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Post by Durandal on Nov 19, 2016 16:21:04 GMT
www.iflscience.com/space/the-peer-reviewed-emdrive-paper-is-officially-out/So apparently...it works. It produces 1.2 mN per kW. In gameplay terms for us: (1.2 (millinewtons per kilowatt)) * 1 Gigawatt = 1200 newtons Twenty of them strapped to the back of a ship would be 24 kilonewtons of thrust.. with no propellant. If this thing is really, actually real...we're in for some cool stuff in the next few decades.
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Post by ash19256 on Nov 19, 2016 19:55:33 GMT
www.iflscience.com/space/the-peer-reviewed-emdrive-paper-is-officially-out/So apparently...it works. It produces 1.2 mN per kW. In gameplay terms for us: (1.2 (millinewtons per kilowatt)) * 1 Gigawatt = 1200 newtons Twenty of them strapped to the back of a ship would be 24 kilonewtons of thrust.. with no propellant. If this thing is really, actually real...we're in for some cool stuff in the next few decades. True, but that 24 kN of thrust would also require 20 GW of power, which isn't going to be easy to produce. You're much more likely to see at an absolute maximum 1 GW EM Drive thrusters as main engines, possibly with smaller EM Drive thrusters as reaction control thrusters. Granted, this does make missions to mars much more feasible, because now all you need to do is push the payload (be it crew or rover or whatever) and power generation, allowing you to accelerate almost constantly along the first half of the trip, possibly flipping around to decelerate for the second half. |
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Post by beta on Nov 19, 2016 21:16:05 GMT
That number is an estimate and the increase in power may not increase the thrust linearly. Also, an ion engine can produce 20mN thrust for the same power output. So, it may not end up being very economical for the relatively short transit times to Mars or similar.
They would be fantastic for long range exploration and satellite station-keeping however.
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Post by apophys on Nov 19, 2016 22:15:49 GMT
This is definitely news to me. Interesting... maybe low-energy nuclear reactions like the E-Cat are next in line for weird things for NASA to verify.  So I guess the EM drive can be equated to a thruster with an exhaust velocity of c? If so, it might actually be seriously competitive with MPDs. Power may not scale linearly for a single module, but it should be linear if you use a bunch of modules. Assuming they don't interfere with each others' function. 20GW of power, and radiators, can be done in less than 400 tons, if ingame designs can be exported to the real world. It's not that bad. |
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Post by ash19256 on Nov 20, 2016 13:48:35 GMT
This is definitely news to me. Interesting... maybe low-energy nuclear reactions like the E-Cat are next in line for weird things for NASA to verify. So I guess the EM drive can be equated to a thruster with an exhaust velocity of c? If so, it might actually be seriously competitive with MPDs. Power may not scale linearly for a single module, but it should be linear if you use a bunch of modules. Assuming they don't interfere with each others' function. 20GW of power, and radiators, can be done in less than 400 tons, if ingame designs can be exported to the real world. It's not that bad. True enough, but I imagine it would only be practical for applications where the power generation and propellant for ion engines would mass more than what that 20 GW of power generation plus radiators does. |
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Post by bigbombr on Nov 20, 2016 14:07:02 GMT
This is definitely news to me. Interesting... maybe low-energy nuclear reactions like the E-Cat are next in line for weird things for NASA to verify. So I guess the EM drive can be equated to a thruster with an exhaust velocity of c? If so, it might actually be seriously competitive with MPDs. Power may not scale linearly for a single module, but it should be linear if you use a bunch of modules. Assuming they don't interfere with each others' function. 20GW of power, and radiators, can be done in less than 400 tons, if ingame designs can be exported to the real world. It's not that bad. True enough, but I imagine it would only be practical for applications where the power generation and propellant for ion engines would mass more than what that 20 GW of power generation plus radiators does. What about beamed power? |
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Post by cuddlefish on Nov 20, 2016 15:04:04 GMT
So... do they think we have special frames, or that we don't have conservation of energy? Because that squared term in kinetic energy is a bit of a problem.
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Post by Easy on Nov 20, 2016 18:58:36 GMT
I would advise caution rather than optimism. But it isn't helpful to simply dismiss the EM drive as impossible because it doesn't conform to your understanding of physics or assumptions about the drive.
If it works as advertised, its going to replace ion engines. If it works better than advertised we might have a future as bright as the most optimistic pulp-scifi novella.
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Post by millesmissiles on Nov 20, 2016 19:27:42 GMT
One limiting factor on the EM Drive, as far as I understand NASA's paper, is the efficiency of the drive itself. There is no way that this drive magically converts 100% of its power input into thrust with no thermal inefficiency. I foresee practical upper limits on the amount of power which can be pumped into these things without melting them, even with a high-tech radiator system.
We even have 1.3 gigawatt nuclear reactors already (http://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/). But we haven't put one into space yet, and it seems impossible in the current political climate to do something like orbit a gigawatt nuclear power plant. We already know how mass-inhibiting the radiator system for a 1-gigawatt nuclear reactor is in this game's universe.
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Post by goduranus on Nov 20, 2016 20:21:56 GMT
This is definitely news to me. Interesting... maybe low-energy nuclear reactions like the E-Cat are next in line for weird things for NASA to verify. So I guess the EM drive can be equated to a thruster with an exhaust velocity of c? If so, it might actually be seriously competitive with MPDs. Power may not scale linearly for a single module, but it should be linear if you use a bunch of modules. Assuming they don't interfere with each others' function. 20GW of power, and radiators, can be done in less than 400 tons, if ingame designs can be exported to the real world. It's not that bad. This is exactly what I thought after reading about the EM Drive, ECat. The thing that everyone else also said was impossbile. Maybe it really works too. |
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Post by cuddlefish on Nov 20, 2016 21:00:27 GMT
One limiting factor on the EM Drive, as far as I understand NASA's paper, is the efficiency of the drive itself. There is no way that this drive magically converts 100% of its power input into thrust with no thermal inefficiency. I foresee practical upper limits on the amount of power which can be pumped into these things without melting them, even with a high-tech radiator system. We even have 1.3 gigawatt nuclear reactors already (http://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/). But we haven't put one into space yet, and it seems impossible in the current political climate to do something like orbit a gigawatt nuclear power plant. We already know how mass-inhibiting the radiator system for a 1-gigawatt nuclear reactor is in this game's universe. That doesn't really help with the physics problem, though. If P-In produces T-Out without needing to haul propellant, conservation of energy is dead, because of that damned squared term in kinetic energy. The faster relative to a thing the object is going, the more energy it 'gains' from every additional m/s, so if power in produces m/s, sooner or later you'll get a net positive. |
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Post by ash19256 on Nov 21, 2016 3:27:21 GMT
One limiting factor on the EM Drive, as far as I understand NASA's paper, is the efficiency of the drive itself. There is no way that this drive magically converts 100% of its power input into thrust with no thermal inefficiency. I foresee practical upper limits on the amount of power which can be pumped into these things without melting them, even with a high-tech radiator system. We even have 1.3 gigawatt nuclear reactors already (http://www.power-technology.com/features/feature-largest-nuclear-power-plants-world/). But we haven't put one into space yet, and it seems impossible in the current political climate to do something like orbit a gigawatt nuclear power plant. We already know how mass-inhibiting the radiator system for a 1-gigawatt nuclear reactor is in this game's universe. That doesn't really help with the physics problem, though. If P-In produces T-Out without needing to haul propellant, conservation of energy is dead, because of that damned squared term in kinetic energy. The faster relative to a thing the object is going, the more energy it 'gains' from every additional m/s, so if power in produces m/s, sooner or later you'll get a net positive. My running theory on how the EM Drive works is that it smacks the aft end of the resonant chamber with so many microwave frequency photons that it starts losing electrons, which are launched away from the engine at high speed, with the truncated cone shape causing this to preferentially happen towards the wider end of the cone. This means that while it does produce thrust, it isn't technically reaction-less, as it uses the copper end plate of the cone as reaction mass. Granted, my understanding of physics comes from browsing through this forum, Spacebattles, Sufficient Velocity, along with watching Scott Manley videos and reading Atomic Rockets, so if some smart person (paging illectro , paging illectro) could tell me if I'm being an idiot, that would be much appreciated. |
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Post by Durandal on Nov 21, 2016 6:57:41 GMT
I haven't messed with blackbox technologies yet, but has anyone tried working one into the game?
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Post by tukuro on Nov 21, 2016 8:22:32 GMT
I haven't messed with blackbox technologies yet, but has anyone tried working one into the game? I tried, but it messes up the physics as you're forced to use some form of propellant. It also doesn't calculate acceleration properly, allowing you to accelerate to 0.3c speeds in a matter of weeks. When I calculated the values manually it wasn't that impressive. It would take months to get up to speed. The test craft I had prepared (<500 tons) would (using the values from the article) take 6 months to get up to around 30km/s. Arguably it's very efficient (The reactor I was using used 257 kg of 97% enriched U-235), but this won't get us to Alpha Centauri any time soon. |
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Post by Durandal on Nov 21, 2016 13:34:55 GMT
I haven't messed with blackbox technologies yet, but has anyone tried working one into the game? I tried, but it messes up the physics as you're forced to use some form of propellant. It also doesn't calculate acceleration properly, allowing you to accelerate to 0.3c speeds in a matter of weeks. When I calculated the values manually it wasn't that impressive. It would take months to get up to speed. The test craft I had prepared (<500 tons) would (using the values from the article) take 6 months to get up to around 30km/s. Arguably it's very efficient (The reactor I was using used 257 kg of 97% enriched U-235), but this won't get us to Alpha Centauri any time soon. DI'd you have that 3 c figure peer reviews? Might be onto something.  |
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