RCgothic

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Everything posted by RCgothic

  1. Can we back calculate what the maximum payload to the minimum GTO is and compare it to Spacex's stated values?
  2. Three: Even copper corrodes over cosmologically significant time periods (millions of years). Just because something is frozen does not mean it will remain intact and functional ready to be defrosted. I've some professional experience with trying to keep things protected over mere geologically significant time (tens of thousands of years) and I'd say the only hopes lie at a significant fraction of the speed of light. As we can't use the entire mass of the solar system as reaction material you are going to have to find a very large black hole with a shallow gravity well in a quiet neighbourhood (the less the black hole is consuming the lower the radiation/bombardment hazard) and slingshot very close to the event horizon. Of course, finding and travelling to such a black hole will take a cosmologically significant time period, so basically no. Not even a digitally stored simulation of a person's consciousness could be kept over that sort of time period.
  3. Thank you for clarifying.
  4. How is 'most reliable' and 'heavy' defined in that analysis? As far as I'm aware Saturn 1B had 100% success.
  5. Lift is a function of both wing area and velocity. A Cessna needs to go supersonic. Something built like a U2 would not.
  6. Still doesn't make sense. Orion is massively over engineered for trips to LEO which for the foreseeable is the most sensible place to assemble the mars mothership. It's rated for lunar returns. In that respect it's well suited for DSG, but DSG is just make-work. DSG isn't a sensible assembly location because it takes more propellant to send assembly materials to DSG and then to mars than it does to just send straight to mars from LEO. There are still no serious plans to revisit the lunar surface. As far as Martian returns go, the Orion is a heavy piece of hardware you don't want to take with you. On return the mothership is expensive enough that you're going to brake it into LEO rather than lose it and re-enter direct from Mars in an Orion whilst losing the rest of the ship.
  7. Orion isn't designed to go to Mars. It has nowhere near the required habitable volume for that duration. Neither is SLS - it can't loft nearly enough propellant for a crewed mission to mars and the hydrogen upper stage doesn't have the endurance for on-orbit assembly at the proposed launch cadence. Nasa does not yet have a serious plan to get there and the hardware required is currently all vapourware.
  8. Also, though it didn't have any loss of craft, Saturn and Apollo had several very near misses. If it had kept flying there'd probably have been a tragedy. It was an amazing machine, but let's not pretend it was perfect. A new booster would have better payload fraction and better safety margins for lower cost than resurrecting the dead. Not that SLS is the right approach either.
  9. Remembered and tuned in at t-5! Very lucky!
  10. I'm up to bag 5/6. Stage IC nearly complete! It's nice and solid, but I'm a little disappointed the interstage ring remains attached to SIC. I'm already pondering if I can alter it to be a separate piece. Just the F1s let to do! Also noticed looking ahead that for the command module you have to swap between the Boost Protective Cover version and the one without. Guess they don't have a hollow piece to go over the top of a cone piece!
  11. Presumably the ICPS does make a difference for less than full payloads to beyond LEO. But that is ridiculous. As if we needed more reason to diss the SLS.
  12. Very little unless it launches with the payload or can rendezvous with it very shortly thereafter.
  13. I also note that first it was an update 'in a month', then it was 'six weeks', and now it's 'couple months'.
  14. I'm still running the numbers, but I reckon Michoud and the VAB should be able to construct a 125m x 10m diameter rocket powered by 10-12 F1Bs with a 36m x 12m fairing and 800t to LEO in two stages. More with strap on boosters which can be up to 4x 6m diameter. Don't bother man-rating. Just a big dumb booster.
  15. Might be worth establishing a list of things we know we can't throw out. E.g: Vehicle Assembly Building. 125m max height (doors minus mobile platform). Max width 22m. Michoud Assembly Facility. Max core 10m dia.
  16. There are two ways to make a warhead that fits on a missile. One is to miniaturize the warhead. The other is to build a bigger missile. I imagine building a bigger missile is the easier of the two tasks.
  17. Which is then basically ITS.
  18. Falcon 9 is now flying heavier payloads reusable than it initially did expendable. Maybe it might save a little material cost to build a shorter tank for lighter payloads, but you almost certainly wouldn't save more than half the price of a complete booster, as it appears is possible with reusability. Most of the cost is in the engines and if you cut down on mass too much you get over-engined. Redesigning that octaweb is non-trivial. Also, there are additional tooling and inventory management concerns that would eat into your savings. Finally, Falcon 9 went reuseable because Elon Musk wants to go to mars and things like supersonic retropropulsion and reusability are seen as necessary technologies. I'm convinced he'd go for this direction anyway even if it weren't totally financially optimal.
  19. Building a surface colony on Mars is also probably easier than building a floating colony on Venus.
  20. Stage 2 is weird. It provides most of the DV for falcon 9 in order to keep the first stage slow for recovery. But the Space x website advertises the same burn time for F9 and FH second stages, implying no more propellant for S2 on FH. Combined with doubling the payload, that has got to do awful things to S2's DV. Either I'm missing something or the core stage 1 is going to have to separate crazy-fast compared to falcon 9. How then do they plan to do core recovery?
  21. Alas poor Jeb. First casualty of this hardcore campaign. Veteran pioneer of the kerbal space program and in particular the first spacewalk and Gemini Rendevous missions. Killed in a tragic launchpad accident when the launch clamps released prematurely. Unphased he initiated the abort procedure but a second oversight meant that at sea level the munar module did not have enough TWR to pull itself clear of the ensuing fireball. He will be missed. As soon as the space program can find two more credits to rub together Valentina will lead on in his stead.
  22. They probably won't announce that, it being a military payload. Having a winged payload without fins may be doable these days. Heck of a dynamic stability problem though.
  23. I notice that 'fully reuseable' craft doesn't reuse the trunk!
  24. I don't think sci-fi shuttles generally are SSTOs in the conventional sense. When you have enough power to maintain 1g indefinitely you don't have to maintain orbital velocities. Re-entries also don't have to be heat shielded because you don't come in that hot. This also explains why sci-fi ships tend to fall out of orbit when they're damaged/lose power. It's because they were actively maintaining their altitude rather than falling around the planet and missing.
  25. Landing successful? Much cheering!