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About farmerben

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    Spacecraft Engineer

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  1. Let me get this straight. You want to ionize O2 so that radical oxygen ions react suddenly with fuel. There is a device which does exactly this. There is some debate about whether boosting the ionization (by adding two spark plugs per cylinder, etc) provides any benefit. In general the answer is no, or almost negligible, but the double spark plugs may resist corrosion and contamination longer. Would there be any benefit to keeping to keeping the reactants ionized before mixing them together? I think you would have to supply energy during this time, for no net benefit. The arcjet appears to simply heat the exhaust products. The electric force is pointed the wrong way. Reversing the anode and cathode would give more boost. Maybe doing so would make the engine more massive? I don't really understand why the electric force in an arcjet is pointed opposite what makes sense.
  2. A planet sized telescope is not so unreasonable. I hope we build one soon. At some range all our signals are undetectable for a given receiver. My argument starts with the assumption that some signals are detected. If some of our signals are detectable, then there is really nothing we can do to prevent other humans from transmitting messages that will drown out all other man made radio noise. Also, people have already tried it. I love the part where Seth Shostak and Frank Drake refused to sign a resolution saying "worldwide scientific, political and humanitarian discussion must occur before any message is sent"
  3. Does anyone know why the arcjet cathode and anode are this way and not the reverse?
  4. I have to say thank you to Cheif Operations Director for continuing to argue for what he thinks is right when everyone tells him he is wrong, and for remaining positive when abuse comes his way. That is the stuff I like to see on this forum, and in other areas of life.
  5. I'm pretty sure it works better the other way around. Chemically react cold stuff, and then use electromagnetic forces to push the hot stuff.
  6. There are many isotopes which could make RTG's far more powerful than the Pu 238 ones. For example, Po 210 is about 300 times more powerful. And we know the Russians are capable of making things with it. Some isotopes are way more powerful than that, but could they be used? The stuff would not store well. More than likely it was a fission reactor.
  7. The voyager probe is using a 3.7m dish and less than 500 W of power. Exceeding the strength of that signal is trivial for a 14 year old boy. Coast to Coast AM with George Norry is broadcast simultaneously from multiple 50 kW transmitters. I have switched back and forth between Amarillo, Minneapolis and Denver with the receiver in a car on a cloudy night. So the aliens have already heard about the lizard people who live inside our hollow planet. And they are busy right now figuring out if broadcast high school football games are actually encrypted messages. A decent rectenna is easy to conceal, since the individual wires cannot be resolved by satellite imaging and they can be laid out on the ground, or disguised as power lines. Nearly every small city already has the stuff on hand to send a directed transmission vastly stronger than all the other radio noise combined.
  8. Two different functions. We want tungsten to stop gamma rays and not disintegrate. We want carbon to absorb X rays and disintegrate as the exhaust. So putting oil on the surface of the tungsten plate is a good idea.
  9. I love the part of the video where they have built a truss for branching coral. There are several shots of it 1:04 is one. I want to use this technology to built caltrops against drag net fishermen.
  10. Accelerator driven hybrids could be the key. High energy positive ion beams striking a metal foil target will either pass through or chip off nucleons. Almost any metal beyond lead will chip off lots of nucleons or even fission. 500 MeV - 1GeV is about the particle beam energy we want. Then it is a problem of getting high current pulses. Cyclotrons are getting there, but the current would be multiplied by 10 if we converged the beams of 10 cyclotrons. We would probably need even more beams for a similar amount of electrons to help focus the positive ions. Behind the foil target can be a sub critical reactor of almost any type, even a polywell and it will recieve an extreme kick of high energy radiation. The particle beams provide throttle. When the beams turn off the reactor idles along just below the temperature of fusion.
  11. Bah, fission is so cheap they could give electricity away for free. The plutonium product alone can more than pay for the entire plant. The RBMK 1000 uses natural uranium and light water, so its inputs are drastically cheaper than any operating western reactor. In vaporized sodium coolant with unclad metal fuel pellets the cesium and iodine come right out in the coolant, so the fuel pellets don't get poisoned.
  12. We could use the solar corona as a lasing medium. The Corona is 3 million degree plasma that emits X-rays, but at such low density it is mostly transparent. All we need is 2 large mirrors to build up a coherent wave of X-rays where they already exist, and send the beam through an aperture. We might be able to use mirrors located at Mercury's Lagrange points, so that the Sun is cornered by a triangle of mirrors. Our beam might be constrained to spin like a lighthouse, but talk about a lot of bang for the buck.
  13. Takeoff weight 10.245t Cost $3982 While slightly bigger than The Flying Kerman's entry, mine can land safely. I did not see his entry before I designed this. Always looking for a legitimate reason to use the puff engine. It's light and cheap, but the 10 extra mono propellant in the capsule are an advantage this once.
  14. The first nuclear reaction discovered goes by the name "disintegration". "Disintegration of Lithium by Swift Protons" JD Cockcroft 1932. Lithium, Beryllium, and Boron barely exist in main sequence stars because the radiation blasts them apart, or fuses them into carbon. Lithium disintegrations are extremely exothermic, and release tritium. Lithium 7 and Boron 11 are the best proton beam eaters (low input energy, high exothermic release, high cross section) Lithium 6 and Boron 10 can be disintegrated exothermically by slow or fast neutrons. Beryllium 8 has the lowest barrier to alpha particle absorbtion. The triple alpha process, which makes carbon plus a neutron. +7 MeV The rest of the periodic table can be made to do interesting things when struck with high energy particles. Most of these reactions are called "spallation". It is a good way to multiply the number of particles, but usually endothermic. I'd love to find similar data for deuteron beams and alpha beams, but I haven't found it yet. At energies above the rest mass of a proton >1GeV, the kinetic energy of the beam creates new massive particles within the target. As I understand it, these collisions throw off a shower of Kaons - quark, anti-quark pairs, which live long enough to reach nearby atoms, but not much longer.
  15. I was thinking about beavers. How smart do you have to be to understand levers and teamwork? It seems like if one beaver could tell another beaver something really useful to coordinate their actions, civilization would naturally follow. But that didn't happen. Once beavers did abandon the water and roam the land as predators, but they did not get technology and died out. Beaver society has nothing on monkey society, and our basic primate family has about a 1% success ratio of developing simple technology and surviving. The biological great filters are a poodle. Uplifted raccoons could rise up and become a threat to our species. I think we must start with our pets and livestock and add thumbs, rather than starting with creatures with thumbs and altering their personality. A dog brain with a goat digestive system, and thumbs on all four feet would truly be man's best friend. It can eat all the crop products we don't eat, or mow the lawn, or thin the trees so we can have 50% shade everywhere. And sacrifice the ability to run fast for the ability to climb trees. Also saying, for those who want to fully merge with computers, then what? What specific capabilities then? Ok, patch the optic nerve with an augmented reality interactive visual display. That is like having a laptop inside your eyeball. If you want to exist as a virtual person detatched from flesh, please explain what you would do with that?