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RCgothic

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Everything posted by RCgothic

  1. I wonder how much DV that dragon has as an independent vehicle
  2. We don't need an abandoned space station slowly shedding debris into an orbit with decay times measured in centuries to millennia. NASA's got this call right IMO.
  3. Using sat thrusters to recover a useful orbit is pretty much exactly how JMcD defines "useable".
  4. I guess that's why JMcD scores non-nominal but usable orbits 0.75 of a success, and orbital but unusable 0.4.
  5. Oh dear Arianespace. Not another one. Wikipedia is saying failure of Vinci's APU, and it was an intended de-orbit burn (with apoapsis raise as well for steeper descent?) That doesn't sound too critical, should sort it in the next flight.
  6. Booster explodes in landing conditions it's not designed for shocker.
  7. By my count Raptor is coming up on half as many launch and in flight ignitions as Rocketlab's Rutherford by the way. I think Raptor is on 224 counting all of those that started and burned for more than a second from Starhopper through IFT4. Rutherford is on about 490 I think?
  8. I don't know who originally started the "Boeing Astronauts Stranded" line, but it's never actually been the case and it seems like a lot of outlets are just copying the lede and running with it.
  9. Europe clearly needs to do something to compete. But even if they put forward a design targeting falcon-like cadence and reusability, by the time it's ready it'd already be obsolete. Needs a much larger rethink than just producing an all-liquid ariane variant. They need an engine that can be produced at a rate of several per day, with better-than-Merlin levels of reusability, and enough thrust to not need solid boosters for assistance. Hydrogen engines are out on poor thrust and difficulty to refurb (tricky h2 seals). Kerolox is out because of coking. So they probably need a methalox engine as a starting point
  10. Because it can't be fixed or adequately preserved and will inevitably disintegrate, posing a hazard to all spaceflight in it's orbit and nearby orbits. Far better to end it decisively.
  11. Superdracos would break the ISS into bits. It'll be standard Dracos.
  12. Speaking of: https://arstechnica.com/space/2024/06/mere-days-before-its-debut-the-ariane-6-rocket-loses-a-key-customer-to-spacex/ Even government payloads not safe for Ariane it seems.
  13. Lol, Europe doesn't have a rocket market anymore. There'll be a few mandatory government payloads and that's it. Ariane 6 won't be competing with Starship because it can't even compete with Falcon.
  14. The header tanks also have helium COPVs for pressurisation. But also it's probably not safe for NASA to sell the ISS. It's a station that's getting gradually more decrepit and can't reasonably be fixed. If a private entity ended up getting someone killed, NASA could be liable.
  15. Sometimes it's acceptable to just accept the remote chance of a fault because covering it off completely would be grossly disproportionate. The chances of a well-designed cable breaking in normal operation are remote. So we're talking fault cases. What sort of faults could be encountered in interplanetary space? Micrometeoroid impact? And the chances of that severing all the strands of a cable are? If the strands are cross-coupled every so often the broken end wouldn't even rebound especially fast. Any strike large enough to take out multiple strands would probably be a LOCA in the far higher probability of striking the main spacecraft anyway. Any other plausible fault cases? I'm struggling to think of any
  16. Also the gas will be colder by the time it reaches the main tank and less useful as pressurant.
  17. SpaceX appear to be preparing a simulated tower catch.
  18. And for all you know a Merlin (most reliable rocket engine in flight hours ever by a long margin) would have exploded in those circumstances as well. Pretty much every instance of engine-out so far on Starship/Superheavy appears to be some form of "rocket failed to provide the engine with acceptable/survivable operating conditions". A rocket needs to be looked at holistically. Is direct exhaust autogenous pressurisation turning out to be harder than expected? Possibly. But heat exchangers are also massive and complicated and need to move enormous quantities of liquid through a phase change, so we may not yet have reached the point where "stick more filters on it" isn't a better solution. For context, each of the steam generators on a nuclear reactor are about half the size of the reactor vessel itself, and there are typically 2-4 of them.
  19. Part two of Tim's interview with Musk is up. Notably it was only the front-right flap that really let go, they can tell by the deployment data. That one was fully deploying, the other 3 more nominally. Also where the tiles were missing on the skirt, seems 2 layers of backup ablative didn't burn through, one layer did but not clear that the steel also failed, might have survived. They don't even need infra-red cameras for seeing the hotspots internally, they glow in the visible spectrum.
  20. Although I have many, many criticisms of Musk, as a chartered engineer myself "not being a proper engineer" isn't one of them. By all appearances he has as much of a grasp of technical details as top engineers for a nuclear power plant. There are many decisions that get made during the design process of any system, and they're not always good ones. Iteration is part of the process. The only difference with SpaceX is that we see the iterations happen publicly in hardware rather than purely in private sim.
  21. He followed up by saying that there's no great rush to refuel HLS in orbit, it can be done with sequential tanker flights and the boil-off won't be too bad. Propellant transfer is just docking, and docking to other starships is easy - much easier than docking to the ISS which they do regularly.
  22. There's "never done before" and there's "never done before in a rocket engine". For whatever reason there's never been a good enough motive for someone to try and integrate cooling of secondary systems (because regenerative cooling of combustion chambers and nozzles have been implemented since forever) before. Maybe a rocket needs to have a particular mass of fire suppression, number of engines, or level of reusability before advanced integration of instrument lines and wiring inside housings and elimination of flanges makes sense. In my own work I'm bringing together a lot of different things that are fairly common elsewhere but nevertheless equal "never done before in a power plant". The main reason for us at least seems to be that when production of a thing is at a fairly steady rate, the people building power plants go on to build new power plants the same as they've always done, and train their replacements to do what they've always done. When demand for a thing exceeds the resource pool, people with different experiences need to get brought in from other sectors and the combination of experiences often unlocks doing things differently from then on.
  23. Nah, pez dispensers have been a thing for decades, I remember them when I was young. A quick search turned up they've been around since 1927.
  24. Starship: *Fin fails during first true test of re-entry.* "This was clearly Raptor's fault."
  25. I was in a work meeting and only caught the stream as the camera was getting coated in debris and just before the lens cracked. Saw the landing, came on here and started reading back. A fin melted. Wait. What?! Only then went back and rewatched the stream. Can't believe it made it to a successful ocean landing with that!
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