|
Post by nerd1000 on Jul 23, 2017 2:34:42 GMT
I'm quite attracted to liquid drop radiators for sci-fi settings because of their (probable) appearance: They'd be like a waterfall of liquid fire. Even better, if you're aiming the sprayers to account for acceleration the drops will follow a curved path relative to the ship, which would look really fascinating.
|
|
|
Post by nerd1000 on Jul 15, 2017 13:09:09 GMT
Asymmetry has another benefit if you're keen on using aerobraking (and let's face it, unless you're a giga-laser dreadnaught with overpowered MPD thrusters you probably NEED to use aerobraking). That advantage is, of course, the opportunity to produce lift- far more than what's achievable with any symmetrical design.
|
|
|
Post by nerd1000 on Jul 15, 2017 11:51:25 GMT
You are going to need multiple types of sensors depending on what your trying to do, regardless of the ship type if we had to. One sensor for long range identification, one for optimal range of the primary weapons, and one sensor set for finding extremely small incoming objects (eg, meteors, micromissiles, gunfire). If you have all three of these, your weapons will become increasingly powerful, if you've only got one or two (or a directional gap in sight) that opens you up to huge weaknesses. These sensors are extremely weak, or extremely pricy too. It'd be interesting to see someone try and blind the opposite ship by pointing lasers at them though. If this were the case, it would push the meta back to large arrays of counter-battery lasers. Every engagement would revolved around sniping enemy sensors to blind their weapons. How would this effect missiles? I assume each missile would need a seeker, and I'm sure we've been over this several times on this forum. I'm with the consensus that modeling sensors and communications are beyond the scope of this game. I believe qswitched addressed this on the blog with the idea of ubiquitous system-wide sensor nets that all factions could easily access. Missiles don't need a seeker over shorter ranges. They can instead use command guidance or beam-riding, both of which can be carried out using small photoreceptors or radio antennae mounted on the rear of the missile. You may need to devise some scheme that prevents rocket exhaust from messing with the sensors- the Russians' answer to this problem in modern missiles is to put the rocket nozzles near the nose, exhausting to the rear and slightly sideways. The major downside to this method of guidance is that the missile becomes less accurate as the range to target decreases, wheras homing guidance systems become more accurate as the range to target decreases. As a result, the ideal approach may be to use a hybrid setup: Command guidance until the missile is within 50km or so of the target, then the missile switches to active radar homing (radar cannot be blinded by lasers, so any laser defense must instead destroy the seeker completely by overheating it) or passive IR homing for the final stages of interception.
|
|
|
Post by nerd1000 on Jul 4, 2017 1:54:58 GMT
This reminded me of a ship built by someone back then called 'heart of gold'. It was made mostly by gold, and it sucks, too. Heavy, weak materials won't do much good. That was mine. The only non-gold parts were the reactor fuel, the propellant in the tanks and half the thermocouple (I used platinum).
|
|
|
Post by nerd1000 on Jun 14, 2017 6:19:07 GMT
|
|
|
Post by nerd1000 on May 31, 2017 9:41:11 GMT
A small sphere of superheated plasma expanding inside a 'bird cage' style magnetic nozzle converts 80% or better of its energy into the spaceship's kinetic energy. This because it expands in three dimensions and six axis: the kinetic theory of gasses state that as it expands, it cools. If it cools, then the thermal energy is being converted into kinetic energy of the particles. This is the effect you see in deLaval nozzles. At 10kT/1kg, you are certain to have 100% ionization of the reaction products. Nothing will slip through the magnetic field. The problem then becomes providing a magnetic field strong enough to deflect all the particles without being pushed out of the way are basically ignored by nearly relativistic particles. That's why I choose a Medusa design, a magnetic nozzle might heavily increase energy efficiency, but it would mean that I have to reduce the mass flow to gram scale, and that would mean that I'd need several hundred times longer to reach a desired velocity of 2,4Mm/s. Also, how would I power such a magnetic nozzle? I had to add a reactor and radiators adding further complexity and mass to the missile. If you're using beamed laser power to heat the reaction mass it should be easy enough to power the magnetic nozzle with energy harvested from the laser beam. Just add a ring of solar panels (tuned for your laser wavelength) around the drive and defocus the beam a little bit so some of the energy hits them. A small increase in beam power should be enough to provide all the extra energy you need, and the panels should be much lighter and cheaper than an on-board reactor and radiators.
|
|
|
Post by nerd1000 on May 30, 2017 13:48:20 GMT
Thou shalt know fear from your TRUE gods! I have created a monster...
|
|
|
Post by nerd1000 on May 30, 2017 13:44:45 GMT
This is why the game has a limits.txt file. It's likely that many of the equations running behind the scenes are approximations that only hold across a range of values, either because exact equations are not known or because QSwitched had to choose between accuracy and game performance. By editing limits.txt we're breaking the assumptions all those approximations are based on, and as such the game acts in unphysical ways. You can get similar inaccuracy with 10 Gw lasers. They can reach the same intensities at shorter ranges and have the same issues. IIRC the original laser limit was 1 GW, but it was increased by popular demand when people started making absurdly powerful reactors. All the same, it's probably possible to get the same issues even with a 100MW laser if you use a giant mirror. Point is, the more you increase the limits of what the game allows, the less likely it is that the game's base assumptions will be valid. The armour model may be especially problematic in this regard.
|
|
|
Post by nerd1000 on May 30, 2017 1:58:09 GMT
I believe this is the first serious attempt at an MPD missile. Nice! If we had serial staging you could use that as the 1st stage for a standard chemical missile and get the best of both worlds (i.e. >1g acceleration in terminal phase).
|
|
|
Post by nerd1000 on May 30, 2017 1:51:22 GMT
This is why the game has a limits.txt file. It's likely that many of the equations running behind the scenes are approximations that only hold across a range of values, either because exact equations are not known or because QSwitched had to choose between accuracy and game performance. By editing limits.txt we're breaking the assumptions all those approximations are based on, and as such the game acts in unphysical ways.
|
|
|
Post by nerd1000 on May 28, 2017 23:10:11 GMT
In-game laser mirrors are not actively cooled. Otherwise your aluminium mirror would melt in the face of your 1200K laser coolant temperature. Secondary coolant loop. And the radiator or heat pump for this secondary loop is where, exactly? The cost and power consumption of my lasers doesn't change when I change the primary mirror material, which it should if there's an abstracted radiator or heat pump system. Also the mirror in the laser cavity doesn't worry about its threshold, only the cavity coolant temperature. This suggests to me that QSwitched did think about active cooling in that case, but deliberately left it out for the primary mirror in the turret.
|
|
|
Post by nerd1000 on May 28, 2017 11:47:11 GMT
I suggest going full Alastair Reynolds. The Conjoiner Drive from his Revalation Space series is powered by a wormhole leading back in time to the universe a few milliseconds after the big bang. The drive siphons off some of the primordial quark-gluon plasma, uses it to heat gas taken from the interstellar medium via a bussard ramscoop, then dumps the whole lot out through some kind of super efficient nozzle to produce an exhaust beam so tightly collimated that I'm surprised nobody thought of using it as a weapon. That should give you the performance you need . More seriously, I suggest a Laser lightcraft. The missile has a parabolic reflector on the tail. The mothership/base directs a high powered laser pulse at the reflector, which focuses the energy onto a pellet of solid fuel. The fuel instantly flashes to plasma and accelerates out the back via magnetic nozzle. Your exhaust velocity is bounded only by your mirror (which will need to be very large to avoid being vaporized by the laser, but can also be very thin and lightweight like a solar sail) and how much energy you can dump into the plasma before it escapes. With this system the missile does not need to carry a terawatt range power plant of its own, which saves a great deal of weight. Once the missile is outside effective boost range the lightcraft drive section separates and the missile uses some other propulsion system (maybe a more sane NSWR or Orion drive) for terminal maneuvering.
|
|
|
Post by nerd1000 on May 28, 2017 8:52:33 GMT
... I guess the cans should also be polished to laser-mirror level shine: this will let them resist around 1.2 GW/m^2 if the skin is aluminium... If their skin is actively cooled. Otherwise, it would probably last a few seconds at most. Active cooling requires coolant, pipes, a turbopump, radiators and energy. This increases the mass and complexity of your missiles considerably. This means you can field considerably less of them. In-game laser mirrors are not actively cooled. Otherwise your aluminium mirror would melt in the face of your 1200K laser coolant temperature.
|
|
|
Post by nerd1000 on May 28, 2017 6:10:42 GMT
Any of these laserstars is a colossal heat signature whose movements are obvious anywhere in the solar system- there's no mistaking what's going on when one of these things leaves port. So rather than attacking with a warship, you build a bunch of MPD powered missile buses at your main base and send them to intercept. Any MPD drive is a large visible heat signature due to the power required, and a fleet of them is a very very large signature. There is nothing to write home about here. There is no need to focus on each individual munition specifically if they are that small. The beam of the 1 TW laser would encompass ~1570 m 2 at 10 Gm with intensity 24.9 MW/m 2 (and of course its efficiency is a measly 3.92% because it doesn't use mods). Jinking around at random won't get them very far in the time it takes for light to reach them. That's pretty good. But 70 km/s speeds will get the fleet through the 10 Gm killzone in 40 hours... assuming the laserstar didn't decide to accelerate away from you and either dodge entirely or match your trajectory, turning it into a game of shooting fish in a barrel. An MPD-based railgun capital could do more or less exactly the same. Delta-V is king in defining encounters; it goes for both sides. 70 km/s isn't anywhere near enough. I wish we had particle accelerators for another weapon to try; I think they could outclass railguns. Why would I put the submunitions so close together that you can hit more than one at the same time? Your beam has radius 22m at 10Gm, making dodges difficult (22 m/s per jink at 1 light second? not happening, especially over a 40 hour flight) but I could easily have them spaced out so that they're over 1000m from their neighbors during most of the trajectory. I guess the cans should also be polished to laser-mirror level shine: this will let them resist around 1.2 GW/m^2 if the skin is aluminium. If the laserstar accelerates away from my missiles and matches their speed I've won: he might have been able to kill all my munitions, but he's also burned 70 km/s or more of his Delta-V, so he probably won't be able to go wherever he was planning to go (well, not fast anyway). This makes an interesting tactical situation: the laserstar must guess the performance (and numbers- there's no reason to assume all my buses carry the same amount) of my missiles, and decide whether he can simply zap them all while staying on course. If he can, my missiles are totally wasted. If he can't, he has no choice but to spend delta-V to keep them at arms length for long enough to destroy them. At the same time, he may have enough Delta-V for multiple dodges, so I have to decide how many missiles to send in each salvo: too few and they'll be wasted, too many and I won't have enough left to force another dodge later. TBH the way MPDs scale with power means that I'd probably be better off putting more eggs in each basket and having bigger missile buses, possibly to the point where they're a fully crewed 'missilestar' as opposed to a laserstar. The problem with that idea is that once I've built such a large MPD powered ship there's no reason not to put a laser on it, so we end up with laserstar vs. laserstar again. And I agree on particle beams. While they're sure to be shorter ranged than lasers, they also don't need giant mirrors (a pencil sized firing port will suffice) which makes them much harder to destroy with other beam weapons. Speaking of which, how well would your 1TW laserstar fare against smaller counter-laser ships? The mirror appears to be the size of a football pitch, so the counterbattery doesn't really need a big aperture to focus all of its laser energy onto a small part of the beam spreader. Edit: I just redesigned my missile buses. They now cost 9 Mc, carry 60 sub-drones each and have 120 km/s of Delta-V with terminal acceleration of 20 mg, which should be enough to deal with the Finger of Boron Almighty's maneuvering capabilities. I feel that it's a little unrealistic to be pumping 1.02 GW through each of the 180 gram MPD thrusters... But the game let me get away with it.
|
|
|
Post by nerd1000 on May 28, 2017 1:51:02 GMT
Why use railguns when you can use missiles?
Any of these laserstars is a colossal heat signature whose movements are obvious anywhere in the solar system- there's no mistaking what's going on when one of these things leaves port. So rather than attacking with a warship, you build a bunch of MPD powered missile buses at your main base and send them to intercept. Now the laser can of course start shooting at the missiles from 10Gm or whatever, but this is also the point where we go recursive ammo on the laserstar's ass: the buses launch a bunch of smaller sub-buses, which have higher-G NTR drives for course corrections. Maybe we carry 4 per bus. At 10Gm, a fleet of 50 buses becomes 200 sub-buses. The sub-buses finish their burns and release their own submunitions.
Now if we assume that modern computer tech is a good guide, these sub-munitions can be made very lightweight: a simple CCD seeker, computer, battery and so forth should weigh less than 50 grams, so we can have a projectile massing around 300g with mass fraction of around 3, giving a nice supply of delta-V for the terminal stage with chemical rockets. A missile with 3kg payload could carry 10 of them, but there's no reason our sub-buses couldn't be built up to a payload of around 30 kg and thus carry 100 'soda cans of death'. We now have 20000 homing impactors inbound on the laserstar. The impactors spread out into a field that encompasses the entire area the laserstar could maneuver into in the remaining time before impact. Because these munitions are very small, they'll be hard to hit even with a mega-laser and they can avoid the beam by jinking around at random until they're close enough for random walk to be ineffective. With 300g mass at impact velocities of up to 50 km/s, a single impactor successfully striking the target will be an instant kill. It would be trivial to also carry dumb kinetic 'sand' that follows the SCoDs, further enhancing the kill probability. If you suspect that the laserstar will shoot down all 20,000 impactors before they get to it, it is trivial to send more missile buses because they're way cheaper than a laserstar can be.
CoaDE of course doesn't let you mess about with such tiny submunitions, but I was easily able to build a missile bus that has 70 km/s deltaV, 4.5 mg acceleration and carries 30 sub-drones for a little under 5 Mc. Each sub-drone carries 20 13.9 kg flak missiles, for a total of 600 submunitions per bus. For the cost of a single 'Finger of Boron Almighty' I could have 140 buses, 4200 sub-drones and 84000 flak missiles all on a collision course with the laserstar. With such high closure speeds, my missiles don't need to fly all the way in to a hit: they can burn out into a 'shotgun' pattern and detonate their flak bombs long before they enter the range at which the laser can zap them almost instantly, and even if it does kill them the debris is still inbound and will have to be avoided. Missile spam FTW!
|
|