Interplanetary WAR!

[Jouni]

with railguns unlike lasers, you could fire it on the other side of the planet and hit your target without you having to be anywhere near them, also if you were a closer ranges you could hit your target before they could make any kind of maneuver, or you could equip the railgun with ammunition that cold guide itself to its target.

Ballistic projectiles are a pretty bad idea in orbit. Your ship would encounter the enemy first, with the projectiles coming in later. Besides, the projectiles would need nontrivial delta-v for course corrections, making them effectively guided missiles. The railgun would then become just an expensive firing mechanism.

At short ranges, railgun projectiles would be hard to dodge, but obviously the combat would not be fought at such short distances. As a rule of thumb, the combat always begins either by surprise, or at a range where your weapons are ineffective.

[krona14]

Ballistic projectiles are a pretty bad idea in orbit. Your ship would encounter the enemy first, with the projectiles coming in later. Besides, the projectiles would need nontrivial delta-v for course corrections, making them effectively guided missiles. The railgun would then become just an expensive firing mechanism.

At short ranges, railgun projectiles would be hard to dodge, but obviously the combat would not be fought at such short distances. As a rule of thumb, the combat always begins either by surprise, or at a range where your weapons are ineffective.

ballistic projectiles would encounter your target first, not your ship. that makes no sense. also, a railgun could be used a an excellent surface to orbit defence.

[Jouni]

ballistic projectiles would encounter your target first, not your ship. that makes no sense. also, a railgun could be used a an excellent surface to orbit defence.

You can try it yourself in KSP. If the projectile moves faster, its orbital period is longer, so it reaches the other side of the planet later.

[mic_e]

I think the most realistic premise would be that there are still nations/alliances on earth, which would fight war with each other. Space would only be an additional combat field.

To some extent, space has been used for war since the second world war: The german V2/Aggregat 4 was the first man-made object in space. These days, ICBMs use suborbital trajectories to reach their targets as fast as possible. It is known that the CCCP was working on orbital nuclear weapons, which would be de-orbited at any point of the orbit, making defense much more difficult. In combination with hypersonic gliders, the actual impact location would be almost impossible to predict. Spy satellites are essential for military inteligence, and it can safely be assumed that all superpowers have already built spy sats designed to rendezvouz with enemy spy sats. The space shuttle could have been used for that purpose as well (but was never).

From that perspective, war in space is not very different from 'normal' war. But let's take a look at what will become possible in the near future:

Near-Earth asteroids can _very_ effectively be re-directed to collide with earth; with sufficient technology, even a specific city can be targeted. The destructive force would be far higher than possible with nuclear bombs. Even very large (>1km) asteroids can be re-directed by using rocks from the asteroid itself as reaction mass.

Humans are incredibly easy to kill; especially in a place like space. Even with today's technology, you could build a 100,000$ cubesat that is capable of killing the entire crew of the ISS, simply by crashing into the station at an appropriate relative velocity. It could be built to be impossible to detect for radars, and will be impossible to evade. It wouldn't even be that hard to launch; just tell the launch provider that you are testing a new ion engine, or something. Even on earth, humans will soon be completely obsolete; we already have the technology to build a laser, with some attached servos, that will automatically point at the eyes of all enemy soldiers, and permanently blind them, at a rate of tens per second. To a somewhat lesser extent, autonomous spacecraft are incredibly easy to destroy as well. This is why almost any SciFi unvierse employs some magical 'energy shield' that will protect stuff. If you won't include magical 'energy shields' into your universe, you'll have a really hard time at making crewed missions make sense in any way. You could use iron shielding that is mined from asteroids, but even then 99% of your spacecraft's mass will be iron... unless you start thinking _really_ big (a sphere a few hundreds of meters in diameter, with a 1-meter iron hull, might be economic, and weigh several million tons). That gives me a great idea: Just grab a few-hundred-meter asteroid, hollow it out, fill it with Oxygen, and live there... that might actually be very reasonable; it might even survive a nuclear blast. Spun up at the right rate, it will even provide artificial gravity for its inhabitants. Note to self: Build an evil villain lair in a hollowed-out asteroid.

Oh, and of course don't forget large-scale launch sites sucha s space elevators, launch loops etc., which are - like anything in space - extremely easy to destroy, and extremely expensive...

Edited May 12, 2014 by mic_e

[krona14]

You can try it yourself in KSP. If the projectile moves faster, its orbital period is longer, so it reaches the other side of the planet later.

not if you plan it correctly, (ie sent it retrograde when you are in a high orbit) try it in ksp for yourself. maybe i post a video of kebar ballistics!

[KOCOUR]

Balistic projectiles are generaly a bad idea for ship to ship combat in space, cause the ship will just change orbit a bit and your projectile will miss. Can you imagine how big the space battlefield will be? how long it will take the projectile to reach the target? Guyded or homing missiles make more sense.

Projectiles can be used for bombarding fixed surface instalation however.

But actually you can use projectiles if you shoot big wide cloud of them on shorter ranges enemy ship will have hard time to dodge it. Like a shotgun, big spaceshotgun.

I would still rather use something energetic, (Laser, some kind of microwave emitor, or something like this) to heat the enemy ship, kill the crew fry the circuits, but keep it intact to prevent mr.Kessler from endangering my own ships and instalations.

And keep the missiles, "shotguns" and other debries producing weapons only for the most critical situations.

BUT, untill we have colonised other planets, i cant see any reason to fight in space except shooting down enemy satelites, and ICBMs. And that can be done from surface.

[Seret]

But actually you can use projectiles if you shoot big wide cloud of them on shorter ranges enemy ship will have hard time to dodge it. Like a shotgun, big spaceshotgun.

IIRC this is exactly what the Soviets planned to use for their killer satellites. It would maneuver to a close intercept with the target sat and blast it. The Americans were going for a kinetic kill vehicle that actually hit the target directly.

EDIT: This is the one I was thinking of: http://www.russianspaceweb.com/is.html

Edited May 13, 2014 by Seret

[Jouni]

not if you plan it correctly, (ie sent it retrograde when you are in a high orbit) try it in ksp for yourself. maybe i post a video of kebar ballistics!

If you're in high orbit, you're not hiding behind the planet, at least not for long. Hours or even days before your projectiles get near the enemy, you're out in the open, at the mercy of whatever direct-fire weapons the enemy happens to have.

[krona14]

If you're in high orbit, you're not hiding behind the planet, at least not for long. Hours or even days before your projectiles get near the enemy, you're out in the open, at the mercy of whatever direct-fire weapons the enemy happens to have.

Depends on how high an orbit is it. railguns could be used to hit targets a close range, large targets (ie. Space Station) from long ranges

[Jouni]

Depends on how high an orbit is it. railguns could be used to hit targets a close range, large targets (ie. Space Station) from long ranges

You can hit moons and planets at long ranges. Everything else in orbit has the ability to dodge the incoming projectiles. As a rule of thumb, an 1 m/s burn is enough to dodge railgun projectiles at 1000 km, which is still a short range in orbit.

[Rakaydos]

Can your warship carry more railgun rounds than the target station has RCS Delta V?

Though if yo control the high orbitals, launching craft are dead meat- in order to reach orbit, they're pletty much locked into the gravity turn, and if they spend too much DV dodging railgun rounds they'll fall short of orbit and halve to abort.

[Jouni]

Can your warship carry more railgun rounds than the target station has RCS Delta V?

At a short range, yes. At a medium or long range, no. In an interplanetary war, combat should usually begin at a long range, or by surprise.

With plausible near-future technology, I would assume that short range is up to 10^3 km, medium range up to 10^6 km, and long range beyond 10^6 km. Railguns would only be effective at a short range. Lasers would be short-to-medium range weapons, depending on which wavelengths efficient high-power lasers can be built. Guided missiles would work at all ranges.

Though if yo control the high orbitals, launching craft are dead meat- in order to reach orbit, they're pletty much locked into the gravity turn, and if they spend too much DV dodging railgun rounds they'll fall short of orbit and halve to abort.

That depends on the orbit. It only takes something like 10-15 minutes to reach orbit, so assuming that the muzzle velocity of a railgun is 5 km/s, you can pretty much ignore anything fired from 10000 km during the ascent.

[ThirdHorseman]

Also i want a real source on this laser thing, you i dont believe any of the things that you have said about lasers.

GIVE US SOURCES!

Well the two I gave before:

ADAM system burning through rubber-hull small boats

LAWS system burning up a military drone

And here are some others:

ADAM system can destroy small missles in flight

Israel's Iron Beam HELWS system can burn up rockets, mortars, and drones

Boeing's YAL-1 airborne laser system destroys ballistic missle

THEL system destroys rockets, artillery projectiles, mortar rounds, and missles

Lasers have been, and are being, used by several groups to destroy small, fast-moving objects made of a variety of materials.

30 seconds, against a stationary target, against the thermal mass of RUBBER. While powered by a warship that has an entire ocean to dump waste heat into.

My point about lasers being effective against smaller targets stands (and is supported), but lasers are MORE than useless against a comparable (thermal) mass craft.

From the results I've seen in the sources I posted above, and others, it looks like lasers are very effective at destroying small targets made of materials much stronger and thermally resistant than rubber. And that military drone destroyed in the Navy LAWS test seemed to be a "comparable (thermal) mass craft". And again, these tests were all done at distances of a mile or more in thick atmosphere. I don't see any reason why lasers like these, or even more powerful versions, wouldn't be just as effective against satellites or even small drone craft in orbit.

As for heat dissipation, the LAWS system does not dump it's heat into the ocean. If you look at the mount for it, it simply dumps the heat into the air. All of the high-energy laser weapons just dump the excess thermal energy into the air, although some designs talk about using a mist cooling system. So the laser weapons wouldn't have any more issue than any other space-based weapon system when it comes to getting rid of excess thermal energy.

[Seret]

1000 km, which is still a short range in orbit.

1000km isn't necessarily short range in orbit. At the lowest Earth orbits the horizon is only about 1400km away, so two objects in that orbit can only have a maximum line of sight of about 2800km. If you're using IR and have to take the atmosphere into account then that drops to a maximum range of a smidge under 2000km. Factor in time to identify and acquire the target (closing speed could be up to 15km s^-1) and engagements inside 1000km start to look highly likely.

Obviously this changes as your altitude increases, at the extreme end two objects in GEO could be up to 83,000km apart.

This actually gives one major advantage to ballistic or guided weapons, they potentially have much longer range than a line-of sight weapon such as a laser. A missile could potentially hit a target on the opposite side of the planet, so arming your combat spacecraft solely with lasers would be a very bad idea. Your enemy would just sit back behind the horizon and pepper you.

[Jouni]

1000km isn't necessarily short range in orbit. At the lowest Earth orbits the horizon is only about 1400km away, so two objects in that orbit can only have a maximum line of sight of about 2800km. If you're using IR and have to take the atmosphere into account then that drops to a maximum range of a smidge under 2000km. Factor in time to identify and acquire the target (closing speed could be up to 15km s^-1) and engagements inside 1000km start to look highly likely.

By that reasoning, 2000 km would be a short range. It's the limit how far you can delay the combat by hiding near the planet.

I'd assume that any reasonable warship would carry thousands of tiny satellites, each equipped with some sensors and enough propellant to change the orbit significantly. If you can't see what's happening behind the planet, you'll be at a huge disadvantage.

[Seret]

I'd assume that any reasonable warship would carry thousands of tiny satellites, each equipped with some sensors and enough propellant to change the orbit significantly. If you can't see what's happening behind the planet, you'll be at a huge disadvantage.

That'd only be necessary for an expeditionary ship visiting another planet. In Earth orbit you could just use existing infrastructure, which would be a mix of ground-based and orbital. The battle would likely be coordinated from the ground, integrating information from lots of sources. Air combat is already conducted this way, and it'd be air forces that would take on the role of managing any potential combat in space.

Edited May 14, 2014 by Seret

[ThirdHorseman]

This actually gives one major advantage to ballistic or guided weapons, they potentially have much longer range than a line-of sight weapon such as a laser. A missile could potentially hit a target on the opposite side of the planet, so arming your combat spacecraft solely with lasers would be a very bad idea. Your enemy would just sit back behind the horizon and pepper you.

Agreed, although those lasers would also make very good point defense, so the guided weapon would need to be pretty stealthy (or incredibly fast, or heavily armored) to make it in close enough.

[Northstar1989]

I feel the need to chime in again on the lasers vs. railguns vs. missiles issue:

I saw a post before about how kinetic weapons would probably be banned in populated/crowded space- because projectiles that missed their target (due to evasive maneuvers at long range, for instance) would be left shooting all over the system, and could easily set off some kind of Kesseler Syndrome...

What do you guys think of that point? I think it's a very good argument in favor of beam-based weaponry (such as lasers- but also eventually including things such as controlled plasma streams), as such weapons wouldn't leave the dangerous mess of spent round zipping around the system at all sorts of highly elliptical orbits... Even if beam weapons were less effective than the alternatives (I can definitely see an argument for kinetic weaponry being superior at close quarters, and missiles at long range- but I think beams/lasers would dominate somewhere in the middle...), it would be very good argument AGAINST use of kinetic weaponry- and to a lesser degree missiles.

It should also be pointed out that any round you fire off in orbit that misses its target will eventually come back to your firing location, given enough time, if it doesn't reach escape velocity. Given a large/complex fleet-style battle, I could easily imagine some rounds phasing back to hit the ship that fired them in a few hours or so if it didn't move from its position...

If kinetics and missiles were allowed, I would imagine a hierarchy something like the following might develop, with different weapons systems being best at different ranges:

Close Range: Kinetic weapons and unguided rockets (unguided rockets don't transfer nearly as much waste heat to the ship firing them as railguns, etc., for their final velocity)

Medium Range: Lasers and beam weapons (beams can be swept across angles, creating interlocking boxes/triangles of fire that *cannot* easily be dodged. Lasers also move at the speed of light!)

Long Range: Guided missiles and disposable parasite drones (the ability to maneuver around moons, planetary horizons, etc., and make course-corrections would be invaluable)

It need not be said that at long range, lasers/beams would be superior to kinetics and unguided rockets, although inferior to missiles.

I would imagine a strong preference for lasers/beams both in order to give warships range versatility, and to avoid filling planetary orbital space with dangerous dodged spent missiles and kinetics...

Regards,

Northstar

[Northstar1989]

I was also reading an article just last night (technically this morning- after midnight) that said that jamming of military-grade drones is definitely not something we would be able to rule out, especially in the future. (I think the article was on RocketManifesto, though don't quote me on that...)

Given that autonomous drones would have to either be sentient (which creates its own problems), or imbued with programming that wouldn't necessarily enable them to carry out many of the advanced tactics and maneuvers that would be utilized by manned/AI ships; and as I read, RC drones could be jammed; I'm even more convinced than before that manned warships would have at least SOME role in space- although I can imagine a number of niches (such as low-action garrison duty) where unmanned craft would still be vastly superior...

Regards,

Northstar

[Everten P.]

Make it a thing that one faction made a belt of asteroids that have abandoned bases and that the faction that made it was separated into the factions and they are fighting each other!

[Seret]

I saw a post before about how kinetic weapons would probably be banned in populated/crowded space- because projectiles that missed their target (due to evasive maneuvers at long range, for instance) would be left shooting all over the system, and could easily set off some kind of Kesseler Syndrome...

What do you guys think of that point?

It's not really an issue. Damaging another spacecraft would usually generate lots of debris, even if you did it with a directed energy weapon. You can't smash up the other guy's toys without creating a mess. The fact that every ASAT weapon ever used or designed has been a kinetic energy weapon should give you a clue how seriously the military consider Kessler Syndrome to be a constraint on their activities.

It should also be pointed out that any round you fire off in orbit that misses its target will eventually come back to your firing location

That's the last place it will come back, since by definition everything you fire will have substantial velocity relative to you. It might hit anybody and everybody else, but it definitely won't hit you unless you move to intercept it.

[JethroReading]

Just one thing you might need to consider- asteroid belts are actually massively dispersed, so it might not be all that realistic to have people colonised there. That said, it would be cool if there was some sort of huge rubble-pile asteroid being built around Ceres or something like that!

[Sovnheim]

Just one thing you might need to consider- asteroid belts are actually massively dispersed, so it might not be all that realistic to have people colonised there. That said, it would be cool if there was some sort of huge rubble-pile asteroid being built around Ceres or something like that!

That's kind of disappointing. I've always imagined asteroid belts to be a giant mess of big asteroids bumping into each other constantly.

I just read a very interesting article from The Economist that I believe would be a very interesting input :

The best moment to shoot down a missile is at launch - once in space, even though deadbody radiation may give avay the location of the missiles, it seems easy enough to add decoys.

In the case of interplanetary war, a focus on anticipating ennemy launches (through infiltration, observation, etc) could be an interesting lead.

[krona14]

I was also reading an article just last night (technically this morning- after midnight) that said that jamming of military-grade drones is definitely not something we would be able to rule out, especially in the future. (I think the article was on RocketManifesto, though don't quote me on that...)

Given that autonomous drones would have to either be sentient (which creates its own problems), or imbued with programming that wouldn't necessarily enable them to carry out many of the advanced tactics and maneuvers that would be utilized by manned/AI ships; and as I read, RC drones could be jammed; I'm even more convinced than before that manned warships would have at least SOME role in space- although I can imagine a number of niches (such as low-action garrison duty) where unmanned craft would still be vastly superior...

Regards,

Northstar

They are drones, that means they are remotely controlled, having them being remotely controlled means they have a human piotet so where else controlling it. Also if you wanted to hack a drone, you could not do it in the little time in which a battle would take place in, it is not like a game where you can just go on a computer for a few minutes and all of a sudden have control of the enemy ship. Also jamming radio signals is very hard to do, if it was, people would be doing it with us drones. Also why would a drone be limited to a few uses?

[krona14]

Can your warship carry more railgun rounds than the target station has RCS Delta V?

Though if yo control the high orbitals, launching craft are dead meat- in order to reach orbit, they're pletty much locked into the gravity turn, and if they spend too much DV dodging railgun rounds they'll fall short of orbit and halve to abort.

The rod of tungsten that is used in a railgun could be made invisible to most detection methods, plus it is very small. If properly aimed a rail gun could launch a projectile the opposite side of a planet and hit its target before anyone can do anything about it, to this day we can't track objects that small that are in orbit.