I hadn't thought about the realism of sandcasters until now. Thanks for the hint.
Though I suppose some kind of active countermeasures will be available. Now, what that could be probably requires a bit more thought...
The Chemical Rocket Third Imperium
- Thread starter Thot
- Start date
I hadn't thought about the realism of sandcasters until now. Thanks for the hint.
Though I suppose some kind of active countermeasures will be available. Now, what that could be probably requires a bit more thought...
The TNE model is how...
Sand is
The thing is, with laser at realistic ranges, it's not a great idea... but it's preferable to monolithic armor because Nyrath/Winchel overlooks one key point: The sand reduces the energy density more than monolithic armor of the same mass.
I don't have to stop the whole beam. I just have to make the beam drop below delivering more energy to my hull than the hull can dissipate. It doesn't matter if it does this by being a block (100%) or a 50% halftone screen - any energy spent on the sand reduces the energy on target as a unit density.
Also, the sand is MUCH easier to replace/repair than the monolithic hull armor is.
Sand is
- reflective in the laser frequencies used in space combat
- Not fired blindly, but to put that directly between by noting the targeting system ping and responding before the fire return (at several hundred G's)
- Expended 1 canister per incoming laser.
The thing is, with laser at realistic ranges, it's not a great idea... but it's preferable to monolithic armor because Nyrath/Winchel overlooks one key point: The sand reduces the energy density more than monolithic armor of the same mass.
I don't have to stop the whole beam. I just have to make the beam drop below delivering more energy to my hull than the hull can dissipate. It doesn't matter if it does this by being a block (100%) or a 50% halftone screen - any energy spent on the sand reduces the energy on target as a unit density.
Also, the sand is MUCH easier to replace/repair than the monolithic hull armor is.
mike wightman
SOC-14 10K
Yes I agree, it was TNE that first pointed the way to lasers being autohit under a certain range, in fact they had to nerf them for game balance.
However in this hard sci fi setting there is no grav focusing and no magic heat sinks - lasers will not be anywhere near as effective as in Traveller.
mike wightman
SOC-14 10K
I agree with you.
Sand is not special, and in fact it's probably less effective than armor, but it's sprayable.
So you have the ability to spray it right between you and the laser, and then there's the stuff about the targeting system ping, which is a whole lot of handwaving because you don't need to ping your target to hit it, so basically, you need to put up enough sand between your entire ship and the laser to serve as a shield.
Sand, once dispersed, is far less dense than equivalent armor. Let's say it's 1000 times less dense. So you need 1000x more sand than you have hull plating on the one side of your ship to be as effective as armor, and it needs to be placed and timed at laser speeds, and if you delta-V, your placement needs to account for that, too.
With reactionless M-drives, maybe this makes sense (probably not, but let's pretend). When you're worried about a 2:1 reaction mass ratio, hauling tons and tons of sand doesn't make much sense. Also, the thin-hulled torchships that Thot has been describing don't even want to run into a bunch of sand, I'd guess.
So you have the ability to spray it right between you and the laser, and then there's the stuff about the targeting system ping, which is a whole lot of handwaving because you don't need to ping your target to hit it, so basically, you need to put up enough sand between your entire ship and the laser to serve as a shield.
Sand, once dispersed, is far less dense than equivalent armor. Let's say it's 1000 times less dense. So you need 1000x more sand than you have hull plating on the one side of your ship to be as effective as armor, and it needs to be placed and timed at laser speeds, and if you delta-V, your placement needs to account for that, too.
With reactionless M-drives, maybe this makes sense (probably not, but let's pretend). When you're worried about a 2:1 reaction mass ratio, hauling tons and tons of sand doesn't make much sense. Also, the thin-hulled torchships that Thot has been describing don't even want to run into a bunch of sand, I'd guess.
Using the (relatively correct) formulae in FF&S, and not adding grav focusing, combat lasers can be made to about 60000 km.
Turret lasers far less. Still, lasers can be viable to about a quarter LS. And that's well within the "Can't miss the target ship" range.
Whereas projectile weapons have - theoretically - unlimited range, but are going to be hideously inaccurate against even poorly maneuvering targets like spaceships outside far shorter ranges than laser.
Of course, immobile targets like space stations - or bases on a planetary surface - can be hit over far longer distances. Heck, with sufficient computer power to calculate the exact firing solution, you could probably hit a planet from a different star system.
As for the third weapon type, missiles... assuming missiles operate under the same "1400 seconds at 1 g" parameters as spaceships, a quick back-of-the-envelope calculation gives them a maximum range (at which they run out of fuel) of 9.8 million km, with a terminal velocity (assuming firing platform and target are at rest relative to each other) of 14 km/s - meaning a laser with 0.25 light-seconds maximum range would have about an hour and a half to destroy the missile if it comes in at maximum speed.
I don´t know what kind of rate-of-fire that laser is assumed to have, but to me this sounds like you´ll need a MASSIVE salvo of missiles to saturate any kind of point defense.
mike wightman
SOC-14 10K
The waste heat from such a laser would melt the ship that fires it.
Hardly. The waste heat isn't any more an issue than the power source needed for it.
The ROF may be a bit low in order to avoid meltdown over time, but heat pumps are relatively functional, and while radiation isn't efficient, it works well enough to allow such a laser.
True. In fact, it is exactly the same issue, as a significant portion of the reactor's 250 MW-per-dton-output will have to be dissipated. Without an enormous heat radiator tree, that's quite some achievement.
kilemall
SOC-14 5K
This Traveller ATU practically demands MgT engagement ranges and 10D jump limit.
mike wightman
SOC-14 10K
And now we get to the fun bit.
How much energy are you feeding to your laser? (Not to mention how big is the laser in terms of mass and mirror diameter).
How efficient is it?
How big are the radiators needed to deal with all that waste heat...
that last question is the killer, the mass and surface area of the radiators needed so you can cool your monster laser.
For reference, the ISS is able to dissipate heat worth about 70 kW. With a quite impressive array of radiators, I might add.
https://en.wikipedia.org/wiki/External_Active_Thermal_Control_System
https://en.wikipedia.org/wiki/External_Active_Thermal_Control_System
mike wightman
SOC-14 10K
So to deal with the waste heat from a 250MW laser - about 100MW worth - you would need 1500 radiators the size of the ISS array...
kilemall
SOC-14 5K
At our tech level.
Which for most of Traveller is not an issue, a near future without most of the magic tech is removed may be problematic.
On the other hand if we were looking at the future of computing from the 1950s, we would likely not predict the modern state of electronics and how much we can squeeze out of silica.
Materials technology alone may make it possible, as it did the modern mass-produced PC.
There are some limits that are not mere engineering issues, but inherent to physics. Of course, for an interstellar setting, we have to assume that our physical models are somewhat incomplete, but supercooling would require quite fundamental additions to physics, even more so than FTL drives based on some of the better fiction do.
Then again, if you remove "most of the magic tech", you might as well get rid of fusion power as well, and use regular projectile weapons to solve the heat problem (or mitigate it significantly).
But we would have failed there not because our physical models were wrong, but because all the little engineering tricks that came across and that few would have anticipated.
Sure, for heat management, that might be doable, too...
Hm. what kind of material would that be? One that dissipates heat at rates of a MW per m² of surface area or more? I have trouble imagining that. It would end up as a pantropic weapon and energy source.
kilemall
SOC-14 5K
The combination of silica and x-ray lithography would have been hard to imagine ahead of time too.
Whether you like it or not, you are not doing 'hard science' but an aesthetic and an ethos based on what we know now, not what WILL happen.
If the past is any indication, there will be hard limits, but there will also be possibilities that do not occur until either ways of solving problems take a different conceptual direction, or other new technologies renders a previously impossible approach possible.
So, my way of thinking is that you are ultimately making game design aesthetics decisions, go ahead and do so predicated more on the effect you want rather then what has to be acknowledged as limited foreknowledge.
Whether you like it or not, you are not doing 'hard science' but an aesthetic and an ethos based on what we know now, not what WILL happen.
If the past is any indication, there will be hard limits, but there will also be possibilities that do not occur until either ways of solving problems take a different conceptual direction, or other new technologies renders a previously impossible approach possible.
So, my way of thinking is that you are ultimately making game design aesthetics decisions, go ahead and do so predicated more on the effect you want rather then what has to be acknowledged as limited foreknowledge.
In another game I had the concept of an 'open-mode' power plant that took a fusion reactor and used it to heat reaction mass that got pushed out through a MHD generator.
This let you generate lots of power for short bursts, such as powering a warp drive or weapons. You could also dissipate heat by dumping it into the reaction mass and just venting the waste heat.
In normal B.A.U. you could run it in closed mode, which re-circulated the mass through a generator and a heat exchanger to radiate the waste heat. Of course the heat capacity of closed mode was limited.
Of course, nobody knows what will happen.
But we do know that certain things are just extremely unlikely. Why not use that knowledge when its conclusions fit a fun campaign style? Oh, I am doing that, just less openly, for instance by adjusting the FTL so that it allows for quick travel between worlds despite the use of chemical rockets, and by reducing the price of energy and thus fuel cost.
The fun, to me, lies in figuring out what the world currently looks like in terms of space travel. And from what we know, right now, fusion reactors and "reactionless thrusters" on starships aren't a viable option even if we ever figure out how to build ones that do make net energy available, and how to turn that energy directly into movement without using reaction mass. Even then, it is, as far as we can see right now, not going to happen.
It is fun to work with that and figure out how an interstellar future might look like based on it.
At the begining of XIX century, many of the best scientifics were quite sure men could not travel at more than 35 kph wihtout losing his breath...
Fortunately, some people didn't use the scientific knowledge of the moment to fit their imagination, and now we can travel at quite higher speeds (and don't lose our breath)...
Of course, nobody knows what will happen.
That's the only thing we know for certain, and so each one can assume what fits his idea for his own future universe.
You assume chemical rockets will keep being the best propulsion, others assume gravitics and yet others warp or whatever it be. All are fine, all have their unique challenges and assumptions, and none of us can blame the others for not agreeing with us.
In the future, probably, if some of those records are kept, people will question how could we be so ignorant to believe rockets would keep being the best oprion, or so optimistic as to believe we could tap gravitics, or so imaginative to believe about warping...
But for now, anything that allows to play a fun game is fine, and we're free to imagine whatever scientific or technologic marvel we are able to include...
