4 ms·

Are launches permitted when prevailing winds would send liftoff exhaust over populated areas ?

consumer451 3y ago
Up to this point, that's not been a factor considered by anyone in a position of authority. Starship uses Methane-Oxygen, which burns way cleaner than Kerosene-Oxygen, which is used by Falcon 9. The thing people should be concerned about are solid rocket boosters, which SpaceX does not use. Solid boosters have polluted every "untouched" alpine lake on the planet. Those have been used by the new Vulcan, Space Shuttle, and a lot of other rockets. Tim Dodd has an excellent video and write-up on this topic: https://everydayastronaut.com/rocket-pollution/ https://everydayastronaut.com/rocket-pollution/
- deleted 3y ago
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- senectus1 3y ago
  provided it burns yes. any accident that results in the releasing of that amount of methane unburnt would be horribly damaging. luckily, rockets rarely DONT go bang and burn when things go wrong.
  - badcppdev 3y ago
    Like a lot of cow burps right? Basically the equivalent of a herd of 7500 cows burping away for a year. Bad but I'm not sure that 750ton of methane is horribly damaging compared to a billion cows
    - senectus1 3y ago
      but its not compared is it.. its in ADDITION to.
p1mrx 3y ago
The exhaust from Starship is just CO₂ and water (CO₂ causes climate change, but that's not a local effect.) Vulcan is dirtier because of the solid rocket boosters.
- avmich 3y ago
  I'm not sure about Raptors specifically, but usually liquid rocket engines run rich (or, as Russians say, "sweet", rather than "sour", or lean), which means that there's excess of methane in the exhaust. Methane is a powerful (comparing to CO2) greenhouse effect agent, which fortunately doesn't have as long atmospheric life as CO2.
  - MPSimmons 3y ago
    This is a closed cycle, so I would expect it to be cleaner, but I don't know for sure.
  - p1mrx 3y ago
    Raptor (Starship) is closed cycle, and BE-4 (Vulcan) is oxygen rich, so neither should be dumping unburned methane during normal operation.
    - mr_toad 3y ago
      BE-4 has oxygen rich pre-burners, while Raptor is full-flow. However both engines use a fuel rich mix in the main combustion chamber. But the pollution from either is far less than from a solid fuel engine.
      - p1mrx 3y ago
        Interesting. Then I wonder how the GHG emissions of methalox/kerolox engines actually compare? Methalox emits less CO2, but unburned methane is 30X worse than CO2.
        mr_toad 3y ago

Up to this point, that's not been a factor considered by anyone in a position of authority. Starship uses Methane-Oxygen, which burns way cleaner than Kerosene-Oxygen, which is used by Falcon 9. The thing people should be concerned about are solid rocket boosters, which SpaceX does not use. Solid boosters have polluted every "untouched" alpine lake on the planet. Those have been used by the new Vulcan, Space Shuttle, and a lot of other rockets. Tim Dodd has an excellent video and write-up on this topic: https://everydayastronaut.com/rocket-pollution/ https://everydayastronaut.com/rocket-pollution/

deleted 3y ago
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senectus1 3y ago
provided it burns yes. any accident that results in the releasing of that amount of methane unburnt would be horribly damaging. luckily, rockets rarely DONT go bang and burn when things go wrong.
- badcppdev 3y ago
  Like a lot of cow burps right? Basically the equivalent of a herd of 7500 cows burping away for a year. Bad but I'm not sure that 750ton of methane is horribly damaging compared to a billion cows
  - senectus1 3y ago
    but its not compared is it.. its in ADDITION to.

p1mrx 3y ago

The exhaust from Starship is just CO₂ and water (CO₂ causes climate change, but that's not a local effect.) Vulcan is dirtier because of the solid rocket boosters.

avmich 3y ago
I'm not sure about Raptors specifically, but usually liquid rocket engines run rich (or, as Russians say, "sweet", rather than "sour", or lean), which means that there's excess of methane in the exhaust. Methane is a powerful (comparing to CO2) greenhouse effect agent, which fortunately doesn't have as long atmospheric life as CO2.
- MPSimmons 3y ago
  This is a closed cycle, so I would expect it to be cleaner, but I don't know for sure.
- p1mrx 3y ago
  Raptor (Starship) is closed cycle, and BE-4 (Vulcan) is oxygen rich, so neither should be dumping unburned methane during normal operation.
  - mr_toad 3y ago
    BE-4 has oxygen rich pre-burners, while Raptor is full-flow. However both engines use a fuel rich mix in the main combustion chamber. But the pollution from either is far less than from a solid fuel engine.
    - p1mrx 3y ago
      Interesting. Then I wonder how the GHG emissions of methalox/kerolox engines actually compare? Methalox emits less CO2, but unburned methane is 30X worse than CO2.
      - mr_toad 3y ago