Comment on How can we get to Mars faster

• knightly@pawb.social ⁨3⁩ ⁨weeks⁩ ago

  Irradiated water is fine.

  You’re thinking of radioactive water, which is water with radioactive stuff in it.

  Subjecting regular water to regular amounts of radiation is fine, even if it’s high-energy gamma rays. If there’s enough radiation to make water itself radioactive then you have bigger problems than radioactive water.

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  • unlawfulbooger@lemmy.blahaj.zone ⁨3⁩ ⁨weeks⁩ ago

    Ah yes, that’s the difference. Thanks!

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• skillissuer@discuss.tchncs.de ⁨3⁩ ⁨weeks⁩ ago

  “remove” what exactly? water is not alive so it’s okay to irradiate it en.wikipedia.org/wiki/Food_irradiation

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  • just_another_person@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    Dude…wut.

    Can’t tell if you’re joking or not.

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    • skillissuer@discuss.tchncs.de ⁨3⁩ ⁨weeks⁩ ago

      i don’t get what you fail to understand, water doesn’t became radioactive or harmful in any other way after irradiation, and irradiation of food is routinely used for extending its shelf life

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      • just_another_person@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

        The basis for what you’re saying is that water is some kind of magic shield the reflects radiation, which is not a thing.

        At best, if you’re talking about lining the hull of a spacecraft and expecting that to work, that’s not a thing either because of the water is taking on any extra mass of any kind, it would obviously expand. Water in its purest form would have to take on mass to “absorb” radiation, expanding a hull and destroying it over time. If you left room in there for expansion, you’d die on exit or reentry of atmosphere without freezing it.

        The only way you can reflect radiation without absorbing something is by denying it entry. Water doesn’t do that.

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• SkybreakerEngineer@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

  You wouldn’t want to drink reactor coolant water (mostly because of the chemistry additives) but water in a tank that just stays between the people and the hot stuff would mostly just get warm.

  Most of what you’d get at that kind of distance is neutrons, and they are more likely to bounce off the hydrogen than to do something like activate the oxygen into N16 which dies off pretty fast anyway.

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• CrimeDad@lemmy.crimedad.work ⁨3⁩ ⁨weeks⁩ ago

  I don’t think it works that way. The water slows down the neutrons so that when and if they get to you they don’t have enough energy to hurt you. The radiation doesn’t contaminate the water anymore than a microwave oven does.

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• verity_kindle@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

  They used the ice for everything, including cooling and heating the ship as needed. They got the bad effects from the cosmic radiation pinging in from all other directions, not from using the water. The volume of ice was larger than that of the ship, I think it also absorbed physical damage from micrometeorites. Let’s hope someone in the Big Green Machine reads the novel.

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  • verity_kindle@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

    I mean, they put nuclear waste at the bottom of miles deep water wells, because it absorbs alpha, gamma and beta particles and it’s cheap.

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• Bezier@suppo.fi ⁨3⁩ ⁨weeks⁩ ago

  It doesn’t make it radioactive or something, if that was your thought.

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