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Falcon Heavy - 7&8 Reuse - Elon's Roadster Demo - LC-39A

Discussion in 'SpaceX' started by Grendal, Nov 2, 2017.

  1. ecarfan

    ecarfan Well-Known Member

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    I love that. He reiterated that message in his SXSW interview, and he’s said the same thing before; humanity can simultaneously address the terrible problems that must be solved AND undertake the inspiring challenge of making human life interplanetary. And I agree. One is not exclusive of the other.
     
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  2. scaesare

    scaesare Well-Known Member

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    Ah that makes sense too.
     
  3. mongo

    mongo Well-Known Member

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    Interesting fault mode, do you think the turbo pump lit off, or it is just an open fuel valve + deceleration?
     
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  4. Grendal

    Grendal SpaceX Moderator

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    The turbopump would not be working properly if it hadn't been lit in the right way, i think.
     
  5. mongo

    mongo Well-Known Member

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    That's what I'm wondering. Seems like start would be TEA/TEB injection into turbo combustion chamber and main combustion chamber, fuel on, oxygen on, turbo light off, engine light off (with fuel/ox and TEA possibly swapped (yeah too lazy to Google right now)).
    So it seems like the turbo could light without the engine lighting and then pump tons o burny stuff out the bell.
    Or that could have been flow from the turbo.
    Or I should bark at a different tree. ;)
    Cool stuff regardless.
     
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  6. Grendal

    Grendal SpaceX Moderator

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    That's what I pictured too. The fuel is pumped through the turbopump and lit in the combustion chamber which then pulls the fuel and lox efficiently. In this case the mixture lights after the combustion chamber from the properly burning center engine which fouls the process.

    It's probably one of the negatives of such an amazing precision engine that it would have no opportunity to correct itself.

    I wonder if, under a similar circumstance at launch, a misfiring engine could correct itself.
     
  7. mongo

    mongo Well-Known Member

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    Are you refering to main combustion chamber both times? Or the pump's and then the main?

    If you mean external ignition, I don't think so. Partly due to the ability of the flame to back propagate through the nozzle, and partly due to such an ignition being (potentially) really destructive (explode vs burn in a hard start condition).
     
  8. scaesare

    scaesare Well-Known Member

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    #628 scaesare, Mar 13, 2018
    Last edited: Mar 13, 2018
    As I understand it:

    The tanks are pressurized, providing some flow of fuel/oxidizer in to the gas-generator combustion chamber. This is then ignited, producing the hot gas flow necessary to drive the turbopumps. The outlet side of this hot gas is dumped overboard after it passes though the turbopump impeller. These are the "exhaust" outlets which can be seen in-between the engine nozzles.

    The turbo-pumps pump the vast majority of the fuel/ox in to the main combustion chambers (at much higher pressures). This is ignited for main thrust.

    If the above is correct, then I assume that both the gas-generator combustion chamber as well as the mains must be ignited via TEB injection. If the former fails, the latter will obviously as well. It also implies that the turbo pumps aren't operating, so no fuel is getting to the main combustion chamber to dribble out and ignite.

    So I wonder if the mode we are seeing is the tank pressurization pushing fuel in to the gas-generator combustion chamber where it fails to ignite. It then flows out the exhausts where its pushed all around as the rocket is rapidly descending through the atmosphere. That spray is ultimately ignited by the one operating engine and ends up on the booster surface.

    Given the alternative is a RUD, the system may hold the fuel/ox valves open for some time hoping to eventually get an engine start...
     
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  9. Brando

    Brando Active Member

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  10. e-FTW

    e-FTW New electron smell

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    Interesting opinion piece on the topic of sending Elon's Roadster on this trip, and the potential for contamination of another world by things picked up by Elon driving the car aroud California. Written by two Purdue professors, with the subtitle: A backup copy of Earth life?
    Tesla’s space-cruising Roadster is carrying a huge load of Earth’s germs

    “But other, more interesting, fates are possible because its orbit is sensitive to tiny, unknown forces. It stands a fair chance (an estimated 15%) of eventually burning up in the sun. It has a similar chance of swinging wide after a close pass by the Earth and heading out to Jupiter. Once there, Jupiter’s huge mass may fling it entirely out of the solar system. This could take tens of millions of years, but there is about a 1 in 5 chance the red Tesla and its sleeping micro-nauts will someday fly forth toward neighboring stars in our galaxy, taking a sample of Earth life out to the stars.

    Fantastic as this might seem, Francis Crick, famed co-discoverer of the double helix, has speculated that life on Earth began this way: by either the directed or perhaps inadvertent contamination of our early, pristine planet from another technological civilization.

    Our young technological civilization here on Earth is just beginning to leap beyond our birthplace and venture into the wider universe. We don’t yet know whether other civilizations are out there or how they might react to careless contamination of the stars around us, but our actions may have unintended consequences.

    H. Jay Melosh is a University Distinguished Professor of Earth, Atmospheric and Planetary Sciences at Purdue University. Alina Alexeenko is a professor of aeronautics and astronautics at Purdue.”

    Maybe Elon will save us all, Mars or not. :)
     
  11. Uncle Paul

    Uncle Paul Well-Known Member

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    Believe that article about Roadster carrying contaminations was mostly click bate. Author is not expert on that subject but just conjectured something interesting to entice eyeballs.

    Imagine that everything on a space craft, including cargo will be cleaned and sterilized prior to launch.

    By far the greatest danger of contaminating outer space comes from launching human beings and animals into space, along with their organic science experiments. Governments and military are doing lots of weird things in outer space that they do not publish.
     
  12. Electroman

    Electroman Supporting Member

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    This article hit the internet two days after FH was launched and died a quick death in a few days.

    Now in the spirit of keeping some negative news alive on EM this has been resurrected and being recycled as new information.

    Seeking Alpha trolls were gasping for anything negative on the extremely successful FH launch, and when this FUD hit the internet, they went overdrive accusing EM of have no respect to accepted policies and procedures, and this is an example of how he short cuts safety procedures, yada yada... This was around the same time exaggerated reports were circulated on M3 going to production skipping established test procedures.
     
  13. e-FTW

    e-FTW New electron smell

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    Hmm. Had not seen this piece before. As I don't have a bias against Elon, Tesla or SpaceX, I found it an interesting thought experiment.
    ¯\_(ツ)_/¯
     
  14. EldestOyster

    EldestOyster Member

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    The vacuum of space kills most living organisms.

    Except tardigrades :)
     
  15. HankLloydRight

    HankLloydRight No Roads

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    Elon is quoted in one of the videos or Q+As saying they really didn't do much of anything to prepare the Roadster for it's journey other than drain the fluids and bolt things down. I don't even think they removed the battery, since it was a dummy payload they needed for weight. I'm sure it wasn't sterilized.
     
  16. scaesare

    scaesare Well-Known Member

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    1) I gotta imagine solar radiation, the vaccum of space, and the temperature swings, is going to do a number on most biological contaminates.

    B) How about the rockets and probes we've already sent to other planets and out of the solar system? Do we really think that , despite whatever sterilization that was done, no microscopic items managed to make it aboard the craft sent by several countries to the outer regions of the solar system and beyond?

    III) What's gonna happen when we set up the first campsite on Mars and empty the latrine?
     
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  17. Doug_G

    Doug_G Lead Moderator

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    Yes they removed the battery.

    And the article is nonsense. Spacecraft are not sterilized unless they are expected to land on potentially life-bearing worlds like Mars.
     
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  18. Cosmacelf

    Cosmacelf Well-Known Member

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    And regardless, the whole point of SpaceX is to colonize other worlds!
     
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  19. Nikxice

    Nikxice Active Member

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    Yes. Also possible that life was brought to earth (accidentally or intentionally) from elsewhere in the universe. Not a bad thing at all.
     
  20. N5329K

    N5329K Active Member

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    And even then they acknowledge that total sterilization just isn't possible. They "sterilize" to a set point established by COSPAR : https://cosparhq.cnes.fr/content/cospar-strategy-statement, but no further, because to do so would risk damaging the spacecraft and rendering the mission moot.

    Robin
     
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