Venus is often refered to as Earth-twin, simply because of its similar size. In the very hypothetical case of a human mission to Venus, and leaving the all other challenges of Venus toxic atmosphere aside, I am wondering how big the problem of natural radioactivity is on Venus (on cloud top level).

For Mars, I found a reference from MarsOne

Mars's surface receives more radiation than the Earth's but still blocks a considerable amount. Radiation exposure on the surface is 30 µSv per hour during solar minimum; during solar maximum, dosage equivalent of this exposure is reduced by the factor two.

I know that both Mars and Venus do not have a significant magnetic field which would shield away solar winds. Do I assume correctly that the radiation exposure of the solar wind is the main contribution to the "background" radioactivity on Venus?


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    $\begingroup$ I found astrobiology.com/2019/12/… which is talking about Atmospheric Radiation Interaction Simulator (AtRIS) as computer model, but I would be very happy about an order of magnitude in Sv/Earth hour or something like that. $\endgroup$
    – B--rian
    Dec 8, 2020 at 15:18
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    $\begingroup$ I don't have any solid answers, but I doubt solar particle radiation would penetrate that deeply into the atmosphere...what gets through will mostly be galactic cosmic radiation. C-14 production from atmospheric nitrogen by cosmic radiation might be relevant to your question, but I haven't found any information on C-14 in the atmosphere of Venus. $\endgroup$ Dec 8, 2020 at 15:25
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    $\begingroup$ If you want to sit on the surface, radiation is no problem. If you want to float in the temperate region around 1-bar level, that could be more interesting. $\endgroup$ Dec 8, 2020 at 16:50
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    $\begingroup$ @AtmosphericPrisonEscape Unrelated, but I feel urged to mention: I love your nickname. And yes, I would be interested e.g. in the 1-bar level. I just realized that "above clouds on Venus" requires more thoughts where that actually is (in terms of distance from the surface or at which pressure level). $\endgroup$
    – B--rian
    Dec 8, 2020 at 16:54
  • $\begingroup$ According to this NASA Venus fact sheet: "Scale height: 15.9 km" That's of course not going to be true everywhere, but it does remind us that composition and temperature will affect it even though size and gravity of Venus are similar to Earth. If it's really twice Earth's surface scale height above the clouds on Venus, then you've got nearly 3x more mass above you than you would on Earth at a similar pressure. Interesting, let's see where this goes! $\endgroup$
    – uhoh
    Dec 9, 2020 at 4:23


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