[Spaceships] DS-1 Orbital Battle Station

[Lamech]

I'm pretty sure a zetta joule worth of damage is only 2d*100,000. You would need something like cosmic, cosmic, cosmic, cosmic power to get the 2d*1,000,000,000 damage.

[Polydamas]

Vierasmarius, I would suggest that HP are not the best tool to use to model blowing up a planet, because that was not what they were designed for. Since we have beam energy and the energy required to inflict the required damage, I would just use them. I don't know if you can build a beam of 10^32J (100 million YJ) in Spaceships but you can have fun trying.

Raw power seems to fit the style of Star Wars better than a fancy chain reaction does; Mike Wong and Dr. Curtis Saxton have provided the detailed canon argument. But since the game effect of the superlaser is "anything it hits smaller than a gas giant is vapourized" the details probably don't matter too much.

[samd6]

The superlaser on DS-2 had two firing modes, planetbuster and shipkiller. The recharge cycle for shipkiller mode was in combat turns, the recharge cycle for planetbuster was a couple of hours.

[vierasmarius]

Originally Posted by Polydamas

Vierasmarius, I would suggest that HP are not the best tool to use to model blowing up a planet, because that was not what they were designed for. Since we have beam energy and the energy required to inflict the required damage, I would just use them. I don't know if you can build a beam of 10^32J (100 million YJ) in Spaceships but you can have fun trying.

I would tend to agree with you, but considering how close the matches are (12 Trillion HP for the Earth, compared to 150 Trillion damage necessary for annihilating it) I think hit points actually work just fine. Using the square-root damage calculations does give you weapon outputs a couple orders of magnitude too small (1e29 J instead of 1e31 J for ~120 Trillion damage, using a Conversion Beam) but that's still pretty close.

Raw power seems to fit the style of Star Wars better than a fancy chain reaction does; Mike Wong and Dr. Curtis Saxton have provided the detailed canon argument. But since the game effect of the superlaser is "anything it hits smaller than a gas giant is vapourized" the details probably don't matter too much.

That's true. The Superlaser's planet-destroying power is probably handled best as a plot device. Still, it's amusing to figure out just what it would take to accomplish.

[Lamech]

Now the death star may not be feasible with GURPS Spaceships, but I give you:

Lamech's Perfectly Reasonable Planter Killer
Many said it would never work. They said it defifed common sense and the laws of physics. But when this weapon was first used against a planet the results spoke for themselves. The planet was vaporized in under a minute of bombardment. Note this weapon is not effective through cloud cover.

SM+17 (Unstreamlined)
Systems:
Front:
5 systems of SM+7 tertiary batteries, turret mount improved rapid fire UV Lasers. (3,000,000 turrets each, 300KJ, RoF 20, 1d6+2(2) dDamage.)
1 armor of choice
1 control room
Middle:
3 SM+18 major batteries, turret mounted graser (3 turrets total, 10TJ, RoF 1, 4d*100(10) dDamage
2 systems of SM+7 tertiary batteries, turret mount improved rapid fire UV Lasers. (3,000,000 turrets each, 300KJ, RoF 20, 1d6+2(2) dDamage.)
1 armor of choice
Rear:
3 antimatter reactors
1 habitat
1 armor
2 engines of choice.

This weapon of destruction pulls up into low orbit above a planet, and unless a storm of hundreds of millions of lasers. The result inflicts over 2 billion in raw damage. Assuming a planet is a spaceship made of nothing but stone armor the planet loses all of its ablative DR and is then reduced to well below -10*HP vaporizing it. It also has three larger weapons to deal with armored spaceships.

[panton41]

I wouldn't be streamlined. If you read the notes it mentions streamlined ships are long and thin. It also specifically notes spheres would be shorter compared to the official length measurement.

[RyanW]

Originally Posted by Lamech

The planet was vaporized in under a minute of bombardment. Note this weapon is not effective through cloud cover.

Cloud cover is opaque to UVs. This doesn't mean high powered UV lasers bounce harmlessly off of them. Instead, dump enough power and you'll see explosive evacuation. You'll literally blow up the sky!

[vierasmarius]

Even basing HP and damage on the square-root of mass/energy makes it too easy to destroy massive objects through attrition. Using the default cube-root calculations grossly exaggerates this effect. To even approach a reasonable damage amount, you'd need to total up the energy output of all beam weapons, and use that to determine the effective output. For example, 1000 x 1GJ beams deal 4dx5 dDam each, or 4dx5000 if they all hit (and don't even get me started on the Rapid Fire rules at this scale...) If used together, they should more reasonably deal damage comparable to a 1TJ beam - 2dx100, just 1% of the sum of their damages. It's barely better with square-root damage, 1000 x 6dx15 (6dx15,000) versus 6dx500, or 3.33% of the sum.

Firing literally hundreds of millions of shots per turn cranks this disconnect way past 11. Together they have an output of 126 TJ, or around 2dx500 dDam (6dx5000 w/ sqrt scale) but if tracked separately they deal 6dx110,000,000! I suppose this is a fundamental flaw in attrition-based damage systems, the "death by a thousand (or hundred-million) papercuts" dilemma.

[Lamech]

Originally Posted by RyanW

Cloud cover is opaque to UVs. This doesn't mean high powered UV lasers bounce harmlessly off of them. Instead, dump enough power and you'll see explosive evacuation. You'll literally blow up the sky!

The cloud cover DR isn't ablative. This is a design which horribly, horribly abuses the GURPS rules to vaporize an entire planet. If you start trying to include realism... this weapon does nothing. (Well I suppose its a good anti-missile platform.)

[Flyndaran]

Originally Posted by vierasmarius

...Firing literally hundreds of millions of shots per turn cranks this disconnect way past 11. Together they have an output of 126 TJ, or around 2dx500 dDam (6dx5000 w/ sqrt scale) but if tracked separately they deal 6dx110,000,000! I suppose this is a fundamental flaw in attrition-based damage systems, the "death by a thousand (or hundred-million) papercuts" dilemma.

If it isn't enough in a short enough span of time to explode the planet, then "all" you're doing is melting it.

Besides, isn't killing everything on it and making it uninhabitable for geologic timeframes enough?