Space combat hangups

[Artless]

Recently a friend and I were discussing playing a campaign that dealt a lot with ship-to-ship space combat. So stuff that included small personal craft up to larger corvettes, cruisers and warships.

And during this discussion we started to get into the viability of certain kinds of ordnance in any given scenario you might face in the relative vacuum of space, and why every one of them would end up looking like a rave. I feel like I've got a pretty good grasp of the concepts at work here, but in all likelihood I've neglected something significant, so I thought I'd bring the discussion up here in the hopes of getting a satisfying resolution.

Specifically, he was convinced that weapons that operated at light speed or close to it, such as lasers or directed energy weapons would generally be a better choice for engaging another ship than any other type of weapon. The assumptions we were working under for this were that the power requirements of these weapons were rendered negligible by a society capable of creating ships that could travel between star systems in a matter of hours, days and weeks instead of years, and that their targeting would be sufficiently advanced that they would be able to hit things at astronomical distances with relative ease. Also, that whatever exotic method they use to make their ships travel faster than light is not fine-tuned enough that they could just warp warheads into the other ship, like if it relied on relays or a dock of some sort.

I attempted a variety of counters in an effort to support different kinds of weaponry in the combat minigame, but I wasn't really convinced by them and neither was he. What I want to know is if there are any reasons, given the factors of this imaginary future presented above, that a ship would stock material weapons and not just rely on firing flashlights at each other? For example, if there were any kind of debris or object between the ships fighting, like a planet, then obviously something with a linear trajectory wouldn't work. I presented that factor, and the fact that space is full of tiny bits of "stuff" that might diffuse the laser weapon, but that alone doesn't seem like enough. Am I just thinking in the wrong direction?

At the moment I am positing that the energy payload of these weapons is relatively minute compared to something like a railgun or a warhead, comparable to a micrometeorite impact. So lasers would be good for small-scale craft fighting with one another, where the thinner hull being punctured is serious business, but for larger ships with more robust shielding and thicker hulls they would need to rely on other forms of punishment in order to resolve battles quickly.

[Wrathzog]

Putting about a minute of thought into this, but given that you have FTL travel capabilities and the ability to make lasers that can cause any sort of damage over very long distances (as in hundreds of miles or something silly), they will pretty much be the de facto weapon to use for this sort of thing.

The key is travel time. Anything you can fire at another ship is going to be shot out of space before it can do any damage by that ship's laser defense system.
Railguns might be viable if you can cloak your projectiles from being detected and compromised...

Shielding works better against lasers than projectiles? So, you shield your ships and your missiles...? hurm...

-e-
Changed a word, added a sentence...

[...You Lost Me]

Everybody wants to see lazors. I think I have yet to see an interesting space battle where people weren't firing lazors.

I'd just stat them up however it feels comfortable, put the "THIS IS A LAZOR" tag on it, and justify your reasoning by saying "It's a game" when people ask.

[fectin]

Is "albedo" a good enough reason?

[tzor]

Well there are a lot of things that depend on the exact systems you are using; for propulsion; for standard defence (any rapidly moving vessel even below the speed of light is going to be pulverized by the minute debris of interplanetary space); for general observation of the universe. We normally think in terms of direct hull breach only, but slowing, blinding or lowering the shields is just as important and can easily be the first line of attack that makes the hull breach possible.

Then you need to consider the speed of the sub light ships. You can easily have a number of scenarios where one goes from sub psol (psol – percentage of the speed of light) to high warp. In these cases high psol weaponry is just as effective as supersonic weaponry in terms of getting a payload to the target before the target can outmaneuver the payload.

A lot of scenarios involve some kind of plasma magnetic field. (Star Trek and Traveller come to mind) Any weapon that can disrupt this field gives the attacker an advantage. Any significant burst weapon could, in theory, blind a sensor array.

[CapnTthePirateG]

Well, I have to say...

You have lasers. They travel at the speed of light.

You have FTL. It goes faster than light.

Why not FTL drive missiles?

This works better or worse based on your FTL drive.

[Artless]

@Wrathzog: Yeah a big reason I was having trouble with this is that even if there were a distance limit to the lasers, then they'd still make ships virtually untouchable by just shooting or otherwise rendering moot any solid object sent at them.
As to the shields, in addition to a kinetic projectile barrier we always see in Sci-Fi, the shielding against lasers I was thinking of would be providing what fectin just brought up; a sort of silvery reflective screen that deflects light-based weapons.

@ fectin: If by that you mean they'd make ships have a high reflectivity, I don't think ships would be entirely diffusely reflective on their own, given that they'd probably want to keep detection at a minimum, and the profiles of a ship would stand out quite a lot against even irregular bodies like asteroids.

@Cap: I guess I should broaden the problem I want to solve. I'd like if there were multiple avenues to blowing shit up, so that there wasn't always a single option that is in all ways superior to the others. The FTL nuke scenario was what prompted this discussion in the first place, because we talked about why that never happens in other sci-fi universes that have FTL capable ships, so we established that the ships need relays or some externally provided, monumentally power-draining construct to travel between systems. And then the lasers thing happened, and I guess I want my cake and I want to eat it too.

[Winnah]

Several issues. Ordinance has mass and requires storage. On a self contained space vessel, the energy requirements for storage and use are going to be an issue.

Lasers are pretty energy intensive as well, not to mention issues of diffusion and maintaining a sustained beam on a moving target.

Guns are probably still neccesary. Though munitions are likely to take a new form. Such as smart drones. Nothing wrong with missiles either, so long as miniaturisation allows them to approach light speed, even for a short duration.

Tactically speaking, a large field of play could be interesting. Imagine 2 enemy ships detect each other at a massive range, such as a thousand kilometers. Both start lauching attacks that may take minutes to intercept their target. Both ships start moving, possibly toward each other, launching waves of attacks and countermeasures for respective ranges.

Due to the math involved, the majority of these attacks can't simply be eyeballed. They have to be calculated. The information for those calculations comes from sensors. In my opinion, jamming the other guys sensors or remotely hacking parts of his ship is going to be a major part of this style of warfare. Blinding sensors would probably be easiest to achieve, especially if energy weapons are in play.

[K]

The problem with lasers is that you can't do any space opera tropes like battles. It basically ends up with people firing from positions light-minutes away and blowing the hell out of the things before anyone even sees them.

[Artless]

Tactically speaking, a large field of play could be interesting. Imagine 2 enemy ships detect each other at a massive range, such as a thousand kilometers. Both start lauching attacks that may take minutes to intercept their target. Both ships start moving, possibly toward each other, launching waves of attacks and countermeasures for respective ranges

Yeah, at one point we were discussing the idea that space combat would have to take place at generically extreme ranges, otherwise the ships involved would pose as much danger of ramming into each other as they would with shooting each other.

I watch stuff like Star Wars and I wonder what kinds of predictive computers they're working with that let them have small craft engage with each other with only a few meters of room between them without running the risk of just blowing each other up in a collision.

So we got on to stuff that would work with a relatively short window of opportunity at extreme distances, and that became this discussion, which I admit is pretty circular.

The problem with lasers is that you can't do any space opera tropes like battles. It basically ends up with people firing from positions light-minutes away and blowing the hell out of the things before anyone even sees them.

I know. I kinda want to just tell my friend to abandon laser weapons and just have something like guided plasma fulfill the "energy pew pew" portion of the weaponry.

[Wrathzog]

Why not FTL drive missiles?

FTL travel doesn't necessarily mean traveling in a straight line.

[tzor]

Yeah a big reason I was having trouble with this is that even if there were a distance limit to the lasers, then they'd still make ships virtually untouchable by just shooting or otherwise rendering moot any solid object sent at them.

No; that assumes that you can detect these objects comming towards you. A solid black body projectile would be invisible to active EM sensors although it would produce a doppler shifted black body radiation pattern. In the opposite example the projectile could have active EM offenses designed at radically confusing acive/passave EM sensor arrays.

It would be interesting to see if you could generate and accelerate micro black holes such that the decay rate is longer or equal to the distance to the enemy vessel. Such projectiles would be completely undectable.

[Artless]

No; that assumes that you can detect these objects comming towards you. A solid black body projectile would be invisible to active EM sensors although it would produce a doppler shifted black body radiation pattern. In the opposite example the projectile could have active EM offenses designed at radically confusing acive/passave EM sensor arrays.

It would be interesting to see if you could generate and accelerate micro black holes such that the decay rate is longer or equal to the distance to the enemy vessel. Such projectiles would be completely undectable.

That and the fact that these objects, even if detected, would be about the size of any given piece of debris in space, would give something like a warhead considerable stealth chops.

But it seems to me that as soon as it has propulsion, it's detected and tracked.

So we had worked warheads into being like clouds of mines you could just let waft over to other ships and detonate when they were in range.

[ishy]

You could also use it as a defensive measure, that for example a laser can't go through the 'cloud' or smt left behind by an explosion.

Or make laser more precision based weaponry and that you need warheads to take out attacking nanobots etc.

[CatharzGodfoot]

As long as you're using only relativistic maneuvering, you can probably have your cake and eat it too. The most basic kind of non-laser 'weapon' you're going to see is some kind of chaff launcher. Once you toss enough glitter into space, laser weapons are going to be less useful.

A more high-tech 'weapon' is some kind of super-strong magnetic field generator/shaper. As with lasers, this is another light-speed weapon that will be most useful as a sensor, but also for smashing shit up.

If you have fine-tuned gravity generators (I assume you must, because otherwise robots will always win), those can be used to deflect lasers, and if weaponized they could interfere with enemies' inertial dampers enough to turn the enemy crew to jelly.

Anything that doesn't operate at light speed is going to have to either be stealthy and at least as fast as a ship (stealth AI missiles), very close range, or passive and massively scalable (chaff, mine fields, rail guns, or huge amounts of crap launched accelerated to relativistic speeds).

[Josh_Kablack]

For scientific thinking about sci-fi trappings, you could do worse than The Atomic Rockets Site Their space weaponry page has some relevant things to say

However, since you are postulating outerspace warships, you are very very likely postulating FTL travel and other tropes than break known relativistic and scientific constraints. And in that case, you're better off approaching this by first asking what makes the game better or setting more interesting and then inserting semi- or psuedo- scientific justifications to back them up.

[hogarth]

Is "albedo" a good enough reason?

In Larry Niven's Known Space books, he mentions painting ships' hulls with reflective paint (with an indestructible transparent coating).

The ultimate weapons in his books are antimatter and matter -> energy conversion.

[Artless]

For scientific thinking about sci-fi trappings, you could do worse than The Atomic Rockets Site Their space weaponry page has some relevant things to say

However, since you are postulating outerspace warships, you are very very likely postulating FTL travel and other tropes than break known relativistic and scientific constraints. And in that case, you're better off approaching this by first asking what makes the game better or setting more interesting and then inserting semi- or psuedo- scientific justifications to back them up.

That is a very useful resource I had puzzlingly never come across before, thank you.

[Vebyast]

For scientific thinking about sci-fi trappings, you could do worse than The Atomic Rockets Site Their space weaponry page has some relevant things to say

Finally, someone mentions Atomic Rockets. That site rocks.


The strongest weapons are not antimatter, nor are they lasers or FTL missiles. Relativistic Kill Vehicles are where it's at. Build a missile that accelerates up to within several nines of c then dumps a cloud of hydrogen out the hatch. Every atom of hydrogen is carrying about as much energy as an aircraft carrier at full steam and detonates like a grenade on impact. There are tens of thousands of atoms of your hydrogen per square meter of their hull. Their ship is shredded.

For a bit of a change, do this with electrons instead of hydrogen. It works a bit differently (particle accelerator instead of relativistic delivery vehicle), but if you can pull it off you have an even more devastating weapon: bremsstrahlung. When a charged particle hits metal, it throws off a spectacular cloud of radiation. Repeat the relativistic shotgun with electrons, then, and instead of blowing the ship to pieces you'd kill every living thing on board, fry every piece of circuitry they have, and transmute a bunch of their ship into radioactive heavy metals.

[Kaelik]

In Niven's books the actual superweapons are kinetic kill ships/missiles that work on that principle, but since they don't really work on other people's ships (they jump into hyperspace, or whatever it's called because they can damn well see you setting up your run) it only works on planets, and so people are generally MAD enough not to do it.

[hogarth]

The strongest weapons are not antimatter, nor are they lasers or FTL missiles. Relativistic Kill Vehicles are where it's at. Build a missile that accelerates up to within several nines of c then dumps a cloud of hydrogen out the hatch. Every atom of hydrogen is carrying about as much energy as an aircraft carrier at full steam and detonates like a grenade on impact. There are tens of thousands of atoms of your hydrogen per square meter of their hull. Their ship is shredded.

In the Known Space universe, there are not one, not two, but three nigh-invulnerable materials you can make ships out of.

[TheFlatline]

Tactically speaking, a large field of play could be interesting. Imagine 2 enemy ships detect each other at a massive range, such as a thousand kilometers. Both start lauching attacks that may take minutes to intercept their target. Both ships start moving, possibly toward each other, launching waves of attacks and countermeasures for respective ranges.

A thousand kilometers is basically point-blank range for ships that have any real kind of velocity.

In The Forever War ships would travel at about 90% the speed of light, and combat at relativistic speeds was basically handled by computer. The computer would calculate the enemy trajectory (such as it was due to time dilation) and launch a warhead in an intercept path. The warhead would blow up near the ship, sending clouds of matter into the ship's path. A few molecules could be devastating.

In Traveler, we discovered that often explosive decompression was more dangerous to a ship than actual battle damage often was. So everyone tried to take levels of vac suit and whenever combat was likely to break out everyone would suit up in a hard vacuum suit and depressurize the cabin. Often times shots that would have destroyed the ship from explosive decompression pass harmlessly through the superstructure, waiting for a patch job later on.

[hyzmarca]

So we had worked warheads into being like clouds of mines you could just let waft over to other ships and detonate when they were in range.

The problem with mines is the simple fact that space is huge. You'd need trillions upon trillions of mines to intercept an enemy ship, if you knew its exact course in advance. The chances of getting any one anywhere near your target are incredibly small.

[Kaelik]

The strongest weapons are not antimatter, nor are they lasers or FTL missiles. Relativistic Kill Vehicles are where it's at. Build a missile that accelerates up to within several nines of c then dumps a cloud of hydrogen out the hatch. Every atom of hydrogen is carrying about as much energy as an aircraft carrier at full steam and detonates like a grenade on impact. There are tens of thousands of atoms of your hydrogen per square meter of their hull. Their ship is shredded.

In the Known Space universe, there are not one, not two, but three nigh-invulnerable materials you can make ships out of.

Well yeah, but kinetic kill would still exert internal force on the occupants, who would then all be dead, if you ever just let it hit you.

[Vebyast]

In the Known Space universe, there are not one, not two, but three nigh-invulnerable materials you can make ships out of.

Wikipedia says that GP hulls are vulnerable to antimatter; relativistic hydrogen impacts like these will be throwing out loads of exotic particles. Effectiveness will be significantly diminished, but there will still be damage.