Orbital Lasers

AlexanderHowl · 01-19-2019, 10:37 AM

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.

WaterAndWindSpirit · 01-19-2019, 11:31 AM

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.

AlexanderHowl · 01-19-2019, 12:17 PM

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).

kdtipa · 01-19-2019, 12:24 PM

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?

WaterAndWindSpirit · 01-19-2019, 12:39 PM

Quote:

Originally Posted by AlexanderHowl

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.

hal · 01-19-2019, 02:20 PM

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.

Bengt · 01-19-2019, 02:38 PM

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.

PTTG · 01-20-2019, 02:22 AM

Quote:

Originally Posted by AlexanderHowl

Neutron bombs have extremely low area of effect, their radiation has less penetration than standard nuclear weapons...

Nuclear blasts in space are extremely limited in effective radius, especially if the surface of the target has even light armor. Neutron bombs bypass that armor effectively, and therefore increase the effective radius of the warhead.

Whereas a small nuke might need to be within a few hundred meters to score a single-hit kill purely based on the thermal effects, the neutrinos and radiation would kill or sicken the crew if it goes off within kilometers of the target.

Considering the limited time to prepare, I'd recommend that everyone on the far side of the earth when the attack began should prepare literally every spaceflight capable rocket (from ICBMs to sounding rockets or even models) to launch simultaneously. As many of those as possible should be armed with nuclear warheads. As many of the armed missiles as is reasonably possible should have their re-entry shield replaced with graphite or other refractory materials, which will ablatively shield the missile.

Hopefully, the large scale of the wave will provide sacrificial targets that will take the initial brunt of the attack. The graphite will boil away, taking a great deal of energy with it. Hard to estimate how it will hold up to high-energy lasers (the spot size, pulse duration, wavelength, etc, etc, are unknown), but maybe it'll give you a chance.

This goes out the window with an alien ship, but still, people would give it a try.

Rupert · 01-20-2019, 03:08 AM

Quote:

Originally Posted by PTTG

Nuclear blasts in space are extremely limited in effective radius, especially if the surface of the target has even light armor.

That's not really so. The energy that would go into the shockwave and a portion of the thermal pulse in an atmosphere remain as a very powerful x-ray pulse in space. X-rays have fairly good penetration and those that don't penetrate any armour will heat it greatly and very rapidly, quite possibly causing it to vaporise or turn into plasma. Given the extremely short time in which that will happen, that will cause a powerful shock to the ship.

Quote:

Neutron bombs bypass that armor effectively, and therefore increase the effective radius of the warhead.

Neutron shielding is fairly easy to install, and fuel tanks of hydrogen, etc., are quite effective neutron barriers.

AlexanderHowl · 01-20-2019, 06:37 AM

I agree. The neutrons produced by neutron bombs tend to be in the keV range, so a meter of liquid hydrogen will absorb them quite nicely. Also, any carbon-based armor would be quite fine, as it would also absorb the neutrons without issue.

Anyway, why would anyone want a neutron bomb? They are quite literally the most useless nuclear weapon. Their only utility in warfare was a marginal increase in the radioactivity of the detonation site, as the metals in the area become somewhat radioactive, but it greatly reduced the destruction power of a nuclear weapon to do so. It was why the US shelved the neutron bomb program after billions of dollars of development, because it was a less than useful weapon.

01-19-2019, 10:37 AM	#1
AlexanderHowl Join Date: Feb 2016	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.

01-19-2019, 11:31 AM	#2
WaterAndWindSpirit Join Date: Oct 2014	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.

01-19-2019, 12:17 PM	#3
AlexanderHowl Join Date: Feb 2016	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).

01-19-2019, 12:24 PM	#4
kdtipa Join Date: Jun 2007 Location: Southern New Hampshire	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?

01-19-2019, 02:20 PM	#6
hal Join Date: Aug 2004 Location: Buffalo, New York	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.

01-19-2019, 02:38 PM	#7
Bengt Join Date: Oct 2005 Location: Ronneby, Sweden	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.

01-20-2019, 06:37 AM	#10
AlexanderHowl Join Date: Feb 2016	Re: Orbital Lasers I agree. The neutrons produced by neutron bombs tend to be in the keV range, so a meter of liquid hydrogen will absorb them quite nicely. Also, any carbon-based armor would be quite fine, as it would also absorb the neutrons without issue. Anyway, why would anyone want a neutron bomb? They are quite literally the most useless nuclear weapon. Their only utility in warfare was a marginal increase in the radioactivity of the detonation site, as the metals in the area become somewhat radioactive, but it greatly reduced the destruction power of a nuclear weapon to do so. It was why the US shelved the neutron bomb program after billions of dollars of development, because it was a less than useful weapon.