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RCgothic

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Everything posted by RCgothic

  1. The payload envelopes Falcon and Vulcan can fit any crewed capsule ever flown and every space station module bar skylab.
  2. SLS never wasn't obsolete. F9, Falcon Heavy and Vulcan are all perfectly capable of supporting lunar Earth Orbit Rendezvous mission modes. It'd would have been better cheaper and more frequent to spend SLS's budget on the surface mission rather than the marginally useful rocket to nowhere.
  3. 10 in January alone. 120 by year end at this rate!
  4. Your copied text is interfering with dark mode again, @Exoscientist btw. When I rounded up to 60t, it was on the basis that SLS Block 2 Cargo can do 46t to TLI but B2 Crew can only do 43t. There's a 3t penalty associated with the LAS and the intermediate payload fairing (which does get carried through TLI). I inadvertently used 6t, (because apparently 46-43 is difficult math) but with sevenperforce's DV correction it comes out roughly the same anyway: A lander from scratch, stretched ESM, and an SLS Block 3 upgrade would not be better/faster/cheaper than the current approach.
  5. There seems to be a discrepancy in some of the DV maps I've been using. Depending on whether it's 680m/s or ~820m/s - if the latter I get about 10.7t additional mass required to get to LLO with a 15t payload and return with ~100m/s margin for free-flight and rendezvous. So that's 60t to TLI required, as near as matters, to land an Apollo LM on the moon using SLS and Orion. I already think the Apollo LM is far less capable than we need, a 2t Cygnus derived lander ludicrously, even dangerously so. A lander with an ascent stage that light could only be done by cutting margins beyond the bone. Hydrolox is also absolutely not a propellant you consider in the same breath as breath as reliability and endurance. And as for timelines, regardless of the challenges facing Starship and *Blue Origin* HLS, a clean slate design is starting five years behind Starship and 3 years behind BO. If Starship or BO HLS can't meet Artemis III and IV timelines at this point, then it simply can't be done. The timeline needs to change, not the lander. Spaceflight timelines are *never* improved by starting from scratch mid programme. *Never*. I have a lot of sympathy for blowing up the timeline to acquire greater mission scope and craft capability. We should do this to rework the mission architecture to get rid of SLS and Orion. But a skeletal lander proposal does the opposite - it trashes the timeline to make everything worse.
  6. I do agree a larger service module on Orion would be better, given where we've ended up. It would actually improve SLS Block 2's co-manifest payload to NRHO as well, as SLS B2 can throw more combined mass of Orion/ESM and payload to NRHO than Orion can actually brake into that orbit and still return. SLS might *possibly* be able to do a single stack Apollo style mission with an Apollo LM *if* the ESM is upgraded with an additional 6.5t of propellant and 0.6t dry mass. The total mass to TLI would then be ~ 55t including the payload adaptor and intermediate fairing. Block 2's stated capabilities are 49t to TLI, so on paper it's a no-go although they might be sandbagging a bit. But I don't know why we'd want to. Which is what we keep coming back to in this discussion. Apollo style with SLS gets ~3days on the surface every other year and a few hundred kg of samples each time at most, after a multi-year delay to develop a lander that small. Artemis HLS style gets potentially months on the surface per crew launch and tonnes of sample return, with scope to bypass SLS entirely and go multiple times a year and an architecture that also works for Mars, with landers that have already cut metal. I just don't understand why anyone would prefer Apollo-style.
  7. The early statements from BO were "we'll recover New Glenn from the first flight" to which everyone's response was "believe it when I see it". As said, they no longer have any recovery assets so it looks like they've walked back from that statement, and trying a few test landings over water first would indeed be prudent.
  8. IFAIK we've identified no pad or barge hardware and their ship has been sold so probably not, but then this is BO so something might materialise out of nowhere. I'd assume not for now though.
  9. https://spacenews.com/spacex-targets-february-for-third-starship-test-flight/ Next flight hardware ready in Jan, FAA license expected Feb after closeout of IFT-2 mishap investigation actions. Not forthcoming on what those actions are.
  10. I have spent a fair amount of time on fastener tightening in my career. Basically, if the fastener isn't tight enough to bind the joint without slip, then it will fret and chafe and fatigue and fail under repeated load cycles. Castellated nuts and cotter pins are a *terrible* way of securing a bolted joint. The nut has to have enough clearance to get the pin in which means in practice it can back off a little. Depending on torque and wear it's not unusual to shear the pin entirely. At best this will temporarily retain a nut that's come a bit loose before the bolt fails. The best way to make sure a nut doesn't come loose is to ensure it's correctly fastened to begin with (and the best way to do that is with a stud puller) and definitely not with a castellated nut. Yikes.
  11. Following a successful mission by Vulcan, the peregrine lander has suffered a propulsion anomaly that nearly resulted in its battery depleting and solar arrays not pointing towards the sun. The team conducted an improvised manoeuvre to get the spacecraft oriented correctly, but the propulsion failure may be a serious issue. Peregrine Mission 1: Lunar spacecraft back in contact and battery being recharged after 'propulsion anomaly' | Science & Tech News | Sky News
  12. Even if it was a knife-edge of mostly exactly 120s tests with a few falling short (which this data isn't), that would *still* not say anything about raptor's reliability because 3rd party observers have no idea what's being tested or what the abort criteria are. It could be GSE faults. It could be test aborts more conservative than flight. It could be testing above 100% throttle. It could be deliberate tests to failure. Nothing can be inferred definitively from this data.
  13. You don't know those were all supposed to be 120s burns.
  14. https://xkcd.com/2876/ The Range Mischief Officer has modified the trajectory to add a single random spin somewhere in the flight, but won't tell us where.
  15. Also we just don't do things the same way anymore even where the production drawings are explicit. We wouldn't braze a load of individual cooling pipes for instance, and would have a very hard time following any drawings calling for that. We'd 3d machine instead.
  16. The level of reddish colour is fairly constant for the steady state portion of the burn. If it were dirt you'd expect it to decreasing as the dirt was cleared. Whereas if it were nitrogen dioxide production the colour would be fairly constant at constant throttle, which is what we see. I'm not 100% certain, but seems like a much better fit to the evidence to me. Another source would be iron oxide from constant erosion of the steel, but the deluge is supposed to prevent that .
  17. My guess is the water is probably being near-instantaneously vaporised and steam is transparent. It'll still cool the pad. And I think the reddish colour is nitrogen dioxide from the exhaust impinging on air rather than dirt. There's just not that much dirt to blast off a steel pad.
  18. One thing to mention is that poor quality LED light driver units can generate harmonics in the cabling that can lead to interference on radio frequencies. Took a few months to track that problem down on the kitchen radio a few years back. So if you have LED lights you may find you get better reception when they're off.
  19. And now I know why soviet probes often incorporated spherical hulls. I really should have realised they were pressure vessels before now.
  20. Ah, but what if they built a test stand that could accurately represent dynamic flight conditions /s
  21. 1058 was the NASA worm marked booster. A sad loss. 19 flights was a great run. Still, there are three more boosters already on 17 flights, and a further 5 with more than ten.
  22. Many months - as the video timestamp 11th July 2022. So sixteen months and change at this point. It was booster 7 which eventually flew on IFT-1 in April this year. Booster 9 flew on IFT-2. Booster 10 is currently in the launch prep sequence.
  23. I must be thinking of a different X because it is not even close to cash positive, not on a trajectory to be, and is in substantially worse shape than it was before his takeover. Not only do the subscription model and staff firings not recoup even a fraction of the lost advertising revenue (lost for no good reason at all), but it has a heavy debt burden that's over a billion dollars per year and it's currently valued less than a third of what he paid for it. The total mismanagement has completely exploded his aura of competence and poses a direct threat to his control of his other companies SpaceX included. If Shotwell retained control it could even be an improvement.
  24. I was a prodigious twitter user until it became X and witnessed firsthand his descent into echo-chamber and buying into his own trollish cult of personality. It has not been at all edifying, and his decisions related to the site have been almost purely destructive and he's now on the hook for billions a year in debt repayments. Something like 73% of his Tesla stock is leveraged, so if he has to sell any significant amount to cover his twitter debt or default on that debt then that could both crash the value of Tesla and cause banks to call in his collateral and he'll lose the company. It's a small step from there to having to sell his stake in SpaceX to cover debts. He's already previously borrowed $1B from SpaceX (albeit he paid it back quickly on that occasion).
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