Laser battles in space.

POSTED BY: Hjermsted
UPDATED: Monday, March 22, 2004 21:20
VIEWED: 21470
PAGE 7 of 9

PREV PAGE 1 2 3 4 5 6 7 8 9 NEXT PAGE

HANOVERFIST

Friday, March 19, 2004 8:49 PM

I have to admit that Kinetic Energy weapons have a lot of appeal from the 'let's knock the crap out of something' perspective, but I have my doubts about how well they could be implemented in an actual firefight. No projectile in space is going to travel in a straight line. I find it hard to believe that a battle would take place in interstellar space. So most likely any fight is going to take place in a planetary system where you have very complicated orbital mechanics to worry about.

You also have the travel time of a projectile to worry about. Just like in combat now, whoever strikes first, hardest, and most accurately will usually win. (Especially considering the harshness of a space combat environment.) The effective range of an well collimated energy weapon would be far longer than an equivalent KE weapon.

I just do not believe that these two problems could be overcome from a practical standpoint.

Let me just clarify one thing. I am talking about 'dumb' projectiles, not some sort of torpedo or guided missle. I just think that given the distances you are going to have to cross in space combat, I do not think simple projectiles will get the job done.

Now let me muddy the waters a bit...What about a guided missle that contained an h-bomb pumped laser? (ala Niven and Pournelle in Footfall) You have a large torpedo that contains a laser and a small hydrogen bomb as the power source. The torpedo gets within close range and then the bomb explodes supplying the laser with power which then punches a nice hole in the offending ship. In Footfall the lasers were X-ray lasers and I thought it was kind of funny/disturbing how the stupid aliens were becoming sick and dying and at first they weren't sure why.

What do you think?

Hanover Fist

HOTPOINT

Friday, March 19, 2004 8:59 PM

Quote:
Originally posted by HanoverFist:
I have to admit that Kinetic Energy weapons have a lot of appeal from the 'let's knock the crap out of something' perspective, but I have my doubts about how well they could be implemented in an actual firefight. No projectile in space is going to travel in a straight line. I find it hard to believe that a battle would take place in interstellar space. So most likely any fight is going to take place in a planetary system where you have very complicated orbital mechanics to worry about.

Orbital mechanics isn't hugely tricky in itself the maths is actually quite easy assuming that computer technology in the Firefly Verse isn't actually much worse than ours

I read once that one of the Voyager probes ended up within 10 metres of where it was aimed when it reached Jupiter. And that was using 1970's calculations!

Quote:
Originally posted by HanoverFist:
You also have the travel time of a projectile to worry about. Just like in combat now, whoever strikes first, hardest, and most accurately will usually win. (Especially considering the harshness of a space combat environment.) The effective range of an well collimated energy weapon would be far longer than an equivalent KE weapon.

Like I said you would want to get in a sneak attack with a Kinetic Energy weapon. If it was stealthed it would be very hard to detect until it arrived as it is completely inert in itself

Quote:
Originally posted by HanoverFist:
Now let me muddy the waters a bit...What about a guided missle that contained an h-bomb pumped laser? (ala Niven and Pournelle in Footfall) You have a large torpedo that contains a laser and a small hydrogen bomb as the power source

That was an idea mooted by Edward Teller (who invented the Hydrogen Bomb by the way). They never could get it to work but if you could develop a crystal lattice to absorb and funnel a nuclear blast into a coherent blast of X-Rays it would be one heck of a directed energy weapon

...................................
Hurrah, hurrah, when things are at their worst
With cries of “Death or Glory” comes the mighty Twenty-First

ANTHONYT

Friday, March 19, 2004 9:06 PM

Quote:
Kinetic Energy weapons have an infinite range. The problem is the target moving whilst the round is in flight. That's why you would try for an ambush at Long Range. Use Lasers at medium range and go back to Kinetic Energy weapons at point-blank

I agree that a railgun would be good for a long range shot against a stationary object, or one whose flight path is absolutely certain over a course of minutes or hours. So, it's good for attacking a space station.

I also feel that a railgun would be good for point-blank shots against moving targets that do not exceed the speed of the railgun munition. (Targets in the process of accelerating beyond railgun munition speed could not be hit.)

Quote:
It terms of damage a Kinetic Energy hit is far more devastating

I do not agree.

Quote:
Think of it this way. You have a 1 Gigawatt Power-Plant. You can use this to fire a beam but you would need to keep it on target for ten minutes to project the same energy to the target that you would if you charged capacitors for ten minutes to fire a single Railgun Round to a really high velocity

The Railgun round will likely disable the target with one hit whereas the Laser takes time to do the job (during which it fires back)

I think this argument is fallacious. You are proposing that storing energy and transferring it to an object, and then using that object to transmit the energy to a target is more 'devastating' than storing energy and transmitting it directly to a target.

Surely it has occurred to you that if a Gigawatt power plant can charge capacitors for ten minutes to launch an impressive railgun slug, it can also charge capacitors for ten minutes to deliver a Petawatt+ range laser pulse? A laser pulse of such power so as to not require lengthy burn times? A laser pulse capable of explosively vaporizing matter on contact?

There may be applications for railguns in space. I simply do not think that the railgun is THE weapon of choice for Space Combat, and it is certainly not inherently superior to a laser or other directed energy weapon.

--Anthony

"Those who beat their swords into plowshares usually end up plowing for those who didn't."

"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote."

-Benjamin Franklin

HOTPOINT

Friday, March 19, 2004 9:22 PM

Quote:
Originally posted by AnthonyT:

Surely it has occurred to you that if a Gigawatt power plant can charge capacitors for ten minutes to launch an impressive railgun slug, it can also charge capacitors for ten minutes to deliver a Petawatt+ range laser pulse? A laser pulse of such power so as to not require lengthy burn times? A laser pulse capable of explosively vaporizing matter on contact?

Of course you could use your capacitors to do this but then you are looking at a much larger Laser Weapon to fire it which would have to be able to withstand actually firing the pulse without disintegrating itself

I'll think you'll find from an engineering standpoint it is easier to pump additional wattage into a mass-driver than a Laser Emitter you just up the field strength within the Driver

Also I am not sure how waste heat might effect a seriously powerful Laser. Heat is a bitch to get rid of when you have no atmosphere to conduct it away and you have to rely on radiation(The only Laser I ever got to play with used to get hot with continual use but I can't say I'm an expert on the things)

...................................
Hurrah, hurrah, when things are at their worst
With cries of “Death or Glory” comes the mighty Twenty-First

ANTHONYT

Friday, March 19, 2004 9:29 PM

The same issues of heat, stress, cooling, and size apply to a railgun that would apply to a laser. I'm not sure how the railgun is superior in this aspect.

For instance, a railgun designed to operate at 1 GW would have to be redesigned to operate at 1 TW. It would need heavier gage wire and bigger transformers and better magnets, improved cooling, etc. The same applies to a laser. A laser designed to do more would of course necessitate re-engineering.

So I'm still not understanding the point of the argument in that respect.

--Anthony

ANTHONYT

Friday, March 19, 2004 9:36 PM

Incidentally, according to my research

http://www.ee.ust.hk/~eekwok/publications/2001/AP_2001_73_45.pdf.

A 25 Watt, dual pulse industrial laser arrangement can cut through a 1/8 inch thickness of stainless steel in 36 milliseconds.

I have no data on what a kilowatt, megawatt, or terawatt range laser might be capable of, but the short answer suggests itself: A lot.

--Anthony

HOTPOINT

Friday, March 19, 2004 9:54 PM

Quote:
Originally posted by AnthonyT:
The same issues of heat, stress, cooling, and size apply to a railgun that would apply to a laser. I'm not sure how the railgun is superior in this aspect.

For instance, a railgun designed to operate at 1 GW would have to be redesigned to operate at 1 TW. It would need heavier gage wire and bigger transformers and better magnets, improved cooling, etc. The same applies to a laser. A laser designed to do more would of course necessitate re-engineering.

So I'm still not understanding the point of the argument in that respect.

Mass-Drivers do not I believe get hot when in use like Lasers do. Which is where I was coming from it terms of scaling up

They do produce waste heat (everything does it's basic thermondynamics) but they do not get as hot as a Laser of equivalent wattage would and would therefore not require as much cooling gear

I would have thought that a very powerful Laser would be in danger of destroying itself because its own waste heat would be bad news for whatever it was made from surely?

...................................
Hurrah, hurrah, when things are at their worst
With cries of “Death or Glory” comes the mighty Twenty-First

ANTHONYT

Friday, March 19, 2004 10:01 PM

Lasers use electromagnets, capacitors, transformers, and all the assorted other components that a massdriver might use.

I don't know that a laser creates more waste heat than a railgun of equivelant capability. Do you have data on this? I don't. I wouldn't even know where to go to find it. Railgun technology seems a bit more secret than laser technology.

This is probably because lasers have so many commercial uses, whereas railguns are more specifically military.

--Anthony

LTNOWIS

Friday, March 19, 2004 10:01 PM

This is a really good discussion, good points all around. As usual, I enter it late. Personally, I think that a mix of weapons seems fun, but I'm not sure if it would work out if one weapon was a lot better. If a medieval person predicted that we'd be using a mix of arrows and bullets today, they'd be wrong.

In Firefly, however, we don't see any space combat except for the alliance cruiser destroying the derelict, most likely with their short-range boarding-type weapons, and Jayne shooting with Vera. So we really don't know what their main space weapons are.

One important thing you're missing is that none of the lasers in sci-fi are really lasers, as someone pointed out earlier. A real laser you can't see, because:
a) It's going the speed of light.
b) Being made of light, it can't reflect light.

You can only see it dust, fog, etc., and it's only a line, not a beam that moves forewards.

Yet in every sci-fi, including Firefly, you can clearly see the beams. My explanation is that when we invent a "plasma-based beam weapon" or whatever, people will call them laser beams because they've seen all the sci-fi shows, and the companies marketing them will want people to have an instant mental image of their weapon and what it does.

The bottom line to all this rambling is that in most sci-fi reality, laser weapons are really just generic energy beams, explainable only by meaningless technobabble.

KUGELBLITZ

Friday, March 19, 2004 10:17 PM

Getting rid of heat is big. Even a broad low power laser is going to cause a ship far far away to get hot. It doesn't have to be lethal, just bale to create a mission kill, if the crew is in trouble you win either way.

This discussion is overlooking some things.

Firstly, there is some kind of gravity tech being used. I think we can assume that the unit is not larger than a Firefly class ship. That right there is a terrific weapon- a directed gravity beam that creates a steep gravity gradient could wreak havoc on a ship, or cause projectiles or lasers to warp in space and become deflected. The tech is there, we just haven't seen the weapon version of it yet.

The whole electronic aspect of commo, nav and other things is seen at the level of an old, clunky ship. The state of the art must be terrific, so Alliance crusiers may very well be able to disappear if they need to, by going stealthy and deploying decoys or some such stuff.

It could very well be that long range stuff is impossible to do because of this. I would also point out that aircraft made battleships obsolete, not missiles. Therefore any sufficiently lethal weapon carried by a fighter obviates that type of ship in existence. So the Alliance cruisers are probably carriers.

"We are exporting democracy because we have all of this unused democracy lying around at home. Why not make some money doing it?"

PREV PAGE 1 2 3 4 5 6 7 8 9 NEXT PAGE