@nikaaa - eviltoast
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Joined 5 months ago
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Cake day: April 15th, 2024

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  • So, the major issue with settling moon is resource availability: water (!), carbon, fertile soil, and energy.

    On the moon you have none of that. Maybe, with a lot of luck, you find water somewhere. Then you need carbon, energy during the long moon nights, and soil that isn’t razor sharp particles.

    On Mars, you have all of them: low concentrations of water in the atmosphere, carbon from carbon dioxide in the atmosphere, soil that isn’t razor sharp (thanks to erosion), and the nights are short enough that you can make it through them.


  • Yeah I’ve been thinking about condensing the water out of the air, too. Problem is: how do you do that? If you use chemical dessication agents, then it’s effectively the same as if you let the soil absorb the water from the atmosphere. Just that the soil is already there and you don’t need to artificially manufacture dessicants. So it’s a bit simpler.



  • thanks, the link is interesting.

    The value proposition would be that it is important to understand the exact radiation pattern/schemes if we ever want to routinize spaceflight. In other words: effective solutions (to the problem of radiation) requires detailed knowledge of what the problem actually is, in other words, what kind of radiation are we talking about.












  • Oh yes, of course:

    I guess the formula to calculate the momentum p of light is p = E/c where c is the speed of light and E is the energy.

    So, if the Energy is 10 MW, or alternatively, 10 MJ/sec, then E = 1e7 J. c = 3e8 m/s. p = E/c = 1e7/3e8 J/(m/s) = 1e7•1e-17/3e8 kg•(m/s)²/(m/s) = 3e-2 kg•(m/s).

    (Since E = m•c², 1 kg • c² = 1 kg • (3e8 m/s)² = 1e17 kg•(m/s)².)

    Now, if we assume that that momentum gets transferred to the sail, which weighs approximately 20 kg, then we get the velocity of the sail: v = p/20 kg = 3e-2 kg•(m/s)/20 kg ≈ 1e-4 m/s. And this transfer of momentum happens every second, so the acceleration is roughly 1e-4 m/s², or 0.001 m/s².