Nuclear weapons IN SPACE!

[Dangerious P. Cats]

How do you deal with a realitivly hard space setting where you want to make conflict or war to focus of the setting, but at the same time don't want all the person to person or ship to ship fighting that players love to be ruined but people just setting off nukes everywhere?

More to the point how can you make "I just nuke them" not a viable option for players?

[SuedodeuS]

Legality to start. If using a nuclear weapon - even in space - is a war crime, players are going to very much be hesitant to pull out the nukes. Exceptional point defense lasers (and/or making it very common to have huge batteries of small point defense lasers) might be able to make projectiles unviable, so you'd have to use your own beam weapons to take out their point defenses to reliably be able to nuke them - but by that point their ship is probably disabled already!

[Flyndaran]

You have mutually incompatible issues. Realistic setting means that nuclear capable sides will use them in space if and when necessary.

You need to add superscience like reality stabilizers to render nukes useless.

[lexington]

Declare the in this universe uranium and plutonium can only be found in reasonable quantities deep inside of planets. The price of nukes is dramatically higher as a result and those who have them will be hesitant to go tossing them around.

[Captain-Captain]

Originally Posted by SuedodeuS

Legality to start. If using a nuclear weapon - even in space - is a war crime, players are going to very much be hesitant to pull out the nukes. Exceptional point defense lasers (and/or making it very common to have huge batteries of small point defense lasers) might be able to make projectiles unviable, so you'd have to use your own beam weapons to take out their point defenses to reliably be able to nuke them - but by that point their ship is probably disabled already!

Well, nukes in space have a relatively short blast radius. Vaccuum is a lousy wqy to carry a shockwave. One of the things that makes Nukes so dangerous on Earth is an atmosphere that will carry the blast. (The atmosphere is also what produces the EMP effect, X-rays ionize the air a few miles up and that big mass of charged air molecules pulls in electrons like crazy, so using a nuke to short out a spacecraft from a distance isn't going to work.) The damage that comes from the blast is heat light etc for the most part. A very reflective armor on the ship helps tremendously.

[tshiggins]

Originally Posted by Captain-Captain

Well, nukes in space have a relatively short blast radius. Vaccuum is a lousy wqy to carry a shockwave. One of the things that makes Nukes so dangerous on Earth is an atmosphere that will carry the blast. (The atmosphere is also what produces the EMP effect, X-rays ionize the air a few miles up and that big mass of charged air molecules pulls in electrons like crazy, so using a nuke to short out a spacecraft from a distance isn't going to work.) The damage that comes from the blast is heat light etc for the most part. A very reflective armor on the ship helps tremendously.

This.

Space ships will already have shielding against hard rads, and ways to dump heat. Nukes have to detonate really close to the vessel to do much.

Moreover, they're expensive and complex pieces of machinery. Why would anybody use them, when you can just fire a rail-gun round at a velocity of 10 km/s? At that velocity, a the kinetic energy of the mass of the ammunition does 10 times the damage of an equivalent mass of TNT.

Alternatively, fire a missile with a submunitions warhead (basically, a giant shotgun shell) and have it go off so the ball-bearings get in the flight-path of the enemy ship. That's probably a little more expensive than a rail-gun round, but still nowhere near the price and complexity of a nuke.

[Captain-Captain]

Originally Posted by tshiggins

This.

Space ships will already have shielding against hard rads, and ways to dump heat. Nukes have to detonate really close to the vessel to do much.

Moreover, they're expensive and complex pieces of machinery. Why would anybody use them, when you can just fire a rail-gun round at a velocity of 10 km/s? At that velocity, a the kinetic energy of the mass of the ammunition does 10 times the damage of an equivalent mass of TNT.

Alternatively, fire a missile with a submunitions warhead (basically, a giant shotgun shell) and have it go off so the ball-bearings get in the flight-path of the enemy ship. That's probably a little more expensive than a rail-gun round, but still nowhere near the price and complexity of a nuke.

Sandcasters, in other words. With the advantage that accelerators are far more energy efficient as well as mass efficient than rockets.

[Ulzgoroth]

Originally Posted by Captain-Captain

Sandcasters, in other words. With the advantage that accelerators are far more energy efficient as well as mass efficient than rockets.

Except that guns are extremely short ranged in space, but missiles are not. A missile with a sub-munition warhead has potentially unlimited range. A scattergun has an effective range of a few seconds times its muzzle velocity.

[Fred Brackin]

Originally Posted by Captain-Captain

The damage that comes from the blast is heat light etc for the most part. A very reflective armor on the ship helps tremendously.

To my understanding this is inaccurate.

For common fusion reactions the amount of released energy that is in the form of neutrons hits 80%.

The remainder is charged particles and photons with the photons peaking well above the visible range. A great deal of the visible light and heat in an airburst is secondary radiation coming from interaction of the primary radiation with the air.

Damage from a nuke detonated in space will fall off more rapidly than an airburst. It ought to be capable of simplifying into a simple inverse square relationship.

That is if the warhead delivered a full megaton at 1 meter it should be down to "just" a ton at 1000 meters. That would still be fast particles and hard photons that ought to rate about a (5) armor divisor.

So call it 6D x 90 (5) to use round numbers and you need a very thick-skinned ship to shrug that off. A DR 100 ship _could_ handle it at 10 kilometers.

So if point defense is good enough that there is essentially no chance of getting a proximity-fused 1 mt nuke within 10 k of a ship, a 1 mt nuke is not a viable weapon at all.

Maybe that will help.

[Sunrunners_Fire]

Originally Posted by Dangerious P. Cats

How do you deal with a realitivly hard space setting where you want to make conflict or war to focus of the setting, but at the same time don't want all the person to person or ship to ship fighting that players love to be ruined but people just setting off nukes everywhere?

More to the point how can you make "I just nuke them" not a viable option for players?

You sit down with your players and go, "For the purposes of this campaign nuclear weapons don't exist. They will not be available for sale or salvage, you can not make them, they will not be used or mentioned in-setting/in-game. Cool? Cool. Lets' play."

Otherwise you have: no one makes them (queue PC learning how to make them right quick), they're illegal (oh, like that has ever stopped the PCs before) or super-science negates their use (no longer "relatively hard science" setting).

I suggest invoking Genre Convention and write the entire idea out of the campaign/setting.