5 ms·

No, that's the EM drive. This engine is less or more a particle accelerator shooting high velocity noble gas. It's like a rocket (less or more), but instead of

by Elv13 9y ago

No, that's the EM drive. This engine is less or more a particle accelerator shooting high velocity noble gas. It's like a rocket (less or more), but instead of using a lot of slow matter, it use a little, but very fast, matter. It still requires a supply of matter to trow from the back of the spacecraft, it just uses it in a way to minimize the amount required (by trading it by silly amount of power). It's based on the classic `F=m*a` Newtonian second law. But uses high `a` instead of high `m`. The Hall and Ion engines just replace chemical energy with electricity. Edit: Added the `F=ma` part. Edit2: Added that it still requires matter.

samstave 9y ago
But you still need to give it a supply of noble gas, correct? So how many AU per unit of noble gas do you reach at terminal velocity of the thing? Also what are the manufacturing limitations for noble supply - given all the talk about us running out of helium. Aside: it would be ironic if they had helium balloons at the launch party of some such rocket... Finally, what is the state of the noble gas when consumed by this engine in a full vacuum of space? Is it destroyed into a state that is unrecoverable?
- JumpCrisscross 9y ago
  > terminal velocity of the thing? What?
  - hyperbovine 9y ago
    c
    - camiller 9y ago
      probabbly a little less
    - samstave 9y ago
      Do you have to provide it with a fuel load of noble gas that it will consume? Assume I give 1 ton of noble gas fuel in whatever format that is, how far and fast will it get before the fuel is consumed?
      - JumpCrisscross 9y ago
        Ah, got it. So when we think of “rocket fuel” we’re conflating two things: energy source and propellant. Kerosene and oxidiser gives you both heat and combustion products for the heat to fling out of your nozzle. Hall effect thrusters decouple energy and propellant. The noble gas is the propellant. It’s stuff you’re throwing. The energy, however, must come from elsewhere, e.g. solar panels or a nuclear reactor. There is an aerospace term called specific impulse [1]. It measures engine efficiency. Ion thrusters are about as efficient as the turbofans on a modern jetliner. Those, in turn, are about 12x more efficient than the Space Shuttle’s solid-fuel boosters and like 7x better than cryogenic, i.e. hydrogen-oxygen, fuelled engines. [1] https://en.m.wikipedia.org/wiki/Specific_impulse https://en.m.wikipedia.org/wiki/Specific_impulse
        samstave 9y ago
        Apologies then for my other reaction. I was a reactive gas...
  - samstave 9y ago
    Assume you have a thing: rocket, satellite, probe, etc, and you’re pushing it to mars or whatever, and you have an engine that, based on the comment states in consumer noble gasses as fuel, one would assume you have to provide the noble gas, correct? So after you falcon9 the thing into orbit, and push it along, and it then uses this engine to go the distance, will it constantly increase or hit a max terminal velocity. In either case, would that not tell you how much fuel to give it; which comes down to “if it is powered by helium and we are supposedly running out of helium, how much helium would it use vs how much helium is available?” Is that not a sound question? The second part of the question is “if we give it one ton of fuel, how far can it get?” Pretty simple MPG question in my mind...
    - jacobush 9y ago
      You are right. The answer is, it depends. The others just downvoted you because of the ”terminal velocity” thing.
      - samstave 9y ago
        Guess it’s better than reaching terminal volatility on twitter as we have seen how those experiments have been going...
    - camiller 9y ago
      There are a lot of variable not accounted for, like the mass of the ship(and cargo) you are going to attach it to. In theory it can keep accelerating as long as it has fuel, and the maximum speed would be related to the speed of the exhaust. At very high velocity we would have to account for friction with the interstellar medium, space isn't entirely empty just the density is very (very) low. In the real world you probably have a destination in mind... and maybe want to come back. For one way mission, accelerate till half your fuel is gone, perhaps coast for a bit, then decelerate with the remaining fuel (maybe keep some reserves for maneuvering).
      - samstave 9y ago
        So basically, step two of getting to Mars is to setup interstellar refulling stations. Once you get to mars, or any destination, you need fuel to get back/other things... So assuming we have an engine that can deliver us back and forth in a reasonable time, then we need to think about deploying intermediate refueling drones... and then drones to refill them... and then how to manufacture and deliver that fuel to the various nodes... And if we are running out of helium, on earth, we need to find the most harvestable noble gas we can in the solar system... What are the atmospheres of the other planets made up of, specifically Jupiter, how could we slurp off its atmosphere to Bush is around the solar system? Assuming other energy sources don’t pan out
  - samstave 9y ago
    Not everyone is an aerospace investment banker so don’t be a dick. Trying to learn here, not be belittled.
    - JumpCrisscross 9y ago
      There were a lot of questions your comment could imply. I couldn’t think of a simpler way to request clarification. Didn’t mean to offend. On Earth we’re used to power scaling with maximum speed because of drag. In space, there is no drag. The weakest engine can propel something to close to the speed of light given the time and energy. There is a measure called specific impulse. It asks how long an engine would hover if fuelled with a take-off weight ratio of one in Earth’s gravity (ignoring the mass of structure, tanks, et cetera). I don’t have an answer for this engine, but ion thrusters clock in around 30,000 seconds while most rockets are between 250 and 500. Terminal velocity relates to the interaction between drag and an object in free fall.
      - samstave 9y ago
        My apologies, Appreciate the response.
      - samstave 9y ago
        Yes, ok I understand your confusion to my comment as I had forgotten that terminal velocity applies to atmospheric based objects? But I haven’t thought about specific impulse much, so I am very naïve (but curious) So, what, if any, does the mass of the object being pushed by an engine with the 5.4 Newton’s of energy have of the ability of the engine to push it? If you push a 1-ton thing with 5.4, and a 100-ton thing with 5.4 Newtons will they reach mars at the same time? And what will be the fuel consumption diff?
        zamalek 9y ago
        > ability of the engine to push it Acceleration. For equal mass a more powerful engine would make the object go faster, faster. > If you push a 1-ton thing with 5.4, and a 100-ton thing with 5.4 Newtons will they reach mars at the same time? Force = Mass * Acceleration Acceleration = Force / Mass a: 5.4 / 1000 = 0.0054m/ss b: 5.4 / 100 000 = 0.000054m/ss As the space-crow flies, the 100 ton thing would take longer - it's accelerating 100 times slower. You also have to factor in the mass of the fuel, both starting weight and consumption. As the engine depletes the fuel reserves it gets lighter and therefore accelerates faster (increased Jerk[1]). So if the 100 ton engine was a chemical engine the situation might be different. The following would be the same time: "assuming reactionless drives, if you push a 1-ton thing with 5.4N, and a 100-ton thing with 540N." [1]: https://en.wikipedia.org/wiki/Jerk_(physics) https://en.wikipedia.org/wiki/Jerk_(physics)

by Elv13 9y ago

samstave 9y ago

But you still need to give it a supply of noble gas, correct? So how many AU per unit of noble gas do you reach at terminal velocity of the thing? Also what are the manufacturing limitations for noble supply - given all the talk about us running out of helium. Aside: it would be ironic if they had helium balloons at the launch party of some such rocket... Finally, what is the state of the noble gas when consumed by this engine in a full vacuum of space? Is it destroyed into a state that is unrecoverable?

JumpCrisscross 9y ago
> terminal velocity of the thing? What?
- hyperbovine 9y ago
  c
  - camiller 9y ago
    probabbly a little less
  - samstave 9y ago
    Do you have to provide it with a fuel load of noble gas that it will consume? Assume I give 1 ton of noble gas fuel in whatever format that is, how far and fast will it get before the fuel is consumed?
    - JumpCrisscross 9y ago
      Ah, got it. So when we think of “rocket fuel” we’re conflating two things: energy source and propellant. Kerosene and oxidiser gives you both heat and combustion products for the heat to fling out of your nozzle. Hall effect thrusters decouple energy and propellant. The noble gas is the propellant. It’s stuff you’re throwing. The energy, however, must come from elsewhere, e.g. solar panels or a nuclear reactor. There is an aerospace term called specific impulse [1]. It measures engine efficiency. Ion thrusters are about as efficient as the turbofans on a modern jetliner. Those, in turn, are about 12x more efficient than the Space Shuttle’s solid-fuel boosters and like 7x better than cryogenic, i.e. hydrogen-oxygen, fuelled engines. [1] https://en.m.wikipedia.org/wiki/Specific_impulse https://en.m.wikipedia.org/wiki/Specific_impulse
      - samstave 9y ago
        Apologies then for my other reaction. I was a reactive gas...
- samstave 9y ago
  Assume you have a thing: rocket, satellite, probe, etc, and you’re pushing it to mars or whatever, and you have an engine that, based on the comment states in consumer noble gasses as fuel, one would assume you have to provide the noble gas, correct? So after you falcon9 the thing into orbit, and push it along, and it then uses this engine to go the distance, will it constantly increase or hit a max terminal velocity. In either case, would that not tell you how much fuel to give it; which comes down to “if it is powered by helium and we are supposedly running out of helium, how much helium would it use vs how much helium is available?” Is that not a sound question? The second part of the question is “if we give it one ton of fuel, how far can it get?” Pretty simple MPG question in my mind...
  - jacobush 9y ago
    You are right. The answer is, it depends. The others just downvoted you because of the ”terminal velocity” thing.
    - samstave 9y ago
      Guess it’s better than reaching terminal volatility on twitter as we have seen how those experiments have been going...
  - camiller 9y ago
    There are a lot of variable not accounted for, like the mass of the ship(and cargo) you are going to attach it to. In theory it can keep accelerating as long as it has fuel, and the maximum speed would be related to the speed of the exhaust. At very high velocity we would have to account for friction with the interstellar medium, space isn't entirely empty just the density is very (very) low. In the real world you probably have a destination in mind... and maybe want to come back. For one way mission, accelerate till half your fuel is gone, perhaps coast for a bit, then decelerate with the remaining fuel (maybe keep some reserves for maneuvering).
    - samstave 9y ago
      So basically, step two of getting to Mars is to setup interstellar refulling stations. Once you get to mars, or any destination, you need fuel to get back/other things... So assuming we have an engine that can deliver us back and forth in a reasonable time, then we need to think about deploying intermediate refueling drones... and then drones to refill them... and then how to manufacture and deliver that fuel to the various nodes... And if we are running out of helium, on earth, we need to find the most harvestable noble gas we can in the solar system... What are the atmospheres of the other planets made up of, specifically Jupiter, how could we slurp off its atmosphere to Bush is around the solar system? Assuming other energy sources don’t pan out
- samstave 9y ago
  Not everyone is an aerospace investment banker so don’t be a dick. Trying to learn here, not be belittled.
  - JumpCrisscross 9y ago
    There were a lot of questions your comment could imply. I couldn’t think of a simpler way to request clarification. Didn’t mean to offend. On Earth we’re used to power scaling with maximum speed because of drag. In space, there is no drag. The weakest engine can propel something to close to the speed of light given the time and energy. There is a measure called specific impulse. It asks how long an engine would hover if fuelled with a take-off weight ratio of one in Earth’s gravity (ignoring the mass of structure, tanks, et cetera). I don’t have an answer for this engine, but ion thrusters clock in around 30,000 seconds while most rockets are between 250 and 500. Terminal velocity relates to the interaction between drag and an object in free fall.
    - samstave 9y ago
      My apologies, Appreciate the response.
    - samstave 9y ago
      Yes, ok I understand your confusion to my comment as I had forgotten that terminal velocity applies to atmospheric based objects? But I haven’t thought about specific impulse much, so I am very naïve (but curious) So, what, if any, does the mass of the object being pushed by an engine with the 5.4 Newton’s of energy have of the ability of the engine to push it? If you push a 1-ton thing with 5.4, and a 100-ton thing with 5.4 Newtons will they reach mars at the same time? And what will be the fuel consumption diff?
      - zamalek 9y ago
        > ability of the engine to push it Acceleration. For equal mass a more powerful engine would make the object go faster, faster. > If you push a 1-ton thing with 5.4, and a 100-ton thing with 5.4 Newtons will they reach mars at the same time? Force = Mass * Acceleration Acceleration = Force / Mass a: 5.4 / 1000 = 0.0054m/ss b: 5.4 / 100 000 = 0.000054m/ss As the space-crow flies, the 100 ton thing would take longer - it's accelerating 100 times slower. You also have to factor in the mass of the fuel, both starting weight and consumption. As the engine depletes the fuel reserves it gets lighter and therefore accelerates faster (increased Jerk[1]). So if the 100 ton engine was a chemical engine the situation might be different. The following would be the same time: "assuming reactionless drives, if you push a 1-ton thing with 5.4N, and a 100-ton thing with 540N." [1]: https://en.wikipedia.org/wiki/Jerk_(physics) https://en.wikipedia.org/wiki/Jerk_(physics)