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Post by anotherfirefox on Aug 20, 2018 8:03:34 GMT
Oxygen needs to be kept considerably less cool than hydrogen, and if you only have to cool your oxidizer instead of your oxidizer and your fuel you still save a lot of mass. And RP-1 has a decent I sp, it just isn't on the level of hydrogen. True but why the NASA guy has never used it, considering it must be way better option than hypergolic? The venerable Saturn V used RP-1 at first stage only, and its Apollo crew module used hypergolic when it already had oxygen for life support and fuel cell. RP-1 as an orbital fuel is just meh. It's stuck in the middle, no strong point.
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Post by The Astronomer on Aug 20, 2018 8:17:34 GMT
Oxygen needs to be kept considerably less cool than hydrogen, and if you only have to cool your oxidizer instead of your oxidizer and your fuel you still save a lot of mass. And RP-1 has a decent I sp, it just isn't on the level of hydrogen. True but why the NASA guy has never used it, considering it must be way better option than hypergolic? The venerable Saturn V used RP-1 at first stage only, and its Apollo crew module used hypergolic when it already had oxygen for life support and fuel cell. RP-1 as an orbital fuel is just meh. It's stuck in the middle, no strong point. Hypergolic fuels are very reliable: fairly dense, easy to keep around, no ignitions required. I guess that's why. Speaking about cryogenic propellants, would those be easier to use in, say, the outer Solar system?
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Post by anotherfirefox on Aug 20, 2018 8:32:51 GMT
True but why the NASA guy has never used it, considering it must be way better option than hypergolic? The venerable Saturn V used RP-1 at first stage only, and its Apollo crew module used hypergolic when it already had oxygen for life support and fuel cell. RP-1 as an orbital fuel is just meh. It's stuck in the middle, no strong point. Hypergolic fuels are very reliable: fairly dense, easy to keep around, no ignitions required. I guess that's why. Speaking about cryogenic propellants, would those be easier to use in, say, the outer Solar system? With the near future tech, the only concern for the fuel in the extended outer Solar system mission is in-situ resource utilization. If you can get fuel where you are, the other problems like dV and TWR becomes super trivial. In that manner, methane will dominate this system for a while: There's an ocean of methane out there.
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Post by The Astronomer on Aug 20, 2018 9:26:52 GMT
Methane for methane god Problem: nothing to mine resources out of during the transit, when your cryogenic propellant boils away Solution: Use cryogenic peopellant for departure, and storable ones for arrival injection
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Post by anotherfirefox on Aug 20, 2018 9:56:03 GMT
Methane for methane god Problem: nothing to mine resources out of during the transit, when your cryogenic propellant boils away Solution: Use cryogenic peopellant for departure, and storable ones for arrival injection NASA guys aimed higher, take a loot at this: ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170006481.pdf+ In the supposed Mars mission of canceled Constellation program, they tried to store liquid hydrogen for around 5 years so boil off wouldn't be that harsh by then. You can land on Europa with SLS in less than 2 years, not mentioning the glorious BFR + Using SpaceX BFR to Titan may need less than 3 years: crowlspace.com/?p=2900
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Post by The Astronomer on Aug 20, 2018 10:15:11 GMT
Methane for methane god Problem: nothing to mine resources out of during the transit, when your cryogenic propellant boils away Solution: Use cryogenic peopellant for departure, and storable ones for arrival injection NASA guys aimed higher, take a loot at this: ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170006481.pdf+ In the supposed Mars mission of canceled Constellation program, they tried to store liquid hydrogen for around 5 years so boil off wouldn't be that harsh by then. You can land on Europa with SLS in less than 2 years, not mentioning the glorious BFR + Using SpaceX BFR to Titan may need less than 3 years: crowlspace.com/?p=2900Ohhh, they are trying to keep LH2 hanging around for years in space? What a crazy goal.
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Post by gedzilla on Aug 20, 2018 10:18:10 GMT
Methane for methane god Problem: nothing to mine resources out of during the transit, when your cryogenic propellant boils away Solution: Use cryogenic peopellant for departure, and storable ones for arrival injection Its funny; i havent seen a 40k reference here in so long
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Post by anotherfirefox on Aug 20, 2018 10:31:32 GMT
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Post by Apotheon on Aug 20, 2018 14:20:02 GMT
What does your infrastructure do? That's something we must agree before the discussion. The easiest thing to think of is orbital cryogenic fuel depot: Never put it in low orbit, no needs and they'll boil off much faster. In any case, LEO is not a good idea. Note that US is gonna abandon ISS at LEO and going to build one at even farther, Earth-Moon L 1 point. Getting into orbit around Earth is not such a problem: You can use vast infrastructure we already have on the ground. Getting to another body is the problem. Note that we can easily build orbital booster with 9km/s with even 60's tech, yet never was able to build a deep space stage with more than 1kn/s with chemical rockets. Unless you're using super powered VASIMR, never use an ion propulsion around deep gravity well: SUPER longer travel time, which leads to WAY more life support. With current/near future tech, the thing you have to care about is nothing with dV or TWR sorta propulsion things. They can be dealt with more funds. Life support is the crucial thing you have to deal with, which is not simulated by this game. Above is a ship for just 6 crews for Earth-Mars transport, supposed by NASA. It's bigger than ISS, and more than two third of its volume is life support. Lastly, if you're interested in building more civilian, interplanetary things, go and grab KSP Realism Overhaul. When it comes to such a thing, KSP Realism Overhaul is almost as detail as CDE module design. (Triple more, in my personal opinion.) I assume anything is available in low orbit around the Earth, Moon, and Mars and that’s why I’m going lo-to-lo, as a starting point. BTW, does anyone know in what order the planetary orbits and moons were colonised in CDE? Earth, Moon, Mars... then Venus, Ceres, or a Jovian Moon? I dunno where resources are really. But I’m still starting with the E-M-M dynamics.
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Post by anotherfirefox on Aug 20, 2018 14:39:36 GMT
What does your infrastructure do? That's something we must agree before the discussion. The easiest thing to think of is orbital cryogenic fuel depot: Never put it in low orbit, no needs and they'll boil off much faster. In any case, LEO is not a good idea. Note that US is gonna abandon ISS at LEO and going to build one at even farther, Earth-Moon L 1 point. Getting into orbit around Earth is not such a problem: You can use vast infrastructure we already have on the ground. Getting to another body is the problem. Note that we can easily build orbital booster with 9km/s with even 60's tech, yet never was able to build a deep space stage with more than 1kn/s with chemical rockets. Unless you're using super powered VASIMR, never use an ion propulsion around deep gravity well: SUPER longer travel time, which leads to WAY more life support. With current/near future tech, the thing you have to care about is nothing with dV or TWR sorta propulsion things. They can be dealt with more funds. Life support is the crucial thing you have to deal with, which is not simulated by this game. Above is a ship for just 6 crews for Earth-Mars transport, supposed by NASA. It's bigger than ISS, and more than two third of its volume is life support. Lastly, if you're interested in building more civilian, interplanetary things, go and grab KSP Realism Overhaul. When it comes to such a thing, KSP Realism Overhaul is almost as detail as CDE module design. (Triple more, in my personal opinion.) I assume anything is available in low orbit around the Earth, Moon, and Mars and that’s why I’m going lo-to-lo, as a starting point. BTW, does anyone know in what order the planetary orbits and moons were colonised in CDE? Earth, Moon, Mars... then Venus, Ceres, or a Jovian Moon? I dunno where resources are really. But I’m still starting with the E-M-M dynamics. Among the anything available, what would you wanna do? It doesn't help "from 1 to 5, anything can be an answer."
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Post by apophys on Aug 20, 2018 15:42:14 GMT
Normally, you'd want to consider bulk cargo transfers (like phosphorus), specialized/priority cargo transfers (like reactor fuel rods), and personnel transfers; all in each direction.
Bulk cargo needs primarily low cost. Priority cargo needs primarily flexible launch schedules, secondarily low time. Personnel needs primarily low time, secondarily low cost. Having very high exhaust velocity helps all of these requirements, btw.
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Post by Apotheon on Aug 20, 2018 18:56:06 GMT
I assume anything is available in low orbit around the Earth, Moon, and Mars and that’s why I’m going lo-to-lo, as a starting point. BTW, does anyone know in what order the planetary orbits and moons were colonised in CDE? Earth, Moon, Mars... then Venus, Ceres, or a Jovian Moon? I dunno where resources are really. But I’m still starting with the E-M-M dynamics. Among the anything available, what would you wanna do? It doesn't help "from 1 to 5, anything can be an answer." This isn't a challenge thread! My intention with it was to discuss infrastructure theory, for instance the dV, acceleration, dry mass, wet mass, dry cost, and wet cost to go in between Earth, the Moon, Mars, and I'm open to discussing minimums for other objects in the solar system (as well as where it's even worth going) and discuss anything else that may be relevant to ship design, such as ISRU (do you believe the Moon or Mars can self-sustain with ISRU or are Earth tankers necessary?), as well as discuss ship design of whatever ships may be relevant and are within the scope of CDE (stations... not really, but one-way ships, two-way ships to bodies where propellant isn't cheaply available, and ships with payloads, including cargo, passengers, and propellant and maybe even reaching into policiary/military stuff). There are a ton of threads about building ships as big and powerful as CDE possibly can without crashing and not as many threads constraining what's realistic within the 2250 span, IMHO. It's intended for brainstorming... for instance, I've found a 1000 passenger Mars ship is twice as cost-efficient per person as a 100 passenger ship. But how many people do you dare to have aboard a single ship? On Earth, the answer is about 2500 for sea cruisers, AFAIK. Also, figuring out which planets would get their resources (including solids and propellant) from which other planets may help create more realistic levels... and ultimately, realistic civilian/military ships with realistic mission capabilities.
I haven't read this yet (dunno if it was referenced by someone), but it looks relevant: www.projectrho.com/public_html/rocket/infrastructure.php#id--Orbital_Propellant_Depots--Optimizing_Depot_Placement
Edit: I originally designed the Earth-Lunar Apolunar (methalox) and Apolunar X (methane) in Earth-Martian variants also. As I hinted at in my original post, I've rejected the Earth-Martian chemical rocket, because as it turns out, going Earth-Lunar-Martian saves 30% propellant and in theory only adds three days of travelling, assuming you can refuel around the Moon. One of the more interesting findings I've made. I've also re-designed my ships to have custom crew modules and put my current ships up in the original post.
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Post by anotherfirefox on Aug 20, 2018 22:31:21 GMT
This isn't a challenge thread! My intention with it was to discuss infrastructure theory, for instance the dV, acceleration, dry mass, wet mass, dry cost, and wet cost to go in between Earth, the Moon, Mars, and I'm open to discussing minimums for other objects in the solar system (as well as where it's even worth going) and discuss anything else that may be relevant to ship design, such as ISRU (do you believe the Moon or Mars can self-sustain with ISRU or are Earth tankers necessary?), as well as discuss ship design of whatever ships may be relevant and are within the scope of CDE (stations... not really, but one-way ships, two-way ships to bodies where propellant isn't cheaply available, and ships with payloads, including cargo, passengers, and propellant and maybe even reaching into policiary/military stuff). There are a ton of threads about building ships as big and powerful as CDE possibly can without crashing and not as many threads constraining what's realistic within the 2250 span, IMHO. It's intended for brainstorming... for instance, I've found a 1000 passenger Mars ship is twice as cost-efficient per person as a 100 passenger ship. But how many people do you dare to have aboard a single ship? On Earth, the answer is about 2500 for sea cruisers, AFAIK. Also, figuring out which planets would get their resources (including solids and propellant) from which other planets may help create more realistic levels... and ultimately, realistic civilian/military ships with realistic mission capabilities. I want to build an infrastructure on Earth. Where? How much? How big? With what construction method and material? DEPEDNS ON WHAT INFRASTRCTURE IT IS, mate. You have to build highway(transportation infra) from city to city, but you can never build an atomic plant in that way. Infra for central comms nod between E-L-M? Put it on EML4~5. Transport support? EML1. Refuel station for barely orbit ship with their maximum payload? Don't, just send a refuel mission. If you're gonna use near future launch vehicles, you need a temporal residents for the crew because LEO crew capsules can't stand more than a few days: Put it on low inclination LEO. Please read my other comments before further discussion. In short: Life Support. 1,000 passenger liner can't be a thing considering life support. Do you wanna build realistic civilian/military ships with realistic mission capabilities with this game? That sounds like you wanna play baseball in football stadium.
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Post by Apotheon on Aug 21, 2018 0:20:04 GMT
This isn't a challenge thread! My intention with it was to discuss infrastructure theory, for instance the dV, acceleration, dry mass, wet mass, dry cost, and wet cost to go in between Earth, the Moon, Mars, and I'm open to discussing minimums for other objects in the solar system (as well as where it's even worth going) and discuss anything else that may be relevant to ship design, such as ISRU (do you believe the Moon or Mars can self-sustain with ISRU or are Earth tankers necessary?), as well as discuss ship design of whatever ships may be relevant and are within the scope of CDE (stations... not really, but one-way ships, two-way ships to bodies where propellant isn't cheaply available, and ships with payloads, including cargo, passengers, and propellant and maybe even reaching into policiary/military stuff). There are a ton of threads about building ships as big and powerful as CDE possibly can without crashing and not as many threads constraining what's realistic within the 2250 span, IMHO. It's intended for brainstorming... for instance, I've found a 1000 passenger Mars ship is twice as cost-efficient per person as a 100 passenger ship. But how many people do you dare to have aboard a single ship? On Earth, the answer is about 2500 for sea cruisers, AFAIK. Also, figuring out which planets would get their resources (including solids and propellant) from which other planets may help create more realistic levels... and ultimately, realistic civilian/military ships with realistic mission capabilities. I want to build an infrastructure on Earth. Where? How much? How big? With what construction method and material? DEPEDNS ON WHAT INFRASTRCTURE IT IS, mate. You have to build highway(transportation infra) from city to city, but you can never build an atomic plant in that way. Infra for central comms nod between E-L-M? Put it on EML4~5. Transport support? EML1. Refuel station for barely orbit ship with their maximum payload? Don't, just send a refuel mission. If you're gonna use near future launch vehicles, you need a temporal residents for the crew because LEO crew capsules can't stand more than a few days: Put it on low inclination LEO. Please read my other comments before further discussion. In short: Life Support. 1,000 passenger liner can't be a thing considering life support. Do you wanna build realistic civilian/military ships with realistic mission capabilities with this game? That sounds like you wanna play baseball in football stadium. If you don't understand the question, you can stay out of the thread.
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Post by anotherfirefox on Aug 21, 2018 0:33:35 GMT
I want to build an infrastructure on Earth. Where? How much? How big? With what construction method and material? DEPEDNS ON WHAT INFRASTRCTURE IT IS, mate. You have to build highway(transportation infra) from city to city, but you can never build an atomic plant in that way. Infra for central comms nod between E-L-M? Put it on EML4~5. Transport support? EML1. Refuel station for barely orbit ship with their maximum payload? Don't, just send a refuel mission. If you're gonna use near future launch vehicles, you need a temporal residents for the crew because LEO crew capsules can't stand more than a few days: Put it on low inclination LEO. Please read my other comments before further discussion. In short: Life Support. 1,000 passenger liner can't be a thing considering life support. Do you wanna build realistic civilian/military ships with realistic mission capabilities with this game? That sounds like you wanna play baseball in football stadium. If you don't understand the question, you can stay out of the thread. You have to make a valid question. Told you. What. The. Freaking. Infra. Structure. You can't simply ask what would be its dry mass. Dry mass for fuel depot and dry mass for orbital habitat varies like a hell. No dV needed if you wanna make a station, tons of dV needed if you wanna make a transport. Even for a station, the station keeping dV varies like hell: you need a lot for LEO, some for L1, no for L4/L5. and don't be rude to someone try to help you, especially when you have some crappy invalid question.
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