Space Laser and warfare

[Izack]

I'm aware of the lack of blast, but there is one other curious behaviour of nukes in space.

If a missile travelling at 12km/s explodes into a nuclear fireball, that fireball will still be moving at 12km/s. It could simply swallow the ship as it flew by.

 

[statickid]

It seems to me that a vague analogy of dynamite is comparable.

Dynamite does very little damage when it's not crammed into a tight space of dense material to transfer its energy into. When dynamite is thrown into water, the shockwave pulse can kill all the fish in the area.

If I am not mistaken, this is the reason that nuclear weapons are detonated at an altitude, because if they exploded near the ground they would cause far less damage. It's the crushing pressure of the air expanding, and then contracting suddenly beneath and expanding outwards that is key.

what if nuclear weapons were drilled and buried deep into a little asteroid so that it was like a giant flak grenade or more precisely, could one be used directionally to hurl metal in a direction? Similar but more brutal than the metal storm weapon?

ok, not like the metal storm at all really, but i think the idea is there LOL :idea:

 

[jedidia]

Lasers are really limited in the area they can damage, so you could keep fighting for a pretty long time if the crew is suited and your enemy can only hit a 1x1 foot area of the ship per shot. An enemy would have to completely destroy all two or three of your backup systems or blast open each and every section of propellant tank to finally take you out of the fight.

At least in populated areas, a laser breaching the hull is devastating. The air inside could explode (rapid expansion under heat), and all people in the room will at least be permanently blind. But I think most battles in space would be thought by unmaned vehicles, which would reduce that risk of a laser blowing up a whloe compartement because it's helped along by the air in it (might still happen in a fuel tank, though...)

When you can't kill the crew outright by punching a hole in a hab module, it's actually pretty tough to fully destroy a spacecraft. High-speed kinetic weapons are useless because they'll just go in and out like buckshot through a paper bag.

Not quite so, I'm afraid. It's the same effect that hypervelocity ammo has on tanks: They turn to plasma when they hit the armor. So a hypervelocity projectile wouldn't leave a ship on the opposite side, because it turns to a rapidly expanding plasma cloud after impact. And you don't want to have one of those inside your ship!

However, kinetic weapons are a pain to aim, considering the distances and velocities involved in a space battle. And their ammo is cumbersome.

As for laser defences, I think the last thing we'd want to do is distribute the energy over the whole ship. Of course it seems like a good Idea, but what about impulsive shock? If the energy spreads too fast through the armor, it will tear the whole ship apart!

what if nuclear weapons were drilled and buried deep into a little asteroid so that it was like a giant flak grenade or more precisely, could one be used directionally to hurl metal in a direction?

Sounds like a terribly heavy flak grenade to drag around...

 

[T.Neo]

The charges used by Orion were to be constructed such that they aimed the force of the blast directly at the plate. You don't get any more blast effect than that.

Which raises a question of whether nuclear shaped-charges could mitigate such armor if they were designed for penetration, and not thrust...

Even with lots of lead, the neutron flux may serious harm the crew. The "ice shield" idea may be good, since water is a good neutron shield.

And lead is also quite heavy, which incurs a mass penalty.

If a missile travelling at 12km/s explodes into a nuclear fireball, that fireball will still be moving at 12km/s. It could simply swallow the ship as it flew by.

AFAIK the debris resulting from the blast are travelling on the order of tens of kilometers per second anyway, so the effect might be minimal at best.

At least in populated areas, a laser breaching the hull is devastating. The air inside could explode (rapid expansion under heat), and all people in the room will at least be permanently blind. But I think most battles in space would be thought by unmaned vehicles, which would reduce that risk of a laser blowing up a whloe compartement because it's helped along by the air in it (might still happen in a fuel tank, though...)

Can be mitigated somewhat by compartmentalisation and redundancy in the hull (and also some sort of protection for the crew, already in place on modern seagoing battleships as shrapnel protection, though severe heat flux and violent explosive forces could kill them anyway).

I'd be more worried about an impact with a propellant tank, since they are usually quite large.

And their ammo is cumbersome.

Well, an AIM-120 masses 152 kg apiece. M1A1 APFSDS rounds weigh around 18 kg, although railgun projectiles would forgo the mass of the cartridge, propellant and primer.

A laser might not have to carry physical ammunition but it does incur other mass penalties in things such as powerplants and coolant.

Sounds like a terribly heavy flak grenade to drag around...

Perhaps it could make sense, although not with an object as massive as an asteroid, by stuffing mass around what could be a relatively low yield warhead. The warhead would then propel that mass (in the form of small projectiles) at high velocity.

 

[Ghostrider]

What about an aerogel layer? It would be vaporized by the beam, and it could be made so as to produce a particle cloud upon disintegration, dispersing or attenuating the beam.

 

[docabn]

IMO in all likely hood space combat would involve multiple methods of destruction just the way modern warfare does. Do to the lack of air to slow the velocity of kinetic weapons, a carbine modified to work in space may be significantly more effective that on earth.
The goals of the various competing captains will be similar to those of naval warfare. Obtain optimal distance with optimal stealth then engage with enough fire power to prevent the enemy from being able to respond.

HIGH ORBIT ABOVE PLANET OR MOON X​

On the bridge of capital vessel “A” a cry of alarm goes out as multiple contacts are detected on sensors. The crew scrambles. Armored space suits are donned. Robotic fighters are launched and handlers assigned. The capital ship begins to rotate to turning its most shielded portion toward the enemy as the first volley of energy weapons play over the spot that the handwavium drive had been just seconds before.
In the void between capital ship “A” and the still as of yet undetected capital ship “B”. Robotic fighters engage and begin to destroy the dozens of determined six foot long torpedoes closing in on the capital ship. From a point tangential to the battle an array of energy waves play across robotic fighters and capital ship “A” reducing the effectiveness of the EM sensing and communication devises hampering the crews ability to control the Robotic ships. Sensing the communication gap the fighter’s AI programs take over and continue the defense.
The captain of capital ship “A” orders two volleys of projectiles to be launched at the predicted location of the enemy capital ship and the one causing the EM interference. A tight radio and laser beam combination communication is sent toward HQ as well alerting them of the situation. Just as the first of the few remaining torpedoes strike the thickly armored hull of the, small sections of hull explode outward destroying the torpedoes just prior to impact.
Seconds later the now bare hull is peppered by small uranium tipped rounds that were launched over thirty minutes ago from the long gone, capital ship “B”. These rounds begin to punch damaging holes into the heavy ship which is still attempting to maneuver out of the way. The EM field interference clears just enough for the crew to notice a second volley of torpedoes seconds away moments before the first one impacts.
Meanwhile on the bridge of the capital ship “B” under four gravities of acceleration a report flashes across the captains HUD suggesting that the enemy vessel suffered catastrophic damage. He barks the order to stop acceleration and prepare to change course is given. A small series of encoded EM pulses are sent to HQ announcing their successful encounter.

 

[Izack]

IMO in all likely hood space combat would involve multiple methods of destruction just the way modern warfare does. Do to the lack of air to slow the velocity of kinetic weapons, a carbine modified to work in space may be significantly more effective that on earth.
The goals of the various competing captains will be similar to those of naval warfare. Obtain optimal distance with optimal stealth then engage with enough fire power to prevent the enemy from being able to respond.

HIGH ORBIT ABOVE PLANET OR MOON X
​

On the bridge of capital vessel “A” a cry of alarm goes out as multiple contacts are detected on sensors. The crew scrambles. Armored space suits are donned. Robotic fighters are launched and handlers assigned. The capital ship begins to rotate to turning its most shielded portion toward the enemy as the first volley of energy weapons play over the spot that the handwavium drive had been just seconds before.
In the void between capital ship “A” and the still as of yet undetected capital ship “B”. Robotic fighters engage and begin to destroy the dozens of determined six foot long torpedoes closing in on the capital ship. From a point tangential to the battle an array of energy waves play across robotic fighters and capital ship “A” reducing the effectiveness of the EM sensing and communication devises hampering the crews ability to control the Robotic ships. Sensing the communication gap the fighter’s AI programs take over and continue the defense.
The captain of capital ship “A” orders two volleys of projectiles to be launched at the predicted location of the enemy capital ship and the one causing the EM interference. A tight radio and laser beam combination communication is sent toward HQ as well alerting them of the situation. Just as the first of the few remaining torpedoes strike the thickly armored hull of the, small sections of hull explode outward destroying the torpedoes just prior to impact.
Seconds later the now bare hull is peppered by small uranium tipped rounds that were launched over thirty minutes ago from the long gone, capital ship “B”. These rounds begin to punch damaging holes into the heavy ship which is still attempting to maneuver out of the way. The EM field interference clears just enough for the crew to notice a second volley of torpedoes seconds away moments before the first one impacts.
Meanwhile on the bridge of the capital ship “B” under four gravities of acceleration a report flashes across the captains HUD suggesting that the enemy vessel suffered catastrophic damage. He barks the order to stop acceleration and prepare to change course is given. A small series of encoded EM pulses are sent to HQ announcing their successful encounter.

Fixed for those of us who use darker forum skins. In the future, please stick to the default colour, please.

 

[docabn]

I am using the default color :huh:???

 

[Izack]

It looked like this for me:

 

[statickid]

Seconds later the now bare hull is peppered by small uranium tipped rounds that were launched over thirty minutes ago from the long gone, capital ship “B”. These rounds begin to punch damaging holes into the heavy ship which is still attempting to maneuver out of the way. [/I]

I can see the torpedo devices having some kind of active flight control and hitting the large ship, however, I think even if it was slow to maneuver even a puff of thrust would be evasive enough for the uranium tipped rounds to miss by several km. They detect the torpedoes from a distance and fire maximum thrust evasively to basically put themselves in a random location (as far as calculating the where to fire the rounds). The uranium tipped rounds would have to hit the ship by pure chance or stupidity IMO. or they would have to be fired in an EXTREMELY wide cloud, like a huge shotgun spread. Except over the course of half an hour, even a dense cloud would be diffuse over such a wide area that only a few rounds would hit

 

[docabn]

The uranium tipped rounds would have to hit the ship by pure chance or stupidity IMO. or they would have to be fired in an EXTREMELY wide cloud, like a huge shotgun spread. Except over the course of half an hour, even a dense cloud would be diffuse over such a wide area that only a few rounds would hit

That was the idea, a wide torus rather than cloud at the estimated range and velocity. This is just a simple senario to try and demonstate how multiple levels of offense and defense might be used. And yes to have pulled this off Captain A would have to be asleep at the wheel and captain B on his game.

 

[statickid]

A torus is funny because if they didn't move, it wouldn't hit them! Chances are, however, that they would! :blink:

 

[docabn]

yeah... combat is a lot of guessing where the enemy will be:shrug:. I can assure you that as often as not, even in modern combat, we miss guess where the enemy will be... of course that never makes the news.

 

[statickid]

It makes the news in the form of reports of surprise attacks, I do believe. If a helicopter gets shot down, my guess would be that the position of the enemy was misjudged.

 

[Hielor]

Obtain optimal distance with optimal stealth...

I stopped reading there.

There is no stealth in space.

 

[docabn]

I stopped reading there.

There is no stealth in space.

How do you figure? It is not that you could hide, though you could follow the sub tactic of run silent (ie. produce a very small EM profile). But space is big as we have learned from orbiter. In space combat I believe hiding would mean that you are occupying a piece space that your opponent was not looking at. You can’t look at all of it at once and the further away you are the more sensitive the telescope (light, radio wave, ect…) has to be. The more sensitive the device the smaller the piece of sky it has to look at.

 

[Hielor]

How do you figure? It is not that you could hide, though you could follow the sub tactic of run silent (ie. produce a very small EM profile). But space is big as we have learned from orbiter. In space combat I believe hiding would mean that you are occupying a piece space that your opponent was not looking at. You can’t look at all of it at once and the further away you are the more sensitive the telescope (light, radio wave, ect…) has to be. The more sensitive the device the smaller the piece of sky it has to look at.

PLEASE use the default color. Your text is almost impossible to read for those of us using dark forum skins.

There's no stealth in space because there's no such thing as "running silent." If your ship is doing anything at all, or has done anything at all anytime in the recent past, it will be warmer than the background radiation and fairly easily detectable.
http://www.projectrho.com/rocket/rocket3w.html#nostealth

 

[jedidia]

But space is big as we have learned from orbiter. In space combat I believe hiding would mean that you are occupying a piece space that your opponent was not looking at.

that might be a tad difficult if your opponent has a telescope array with IR filter that can photograph the whole sphere of the sky every minute or so, and a moderately efficient algorithm to evaluate those picture. The heat signature of a ship against the cold background of space is just impossible to hide, so most probably any battleship would be equiped with devices that make sure that they detect that signature wherever it is.

 

[docabn]

sorry about the format...
I still think that just as happens now. If conflict comes to space, we will learn tricks to make ourselves less detectable by our enemies while at the same time learn ways to find our enemies who are trying to hide from us. But I agree with modern techniques it would be very difficult to hide a small weapons platform especially in orbit.

 

[Linguofreak]

Hey, I've always wondered this- I don't know much about theoretical high powered lasers, but whenever i'm watchin sci-fi movies i can't help but wonder this:

If people are having laser battles, what would stop people from just having super reflective mirrored ships (or deployable shells) that just reflect the lasers off of them>>?:OMG:

Most likely not. For one thing, if you're using really intense pulses, reflectivity and transparency go away, so that even a shiny mirror or window acts as if it were black and opaque.

Secondly, even with less intensity, you've still got to have a material that's really, really reflective over a large range of frequencies (otherwise your enemy can simply use a different color of laser to zap you). The materials that are reflective over a wide range don't tend to be super refelctive, and the super reflective materials don't tend to be so over a large frequency range.

According to the linked site they were more geared toward abrading incoming projectiles and missiles. I think they would be more effective as counter-laser defenses as you said, though. Especially the versions held in place by a magnetic field.

I've generally heard sandcasters dismissed as ineffective outside of soft sci-fi.

Unfortunately, I have very little knowledge of lasers. So far in my drafts I've taken some artistic license (gasp) with my depictions: invisible unless passing at a very acute angle (IE nearby),

You might see a bit of that, as there would probably be some side-scatter, but there would probably be very little distance between the part where you can't see it, the part where you can, the part where it blinds you too fast for you to see it, the part where it sets you on fire, and the part where it blows your head apart before you're blinded. My gut feeling is that the transition would take place over the space of inches for a well-focused beam, so that your right eye might see a light in the direction of the laser, while your left eye was blinded and its eybrow set ablaze, and your left ear exploded in burning gore.

phasing through the spectrum from more blue towards its point of origin to more red in its direction of travel.

Not a chance. If you were in the fringe area of the beam where the intensity was low enough to be visible without being blinding/fatal, you'd see a light of whatever color the beam was coming from the end of the laser (just like if you look at a spotlight or movie projector from almost straight ahead). In any other direction you wouldn't see anything, except a bright spot at the target, and maybe some of the beam color along the path if you're in atmosphere or a dust cloud and the beam is of low intensity, or else glowing hot air along the path of the beam if you're in atmosphere and the beam is of high intensity. In vacuum, you'd only see beam color in the direction of the firing laser, and incandescent glowing in the direction of the target.

It would make a red circle on the hull of the craft it hit for am instant before that hull violently melted (you could say burst into a molten plume).

What you'd see from the target would generally be fairly consistent: For a low intensity/long duration beam, a red/yellow/white hot spot (depending on how much it was heating up the target, possibly with some of the beam color mixed in). For a high intensity/short duration beam, a bright flash, followed, if you were far away enough that it didn't blind you, by white-hot chunks of target flying every which way.

Your argument against NSWRs seems valid. I'll have to rethink that... :blink:

Plus, Greenpeace would *NEVER* allow them, even if there were no accidents. NSWR's are *worse* for the environment than Orion, if you can imagine such a thing. Heck, I tend to be fairly anti-environmentalist, and I don't want an NSWR any closer to me than lunar orbit.

Seems like the best defense against lasers would be redundant systems, partitioned fuel/02 tanks, and enough space suits for every crew member to suit up when at battle stations.

Lasers are really limited in the area they can damage, so you could keep fighting for a pretty long time if the crew is suited and your enemy can only hit a 1x1 foot area of the ship per shot.

Well, a short-pulse, high-intensity laser could vaporize that 1x1 area fast enough to create a rather violent explosion, how violent depending on how fast and how high-intensity the pulse was.

When you can't kill the crew outright by punching a hole in a hab module, it's actually pretty tough to fully destroy a spacecraft. High-speed kinetic weapons are useless because they'll just go in and out like buckshot through a paper bag.

That's what a bursting charge is for. Smaller impactors, at a given velocity, will penetrate less, so breaking up the shell shortly before impact will make it less penetrating. Ideally, you want your timing and average fragment size to be such that each fragment goes through the armor on the side facing the shot, then the whole ship, and by then is going slow enough to bounce off the inside of the armor on the other side of the ship.

This just suddenly occurred to me:
What about variable velocity projectiles? Say, you launch a large shell at a good velocity, but the shell explodes backwards wrt its velocity vector, sending out a spread out field of slower moving particles?

No need, and impossible without an atmosphere. You can reduce penetration just by reducing fragment size, and conservation of momentum and energy ensure that to slow down part of the shell in vacuum, you have to speed the rest of it up.

At least in populated areas, a laser breaching the hull is devastating. The air inside could explode (rapid expansion under heat), and all people in the room will at least be permanently blind.

At least those looking directly at anything the laser hit would be. From what I've heard, otherwise everybody's eyes should be safe. But yeah, being in a compartment that a short-pulse laser hit would not be fun. It would basically be the same as a few TNT charges going off in the compartment (say one going off on the wall it entered through, and one going off on the wall it exited through). Exactly how much damage it did would depend on the energy that the laser delivered, how quickly it did it, and how small a spot size you had.

But I think most battles in space would be thought by unmaned vehicles, which would reduce that risk of a laser blowing up a whloe compartement because it's helped along by the air in it (might still happen in a fuel tank, though...)

There probably would be a lot of unmanned vehicles involved, but more because of the weight of crews and their life support, and the desire to stretch available manpower as far as possible.

Not quite so, I'm afraid. It's the same effect that hypervelocity ammo has on tanks: They turn to plasma when they hit the armor. So a hypervelocity projectile wouldn't leave a ship on the opposite side, because it turns to a rapidly expanding plasma cloud after impact. And you don't want to have one of those inside your ship!

The plasma cloud can still leave on the opposite side if the ship is thin-skinned enough and the plasma cloud is still dense when it reaches the other side. But that's what bursting charges are for: If your weapon is likely to have most of its energy go through the ship instead of stop inside it, you blow it up into smaller fragments that are individually less penetrating.

However, kinetic weapons are a pain to aim, considering the distances and velocities involved in a space battle.

That depends entirely on how you aim them. If it's just a dead projectile without any kind of maneuvering thrusters or guidance system, it's going to be hard to hit with.

Any kind of projectile would probably at least have some kind of terminal maneuvering system, and, depending on circumstances, a bursting charge could help with aim as well as limiting over-penetration.

If you're fighting with unmanned vehicles alot, you'll likely see alot of use of *RAMMING SPEEEEEEEED*!

And their ammo is cumbersome.

Meh... At 3 km/s, a kinetic strike delivers energy to its target equivalent to its weight in TNT. The energy delivered to the target goes up with the square of impact velocity. So at 6 km/s, you've got 4 times the weight of the projectile in TNT equivalent, at 12 km/s 16 times, and so forth. Pretty soon you get to the point where an empty beer can with a few guidance thrusters rips a 12-foot diameter hole through your ship.

As for laser defences, I think the last thing we'd want to do is distribute the energy over the whole ship.

You mean defenses against lasers? For one, there's not much that would be effective, for another, if you found something that did work, then anything that could spread out the beam would be a good thing. Your enemy is already going to be trying to focus the beam in such a way as to do the most damage possible, so defocussing it can only help you.

Of course it seems like a good Idea, but what about impulsive shock? If the energy spreads too fast through the armor, it will tear the whole ship apart!

The more you spread the beam out, the less likely it is to cause impulsive shock. If he has a beam powerful enough to cause impulsive shock over your whole ship, he'll be firing it defocused so as to hit your whole ship in the first place anyways (especially if firing from really long ranges where light-speed delay is a factor).

How do you figure? It is not that you could hide, though you could follow the sub tactic of run silent (ie. produce a very small EM profile). But space is big as we have learned from orbiter. In space combat I believe hiding would mean that you are occupying a piece space that your opponent was not looking at. You can’t look at all of it at once and the further away you are the more sensitive the telescope (light, radio wave, ect…) has to be. The more sensitive the device the smaller the piece of sky it has to look at.

Space is big, but it is also dark and cold. I have heard stealth in space compared to stealth among penguins with flamethrowers, wearing night-vision goggles, on an antarctic ice sheet, at night.