The specific issue threatening Mars missions is how bone injury from deep-space radiation couples with bone loss from microgravity. They are different mechanisms and we simply don't know how they interact.
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We’ve done super long trips in LEO which have both microgravity & radiation. The radiation (which includes some trapped radiation, BTW) was half as intense but trips lasted well over twice as long as transit. We’ve got some idea now. It’s simply no longer a complete question mark
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You have this wrong; GCR radiation dose is four times as intense on a trip to Mars as it is over an equivalent period on ISS, and includes cosmic rays at lower energies that don't reach LEO.
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Right. And ISS includes a bunch of trapped radiation from the lower part of the Van Allen belts (the South Atlantic Anomaly) which isn’t present in deep space. To account for different effects on tissue, we adjust by the Quality Factor. That’s already included in the Sievert unit
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And the Mars transit exposure for this radiation in Sieverts, with all fudge factors applied, is over four times that of ISS
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No, you looked purely at GCR and not total dose.
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I'm talking about GCR because that is the radiation type we don't have good data on.
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Except we do. We have years of data on it. Low energy GCR is most similar to the trapped radiation ISS. So AGAIN, you have to use Sieverts which already adjusts for the different effects, not cherry-picking just GCR.
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We don't have the data on what deep-space GCR does to humans, because we have never gone there and there is not such an environment on Earth. GCR flux in deep space includes heavy nuclei whose cumulative effect on eyes, bone, etc. is conjectural. You can't handwave that away.
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I’m not handwaving it away; you’re falsely saying ISS is invalid. The data ISS has includes the highest energy heavy ion cosmic rays. As you yourself said: It’s only the low energy GCR (which is most like other radiation and has the least uncertainty) that is shielded away on ISS
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I'm not saying the ISS data is invalid, but incomplete. It doesn't include what gets deflected by the Earth's magnetosphere, and the overall flux on ISS (because Earth fills half the sky, and because of that magnetosphere) is much less than what you get roasted with in deep space
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You aren’t saying it’s invalid? Bro, this you?pic.twitter.com/QwsoOy6ycy
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