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About sevenperforce

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  1. @taterOh these are fun. Dynetics: "Mass estimate physically impossible and at negative margin" Blue Origin: "Unsubstantiated claims for commercial approach" Dynetics: "Lack of awareness of schedule risk" Dynetics: "Lack of detail and technological justification for refueling process" Blue Origin: "Uncertainty over propulsion system component suppliers"
  2. I wonder how many refueling missions this will take and whether they will have reserves to attempt an aerocapture return to LEO.
  3. I agree with all of the above. My point is that they now have a similar OML to the regular starship, which would suggest commonality, but there is none. I will point out, however, that they still need to actuate in the first place. They can't launch deployed like that -- the aero loads would be impossible.
  4. Looks like four banks of six engines each for a total of 24.
  5. Close view on the legs. This just looks like a really ridiculously sloppy render to me. See how the feet clip through the fairing on one side but not the other?
  6. We've got new legs! And they look remarkably similar in shape to the ones shown in the most recent #dearMoon renders. But...but there's no way SpaceX would put a seam in their heat shield! Would they? Could they? And even if they did, surely the heat shield wouldn't contact the ground directly! I'm convinced that they are just spitballing at this point. Those new legs don't have any actual actuation path.
  7. Only mean if you make them in RO. It's mean by calling more attention to it, I think
  8. Whatever "the aliens" used to get here would require some pretty extreme technology. Even if their tech was anything we could possibly create (such as the Orion), they would be likely be operating on timescales of thousands or millions of years. Such an alien "invasion" might not contain any members of the species/culture/whatever who built it but would be just a delivery pod for the "de-terraforming" equipment and lifeforms (assuming the "equipment" is some sort of self-replicating nanotech, the differences would be academic). Oh, I'm not talking about aliens getting here. I mean
  9. The sheer hilarity of tiny Orion docking with that gloriously massive Starship
  10. Would they potentially only choose one? UPDATE: They chose SpaceX alone. https://www.washingtonpost.com/technology/2021/04/16/nasa-lunar-lander-contract-spacex/
  11. Oh yeah, you're right -- I forget that the Dragon 2's capsule mass includes its maneuvering propellant and engines. Why the hell is it so heavy? Yeah, I think it's proprietary. I wonder how it could be estimated. In the pad abort test, Starliner's coast from abort motor cutoff to apogee lasted 11 seconds and its ascent angle was about 41°. It is dense AF so I will ignore air resistance for a first-order estimate. This means the vertical component of its velocity was 11s*9.81m/s2 or 107.9 m/s, making its total velocity 164.5 m/s. This accords fairly well with the observed plu
  12. Reducing the propellant load can't possibly hurt things
  13. Interesting how tiny Orion is. It's the service module that cripples it.
  14. Haha!! It is much easier to pump a liquid than to pump a gas. So there's an advantage. Any decent high-efficiency rocket engine is going to use regenerative cooling at some level, which transfers waste heat to the propellant which makes the whole engine more efficient. There is usually going to be plenty of waste heat available to heat your propellant as warm as necessary. If he had 16,000 psi hydrogen at 0°C then it would get EXTREMELY cold if allowed to exhaust and expand to ambient...fairly certain it would self-liquefy. He has very little information about his fancy rocket engine
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