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One mission profile thought up for the VASIMR involves initially travelling closer to the sun to take advantage of the stronger solar flux to run the engine at high power, releasing a payload on a long coasting trajectory and slowing the launching vehicle back down to return to Earth. The idea is still a little half-baked at present (the engine performance ...


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Yes, ion engines are somewhat of a false economy in the sense that they rely on electrical power on top of their mass and their propellant (e.g. Xenon). So, compared to a chemical rocket engine where engine mass, thrust, specific impulse, plus propellant (and the mass of the tanks to store it) is about everything you need to plan an hypothetical spaceship, ...


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Are you burning the hydrogen in a fuel cell to get the power for an ion drive? I don't think that's wise. You'd get more delta/v using the hydrogen and oxygen in a conventional rocket. A nuclear reactor fuel mass I don't think would be prohibitive. According to this site, generating 200 MW for a year would require about 5 tons of fuel. You're bringing ...


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This 2018 release from Georgia Tech describes one such - claimed to be more practical than previous methane-fueled cells because it operates at a lower temperature. It is a solid-oxide cell. It appears to work by catalytically cracking the methane to hydrogen, and it seems that the advance is in the cracking part. https://www.news.gatech.edu/2018/10/29/...


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Shuttle used both AC and DC power. DC, because that is what the fuel cell power plants generated, and AC, to enable the use of compact three-phase electrical motors. The AC was generated from the DC using inverters. For details on the shuttle electrical power system, read section 2.8 of the Shuttle Crew Operations Manual and/or the Electrical Power System ...


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Batteries, fuel cells, radioisotope thermoelectric generators and solar panels provide DC. To get several different DC voltages AC and a transformer with several secondary windings is needed followed by a recifier and smoothing filter. A switching circuit converts DC to AC. A higher switching frequency allows the use of very small and lightweight ...


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