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RCgothic

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Everything posted by RCgothic

  1. Selecting Starship saved NASA over $14 billion dollars.
  2. We have no way of knowing it to the day. A tumbling object could hit a denser air patch broadside on and come down pretty soon. Or it may not. The rate of decay is irregular. Maybe a tracking company like LEO Labs might have a rough idea, but I haven't seen any public figures.
  3. I also would have picked Dynetics 1st place before reading the selection report. I thought it would be cheaper than BO, with fewer moving parts and a nice underslung module. But it's hard to argue with a negative mass budget likely to get more negative, not less. I also assumed SpaceX were 2nd place at best due to being the biggest schedule risk , but the selection document actually placed them as least risky and most likely to make the nominal schedule. I found that surprising in particular.
  4. Yes, it is wasteful. Return to launch site comes with a hefty performance penalty as Superheavy has to reserve a sizeable amount of fuel for the boostback burn. Not two thirds or even half its fuel though, as relieved of the mass of the Starship Upper Stage it has a very much more favourable mass ratio and can therefore extract a lot more DV from the remaining propellant. It's notable that even with this performance penalty Starship Superheavy manages almost twice Saturn V's mass to LEO.
  5. An ever increasing population of transhumans requiring a baseline human mother to produce sounds like the potential pool of mothers is going to be proportionately declining. Each mother being sterile after producing *one* offspring is not going to be sufficient to supply the rate of replacement. IRL we currently need about 2.2 offspring per mother with a theoretically fully breeding population to maintain a stable population. If transhumans can't produce themselves that number will go up and up until it's unsupportable.
  6. Yes, you're certainly right. I've got to start applying sanity checks before I post.
  7. Being a bigger stage, even though it will almost certainly break up the chances are the bits will be bigger. Bigger first stage engines. Bigger internal tanks. Larger thrust structures. And because it's uncontrolled we're probably not going to get enough time for an actionable warning. A single orbit is around a thousand miles ground track, and twelve minutes is the difference between coming down on NY or London.
  8. Resilience was in space longer than any Skylab capsule mission.
  9. They don't machine aluminium alloy isogrids for the fun of it. It's a ridiculously expensive technique, it's just that acheiving the same result with welding on those materials is basically impossible, it's hard enough to get a decent friction stir in a barrel weld, let alone all those intricate details. On the other hand stainless steel is comparatively not difficult to weld. There's no point isogridding if welded struts work just as well. And the stainless steel is chosen over the more conventional aerospace materials because it can better withstand the heat of re-entry without exc
  10. NASA suspends work on HLS due to protests by Dynetics and NT until GAO sorts them out. Don't think this is going to have any bearing on SpaceX's progress though TBH.
  11. More like C4, but yes, basically. It's a line of charges up the side of the tanks that can be automatically triggered by the on-board guidance system if it detects the rocket straying from its planned flight path. It can also be triggered manually by remote. When triggered the charges unzip the tanks and let all the fuel out so there can be no explosion on the ground and the rocket can't stray even further from its planned safety area (because the engines are starved of fuel). It also compromises the structural integrity of the rocket, which then tends to be ripped into pieces b
  12. Pretty sure expendably it can. Reuse eats a lot of margin both in dry mass and fuel reserved.
  13. Same second stage. Heavier payload = less DV. So first stage has to drop the second stage off higher and faster, reserving less margin for landing.
  14. Well I wouldn't go 2.5 stages for starters. I'd go for a full three stages. 2 to LEO and a 3rd for earth departure. Lugging that huge core to LEO really kills it. That said, the US didn't really have any good engine choices back in 2010.
  15. Then SpaceX get a stern talking to and serious questions to answer about how they allowed that to happen and how they're going to stop it happening again. This would count as a mishap and permission to launch SN16 and 17 could be revoked.
  16. The FAA has granted launch licenses to SN 15, 16 and 17.
  17. Starlinks are pretty heavy payloads, so it would make sense if MECO is a little later than for lighter payloads. Booster has to do more work.
  18. That sounds more likely now that Tianhe-1 has launched successfully, but I presume there wouldn't be any point in launching Tianhe-2 if either of the laboratory modules were to fail.
  19. Nose cone survived its first day of testing:
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