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Thread: SpaceX

  1. #3091
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    Not odd at all, spy satellites that used film really had a short life time and there was a crazy amount of money available for these launches from both the US and USSR...

  2. #3092
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    What will StarLink look like on your device? One listing for each satellite, switching as required.

    IMG_20200612_203439.jpg

    https://twitter.com/FutureJurvetson/...12092957270016

    StarLink 8. No static fire before this launch.

    Date: June 13
    Time: 05:47;23.210 Eastern (09:47;23.210 UTC)

    Time: 05:47;23.210 Eastern (09:47;23.210 UTC)

    https://youtu.be/8riKQXChPGg
    Last edited by docmordrid; 2020-Jun-13 at 01:11 AM.

  3. #3093
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    Like.Clock.Work.

    And for their next trick...and continuing a blistering pace.

    StarLink v1.0 Launch 9 + BlackSky 5&6
    Date: June 22
    Time: 1820 EDT (2220 UT)
    Pad: LC-39A
    Booster recovery: ASDS, likely Of Course I Still Love You
    Fairing recovery: Ms Tree, Ms Chief
    Rideshares:*BlackSky Global 5 & 6

  4. #3094
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    American Astronautical Society conference; SpaceX's Director of Advanced Development for Civil Space Nick Cummings, talking about Lunar Starship landings.

    For the terminal descent of Starship, a few tens of meters before we touch down on the lunar surface, We actually use a high-thrust RCS system so we don’t impinge on the surface of the Moon with a high-thrust Raptor engine. The thrusters planned have a lot of heritage in the Raptor design itself. It uses the same methane and oxygen propellants as Raptor, so there’s a lot of commonality there. We're going to be ramping up some very rapid testing activities in the coming year.
    Last edited by docmordrid; 2020-Jun-13 at 05:43 PM.

  5. #3095
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    Quote Originally Posted by docmordrid View Post
    American Astronautical Society conference; SpaceX's Director of Advanced Development for Civil Space Nick Cummings, talking about Lunar Starship landings.
    For the terminal descent of Starship, a few tens of meters before we touch down on the lunar surface, We actually use a high-thrust RCS system so we don’t impinge on the surface of the Moon with a [I]high-thrust Raptor engine. The thrusters planned have a lot of heritage in the Raptor design itself. It uses the same methane and oxygen propellants as Raptor, so there’s a lot of commonality there. Going to be ramping up some very rapid testing activities in the coming year.
    This doesn't make sense to me.

  6. #3096
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    Quote Originally Posted by bknight View Post
    This doesn't make sense to me.
    A joint NASA/SpaceX study showed Raptor is powerful enough to blast debris off the surface which would 1) come back and impact the vehicle, 2) travel completely around the moon and impact at the landing site ~2 hours later, and 3) some debris could even achieve escape velocity.

    Not exactly optimal.

    To mitigate this, Starship will use methane/lox landing thrusters positioned high up on the vehicle and firing at an outward angle, minimizing the debris lofted during a landing and its velocity. Think methane SuperDraco, Raptor derived but much smaller.

    49839102107_39a2cde996_b.jpg
    Last edited by docmordrid; 2020-Jun-13 at 06:19 PM.

  7. #3097
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    Quote Originally Posted by docmordrid View Post
    A joint NASA/SpaceX study showed Raptor is powerful enough to blast debris off the surface which would 1) come back and impact the vehicle, 2) travel completely around the moon and impact at the landing site ~2 hours later, and 3) some debris could even achieve escape velocity.

    Not exactly optimal.

    To mitigate this, Starship will use methane/lox landing thrusters positioned high up on the vehicle and firing at an outward angle, minimizing the debris lofted during a landing and its velocity. Think methane SuperDraco, Raptor derived but much smaller.

    49839102107_39a2cde996_b.jpg
    Thanks for the expansión. But of you read the quieres pasar,it doesn't make sense.

  8. #3098
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    Quote Originally Posted by docmordrid View Post
    A joint NASA/SpaceX study showed Raptor is powerful enough to blast debris off the surface which would 1) come back and impact the vehicle, 2) travel completely around the moon and impact at the landing site ~2 hours later, and 3) some debris could even achieve escape velocity.

    Not exactly optimal.

    To mitigate this, Starship will use methane/lox landing thrusters positioned high up on the vehicle and firing at an outward angle, minimizing the debris lofted during a landing and its velocity. Think methane SuperDraco, Raptor derived but much smaller.

    49839102107_39a2cde996_b.jpg
    So HyperDracos?

  9. #3099
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    Baby raptors. Or maybe Falconets.

    It reminds me of an old cold war era story by Ben Bova. The US and USSR are just barely avoiding all out nuclear war but the US and Soviet lunar bases are peaceful. Someone wants to know why and goes for an inspection. It turns out the bases previously had a shooting battle, but the bullets had achieved orbital velocity and for any fight, they would have to deal with their own stray bullets coming back around to hit them. The story was layed out as dark comedy.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." — Abraham Lincoln

    I say there is an invisible elf in my backyard. How do you prove that I am wrong?

    The Leif Ericson Cruiser

  10. #3100
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    This will make the VA and Stabilo tractor systems seem tiny.

  11. #3101
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    Starship makes about every space vehicle look tiny.

    SpaceX Starlink 7 --> Starlink 8 broke the US record for pad turnaround & launch

    9 days, 7 hours 55 minutes from LC-40

    The previous record was Gemini 7 --> Gemini 6A

    11 days, 18 hours 7 minutes from LC-19 {1965}

  12. #3102
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    Quote Originally Posted by publiusr View Post
    This will make the VA and Stabilo tractor systems seem tiny.
    Stabilo didn't "seem" tiny, it was tiny. Falcon 1 was around 30 times its mass. Stabilo was a peroxide monopropellant toy built by people who couldn't do the math for balloon launch and didn't even understand the pendulum fallacy.

    VA?

  13. #3103
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    Quote Originally Posted by docmordrid View Post
    What will StarLink look like on your device? One listing for each satellite, switching as required.

    IMG_20200612_203439.jpg

    https://twitter.com/FutureJurvetson/...12092957270016
    A much more reasonable conclusion is that they have several Wifi access points setup. Those could be connected to one or more Starlink user antennae. It's a WiFi setup page after all, your devices will talk Ethernet or WiFi with the antenna, your device will know nothing about the satellites.

  14. #3104
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    Quote Originally Posted by cjameshuff View Post
    Stabilo didn't "seem" tiny, it was tiny. Falcon 1 was around 30 times its mass. Stabilo was a peroxide monopropellant toy built by people who couldn't do the math for balloon launch and didn't even understand the pendulum fallacy.

    VA?
    Had to look up the Stabilo, and then do it again just to be sure it was a real thing...

  15. #3105
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    I think there was a Hercules lander being bandied about with the upper section detaching and landing separately in a similar manner...

  16. #3106
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    Quote Originally Posted by cjameshuff View Post
    Stabilo was a peroxide monopropellant toy built by people who didn't even understand the pendulum fallacy.
    Apparently so, which is very hard to comprehend. I know you can have a go at (unmanned, please) rocketry without understanding many finesses, but the basic physics of non-hinged thrust application are quite paramount for a rocket. It's one thing for Goddard to not realize the pendulum fallacy in 1926, but 80 years later...

    On their website, the motivation is as follows: "The tractor engine offers the possibility to place the manned capsule at the rear end of the vehicle, which offers extended abort capabilities."

    OK, but the very name "Stabilo" smells an awful lot like pendulum fallacy. Also Stabilo 1B suddenly no longer had a tractor but a pusher config. Hmmm.
    Last edited by Nicolas; 2020-Jun-15 at 07:08 AM.
    With sufficient thrust, water towers fly just fine.

  17. #3107
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    Quote Originally Posted by Nicolas View Post
    Apparently so, which is very hard to comprehend. I know you can have a go at (unmanned, please) rocketry without understanding many finesses, but the basic physics of non-hinged thrust application are quite paramount for a rocket. It's one thing for Goddard to not realize the pendulum fallacy in 1926, but 80 years later...

    On their website, the motivation is as follows: "The tractor engine offers the possibility to place the manned capsule at the rear end of the vehicle, which offers extended abort capabilities."

    OK, but the very name "Stabilo" smells an awful lot like pendulum fallacy. Also Stabilo 1B suddenly no longer had a tractor but a pusher config. Hmmm.
    They had white papers and kept their Wikipedia page up to date with their latest press releases (and quickly removed any reference to the pendulum fallacy). They even put their names on it, calling it the "Popescu-Diaconu stabilization method". They seem to have dropped it, but Stabilo was a follow-on from their Helen "demonstrator", the page for which still has some of their claims:

    Vertical rocket stabilization

    Helen used a stabilization method without aerodynamic surfaces or RCS, by towing the other rocket stages and the payload. The towing can be made by cables or by rigid articulated system.
    In order to have a vertically stabilized rocket, under gravitational field, this method uses the towed mass in the same direction with the thrust. The stabilization effect depends on several elements: the mass of the stabilized body, the mass of the towing body and the length between the stabilized body and the stabilizer body.
    This method can be applied in outer space on vertical ascent or descent trajectory under the influence of a gravitational field.
    It was used in flight for the first time, with success, during Mission 4B for the Google Lunar X Prize competition.

  18. #3108
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    Live: SN-07 test tank pressure test (liquid nitrogen) testing 304L stainless steel, new welds, new domes.

    https://youtu.be/6NMRn-2h8X8

  19. #3109
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    Quote Originally Posted by docmordrid View Post
    Live: SN-07 test tank pressure test (liquid nitrogen) testing 304L stainless steel, new welds, new domes.

    https://youtu.be/6NMRn-2h8X8
    Um, I guess I've slept during this thread. What happened to SN5-SN6?

  20. #3110
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    Quote Originally Posted by bknight View Post
    Um, I guess I've slept during this thread. What happened to SN5-SN6?
    Waiting their turn.

    Testing this tank to destruction. Fixes for known weak points are in others.

    https://twitter.com/elonmusk/status/1272624978811187200

    https://twitter.com/elonmusk/status/1272624859705565184
    Last edited by docmordrid; 2020-Jun-15 at 08:57 PM.

  21. #3111
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    Elon Musk ✔ @elonmusk
    Tank didn’t burst, but leaked at 7.6 bar. This is a good result & supports idea of 304L stainless being better than 301. We’re developing our own alloy to take this even further. Leak before burst is highly desirable

    https://twitter.com/elonmusk/status/1272651781630095360

  22. #3112
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  23. #3113
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    Quote Originally Posted by cjameshuff View Post
    They had white papers and kept their Wikipedia page up to date with their latest press releases (and quickly removed any reference to the pendulum fallacy). They even put their names on it, calling it the "Popescu-Diaconu stabilization method". They seem to have dropped it, but Stabilo was a follow-on from their Helen "demonstrator", the page for which still has some of their claims:
    It's difficult to understand what they mean with just words, especially when they use "rigid articulated". But assuming they mean a propulsive tractor which is pulling a separate object below it connected by cables or by articulated beams, you would actually get gravity stabilisation of the lower mass itself. It wouldn't stabilize the tractor part though so what's the point. You'd have created a still just as unstable rocket with a fancy bag underneath it.

    I may want to see this being simulated in Kerbal, it may end...spectacularly.
    Last edited by Nicolas; 2020-Jun-16 at 10:21 AM.
    With sufficient thrust, water towers fly just fine.

  24. #3114
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    Quote Originally Posted by Nicolas View Post
    It's difficult to understand what they mean with just words, especially when they use "rigid articulated". But assuming they mean a propulsive tractor which is pulling a separate object below it connected by cables or by articulated beams, you would actually get gravity stabilisation of the lower mass itself. It wouldn't stabilize the tractor part though so what's the point. You'd have created a still just as unstable rocket with a fancy bag underneath it.

    I may want to see this being simulated in Kerbal, it may end...spectacularly.
    It's pretty clear what they mean when they repeatedly describe it with phrases like "gravitational stabilization". The negligible effects of tidal forces aside, gravity affects all parts of the vehicle equally, with no resulting stabilization.

  25. #3115
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    SpaceX floating spaceports...

    Elon Musk ✔ @elonmusk
    SpaceX is building floating, superheavy-class spaceports for Mars, moon & hypersonic travel around Earth https://twitter.com/spacexfleet/stat...91684070871045
    ||
    Gavin - SpaceXFleet.com @SpaceXFleet
    SpaceX is hiring for Offshore Operations Engineers in Brownsville.

    From the post: "Work as part of a team of engineers and technicians to design and build an operational offshore rocket launch facility"

    With thanks to @CowboyDanPaasch for the scoop.https://boards.greenhouse.io/spacex/...jid=4764403002
    |
    Russ Parrish @russ_parrish
    Replying to @elonmusk
    Referb oil platforms with a hyperloop to transport from land?!
    |
    Elon Musk ✔ @elonmusk
    Pretty much

    https://twitter.com/elonmusk/status/1272972228326379520

    https://twitter.com/elonmusk/status/1272972990326558720

  26. #3116
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    Meanwhile, the Starship SN7 test tank (the first built from the kind of steel they want to use for the actual vehicles) reached a nice pressure before (intended) failure, and apparently could be even stronger with some small modifications. So that appears promising. The failure also was very contained, in contrast to the quick release event from last week. The failed weld didn't even rip open further than the initial point of failure.
    With sufficient thrust, water towers fly just fine.

  27. #3117
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    Video of that almost looked as if it was a safety valve popping. I assume the test fluid was LN2.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  28. #3118
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    It sure was cold and it didn't seem very kaboom-prone.

    BocaChicaGal's video of the next day appears to show the point of failure as somewhere in a weld, so no pre-designed failure point.
    With sufficient thrust, water towers fly just fine.

  29. #3119
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    Quote Originally Posted by Nicolas View Post
    It sure was cold and it didn't seem very kaboom-prone.

    BocaChicaGal's video of the next day appears to show the point of failure as somewhere in a weld, so no pre-designed failure point.
    The change to 304L should reduce carbide precipitation for better welds.

  30. #3120
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    And if I interpret Musk correctly, they could make it even better than this first attempt. I don't know which pressure they need/hope for, but the first test result seemed to make them happy already.
    With sufficient thrust, water towers fly just fine.

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