogen. Namely, because I don't think the tank could handle the millions of atmospheres of pressure metallic hydrogen takes to form.

It means ordinary, molecular hydrogen (H₂) below its 14 Kelvin melting point -- not the exotic metallic hydrogen.

[Rune]

It means ordinary, molecular hydrogen (H₂) below its 14 Kelvin melting point -- not the exotic metallic hydrogen.

Really? We can get solid hydrogen? What is it, a crystal? Gotta read on this.... BRB!

Rune. I like finding out stuff, thanks!

[cryogen]

Really? We can get solid hydrogen? What is it, a crystal? Gotta read on this.... BRB!

I think so,

Molecular hydrogen exists at 1 bar and low temperatures as a rotor phase solid (Phase I) where the H₂ molecules are rotating about their positions in a hexagonal close packed lattice. Above about 110 GPa the molecular rotations are frozen resulting in an ordered broken-symmetry phase (BSP or Phase II)⁵⁷. At pressures above about 150 GPa another phase (Phase III) is observed but the structure of this phase has not been experimentally determined.

Tse, J. S., and D. D. Klug. "Molecular Dynamics Studies of High Pressure Transformations and Structures." In High Pressure Molecular Science, pp. 59-85. Springer Netherlands, 1999.

https://books.google.com/books?id=FYztCAAAQBAJ&pg=PA73&lpg=PA73

Three high-pressure phases of solid hydrogen and deuterium exist to 200 GPa at or below room temperature. X-ray and neutron diffraction identified phase I as having a hexagonal close-packed structure; vibrational spectroscopy established that the structure is molecular, consists of quantum rotors, and has a wide pressure-temperature (P-T) range of stability.

Zha, Chang-sheng, Ronald E. Cohen, Ho-kwang Mao, and Russell J. Hemley. "Raman measurements of phase transitions in dense solid hydrogen and deuterium to 325 GPa." Proceedings of the National Academy of Sciences 111, no. 13 (2014): 4792-4797.

http://www.pnas.org/content/111/13/4792.long

Edited September 7, 2015 by cryogen