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Old 01-19-2019, 10:37 AM   #1
AlexanderHowl
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Default Orbital Lasers

At TL9, 100 GJ lasers have a 1/2D range of 30,000 miles, meaning that a SM+15 spacecraft could easily have 40 100 GJ weapon turrets. Such a spacecraft could engage forty surface targets every space turn from GSO, with every laser blast having the equivalent energy as 24 metric tons of TNT. Within an hour, it would drop the equivalent of six Hirishima's worth of energy on its targets, though it would be far more accurate and discriminating than any nuclear weapon.

How would a TL8 world deal with such a spacecraft? Nuclear weapons have limited ranged and would have to be put on special missiles capable of reaching GSO. Such rockets require days to prepare and would be visible and easy targets from GSO while being prepared. Other weapons would be laughably incapable of reaching GSO.
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Old 01-19-2019, 11:31 AM   #2
WaterAndWindSpirit
 
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Default Re: Orbital Lasers

If it's an orbital laser, it means it's gonna have to either have a geosynchronous orbit and be limited in it's targeting range, or needs to reach the right orbit and thus limited in time.

Is it manned? In this case, you could probably detonate a neutron bomb in near orbit to take out the crew, even if you have to kamikaze a space shuttle and crew to do it. Or is it ground controlled? In the later case, is the encryption secure? Could you take out the ground control facilities? That's assuming the guys working on it are Fanatically (as per the disadvantage) loyal to the cause. Because if they're not, you could get enough of the to defect to sabotage the whole system (which could make a good campaign premise).

It's gonna be expensive too. In D20 Modern Urban Arcana, such a kill sat has in universe been proposed, but the budget to create and operate a single platform is bigger than the DOD budget. Who put it there? Why? How are they funding it? What if you cut funding to them?

For what it's worth, how did they get it in space without anyone noticing? That's a big space project, and TL 9 (even superscience) don't tend to be capable of interstellar travel so it's likely not an alien race.

It's great for destroying High Value Targets like the Pentagon, but as son as Earth has capitulated and the remnants and sympathizers start going asymmetrical warfare, it's gonna be much less useful all of sudden. With all our late TL 8 tech, a bunch of poorly trained guys with obsolete weapons (a mixed match of TL 4-7 with some getting cheap TL 8 guns) are making a mockery of modern military.

Last edited by WaterAndWindSpirit; 01-19-2019 at 11:37 AM.
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Old 01-19-2019, 12:17 PM   #3
AlexanderHowl
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Default Re: Orbital Lasers

Neutron bombs have extremely low area of effect, their radiation has less penetration than standard nuclear weapons, and they have to be launched from the same vehicles as standard nuclear weapons. In effect, neutron bombs are pretty much a waste of money, as standard nuclear weapons are superior in practically every measure. There is a reason why no military produces them right now.

A TL9+ spacecraft does not necessarily have to be human. If it is an alien vehicle, they have come from another star system and are likely part of a larger fleet. In that case, the aliens probably cannot be bribed with anything humans possess and alien computers are probably far too different than human computers to be hacked (at least not without a few years of analysizing the fundamental logic of their computers).
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Old 01-19-2019, 12:24 PM   #4
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Default Re: Orbital Lasers

If the Orbital station needs supplies or just has staff shuttle transitions from the ground, then the way I'd go about trying to kill the station would be to either be a plant as an employee that's supposed to be on the shuttle, and then sabotage the station, or somehow sneak on board the shuttle.

Or if I want a team to make it to the shuttle, steal a shuttle and some codes maybe?
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Old 01-19-2019, 12:39 PM   #5
WaterAndWindSpirit
 
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Default Re: Orbital Lasers

Quote:
Originally Posted by AlexanderHowl View Post
A TL9+ spacecraft does not necessarily have to be human. If it is an alien vehicle, they have come from another star system and are likely part of a larger fleet. In that case, the aliens probably cannot be bribed with anything humans possess and alien computers are probably far too different than human computers to be hacked (at least not without a few years of analysizing the fundamental logic of their computers).
Even if dealing with alien tech, all you really need is a single turncoat who grew a conscience and defected and you have knowledge about at least basic computer infrastructure. The only way it won't happen is if each and every single one is Fanatically (as per the disadvantage) loyal to The Cause.

Why are they attacking? Probably not for resources, as there are plenty of rocks with lots of resources and no one to shoot you.

Any Evil Empire bent on conquest has it's dissidents. If they're exterminating what they see as a threat, they'd just drop nukes until the Earth is turned to class and call it a day. Wouldn't be a campaign then. If they just want slaves, my point about dissidents becomes one about abolitionists. Point is, if they're invading and not exterminating, they likely have dissidents. Make friends with said dissidents to get a leg up on their tech. That's probably the best way to handle it.

Last edited by WaterAndWindSpirit; 01-19-2019 at 12:43 PM.
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Old 01-19-2019, 02:20 PM   #6
hal
 
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Default Re: Orbital Lasers

I originally started to respond to this thread, then backed off, but now have a few thoughts...

If you read a few sci-fi novels, eventually, you might come across one in which an author has posited just what you're talking about. In the novel in question, a covert defense satellite was originally declared to be a science lab. The solution for taking it out after it was discovered to be something more militaristic, was to launch missiles on an intercept orbit from outside its immediate sensor range, and let the multitude of ball bearings launched into its orbital path simply riddle its hull with kinetic energy. LOTS of kinetic energy. The rockets in question were launched by vehicles capable of reaching near low earth orbit altitudes.

Mind you, the station didn't have orbital thrusters to move it out of the way from the swarm, and ultimately was made uninhabitable after killing the operators within. But that was a TL 8 vs TL 8 (almost TL9 actually)

But the next issue is - are ranges in vacuum the same as ranges in an atmosphere?

Per GURPS VEHICLES page 126

"1/2D and Max Ranges in Vacuum: A weapon’s base 1/2D and Max ranges are those achievable in a standard Earth-like atmosphere. In vacuum or trace atmospheres, the ranges of some beams are altered: ×0 for a screamer or stunner (that is, they have no range), ×0.01 for a charged particle beam, ×10 for a laser, IR laser, disruptor, flamer or antiparticle beam, ×50 for a UV or rainbow laser or neutral particle beam and ×100 for an x-ray laser or graser."

Since the same author who crafted those rules also crafted the GURPS SPACESHIPS rules, my guess is that orbital lasers would have their ranges divided by either of 50 or 100 depending upon the laser weapon system itself.

My question would now be...

ICBMs launched by submarines - would they have sufficient range to reach a low earth orbit? Would the use of nuclear detonations in high atmosphere as a form of "Smoke Screen" be able to launch a strike that is temporarily shielded by enemy sensor systems?

I suspect that a desperate nation at TL 8 would adapt their "safe" technology to levels of potentially UNSAFE operations levels - designed to boost their ICBM technology to gain an extra 25% missle range at the risk of a catastrophic launch on the premise some chance is better than no chance.

Otherwise?

Abject submission would seem to be the order of the day and the hope that someday, freedom can be regained through covert resistance or technology theft or even asset theft.
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Old 01-19-2019, 02:38 PM   #7
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Default Re: Orbital Lasers

While there isn't set point as it gets thinner and thinner 100 km is often used as the edge of earths atmosphere, so I don't think the range will be effected much unless you shot really obliquely.

Unless you have a lot of fuel to burn or ^engines, orbital mechanics will seriously cut into your time on target on most targets though.
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Old 01-19-2019, 03:24 PM   #8
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Default Re: Orbital Lasers

Quote:
Originally Posted by AlexanderHowl View Post
At TL9, 100 GJ lasers have a 1/2D range of 30,000 miles, meaning that a SM+15 spacecraft could easily have 40 100 GJ weapon turrets. Such a spacecraft could engage forty surface targets every space turn from GSO, with every laser blast having the equivalent energy as 24 metric tons of TNT. Within an hour, it would drop the equivalent of six Hirishima's worth of energy on its targets, though it would be far more accurate and discriminating than any nuclear weapon.
That is the plan. If they get to put that thing in orbit, the world is basically done. Good narrative for a post-apocalyptic environment, do not you think?
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Old 01-19-2019, 05:31 PM   #9
AlexanderHowl
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Default Re: Orbital Lasers

Of course, it would likely be impossible for anyone on Earth to place a SM+15 station at GSO. Even with HEDM, the lift cost alone would be ruinous. At best, the lift cost using HEDM ends up being $300/kg, meaning that it would cost $900 billion just to send up the required materials.

No, such a spaceship is either an alien object, so it means an alien crew. Now, such a spaceship might have been towed to the Sol System by a hyperspace capable spaceship and left as a subjugation force. It would probably not even have to waste more than a single nation (at GSO, it can dominate an entire hemisphere). The only question is which nation?

The USA would be an obvious choice, as it has the best military. Russia too would be an obvious choice, as it has the largest nuclear arsenal. Finally, China would also be an obvious choice, as it has the largest military.

In the case of the USA, eliminating the US Navy would be relatively easy, quickly followed by any US military base and, if it did not surrender, civilian targets. After a week of orbital bombardment, the US would probably surrender, as there would not be much left. With each blast, hundreds of people would die, and a week would be 1.2 million blasts.
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Old 01-19-2019, 08:43 PM   #10
malloyd
 
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Default Re: Orbital Lasers

Quote:
Originally Posted by Bengt View Post
While there isn't set point as it gets thinner and thinner 100 km is often used as the edge of earths atmosphere, so I don't think the range will be effected much unless you shot really obliquely.
Depends on your realism level probably. Getting any sort of beam weapon to work through the entire depth of an atmosphere is realistically extremely hard, but GURPS lasers, like most RPG and science fiction ones, are pretty unrealistically immune to all sorts of problems that degrade laser range, accuracy and damage.

I want to know what they're using to power this thing (it appears to be consuming about half as much electricity as the United States), and where they put the radiators that are keeping the entire battle station from evaporating.
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