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RCgothic

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Everything posted by RCgothic

  1. The Artemis Program is about landing the next humans on the moon. Artemis I will be an uncrewed test flight of the Orion capsule and SLS Block 1 rocket, roughly analogous to Apollo 4/6. Artemis II will be a crewed flight past the moon, roughly analogous to Apollo 8. The timeline for the first crewed landing is at this point a little unclear. It might be Artemis III or IV depending on the availability of the lander. Launches for the Gateway station and lander supporting the crewed missions won't be assigned a main Artemis number as far as we can tell.
  2. Yes, that exactly! More max Q than lateral is my reading of the design, but it might be capable of a bit of asymmetric loading.
  3. It's a tension member construction, so it's definitely for applying external loads. Aero simulator is my guess.
  4. With RCS in the high atmosphere so aero forces don't overpower the control authority would be my guess.
  5. I've presented plenty of arguments: 1) Re-entry vehicles don't need lift. 2) In any case, cylinders have lift and fins have lift. 3) The design of re-entry vehicles is generally dominated by bluntness for heat transfer purposes, not aerodynamics. 4) Being large, Starship is blunt without special shapes. 5) Sure, the other vehicles can benefit from efficiencies of special shape, but they aren't primarily high pressure pressure vessels which are dominated by other requirements. 6) There have been round re-entry vehicles. 7) Starship has active stability and TPS
  6. I guarantee you're not saying anything SpaceX haven't already thought of. This isn't their first re-entry. Just sit tight and some day (very likely this year) you'll get your wish.
  7. Starship is not a spaceplane. It doesn't need high L/D. Re-entry vehicles don't *need* any lift. Vostok and Voskhod don't have any. All re-entry vehicles need is stability (Starship is actively stable) and a TPS (which Starship has). Also it's not a pure cylinder. It has fins. SpaceX are not idiots. I guarantee if it had to be another shape it would be another shape.
  8. Cylinders are also lifting bodies.
  9. Except for the craft that are round, no craft are round.
  10. Still stainless steel. TPS evolved from transpiration to tiles but otherwise still present.
  11. Well we'll just have to see, but I wouldn't bet money against.
  12. That wouldn't prevent a collision, it'd just be hit by shrapnel instead of a single larger piece. And Starlink does have an automated avoidance system, and it's a very capable and responsive system. Part of the row between OneWeb and SpaceX is that Starlink is capable of conducting such manoeuvres on short notice, typically 12h before the estimated time of collision. In this instance because the probability of collision was low 1 in10⁴-10⁵ and falling, SpaceX were planning to wait until around then to make a decision, because 10⁵ is their threshold for manoeuvres. OneWeb's sat needs
  13. The recent incident between Starlink and OneWeb wasn't a near miss, and the automated collision avoidance manoeuvre system on Starlink was non-operative at OneWeb's request. Naughty OneWeb telling porkies.
  14. And it's the fluid dynamics of the fuel system that's tricky. Not the aerodynamics.
  15. Look, if Russia want to try and build their own space station, nobody's stopping them. But it'll be expensive less capable than a combined effort. Meanwhile the US and its continuing international partners will just put up a couple of outfitted Starships, NBD.
  16. Well in any case, the reason re-entry bodies are blunt - to move the shockwave away from the hull - is also accomplished by being larger. 1) Starship is larger. 2) There's no evidence cylinders don't work - in fact spheres do (Vostok and Voskhod) which are worse. 3) SpaceX aren't amateurs. They know what they're doing.
  17. Good spot here. Potentially Lunaship's tanks have gotten bigger.
  18. This is a great thread on the Crew-2 post-Launch Readiness Review/Pre-Launch briefing. Lots of interesting information and sensible questions (unusually) with good answers.
  19. The Indian military didn't tell ISRO that it was being asked to deploy an ASAT target. Wow.
  20. Wow, the LOX issue was towards the top end of my estimate. That's an extra 1.3 tonnes! With the vent system not sure it still remains at liftoff, but boiling off a tonne of LOX surely isn't easy. That'd be worth over 100kg of additional payload.
  21. Again, not a pressure vessel so doesn't have to be cylindrical. It's not that cylinders don't work, it's that these other shapes have additional benefits *if free to choose them.* Pressure vessels that aren't cylinders incur enormous mass penalties. So yes, it has a flat belly because it can. That doesn't mean non-flat bellies don't work. See Vostok and Voskhod.
  22. If NASA had enough money to pick any of the three it wanted, SpaceX would still have got it is my interpretation of that document. The only reason not to would be keeping angry congresspeople appeased, which wasn't one of the scoreable criteria.
  23. The shuttle wasn't primarily a pressure vessel, it was free to deviate from a cylinder without excessive stress concentration or mass penalty for a bit of extra aerodynamic efficiency which it desperately needed (heck of a cross range requirement). I also note that the top of the shuttle was a half cylinder, which isn't noticeably better than a cylinder for vortex shedding. I also note that a blunt bottom pushes the shockwave away from the hull and blends into the wings, thereby limiting re-entry heating, so that shape may have other functions than aerodynamics. Finally, almost
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