Notice the continuous mention of bones.

  • CrimeDad@lemmy.crimedad.work
    link
    fedilink
    English
    arrow-up
    8
    arrow-down
    1
    ·
    1 month ago

    Since the astronauts need water to survive, why not line the spaceship with reservoirs of it to provide the shielding? Or does water not block space radiation well enough?

    • verity_kindle@sh.itjust.works
      link
      fedilink
      English
      arrow-up
      8
      ·
      1 month ago

      They did that in the novel “Seveneves”, used a massive chunk of ice as the bow of their ship on a one-way, twenty year plus trip. It didn’t stop all the radiation, though. Just enough to keep a minimum number of crew alive to complete their mission. They all developed different types of cancers, anyways,but the kinds that could be treated along the way and extend their chances.

    • unlawfulbooger@lemmy.blahaj.zone
      link
      fedilink
      English
      arrow-up
      7
      arrow-down
      2
      ·
      1 month ago

      But then they’re drinking irradiated water, no?

      Unless it’s really easy to remove the radiation safely, this doesn’t seem like the right solution.

      • knightly the Sneptaur@pawb.social
        link
        fedilink
        English
        arrow-up
        6
        ·
        1 month 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.

      • SkybreakerEngineer@lemmy.world
        link
        fedilink
        English
        arrow-up
        6
        ·
        1 month 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.

          • skillissuer@discuss.tchncs.de
            link
            fedilink
            English
            arrow-up
            6
            arrow-down
            1
            ·
            1 month 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

            • just_another_person@lemmy.world
              link
              fedilink
              English
              arrow-up
              1
              arrow-down
              9
              ·
              edit-2
              1 month ago

              The basis for what you’re saying is that water is some kind of magic shield that 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 if 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.

              • skillissuer@discuss.tchncs.de
                link
                fedilink
                English
                arrow-up
                7
                arrow-down
                1
                ·
                edit-2
                1 month ago

                water does not expand upon irradiation, what the fuck are you talking about. you can’t reflect high energy protons (what would be important in radiation in interplanetary travel) you can only either absorb them or let them pass, there’s no third option, same for anything above uv and electrons

                to a first approximation (rather good one at that) (for gammas) absorption is proportional to how much mass per area unit is used as a barrier. 1 g/cm^2 of water is just as good barrier as 1 g/cm^2 of lead or steel. this means that you can absolutely use completely normal, regular potable water as a radiation shield

                Water in its purest form would have to take on mass to “absorb” radiation, expanding a hull and destroying it over time.

                i’m not even sure what it’s supposed to mean, unless your understanding of ionizing radiation is uncut nonsense

                chemically speaking, it’s completely fine to irradiate water because whatever is formed as a result of radiolysis would just most of the time form water back, with the rest becoming very weak solution of hydrogen peroxide. this is big part of the reason why water is used as a coolant in nuclear reactors

                there are also specific nuances to stopping anything that is not gammas, like secondary x-rays, gammas from neutron absorption etc and this actually favours light element shields, like water or liquid hydrogen, for this kind of radiation shielding

                • just_another_person@lemmy.world
                  link
                  fedilink
                  English
                  arrow-up
                  1
                  arrow-down
                  4
                  ·
                  edit-2
                  1 month ago

                  Okay, so where do the neutrons go in your head? Gotta go somewhere.

                  Re: your point about water in its purest form. It means zero contamination. We aren’t even capable of doing that, and the purest we can make would kill humans pretty quickly for the similar amount we ingest.

                  • skillissuer@discuss.tchncs.de
                    link
                    fedilink
                    English
                    arrow-up
                    4
                    arrow-down
                    1
                    ·
                    1 month ago

                    what neutrons? we’re talking about shielding of spacecraft moving out of earth’s magnetosphere, not a spacecraft travelling through core of active nuclear reactor

                    the kind of radiation that is relevant are high energy protons (and alphas and electrons, with a sprinkle of heavier nuclei) from sun, mostly. there’s no relevant source of neutrons

                    (and incidentally water is pretty good at absorbing neutrons too)

      • CrimeDad@lemmy.crimedad.work
        link
        fedilink
        English
        arrow-up
        4
        ·
        edit-2
        1 month 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 any more than a microwave oven does.

      • verity_kindle@sh.itjust.works
        link
        fedilink
        English
        arrow-up
        2
        ·
        1 month 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.

        • verity_kindle@sh.itjust.works
          link
          fedilink
          English
          arrow-up
          1
          ·
          1 month 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.

    • Grimy@lemmy.world
      link
      fedilink
      English
      arrow-up
      3
      ·
      1 month ago

      You would need a pretty good thickness of water and it becomes complicated shipping it up into space.

      • CrimeDad@lemmy.crimedad.work
        link
        fedilink
        English
        arrow-up
        4
        ·
        1 month ago

        Well, the water is necessary for for life support and needs to be sourced somehow anyway. It kind of sets a minimum crew and passenger capacity if you want to make the most use of your shielding water.

    • just_another_person@lemmy.world
      link
      fedilink
      English
      arrow-up
      1
      arrow-down
      2
      ·
      1 month ago

      Liquid and rockets is a death sentence.

      Liquid and space vessels is worse.

      Liquids on reentry is never going to happen.

      • CrimeDad@lemmy.crimedad.work
        link
        fedilink
        English
        arrow-up
        4
        ·
        1 month ago

        Water doesn’t have to be a liquid, but don’t actual spacecraft typically contain liquids during wall of those cases? What do you mean?

        • just_another_person@lemmy.world
          link
          fedilink
          English
          arrow-up
          1
          arrow-down
          4
          ·
          edit-2
          1 month ago

          You can freeze it before launch, but you’d have to freeze it again before reentry. Not possible, especially if you’re talking about lining a craft with it during months of space travel. Water expands when frozen, and contracts when liquid. Metal does the opposite. How would you engineer that?

            • just_another_person@lemmy.world
              link
              fedilink
              English
              arrow-up
              1
              arrow-down
              3
              ·
              edit-2
              1 month ago

              Didn’t think I needed to stoop to that level. Thought I was talking to about obvious things and didn’t want to sound patronizing.

              Thanks for clearing that up.

          • verity_kindle@sh.itjust.works
            link
            fedilink
            English
            arrow-up
            2
            arrow-down
            1
            ·
            1 month ago

            Build the hypothetical ship in space and you never have to deal with it except as ice, which is easier to move around and shape into what you need. The ISS has a lot of liquids on board in all sorts of forms, from chicken soup, to ink pens, to the urine inside astronaut bladders. I don’t understand what you’re trying to say.