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I was close to down voting not for trump but for "more rockets for moon tourism". We are already messing up our planet with air travel. IMHO, make moon tourism

I was close to down voting not for trump but for "more rockets for moon tourism". We are already messing up our planet with air travel. IMHO, make moon tourism a thing, with the associated rise in rockets launched, and rockets go from "amazing tech that sciences" to "yet another thing super rich people use for enjoyment while fucking over literally the entire planet" From what I understand, the amount of stuff rockets carry into literally every layer of the atmosphere is already concerning. If someone can put my mind at ease with a paper not written by Big Rocket I'd be all the happier. ;)

hutzlibu 8y ago
"From what I understand, the amount of stuff rockets carry into literally every layer of the atmosphere is already concerning. If someone can put my mind at ease with a paper not written by Big Rocket I'd be all the happier. ;) " Not an expert, but I believe the Saturn moon rockets did run on hydrogen, so there should not have been much pollution. The falcon-9 though runs on RP-1, refined kerosine.
- skykooler 8y ago
  The Saturn V only used hydrogen for its third stage. The first two stages (i.e. the ones that operated while it was still in the atmosphere) ran on RP-1.
  - hutzlibu 8y ago
    Are there fundamental flaws with using hydrogen in the atmosphere? Too volatile to handle?
    - philipkglass 8y ago
      The Delta IV Heavy uses hydrogen fuel even for the first stage: https://en.wikipedia.org/wiki/Delta_IV_Heavy https://en.wikipedia.org/wiki/Delta_IV_Heavy Hydrogen offers excellent ISP but poor volumetric energy density, and it needs to stay much colder than oxygen to remain liquid. Fuel tanks for containing hydrogen tend to be more complicated and larger than those for other liquid rocket fuels. Upper stages see more relative benefit from the higher performance achievable with hydrogen fuel. The cost:benefit comparison has led to most rockets not using hydrogen for the first stage.
      - hutzlibu 8y ago
        Thanks dor the detailed explaination! But I assume "The cost:benefit comparison has led to most rockets not using hydrogen for the first stage." nobody factored in the long term climate cost with kerosine. But since most hydrogen is generated with fossils, it might not make a big difference right now.
    - skykooler 8y ago
      Hydrogen yields higher efficiency (specific impulse) with lower thrust. Larger-molecule fuels, such as kerosene, have higher thrust and lower efficiency. When in the atmosphere, the rocket engines are spending a lot of energy counteracting gravity, so higher thrust is important. Once in orbit, efficiency is far more important (indeed, some deep space engines such as ion engines produce only millinewtons of force, but are very efficient.)
TomMarius 8y ago
Consider that the moon hotel would enable Moon solar power plant

hutzlibu 8y ago

"From what I understand, the amount of stuff rockets carry into literally every layer of the atmosphere is already concerning. If someone can put my mind at ease with a paper not written by Big Rocket I'd be all the happier. ;) " Not an expert, but I believe the Saturn moon rockets did run on hydrogen, so there should not have been much pollution. The falcon-9 though runs on RP-1, refined kerosine.

skykooler 8y ago
The Saturn V only used hydrogen for its third stage. The first two stages (i.e. the ones that operated while it was still in the atmosphere) ran on RP-1.
- hutzlibu 8y ago
  Are there fundamental flaws with using hydrogen in the atmosphere? Too volatile to handle?
  - philipkglass 8y ago
    The Delta IV Heavy uses hydrogen fuel even for the first stage: https://en.wikipedia.org/wiki/Delta_IV_Heavy https://en.wikipedia.org/wiki/Delta_IV_Heavy Hydrogen offers excellent ISP but poor volumetric energy density, and it needs to stay much colder than oxygen to remain liquid. Fuel tanks for containing hydrogen tend to be more complicated and larger than those for other liquid rocket fuels. Upper stages see more relative benefit from the higher performance achievable with hydrogen fuel. The cost:benefit comparison has led to most rockets not using hydrogen for the first stage.
    - hutzlibu 8y ago
      Thanks dor the detailed explaination! But I assume "The cost:benefit comparison has led to most rockets not using hydrogen for the first stage." nobody factored in the long term climate cost with kerosine. But since most hydrogen is generated with fossils, it might not make a big difference right now.
  - skykooler 8y ago
    Hydrogen yields higher efficiency (specific impulse) with lower thrust. Larger-molecule fuels, such as kerosene, have higher thrust and lower efficiency. When in the atmosphere, the rocket engines are spending a lot of energy counteracting gravity, so higher thrust is important. Once in orbit, efficiency is far more important (indeed, some deep space engines such as ion engines produce only millinewtons of force, but are very efficient.)

TomMarius 8y ago

Consider that the moon hotel would enable Moon solar power plant