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Post by srbrant on Oct 8, 2017 4:35:24 GMT
Copied and pasted. Thanks. Back to the issue of efficiency. In CDE, I've found that drop-tanks are a godsend for travel, but that would end up with a lot of remass wasted in space and a lot more debris. Then again, Kessler syndrome in my story is already a problem. Two words: scrap asteroids. At this point, I'm afraid to say that this will have to be handwavium. Just have to make it as less wavy as possible. If you're going to handwave tech, make a kind of substance that converts into directional energy, with no waste heat problems whatsoever. It'd make the ultimate drive, if you don't fancy Alcubierre reactionless drives (the one which likes to fry/vaporize planets at your destination if you go superluminal) or EMDrives. No waste-heat problems sounds...not...right. Well, lemme get crackin'!
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Post by srbrant on Oct 8, 2017 3:58:35 GMT
Example of time dilationAt .8c, every 36 minutes on your ship equals an hour on Earth. If your handwavium hyperspace's time rate is synced with the real space, a trip to AlphCen (4.3 ly) at .8c in real space would take 5.375 years according to a person on a still frame and would still take 5.375 years if you travel in hyperspace according to a person on a still frame, but it'd take 3.225 years according to your ship. The only thing that will help is the lack of obstacles, possibly. Copied and pasted. Thanks. Back to the issue of efficiency. In CDE, I've found that drop-tanks are a godsend for travel, but that would end up with a lot of remass wasted in space and a lot more debris. Then again, Kessler syndrome in my story is already a problem. Two words: scrap asteroids. At this point, I'm afraid to say that this will have to be handwavium. Just have to make it as less wavy as possible.
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Post by srbrant on Oct 8, 2017 3:17:39 GMT
Relax, it's time-dilation. All warp cores are carefully designed so that the travel time within hyperspace is synced with the passage of time in real space by default. (For example, 15 hours in hyperspace means 15 hours have passed in the rest of the world.) It looks like it's contradicting itself. Oh dear...
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Post by srbrant on Oct 8, 2017 3:07:19 GMT
"I like the Lagrange point idea, however there are interesting considerations: Can you jump directly to, say, Moon L1 from Alpha Centauri? What happens to conservation of momentum when you jump between solar systems? Nearby stars are usually moving at 20 - 100 km/s relative to each other. Theoretically for most types of jump-like FTL this velocity shouldn't magically cancel out (conservation of momentum). If you can do the former and momentum is conserved, you can use this speed to your advantage. Just select your destination so that your velocity after the jump points into the general direction of your target. That means there are certain windows of opportunity where you can gain the most advantage out of your relative speed. That also means all interstellar ships in this universe need to have at least a few dozen km/s of delta-v to be of any use. That also means that certain systems, like Barnard's star would be harder to get to even if they are closer to home. Still, could you please clarify how efficient you want your drives to be?" Yep. Jump from L1 to Alpha Centauri with a travel time of two or three days. Not sure about the momentum thing. The ship might not be "shot out" of "hyperspace" due to the drive folding space around it. As for efficiency, I'm looking for a ship that can get some decent (14.5?) Delta-V with only 50 or even 20 percent of its mass being reaction mass. Ridiculous, I know... L1 to Alpha Centauri in 2-3 days? I hope that means time dilation and not just brute speed, if it is the later you have to deal with time travelling. Relax, it's time-dilation. All warp cores are carefully designed so that the travel time within hyperspace is synced with the passage of time in real space by default. (For example, 15 hours in hyperspace means 15 hours have passed in the rest of the world.)
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Post by srbrant on Oct 4, 2017 5:21:07 GMT
"I like the Lagrange point idea, however there are interesting considerations: Can you jump directly to, say, Moon L1 from Alpha Centauri? What happens to conservation of momentum when you jump between solar systems? Nearby stars are usually moving at 20 - 100 km/s relative to each other. Theoretically for most types of jump-like FTL this velocity shouldn't magically cancel out (conservation of momentum).
If you can do the former and momentum is conserved, you can use this speed to your advantage. Just select your destination so that your velocity after the jump points into the general direction of your target. That means there are certain windows of opportunity where you can gain the most advantage out of your relative speed. That also means all interstellar ships in this universe need to have at least a few dozen km/s of delta-v to be of any use. That also means that certain systems, like Barnard's star would be harder to get to even if they are closer to home.
Still, could you please clarify how efficient you want your drives to be?"
Yep. Jump from L1 to Alpha Centauri with a travel time of two or three days. Not sure about the momentum thing. The ship might not be "shot out" of "hyperspace" due to the drive folding space around it. As for efficiency, I'm looking for a ship that can get some decent (14.5?) Delta-V with only 50 or even 20 percent of its mass being reaction mass. Ridiculous, I know...
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Post by srbrant on Oct 2, 2017 19:21:23 GMT
srbrant What kind of efficiency do you need for your story? Could you give us a few example missions, like "Earth to Mars in 5 days, fuel fraction below 2" or "Earth to Pluto in three months, fuel fraction is 1.3"? If you want to never worry about fuel at all, like in the Expanse, there is nothing that can help you short of including something like sub-light warp drive or some purely fictional device with the giant can of worms it opens. If you want some 100 km/s of delta-v with hundreds of mg of acceleration, there are many choices of different degrees of viability, like others mentioned. You can't escape with tyranny of the Rocket Equation. Technically you can, but you have to be really careful about that. While I applaud srbrant 's dedication to getting the physics right, 99.9% of his readers won't appreciate clever propulsion ideas in and off themselves. They are only relevant in the context of what kind of world they allow you to build. If Arthur Clark needed a reactionless (still sublight) drive for his Rama stories to work, so be it. The problem is many authors and readers are so subscribed to the cozy standard space opera universe they want to get it no matter what laws of physics they need to bend in the process. That's the canon they are familiar with, they know which stories can work there and they have a few favorite twists of their own they want to add. And they need not do any tiring research of their own since it was done before them during fifties and sixties. Heinlein said he and his wife had to do two weeks of research that went into a single line of text in the book. Many of their followers did nothing like that, but since space opera setting became so convincing, it needs not adhere to reality any longer. As science and space opera conventions diverged, the genre started to mix with fantasy more and more. А story will work (i.e. captivate the reader) whether your plot devices are well grounded in science or not. When I played Mass Effect so much technology there sounded like pure magic (even more so in Andromeda), and so many themes of classic fantasy were integrated into SF, you can barely make the two genres apart anymore. Expanse, for example is riddled with artistic license in physics and biology. Later books added FTL into the mix too, but at the same time it updated many other elements (no artificial gravity at first, some more realistic weapons) to modern day standards and lo and behold, it is praised as hard science fiction. I'm writing all of this to say: do not try to select the laws of physics to fit your imagined world. If you have a picture of the world you want, it is too late to justify any of the technology required for it. Instead look at all those ideas for plausible future technologies and try to imagine what kind of world they would enable. That's what I'm doing, actually: choosing different technologies to be used and understanding their implications while keeping physics relatively unharmed. Many races are wary of nanorobotics to varying degrees due to the events of the Technocaust and the absolute havoc they wrought during that dark time. Reactionless drives are possible, but they are _very_ illegal and firing one up is the moral and political equivalent of launching an ICBM. As for travel efficiency it's more like "burn to Lagrange point, wait several days, reach Lagrange point, activate warp drive, wait a few days, then get spat out at the Lagrange point of your final destination." Each core and drive is designed so that the amount of travel time that passes is the same as the amount of time passed in normal space. As for what things will look like during transit... The trick, to me at least, is to show the kind of possibilities that ACTUAL astrodynamics provide as opposed to the _Star Wars_ school of space combat and physics. Not showing people what can't happen, but what CAN happen.
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Post by srbrant on Oct 2, 2017 16:31:32 GMT
srbrant What kind of efficiency do you need for your story? Could you give us a few example missions, like "Earth to Mars in 5 days, fuel fraction below 2" or "Earth to Pluto in three months, fuel fraction is 1.3"? If you want to never worry about fuel at all, like in the Expanse, there is nothing that can help you short of including something like sub-light warp drive or some purely fictional device with the giant can of worms it opens. If you want some 100 km/s of delta-v with hundreds of mg of acceleration, there are many choices of different degrees of viability, like others mentioned. You can't escape with tyranny of the Rocket Equation. Technically you can, but you have to be really careful about that. While I applaud srbrant 's dedication to getting the physics right, 99.9% of his readers won't appreciate clever propulsion ideas in and off themselves. They are only relevant in the context of what kind of world they allow you to build. If Arthur Clark needed a reactionless (still sublight) drive for his Rama stories to work, so be it. The problem is many authors and readers are so subscribed to the cozy standard space opera universe they want to get it no matter what laws of physics they need to bend in the process. That's the canon they are familiar with, they know which stories can work there and they have a few favorite twists of their own they want to add. And they need not do any tiring research of their own since it was done before them during fifties and sixties. Heinlein said he and his wife had to do two weeks of research that went into a single line of text in the book. Many of their followers did nothing like that, but since space opera setting became so convincing, it needs not adhere to reality any longer. As science and space opera conventions diverged, the genre started to mix with fantasy more and more. А story will work (i.e. captivate the reader) whether your plot devices are well grounded in science or not. When I played Mass Effect so much technology there sounded like pure magic (even more so in Andromeda), and so many themes of classic fantasy were integrated into SF, you can barely make the two genres apart anymore. Expanse, for example is riddled with artistic license in physics and biology. Later books added FTL into the mix too, but at the same time it updated many other elements (no artificial gravity at first, some more realistic weapons) to modern day standards and lo and behold, it is praised as hard science fiction. I'm writing all of this to say: do not try to select the laws of physics to fit your imagined world. If you have a picture of the world you want, it is too late to justify any of the technology required for it. Instead look at all those ideas for plausible future technologies and try to imagine what kind of world they would enable. (Sincerest applause) I like your style.
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Post by srbrant on Oct 2, 2017 6:28:13 GMT
Yep. Or on large orbital colonies. Then stuffed into a docked ship's remass tanks by the ton. Or as I previously mentioned, have a hydrocarbon-rich algae that's able to thrive on astronaut poop onboard. Another solution could be the use of "vacuum energy" propulsion like in Clarke's novel Songs of Distant Earth. Although that sounds like it dips its toes a little too deeply into Killing Star territory. Why don't you recycle that poop back to food? Also, vacuum energy propulsion sounds weird as it seems. There are chances that the vacuum energy is crazy powerful or awfully weak. Choose one. One farm for food, one for biofuel. Not sure, but it may be a key factor into the vague workings of a warp core in Kemono.
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Post by srbrant on Oct 2, 2017 5:27:13 GMT
I think I'll add degenerate star systems into my story as "Pariah Stars."
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Post by srbrant on Oct 2, 2017 5:18:38 GMT
Hoo boy. This isn't looking so well. Perhaps have the biofuel grown on planets or in space and pumped into the ships rather than having them have it on board...? Kind of surprised that the biofuel thing didn't work out. What is wrong with my brain these past few days? You mean, biofuel production stations on planets? That doesn't help the ship at all. Zero efficiency improvement. Yep. Or on large orbital colonies. Then stuffed into a docked ship's remass tanks by the ton. Or as I previously mentioned, have a hydrocarbon-rich algae that's able to thrive on astronaut poop onboard. Another solution could be the use of "vacuum energy" propulsion like in Clarke's novel Songs of Distant Earth. Although that sounds like it dips its toes a little too deeply into Killing Star territory.
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Post by srbrant on Oct 2, 2017 4:13:30 GMT
1. I don't understand how would that help improve exhaust velocity in any way. Probably good for a pseudoscience clickbait article for INTPAge goers, providing that they don't have enough rocket science studies. 2. What are you ( srbrant ) confusing about, you thought photosynthesis produces more matter? If you really want to synthesis matter out of energy, visit amat farm. Hoo boy. This isn't looking so well. Perhaps have the biofuel grown on planets or in space and pumped into the ships rather than having them have it on board...? Kind of surprised that the biofuel thing didn't work out. What is wrong with my brain these past few days?
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Post by srbrant on Oct 1, 2017 23:04:42 GMT
Sorry folks, it's been a while. I might have found a way to have ships that aren't 75% reaction mass in tonnage: improving the fuel efficiency of engines. Since my story takes place far into the future, the rules can be bent around a bit, but I want to make things believable of course. On each engine, between the nozzle and the engine proper, is a cylinder that, through some black-box method I need to figure out, is able to stretch out the delta-V of a ship ten-fold. Perhaps because of a better understanding of how hydrocarbons work? If that doesn't work, then perhaps onboard algae farms can produce biofuel to act as a propellant. Sustainable too, if you're looking at the big picture on a cosmic scale and don't want to suck gas giants dry. Though I imagine that onboard production of the stuff would be like filling a fish tank with a squirt gun - all the more reason for refueling stations as well. If the first suggestion works, I could scale down the remass tanks so that you can have more crew space and less fear about relativistic suicide bombers. Thoughts, comments or suggestions? 1. Idk what you mean by that, you think that this cylinder of yours can increase the chemical bond energy and thereby increase exhaust velocity? 2. Conservation of mass, mass inside a closed system must remain constant. But maybe your algae farm is made out of sixth dimensional algae which produce a wormhole to another universe where it extracts remass. 1. A good idea, but the mechanism of that would require some emergency phlebetonium implantation. The stuff I'm working on is something that's realistic but at the same time and of equal measure something that will inspire engineers, physicists and scientists. 2. No, it produces algae that acts as a potent biofuel, using the onboard septic tanks as fertilizer to grow it all. Although you'd need a lot of people to produce the...stuff necessary to make it all happen. Perfect for large-scale exploration ships. But something isn't adding up...
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Post by srbrant on Oct 1, 2017 22:56:36 GMT
Sorry folks, it's been a while. I might have found a way to have ships that aren't 75% reaction mass in tonnage: improving the fuel efficiency of engines. Since my story takes place far into the future, the rules can be bent around a bit, but I want to make things believable of course. On each engine, between the nozzle and the engine proper, is a cylinder that, through some black-box method I need to figure out, is able to stretch out the delta-V of a ship ten-fold. Perhaps because of a better understanding of how hydrocarbons work? If that doesn't work, then perhaps onboard algae farms can produce biofuel to act as a propellant. Sustainable too, if you're looking at the big picture on a cosmic scale and don't want to suck gas giants dry. Though I imagine that onboard production of the stuff would be like filling a fish tank with a squirt gun - all the more reason for refueling stations as well. If the first suggestion works, I could scale down the remass tanks so that you can have more crew space and less fear about relativistic suicide bombers. Thoughts, comments or suggestions? I have no idea how that would work, what kind of engines are you using?Algae can't magically create mass, they need water and organics to grow. The energy in these ingredients would be much higher than any fuel they algae could possibly make. There is no point to carrying a farm except for biomass recycling for crew.Any kind in CDE. Sorry, it was really late at night.
It's not the algae that produces reaction mass, it IS the reaction mass, specially engineered to act as an efficient, renewable fuel. A special onboard farm would be able to produce more of the stuff, but at a very sluggish pace as previously mentioned.
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Post by srbrant on Oct 1, 2017 5:10:49 GMT
Sorry folks, it's been a while.
I might have found a way to have ships that aren't 75% reaction mass in tonnage: improving the fuel efficiency of engines.
Since my story takes place far into the future, the rules can be bent around a bit, but I want to make things believable of course. On each engine, between the nozzle and the engine proper, is a cylinder that, through some black-box method I need to figure out, is able to stretch out the delta-V of a ship ten-fold. Perhaps because of a better understanding of how hydrocarbons work?
If that doesn't work, then perhaps onboard algae farms can produce biofuel to act as a propellant. Sustainable too, if you're looking at the big picture on a cosmic scale and don't want to suck gas giants dry. Though I imagine that onboard production of the stuff would be like filling a fish tank with a squirt gun - all the more reason for refueling stations as well.
If the first suggestion works, I could scale down the remass tanks so that you can have more crew space and less fear about relativistic suicide bombers. Thoughts, comments or suggestions?
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Post by srbrant on Jul 18, 2017 3:34:33 GMT
I have some questions! What are those ships like and what are they doing there? Is the fighting between two Trojans or between two outside powers over a target in the Trojans? Is it like in this game where nuclear powered death star laser telescopes are the simplest and most effective weapon of war, or like in real life where interplanetary ASATs (probably) will be, or neither? It's the ship's I've drawn and posted here. The fighting is over a single asteroid colony between three forces.
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