Spacescifi

I wanted to design a scifi SSTO around the gimmick of being able to cancel the pull of gravity. I soon realized rocketry would be wastefull when I could just turbofan and coast into space. Sure it will take longer but not unbearably so, maybe an hour more. But it's worth it for not having to expend propellant. For space travel they would use a special vacuum reaction drive that pushes off space vacuum itself for thrust and won't work within thick atmosphere. Requires vacuum conditions to work.

I don't mind your feedback. Carry on or not as you wish. Telling a good story is what matters in the end. And there are different levels of SOFT scifi... theres Star Wars science fantasy that is soft as a marshmallow, and then there is Stargate SG1, which is like a jelly bean. A bit of thin candy hard science, but ultimately full of fiction in it's gòoey center.

Does not bother me. Possible solutions: 1. Access to unobtanium that specifically generates a zero gravity field when electric current is applied, which grows larger the more current is applied. Earth has none, or if it did once, was mined of all of it a long time ago by space aliens who use it. That's basically taken from Stargate, only a different function as opposed to naquadah. Can be found on select alien worlds. It also allows the excuse for not visiting Earth even though they know where it is (they have no unobtanium so nobody cares about Earth lol). 2. Bootstrapping alien tech so advanced you cannot retroengineer it (thus the turbofan). Yet claiming you made it to appear you're more technologically advanced than you really are (also from Stargate, Goauld loved doing this).

https://medium.com/@marek.janda.eng/nuclear-powered-jet-engine-is-there-a-case-for-reviving-this-idea-34954e20e31a Cool.

We make turbofans for flight on earth. Scenario: Attempt to fly a turbofan jet plane on: Mars: Nothing much happens right? No air. Jet engines need oxygen. Neptune: Same? Saturn: Same? Jupiter: Same? Conclusion: In theory you could bring liquid oxidizer but that just makes the plane weigh more and reduces flight range. Which leads to the conclusion that ductfans and propeller craft powered by electric power are the ways we know could work for flight virtually anywhere. Since all you need is atmosphere to react with. Anything requiring oxygen or any specific chemical is niche. Yes you could design aircraft specifically FOR Neptune or Saturn to exploit their specific chemicals in the air, but they would not be craft good for flying almost on any other planet with atmosphere. The foundation of modern industrial power began with mechanical power (pulleys, levers, etc), graduated with chemical power (gunpowder, dynamite, oil and gas, and rocketry), and has entered the age of electrical power, although we have not fully exploited it yet. Chemical power has limits based on chemical reaction power released. Electric only has limits based off heat and storage, and so far chemical beats it purely based on chemical storing more power. EDIT: I did not mention nuclear, because although you could make a nuclear turbofan... the nuclear part is the danger. Specifically the radiation. Although if you had no better alternative it would be perhaps a good alternative in any atmosphere where free oxygen is rare or nonexistent.

How about ductfans instead? They are more thrust efficient and make less noise. In practice how an OP spaceship would enter an atmosphere from space: 1 . Slow speed to geostationary orbit while in low orbit using vacuum reaction engines and gravity cancellation in tandem. Because normally you would be falling in a curved trajectory as the atmosphere slows you. Here you slow in space without falling. 2. Toggle gravity cancellation field off. The result is you fall straight down... only long enough for you to reach an optimal velocity that you know your ductfans can counter to avoid crashing into the ground. In practice this also means traveling to a planet's surface will take longer, I don't know how long. Maybe an hour or two? Good news is you no longer have to worry about ablative heat tiles, because you never go fast enough in atmosphere to need them. 3. Leaving an atmosphere likewise will take longer than it would with rocketry. So do proper reconaissance before you decide to fly down to a planet, because if there is an enemy airforce chances are high you will be a BIG sitting duck to them. 4. I don't know if ductfans can do reverse thrust, but I think so, as I have seen turbofans on jet engines do it, and all turbofans are is a ducted fan with a jet engine in the middle. Ductfans rely on electric power, something a scifi spaceship will have plenty of usually by default. Gravity cancellation helps as well, but I would also presume that scifi spaceships can store larger amounts of electricity than modern batteries do.

That won't work so well on planets like Mars with barely there atmosphere. Nor planets that don't have much oxygen (Saturn, Neptune, ect) unless you have an electrode jet, and those wear out with use. Plasma jets are a thing but thrust is kinda weak compared to normal air jets. To have something that will work anywhere you need rocketry.

Scenario: A star wars like setting with SSTO vessels with hyperdrives being common. Technology: All SSTOs possess gravity canceler tech, which allow vessels to float around as if in zero g despite gravity levels. Space propulsion: A special vacuum seemingly reactionless drive is used for outer space only propulsion. In actuality it reacts with the vacuum itself... a kind of vacuum propulsion akin to how air travel relies on the air itself. Main Question: Obviously rocketry is still used to reach space, but due to gravity cancelation tech, SSTOs are far easier to make. So the question now is... is there ANY legitimate reason NOT to use aerospike engines on SSTOs? Because I cannot think of one, and if I were an engineer in the setting I would propose slapping aerospike rockets onto every SSTO in the fleet I worked with. Obviously star wars is not science accurate, and they use the same rocket engines for taking off planets that they use in space.... even though practically in real life this virtually is never optimal, efficient, or safe. Star Wars also never seems to utilize aerospikes either... with perhaps a few rare exceptions. In the OP setting, special vacuum based non-rocket engines are used for outer space travel, which means you can afford to optimize your rocket engines purely for SSTO duty and RCS for steering in space. So once again... any good reason to use a cluster of traditional bell nozzles over a singular big truncated aerospike surrounded by a ring of combustion chamber outlets? Just to reach outer space? Since once there the vacuum space reaction engines take over for main thrust, and rocketry is only used for steering via the RCS.

Scenario: Pick the most capable Roman Emperor from the 1st century onward, and have him SUDDENLY know all of modern science and engineering know-how of how to make EVERY bit of modern technology in existence since the industrial age... plus knowledge of how the original timeline went. 1. Which emperor would you pick? 2. What are his odds of developing any technology? My analysis: Even if you picked a competent emperor how far they progress would be limited by the very nature of how power was in the Roman Empire. Emperors were assasinated all tye time, and who knows how much backing you could really get on your scientific endeavors. My guess is you would have to start with something, anything, that will reap rewards and fast, so folks could get behind supporting tye Emperor's mad quest for better industrial machinery. From there? Complexity until you can't or you get assasinated lol.

Oh I know... real life is like the classic old videogame asteroids... only in 3D and with all the real life physics installed for additional difficulty. I once played Oolite (based off the original Elite with a lot more mods), and even though it is essentially airplanes in space, there is a "dark laser" laser mod I installed where laser beams are invisible as they should be in vacuum. I can tell you space combat became much harder as I could no longer gauge where to fly to totally dodge the laser beams. At best I could dodge and pray.... worse yet was when I was tailing an enemy ship and I get hit by laser fire. I had a hard time knowing who shot me (ships often have both fore and rear lasers), as I did'nt know if the one I was chasing zapped me with rear lasers or if his "friends" came to his aid.

I was thinking about how we handle g-force better lying down on our backs, and how it probably would hurt a pilot's lower back in the sitting position when they pull a bunch of gees in a tight turn all of a sudden. Typically there is no reason to pull off such tight turns, but who knows? Maybe super manuverable jet fighterd will be made one day that can do that casually. Anyways... any merit in making standing seat jet fighters today or would the miltary industry just laugh at the idea if anyone presented it to them?

Often in science fiction scifi humanoids are either given pointy ears or odd colored skin as their sign to show their alien-ness. Personally, I favor more practical effects. Scenario: Like is common, their skin is some odd color, but beyond that their body appears human... only their hands are different. Instead of soft hands of flesh with endoskeletal bone, they are exoskeletal hands with whatever muscle/tendons working beneath it without bone. In addition to this, the hands have a small valve hole in the middle of each palm that can open or close. When open one hand can can squirt an orange liquid 70 feet (if sprayed along an arc path) while the other shoots a blue liquid. If the liquids come into contact they cause chemical combustion on contact. Humanoids have a limited reserve of these liquids but generate more daily, especially while sleeping. Reason: It's a designer humanoid race, designed specifically to have the ability to start fires without any tools required, which is also useful for self defense obviously besides combat. Main Question: How feasible is this according to physics? I think there is nothing in physics that says such a concept is impossible to exist. Also how practical would it be? I know exoskeletons are lethargic when molting and cannot be used as actively since they are softer, but according to youtube videos crabs only take about 30 minute to shed their exoskeleton and two days to fully harden up. With the OP humanoid race, it's only the hands, so the process should go faster I think. In practice I suppose work staff would be larger to substitute folks on their hand molt days off. Thoughts? Not sure about dexterity, but per scifi desire, I want dexterity to be on par with normal humans. They also have tiny hairs on the exoskeleton that allow a sense of touch.

What? How would that even look? No lens on laser? I always thought lasers would look like camera lenses, only instead of snapping pictures they burn you with concentrated photonic beams. And if you can go without a lens then why do atmospheric military shipboard lasers seem to use lenses?

It is my understanding that the bigger the radius of your laser lens, the greater range you get from a given beam. Also I have read that lasers are great at focusing all their energy on small spots. So ideally you would want a large radius laser lens to have it's beam converge onto a spot size much smaller than it's radius... right? And with distance all laser beams widen out anyway. Which I don't have any issue understanding. Main question: How would or would a long range laser focus on a tiny spot much smalker than the lens radius? Or would it simply fire a beam equal to the kens radius which grows wider with distance? The weird thing is that if you really do have a converging long range laser beam which widens out again farther out, there is a sweet spot distance where the beam would miss you if you were not dead center or close to the focal point of the beam. Since it would be like narrowly avoiding a converging cone shaped beam. Thoughts?

True. So if capitalism still thrives, the only real dangers would be pollution and eviromental resource control.... making sure we don't run out of natural resources. Scifi may be fiction, but I really do get why sometinds old but advanced scifi races are depictef as having homeworlds that are depleted of natural resources. Because they spent them getting to where they currently are.

Scenario: We just developed immortality and can choose who gets it and who does not. Like all technology, no one holds a monopoly on developing it, and it is only a matter of time before the have-nots either purchase or develop it themselves. Nevermind the black market too. How it works: The first were designer babies that were biologically immortal. The male babies carry the immortality DNA, so they won't age past 40. They can pass on their immortality to their offspring, even if the woman mated with is not immortal. Female immortal babies cannot pass on the immortal trait to their offspring as adults unless the father is also immortal. Why I even started this thread: No healthy person wants to die, but I could not help but wonder about the alternative, and I considered perhaps it is for the best that we are not immortal. Since it is reasonable to conclude that both the best, the worst, and the pragmatic side of humanity would decide not only our fate, but the worlds'. And on a faster time scale. Think civilization evolution... on steroids. The most obvious problem is overpopulation. Child bearing age for women is ideal in the 20's, less so in the 30's, and definitely not at 40. Initially space colonization won't be available, so I suppose the humane way to prevent overpopulation would be to government regulate reproduction and only allow the act in goverment hotels after you have cleared all paperwork giving you the OK and what you need or won't. Birth control would be the rule and not the exception, and goverment hotel staff would make sure of this before any reproductive acts take place. Having a child illegally would be punishable by jail time and the baby would be taken from you to be a ward of the state. My conclusions: I don't like to admit it, but the death of humans seems to be part of a fine tuned system, which would quickly malfunction if every one of us became immortal. Some religions teach humanity will live forever on Earth, but barring anything beyond divine intervention, as long as we are running this planet, I am not sure giving us immortality is healthy in the long run. Why? Consider how capitalism works I dare say immortality and capitalism don't get along, since overpopulation creates scarcity of resources and the number of jobs to fill in any society is limited. Which at some point unless the majority were allowed to die like we already do, capitalism as we know it would break down. Entire economies would be forced to adjust for a population that is not going to pass away. What are your tboughts? Please try to not get the thread locked. Avoid politics and talk of.... eradication of undesirables Thank you.

It is common for starships to do it by means of on board powerplant, presupposing that that the energy required is not astronomical. When in reality it virtually is. And yet I still wanna take a crack at this with scifi tech anyway just as a demonstration to see what... or even if we could do FTL warp shenanigans even with scifi tech. Scenario: We figured out how to make a kind of FTL hyperdrive. We also figured out how to generate and store antimatter but due to it's inherent danger we won't be using it on our starship. Supplying power: We covered the moon with tall solar panels, and via hyperspace link they generate power instantly to all our starships no matter WHERE they are in the universe. It also allows for instant communication Main Question: Provided the energy cost is equivalent to Alcubierre's warp drive, could a moon covered in 99% efficient solar panels directly supplying power to a 500 ton starship generate the required energy to do it or not? If so, how many 500 ton starships could it power for FTL simultaneously? Since there would be a limit to how many it could power because the moon surface is not infinite.

Again it is a heat and safefy issue with the rocket. A rocket is more or less a directed explosion. Despite the fact that antimatter requires bomb mass, to try to replicate the same feat using regenerative cooling on a rocket nozzle I presume would require more propellant mass expended than if you just detonated an AM bomb orion style against the pusher plate. Reason being you have to carry away the heat. Whereas with Orion you do not have a heat problem nearly as much because of distance and the pusher plate. You can also detonate higher and higher energy yield bombs without increasing your pusher plate equipped ship's mass to cope with it. Whereas your energy yield of your rocket exhaust is capped by however much it's reaction chamber can take. Mini-mag is like the limits of rocketry and Orion mixed into one. A magnetic nozzle being propelled by external pulse propulsion. In fact the main form of propellant you lose on an Orion pusher plate is the sacrificial oil used to absorb the plasma every time it hits the plate.

NSWR are the only theoretical realistic torchdrive rockets that have ever been designed. It is my understanding that the energy release is equal to a constantly exploding nuke.... only directed as a rocket plume. This reaction somehow does not occur until what? Once it's already leaving the nozzle?

My point is you cannot have the same TWR as external pulse propulsion using rocketry. For all the mass required for rocketry (most of it being propellant), and the engine waste heat being a factor, you won't be able to ever have the TWR of nuke or antimatter external pulse propulsion, unless you try something dangerous like NSWR.

I meant efficiency with the thrust to weight ratio. Detonating a nuclear or antimatter bomb requires less mass/weight than exhausting enough propellant to gain the equivalent amount of thrust if you just detonated the bomb. By the time you reach the TWR of the bomb with a rocket your engine will either melt or you have some type of nuclear saltwater rocket shenanigans going on that are teetering at the edge of blowing up your vessel in a catastrophic explosion the whole time.

While a thermal antimatter rocket is possible, engine heat limits how efficient you can get using reaction mass. In other words, there is no getting around using tons of propellant because you would still need it. Since cranking the rocket up to max efficiency by reacting more antimatter with mass is not possible because you would destroy the engine. Arguably one of the most efficient engines using antimatter would be a variation on mini magnetic Orion external pulse propulsion, just subbing the nuke for a photon torpedo lol.

I see... so they would need skin, muscle, and organs as strong as graphene.

Spider silk has 5 times the tensile strength than steel at the same diameter strand. Steel is about 1 Newton per square meter compared to spider silk which about 5 newtons per square meter. Additionally, spider silk can elongate 35–50% its length before snapping compared to 8% steel. So imagine a scifi alien humanoid of average height and weight with skin and muscle fibers that had those properties but weight is normal for a human (180 kilograms). Would they have superhuman abilities at all? My Analysis: Yes. I think. But to be truly super their bones would need to be stronger still than their muscles so the muscles would not crush them. The bones would not be able to stretch like the muscle and organs, but they would need to be strong enough to withstand the pressure put upon them by the muscles. Thoughts? I assume they would be bullet proof more or less but it would still cause them pain if they were shot and they would get knocked down from the force alone. So superman-lite basically. Super durable to piercing attacks, but still vulnerable to chemical and heat attacks.

I think the future of uber magnetic manmade fields lies in advanced magnetohydrodynamics. For example, the massive magnetic field of earth is said to be caused from the rotating molten iron core. And magnetars (uber magnetic neutron stars) are theorized to generate their fields from as follows below from wikipedia: Origins of magnetic fields edit The dominant theory of the strong fields of magnetars is that it results from a magnetohydrodynamic dynamo process in the turbulent, extremely dense conducting fluid that exists before the neutron star settles into its equilibrium configuration.[16] These fields then persist due to persistent currents in a proton-superconductor phase of matter that exists at an intermediate depth within the neutron star (where neutrons predominate by mass). A similar magnetohydrodynamic dynamo process produces even more intense transient fields during coalescence of pairs of neutron stars.[17] But another theory is that they simply result from the collapse of stars with unusually strong magnetic fields.[18] Questions: 1. Has anyone tried to generate a magnetic field by rotating molten iron? 2. Do you think we could develop uber magnetic fields with magnetohydrodynamics, or is it simply a matter of mass, meaning more mass applied allows for stronger fields etc as in the case of magnetars. Interestingly in pulse pure fusion detonation research, uber magnetic fields have been created, albeit only momentarily. So it seems you either need a ton of mass or a lot of energy, because mass and energy are two sides of the same coin and are interchangeable and convertible. Thoughts?