New answers tagged

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Asteroid Launcher The ship sneaks into the asteroid belt and starts manufacturing engines on the asteroids. When enough is made, it launches them at the Earth and/or other targets. Sure the Earth forces can try and blow them up but that's not really going to help as it just changes a single shot round into a shotgun round. Multiply that by thousands of ...


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Local singularity. Deploy AI into the local system that is more advanced than whatever is present. This frightening prospect is real even for people today. Secondly, hallucinogenic weapons. For some reason never deployed even in the worst horrors of human war. LSD bombs.


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Not meant to be a top answer but as something to consider: what if it isnt superior technology but superior design? The human ships are all efficient, they dont waste space and are build as compact and capable as possible. That makes turning easier and gives you a smaller profile to hit. Great atteibutes right? But the aliens come with an absolutely ...


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"The Three Body Problem" by Liu Cixin has several ideas for crazy advanced technology and I recommend reading it for the full details (it's also really good). The two most applicable to you: multi-dimensional entities The ship is just the 3D projection of something that is actually an eleven-dimensional object. Among other things, that means its internal "...


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I would strongly recommend relaxing your rules for the aliens A LOT. I will assume that you want to have some kind of narrative. To really make the alien alien, the other, I would give them future-fantasy devices. Not necessarily the most used in future fantasy, but offense and defense impossible by our current understanding of physics. Examples: Short-...


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The other idea's here are all good, but there isn't going to be a silver bullet. A human civilization like you're describing is a large, diverse ecosystem of adaptable self-replicating intelligent agents. (And it may have access to it's own super-intelligent AI, or it may not, IDK.) Even if you can get 99% fatalities in your first volley, the invader is ...


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With all due credit given to Roddenberry's masterpiece... Cloaking Field If the alien vessel can absorb all of the energies (including visible light) that our active sensors use, and if it can also store/conceal all of this collected energy plus its' own emitted energies from our passive sensors, then all of our weapons and maneuverability won't help. ...


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Trojan horse The automatic warship limps into the system, obviously disabled, flying blind. The long dead corpses of its crew are still aboard. Earth recognizes its alien nature and realizes that it is a ghost ship. The military wants that alien tech! And the ship does have excellent and complex tech. It is brought back to earth for study. As its ...


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von Neumann Machines aka Gray Goo, one of the more horrific potential apocalypses facing the humans race. Raw numbers are probably the strongest of force multipliers you could ask for, which means that unless you give this alien warship weapons and technology which just outclass the humans, which, given that humans have kinetic projectiles at sizeable ...


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What about the effects of adding an electromagnetic charge to the shield? While it might not do much to negate that kinetic energy, maybe it could deflect the rod or its fragments in harmless directions...


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As many other posters pointed out, the Whipple Shield isn't going to do much against a vary large, dense projectile. It's purpose is to absorb the impact of very small objects like dust grains or micrometeors. However, it is possible to take this principle and apply it as a form of active armour. Rather than a fixed plate, the ship carries batteries of ...


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To pull up an old but useful formula derived from work on shaped charge jets penetrating tank armour: $$P = L\sqrt{\frac{\rho_j}{\rho_t}}$$ $P$ is the penetration depth, $L$ is the length of the penetrator, $\rho_j$ and $\rho_t$ are the densities of the penetrator and target respectively. Note that this is different from the classic Newtonian penetrator ...


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60 km/s is so high, that you can neglect any inter-atom bounds and thermal movement and consider both armor and missile as a set of independent atoms. At first stages of impact missile atoms would pass through atoms of armor. Then scattering of tungsten atoms on tungsten atoms begins. You just can't call it evaporation - it would be an understatement. Since ...


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I think I'm pretty much saying the same thing as Thucydides except in laymen's terms. The issue with using a nuke would be blow back and fouling. Blowback being the amount of energy released back onto the, i guess you could say nuke cannon. That would be a very bad thing in zero-g. It would act as a propellant against the ship. And the fouling could be ...


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It won't be a cannon at all, but a warhead. This sort of device was actually investigated as far back as the 1980's under the Strategic Defense Initiative, and was part of a wider ranging investigation to harness the power of nuclear devices to drive weapons effects, so called "Third Generation Nuclear Weapons" The basis of all these devices is to encase ...


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More important than the size of the object is its heat signature. Slowing down from 200 km/s to 3 km/s, without having the ship be 99.9% propellant, requires a LOT of energy, and that energy will show up as a bright heat signature even if the deceleration burn starts months in advance. It's my understanding that heat signatures in space are very, very easy ...


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If the ship's orbit is perfectly circular and with a speed of 3km/s, it will be orbiting at an altitude of approximately 37,917 kilometers above sea level. That is just a very little bit above geosynchronous orbit. This may be interesting for you: geosync altitude is kinda the sweet spot for communication satellites, so slots in it are in high demand. If ...


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Without any kind of stealth technology, it is 100% likely to be seen long before it gets anywhere close to Earth Orbit. This might give you some perspective: A comet coming in unannounced from intersteller space, from outside of the ecliptic, was detected at 3au (three times as far from the sun as the earth is), by more than 20 different telescopes. ...


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Instead of a reflective layer of aluminium, you can technically use the principle behind gradient optical fibre and use multiple films of transparent materials to guide the laser along the surface of the hull and redirect it. The gradient has to be such that no matter what angle the laser hits, it would work.


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I think if you build the ship wall out of retroreflectors, with a layer of high melting point material below, then you've got the perfect defence against attack lasers. Any laser directed at your hull will be, to a large percentage of the energy, directed right back to the attacking ship. And the layer below makes sure that the heat from what gets absorbed ...


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The thing that kills lasers at range is beam spread. A laser spreads a lot less than, say a flashlight, but it does spread. That makes the energy density go down. It is the energy density that burns through a ship. If the energy density isn't enough to damage the hull, it just heats the target and, as you pointed out, you lose the heat war. So, things ...


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Which laser? There are many kinds of lasers available with wavelengths from radio "masers" all the way to ultraviolet "excimer" lasers, potentially more available with technological progress. And there is no known material that fully reflects all these wavelengths. For example, aluminium does have a dip in its reflectivity in the infrared 700nm – 900nm ...


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It's been my assumption that a laser would be an effective weapon at short enough ranges that a pulse can vaporize hull plating. "Short range" is a tricky thing to quantify. It very much depends on your own tech level assumptions and requirements, and as you haven't communicated them to us then I can't really speculate. The shorter the wavelength, the ...


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Wallpapering spaceship with 2-5 mm aluminum (steel would be much better) and active cooling will save you from any reasonable laser if you keep your distance. 80% dissipating energy is only for laboratoy lasers. For powerfull "battle lasers" only 0.1% - 5% of energy goes to the beam. And the beam itself greatly looses energy density with range due to ...


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Reflective surfaces will always help deflect some of the power, however no material is capable of reflecting 100% and some of that energy will always be absorbed. So even if you have a 99.99999% reflective surface, you still absorb a tiny bit of energy which is the main point. A laser is powerful because it can focus a decent amount of energy into a very ...


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It depends on the power that is being fired at you. Conventional mirrors are not 100% reflective. They normally reflect a bit more than 90% of the impinging light, meaning that around 10% of that power is absorbed or transmitted. If you are targeted with a mW laser, 10% of that are peanuts, and you don't have to worry. If you are targeted with a petawatt ...


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Answering the question as it's asked - sure. If you're burning it (rather than pouring it through a nuclear thermal rocket), then it's inarguably a chemical rocket fuel. As some of the commenters have pointed out, it's potentially a little hoity-toity for the tough, grizzled space adventurers using it - probably they'd call it LMH/fuel, and then shorten it ...


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The idea sounds faintly troubling, in that the aether has become some magical place where you can just send unwanted energy and everything will be ok, but so long as it doesn't allow FTL or form a privileged reference frame then you might just about be ok, from the point of view of not annihilating physics as we know it. (also, make sure you have a read of ...


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There are two general requirements - power and space. Power 1,000,000 humans need about 2,000 calories per day each plus energy for day-to-day functions. Total up the calories and convert it to something workable, and we have a total of 96.85 MW. That is a lot, but that pales in comparison to energy. The average US household uses 900 kWH per month, giving ...


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The answer given by mcRobusta accounts very well for the circular accelerator. The formula is indeed $F=\frac{m v^2}{r}$. But to compare to the linear case, consider a linear gun with barrel length $d=2 r$. At constant acceleration the exit velocity is $\sqrt{2 d a}$. That is, to get a velocity of $v$ you need a force as follows. $$ F = m \frac{v^2}{2d}= m\...


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Our friend Isaac Newton can help us here with his equation of circular motion: $F = \frac{mv^2}{r}$ where F is the force produced, m is your object mass, v is your object's linear velocity, and r is the radius of motion. As you can see, it's the speed you want to reach that is going to have more of an impact than your mass (which, by the way, is still a ...


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This very much depends on the sort of story you want to write and whether the technology itself is effectively a character in that story. Star Wars. It's entirely fantasy, it has wizards and magic swords, for all practical purposes they might as well be riding horses or flying carpets as in spaceships. Everything runs on handwavium and technology is ...


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Write what you know. You are conflicted about your desire for certain SF tech and your inability to explain them. Clearly that interests you. You can get good traction from that for your story! Your engineering characters have the same concerns and are conflicted in the same way. You can have one or more scenes where they walk thru the tech. I ...


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Circular Coilgun Why not make the coilgun circular like a collider and keep circulating low mass projectiles until they reach high speed and then release them. It works for atom smashers so should work in principle. The limiting factors is the strength of the magnets and size of the ring. The bigger both are, the faster you can go.


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The problem with shields, in this context You need to reconcile the Star Trek transporter dilemma wherein having shields up prevents certain high density data signal data transfers, such as transporters. At the end of the day, since the field units are limited to non-FTL communications, they are going to be limited to radio signals. They can be encrypted, ...


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I'd like a way to justify having 100 meter long guns be able to throw out 1-ton projectiles at 30 km/s or better I don't understand your strange "tons", so lets use a nice easy measurement like a tonne. Your projectile will leave the barrel with a hefty $4.5*10^{11}$ joules of kinetic energy. If your coilgun only wastes 1% of that energy in heating the ...


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Muzzle velocities may be more modest than your projected velocity of 21 km/s. When Gerard O'Neill was conducting trials with mass-drivers. This was pioneering work for the construction of his proposed Lagrange cylinder habitats. This research found there was a limiting velocity of around 4 km/s. After which any projectile launched with a mass-river tended to ...


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So it's probably important to explain a few things here about physics and Newton's Laws. The whole point of a railgun is to be able to do a lot of damage with a smaller projectile by giving it far more velocity. Momentum = Mass x Velocity In this equation, what we're saying is that you can increase the damage caused in a collision with something in two ...


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For the sake of convenience let’s start with the assumption that your population will desire a North American urban population density and a globally averaged diet. The city of Austin TX has approximately 1,000,000 residents and a surface area of approx. 800 km^2, for a density of about 1,250/km^2. The City of New York (5 boroughs) NY also has a surface ...


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If you're talking about war ships, maybe independant, conventional, unpowered space stations with conventional equipped canons would work. Big motherships place them in space where they operate a few days/weeks and then gather them again. As a weapon I can think of (untraceable) mines placed in space or mines which get shot out of starships. They unfold ...


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See the Honor Harrington series by Weber. He actually goes through a several generation series of offence and defence weapons. Miltary grade ships have accelerations of 400 to 700 Gs with smaller ships being more capable. Missiles have accelerations of 10-50 times that, but their 'impellers' burn out. But 3 minutes acceleration at 20,000Gs covers major ...


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