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Thread: SpaceX

  1. #2551
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    My concern isn't expecting 100% and getting 101%. I'm worried they expected 80-85% (expecting some margin) and got 101%.

  2. #2552
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    Mk1's propulsion module has gone to the pad for tests. Later, the cargo module and fins will be attached for first flight.

    Moving to the pad (time lapse)
    https://youtu.be/GpkX2QXLwFY

    SPadre @SpacePadreIsle
    One week until Starship’s fueling and systems tests begin at Boca Chica on Nov 7, from 12-8pm. 3 raptor engines to be installed and tested as well, then final assembly and...!!

    https://twitter.com/SpacePadreIsle/s...05354668679168

    IMG_20191031_231021.jpg
    Last edited by docmordrid; 2019-Nov-01 at 03:32 AM.

  3. #2553
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    Quote Originally Posted by docmordrid View Post
    My concern isn't expecting 100% and getting 101%. I'm worried they expected 80-85% (expecting some margin) and got 101%.
    And that 101% is on paper. What if it's slightly more in reality?
    With sufficient thrust, water towers fly just fine.

  4. #2554
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    Quote Originally Posted by Nicolas View Post
    And that 101% is on paper. What if it's slightly more in reality?
    That depends on how much.

    The structural margin for crew vehicles is higher than the ~1.2 (+20%) used for uncrewed, often near 1.4. If they significantly miss the design margin a little wind tunnel work may not suffice.

    This reminds me of Starliner; Boeing had to add a shroud around the Centaur upper stage to prevent it from collapsing due to aero load generated by Starliner.
    Last edited by docmordrid; 2019-Nov-01 at 07:46 PM.

  5. #2555
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    Quote Originally Posted by docmordrid View Post
    That depends on how much.

    The structural margin for crew vehicles is higher than the ~1.2 (+20%) used for uncrewed, often near 1.4. If they significantly miss the design margin a little wind tunnel work may not suffice.

    This reminds me of Starliner; Boeing had to add a shroud around the Centaur upper stage to prevent it from collapsing due to aero load generated by Starliner.
    Still less than 1.5 in aircraft.

  6. #2556
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    Quote Originally Posted by Glom View Post
    Still less than 1.5 in aircraft.
    For now Starship is much higher. Mk1 is 6.3mm steel, but later iterations will go down to 1/3 that. Perhaps less in the payload section to mitigate bremstrahlung x-rays from particle impacts, but adding high density polyethylene rad shields. Personally, I'd use HDPE doped with 5% boron for neutrons.

  7. #2557
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    Here we go - getting Mk1's cargo module ready to hit the road...

    Mary @BocaChicaGal
    A canard is being attached to Starship Mk1's nosecone. @NASASpaceflight

    EIUst5ZW4AESfgj.jpeg

    https://twitter.com/BocaChicaGal/sta...06857795477504

  8. #2558
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    SpaceFlightNow reports StarLink 1 (first launch of the v1.0 satellites)

    Date: Monday, November 11
    Time: ~1000 Eastern (~1500 UTC)

    Rub: that's Veterans Day, a US federal holiday

  9. #2559
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    1)

    Elon Musk ✔ @elonmusk
    Replying to @TJ_Cooney

    Wow, 2011 seems like eons ago! With fairing recovery, Falcon is ~80% reusable, but reflight takes several days & requires boats. Starship will be fully reusable with booster reflight possible every few hours & ship reflight every 8 hours. No boats needed.
    |
    That said, most Starship spaceports will probably need to be ~20 miles / 30km offshore for acceptable noise levels, especially for frequent daily flights, as would occur for point to point flights on Earth

    https://twitter.com/elonmusk/status/1191496935250616321

    2) cargo module fin installation (time lapse)

    https://youtu.be/I7E3GpYWC_k

  10. #2560
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    Those canards look *so* Flash Gordon


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  11. #2561
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    Quote Originally Posted by docmordrid View Post
    1)

    Elon Musk ✔ @elonmusk
    Replying to @TJ_Cooney

    Wow, 2011 seems like eons ago! With fairing recovery, Falcon is ~80% reusable, but reflight takes several days & requires boats. Starship will be fully reusable with booster reflight possible every few hours & ship reflight every 8 hours. No boats needed.
    |
    That said, most Starship spaceports will probably need to be ~20 miles / 30km offshore for acceptable noise levels, especially for frequent daily flights, as would occur for point to point flights on Earth

    https://twitter.com/elonmusk/status/1191496935250616321

    2) cargo module fin installation (time lapse)

    https://youtu.be/I7E3GpYWC_k
    So they plan on having a floating landing zone, which could be construed as a large boat.

  12. #2562
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    Quote Originally Posted by bknight View Post
    So they plan on having a floating landing zone, which could be construed as a large boat.
    I wonder what that sealaunch one Boeing built is doing these days. Maybe Elon can get it cheap .
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    Quote Originally Posted by Trebuchet View Post
    I wonder what that sealaunch one Boeing built is doing these days. Maybe Elon can get it cheap .
    I don't know but it is a floating object much like the floaters in the drilling business. Still they could be considered very large boats. They do station keep with thrusters. Another option would be a tethered platform and thirdly a platform sitting on the sea floor. That one is not floating, like the rest, but would be pricey given the distance Elon mentioned in his tweet.

  14. #2564
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    I hope Elon has a fast ship to get the people from that far offshore to land and vise versa, otherwise any point-to-point time won in flight is lost again at sea.
    With sufficient thrust, water towers fly just fine.

  15. #2565
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    Quote Originally Posted by Nicolas View Post
    I hope Elon has a fast ship to get the people from that far offshore to land and vise versa, otherwise any point-to-point time won in flight is lost again at sea.
    Hyperloop along the sea floor to a shore terminal.

  16. #2566
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    Quote Originally Posted by Nicolas View Post
    I hope Elon has a fast ship to get the people from that far offshore to land and vise versa, otherwise any point-to-point time won in flight is lost again at sea.
    Jack-up platforms. Movable if the natives get restless, just raise the legs and tow it away, but extremely solid. After projects are completed you can often buy them for scrap prices.

    Quote Originally Posted by Darrell View Post
    Hyperloop along the sea floor to a shore terminal.
    Funny you should mention that...

    Bob Burrough @bob_burrough
    Hey @elonmusk
    I get why BFR is likely to launch at sea, but that means a relatively slow boat ride to the pad. Any chance of underwater Hyperloop to the pad instead?
    |
    Elon Musk @elonmusk
    Replying to @bob_burrough
    Yes

    https://twitter.com/elonmusk/status/1191744578157547520
    Last edited by docmordrid; 2019-Nov-05 at 10:39 PM.

  17. #2567
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    We have a bunch of self-propelled jackup platforms, the most advanced in the world. Those are intensely slow. So you'll still need fast transport to/fro to make the concept work. Hyperloop might do the trick indeed.
    With sufficient thrust, water towers fly just fine.

  18. #2568
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    I am very skeptical of the suborbital flights, as I doubt the economics would work out, and I also wonder if countries would be happy with regular international rocket flights. It might look a little too much like ICBMs to sensors, and we wouldn’t want anyone getting nervous or confused.

    I am also very skeptical of the practicality of Hyperloop.

    But, my key interest is to see a practical fully reusable earth to orbit rocket. If SpaceX can achieve that, I will be very happy. Whether it does suborbital or goes on its own to the moon is, I think, far less important than if it can change the economics of reaching LEO.

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  19. #2569
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    I'm also not convinced about the suborbital part. Something like Skylon -over 15 years in the making and no complete engine yet, but anyway- might be more convenient for suborbital services.
    With sufficient thrust, water towers fly just fine.

  20. #2570
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    Quote Originally Posted by Van Rijn View Post
    I am very skeptical of the suborbital flights, as I doubt the economics would work out, and I also wonder if countries would be happy with regular international rocket flights. It might look a little too much like ICBMs to sensors, and we wouldn’t want anyone getting nervous or confused.

    I am also very skeptical of the practicality of Hyperloop.

    But, my key interest is to see a practical fully reusable earth to orbit rocket. If SpaceX can achieve that, I will be very happy. Whether it does suborbital or goes on its own to the moon is, I think, far less important than if it can change the economics of reaching LEO.
    Completely agree.

    There is also the environmental side of the sub-orbital flights. How does the CO2-footprint for a SpaceX suborbital flight compare to a more conventional aircraft? Will passengers and countries be interested in a technology with a severe environmental impact so a wealthy few can hop over the ocean faster?
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  21. #2571
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    A lesser talked about issue is the impact of noise on the environment. Sure, there's a concern on land, but the effects at sea would be wider.

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  22. #2572
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    Quote Originally Posted by Van Rijn View Post
    I am very skeptical of the suborbital flights, as I doubt the economics would work out,
    Musk receñtly spoke at a USAF event, saying their operational costs for a Starship launch will be about $2million + propellants. This would be with Super Heavy, but Starship can do many point to point flights by itself. The guessing is they replace the 3 RaptorVacs and 3 aft cargo bins with 6 sea level engines, for a total of 9.

    and I also wonder if countries would be happy with regular international rocket flights. It might look a little too much like ICBMs to sensors, and we wouldn’t want anyone getting nervous or confused.
    The platform would be in international waters, and the Air Traffic Control system is in the midst of an upgrade to incorporate spacecraft. For the last few years Dragon has been flying the hardware for testing.

    I am also very skeptical of the practicality of Hyperloop.
    This being a short range trip, I'm betting it'd be more like the slower/non-vacuum Urban Loop system now going in at Las Vegas.

    But, my key interest is to see a practical fully reusable earth to orbit rocket. If SpaceX can achieve that, I will be very happy. Whether it does suborbital or goes on its own to the moon is, I think, far less important than if it can change the economics of reaching LEO.
    FWIW, SpaceX presented P2P at the National Space Council, and regulators are working on regulations for it. And not just from SpaceX, others want a piece of that pie.

  23. #2573
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    Quote Originally Posted by CJSF View Post
    A lesser talked about issue is the impact of noise on the environment. Sure, there's a concern on land, but the effects at sea would be wider.

    CJSF
    SpaceX will be using a rather advanced noise suppression system for Starship and Super Heavy launches, consisting of an actively cooled flame deflector (it's redirected horizontally) and a huge array of "rainbirds" to quench the acoustics. The Phase 1 Starship pad is co-located at KSC KC-39A and going in as we type, and the full stack version with the big suppression system goes in with Phase 2 before Super Heavy flies. That could be next year.

  24. #2574
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    Quote Originally Posted by docmordrid View Post
    SpaceX will be using a rather advanced noise suppression system for Starship and Super Heavy launches, consisting of an actively cooled flame deflector (it's redirected horizontally) and a huge array of "rainbirds" to quench the acoustics. The Phase 1 Starship pad is co-located at KSC KC-39A and going in as we type, and the full stack version with the big suppression system goes in with Phase 2 before Super Heavy flies. That could be next year.
    Does anyone know the level of noise compare to the Saturn V?

  25. #2575
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    Quote Originally Posted by bknight View Post
    Does anyone know the level of noise compare to the Saturn V?
    From the LC-39A Super Heavy / Starship environmental assessment,

    Launch Noise

    The loudest noise generated at the site would result from launches. Other intermittent raised levels of noise would occur during operation of lifting equipment, diesel-powered generators, and heavy-duty
    service vehicles.

    The model RNOISE was used to compute the LAmax, SEL, and DNL contours, which are shown in the figures provided in the KBRwyle report in Appendix A. The LAmax contours indicate the maximum sound level at each location over the duration of the launch. Maximum LAmax levels of 90 dB through 140 dB are estimated for the Starship/Super Heavy launch at LC-39A. The higher LAmax contours (100 - 140 dB) are located entirely within both the CCAFS and KSC properties, although the 90 dB contour extends into parts of Titusville, west of LC-39A, and Merritt Island, southwest of LC-39A.

    If a Starship/Super Heavy launch occurs during the day, when background levels are in the 50 dB to 60 dB range, residents of Titusville, Merritt Island, and Cape Canaveral may notice launch noise levels above 70 dB. If the same launch occurs during the night, when background levels are lower than during the day (e.g., below 40 dB to 50 dB range), these residents may notice launch noise levels that exceed 60 dB. A prevailing onshore or offshore breeze may also strongly influence noise levels in these communities (KBRwyle 2019).
    >
    The 110 dB and higher level SEL contours are expected to remain entirely within the CCAFS and KSC properties. The 100 dB SEL contour extends past Titusville to the west and beyond Cocoa Beach to the south.
    >
    Launch
    Starship LC-39A EA acoustics-800.jpeg
    Last edited by docmordrid; 2019-Nov-07 at 07:09 AM.

  26. #2576
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    From the web
    Sounds at 90-95 decibels are where humans start to experience hearing loss from sustained exposure. We start to experience pain at 125 decibels and louder. 140 decibels and up can quickly cause irreversible ear damage. One of the loudest sounds ever recorded was NASA's Saturn V rocket, which registered 204 decibels. vs. 140 for Starship/Super Heavy launch at LC-39A

  27. #2577
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    Quote Originally Posted by docmordrid View Post
    Jack-up platforms. Movable if the natives get restless, just raise the legs and tow it away, but extremely solid. After projects are completed you can often buy them for scrap prices.



    <snip>
    That's is not as easy as you infer. Water depths +/- 20 miles from shore could be +/- 300-400'. Platform needs stability (at any water depth), this is attained by loading the platform legs at depth(below mud line). This in my experience can take up to 24 hours, removing the legs from the mud could take the same amount of time or a bit longer due to suction forces as the legs are withdrawn. Matted platforms are a bit easier as there is a broad mat on resting bottom, not just the narrow legs. I don't know if any of these are built for this type of depth, more in the 100-200' WD.
    But it might be a doable task, given the depth and equipment available.

  28. #2578
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    I'd guess semi-submersible rather than jack-up platforms. That's what Sea-Launch used.
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  29. #2579
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    Quote Originally Posted by Trebuchet View Post
    I'd guess semi-submersible rather than jack-up platforms. That's what Sea-Launch used.
    That would work if there are rather calm seas, without the platform oscillating with waves or some method of launch pad dampening, much like a drilling assembly stabilization.

  30. #2580
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    although the 90 dB contour extends into parts of Titusville
    aka Tinnitusville.
    With sufficient thrust, water towers fly just fine.

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