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Thread: SpaceX

  1. #2911
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    Quote Originally Posted by docmordrid View Post
    There are 3 sea level Raptors at Boca Chica, and it's plumbed for all 3. Each S/L Raptor is roughly equivalent to a Space Shuttle Main Engine, but they're going to evolve to be much more powerful.

    It"s gonna get noisy.
    There's going to be a version with around 3 MN thrust (compared to the 2 MN standard version) and no throttle or gimbaling, but it's probably not going to evolve much apart from that. It's starting off as a much more highly optimized engine than Merlin did.

  2. #2912
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    Yup.

    Last night SN-04 passed the ambient temp nitrogen gas test.

    Tonight is the liquid nitrogen cryogenic test.

  3. #2913
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  4. #2914
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    Great! Onwards and upwards! Is this already the kind of steel they plan on using on the real deal?
    With sufficient thrust, water towers fly just fine.

  5. #2915
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    That’s a relief - clear progress and finally past the earlier problems. Hopefully the flight tests will go well. One way or another, they should be pretty spectacular. I’m looking forward to them.

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  6. #2916
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    Quote Originally Posted by Van Rijn View Post
    That’s a relief - clear progress and finally past the earlier problems. Hopefully the flight tests will go well. One way or another, they should be pretty spectacular. I’m looking forward to them.
    They are going to be loud and conspicuous! It does make me worry when they start launching from Florida. I don't know how well the impacts on local wildlife in the NWR have been studied. This is likely to be a bigger bang and roar than the Saturn V (and environmental impact studies have come a long way since the 1960s).

    CJSF
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  7. #2917
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    STS was quite loud too.
    With sufficient thrust, water towers fly just fine.

  8. #2918
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    Quote Originally Posted by CJSF View Post
    They are going to be loud and conspicuous! It does make me worry when they start launching from Florida. I don't know how well the impacts on local wildlife in the NWR have been studied. This is likely to be a bigger bang and roar than the Saturn V (and environmental impact studies have come a long way since the 1960s).
    It will have higher total thrust, but a larger number of smaller engines, each an independent, incoherent noise source. Starship might actually be quieter than Saturn V. If they have a problem with Starship, they'd have a much bigger problem with the SLS solids.

  9. #2919
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    Quote Originally Posted by cjameshuff View Post
    It will have higher total thrust, but a larger number of smaller engines, each an independent, incoherent noise source. Starship might actually be quieter than Saturn V. If they have a problem with Starship, they'd have a much bigger problem with the SLS solids.
    Well, in any case my environmental concerns stand.

    CJSF
    "I like the stories
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  10. #2920
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    Quote Originally Posted by CJSF View Post
    Well, in any case my environmental concerns stand.

    CJSF
    Almost all rockets use a hydrocarbon fuel and mainly enit CO2 & water vapor,p. An exception is Delta IV which uses liquid hydrogen and emits water vapor. Still, the worldwide CO2 tonnage from hydrocarbon rockets is a miniscule proportion of total emissions.

    OTOH, rockets which use solid boosters also emit unburned perchlorates and hydrochloric acid vapor. These fall on wetlands etc. near the pad. Shuttle, Atlas V, Delta IV, the upcoming Vulcan & OmegA, SLS, etc.

    Starship uses methane and liquid oxygen, emitting CO2 and water vapor. Further, Starship's Raptor full-flow staged combustion engine is highly efficient, so little methane goes unburned. The first FFSC to fly after the US and USSR tried and gave up. The Russians never could overcome combustion instabilities in RD-270.
    Last edited by docmordrid; 2020-Apr-27 at 11:34 PM.

  11. #2921
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    Yes, that's great, but I was specifically referring to sonic effects in this particular instance.

    CJSF
    "I like the stories
    About angels, unicorns and elves
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    The facts are with science"

    -They Might Be Giants, "Science Is Real"


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  12. #2922
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    As I said, STS also was very loud. Any lessons about the impact of noise could have been learned over the 100+ shuttle launches. I never looked into what if any study they actually did. But it's not like Starship will be the first Very Loud Thing to lift off from the Cape.
    With sufficient thrust, water towers fly just fine.

  13. #2923
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    I found this:
    Final Constellation Programmatic Environmental Impact Statement
    PDF page 8 (document page 4-8) has a table comparing noise levels of various rockets (but not any of SpaceX's)
    At night the stars put on a show for free (Carole King)

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  14. #2924
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    So basically Space Shuttle was about as loud as Saturn V. And I don't expect future rockets to be much louder, as you get at levels where they'd shake themselves to pieces. Conclusion: environmental impact should be no different from what potentially happened during decades of Shuttle launches.
    With sufficient thrust, water towers fly just fine.

  15. #2925
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    Quote Originally Posted by Nicolas View Post
    So basically Space Shuttle was about as loud as Saturn V. And I don't expect future rockets to be much louder, as you get at levels where they'd shake themselves to pieces. Conclusion: environmental impact should be no different from what potentially happened during decades of Shuttle launches.
    I see them about equal 91 vs 90 at ~9400 m from pad.

  16. #2926
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    I was just watching a BocaChicaGal video and realized that SN4 not only has no landing legs, but no visible provisions for them. Any idea how they would attach?
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  17. #2927
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    Quote Originally Posted by Trebuchet View Post
    I was just watching a BocaChicaGal video and realized that SN4 not only has no landing legs, but no visible provisions for them. Any idea how they would attach?
    6 legs stowed inside the engine skirt, unfolding and telescoping just before touchdown. 4 are easily seen in this upskirt view, but 2 are hidden by the yellow load simulator jacks. This image is of SN-03. Its engine skirt & legs were undamaged and recycled into SN-04. SN5/6 legs will be larger..

    Starship SN-03 Landing Legs + Load Jacks.jpg

    https://youtu.be/hSCkKeNZcxI

    SN-04 static fire Friday night. The window opens at 2200 Eastern.
    Last edited by docmordrid; 2020-Apr-29 at 01:49 AM.

  18. #2928
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    Quote Originally Posted by docmordrid View Post
    6 legs stowed inside the engine skirt, unfolding and telescoping just before touchdown. 4 are easily seen in this upskirt view, but 2 are hidden by the yellow load simulator jacks. This image is of SN-03. Its engine skirt & legs were undamaged and recycled into SN-04. SN5/6 legs will be larger..

    Starship SN-03 Landing Legs + Load Jacks.jpg

    https://youtu.be/hSCkKeNZcxI

    SN-04 static fire Friday night. The window opens at 2200 Eastern.
    Makes sense since anything on the outside of the ship could be exposed to re-entry heat and they want clean lines to simplify the aerodynamics of the Starliner.

  19. #2929
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    of the WHAT???
    With sufficient thrust, water towers fly just fine.

  20. #2930
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    Quote Originally Posted by Nicolas View Post
    of the WHAT???
    I meant in the final version, which I assumed was rather obvious.

  21. #2931
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    You said "Starliner". I don't think that's what you intended...
    With sufficient thrust, water towers fly just fine.

  22. #2932
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    I'm still stuck on "upskirt view".
    Thanks for the info!
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  23. #2933
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    Quote Originally Posted by Trebuchet View Post
    I'm still stuck on "upskirt view".
    Thanks for the info!
    Its ok as long as you ask first and the rocket says yes.
    At night the stars put on a show for free (Carole King)

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  24. #2934
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    I wish they would all pick names that weren't so damn similar...

  25. #2935
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    Quote Originally Posted by Garrison View Post
    I wish they would all pick names that weren't so damn similar...
    As in the rocket variant?

  26. #2936
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    Quote Originally Posted by bknight View Post
    As in the rocket variant?
    As in Starliner versus Starship.

  27. #2937
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    Quote Originally Posted by Garrison View Post
    As in Starliner versus Starship.
    Just refer to the latter as the Starship Launch System. Nice and unambiguous.

  28. #2938
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    Quote Originally Posted by cjameshuff View Post
    Just refer to the latter as the Starship Launch System. Nice and unambiguous.
    Too wordy, I'll just go with the initials, that can't go wrong.

  29. #2939
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    Starlink presentation at the National Academy of Sciences

    Tons of info about light mitigation, orbital ops, etc.

    https://www.spacex.com/news

  30. #2940
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    Quote Originally Posted by Garrison View Post
    Too wordy, I'll just go with the initials, that can't go wrong.
    Yes, but two SLS?

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