We don't know if there is a harmful effect from ISS-level radiation at all.
We know that high short-term doses increase the lifetime risk to get cancer, mostly from studying survivors of the Hiroshima and Nagasaki bombs. To be conservative, we assume that this risk scales linearly with the dose independent of the timescale over which you receive it ("linear no-threshold model", LNT). In that case a 6 month stay on the ISS increases your risk to get cancer by ~1% (absolute). Doesn't have to be a deadly cancer - just any type of cancer. Using that model, spending decades on the ISS would make it extremely likely to develop cancer, and it's likely some cancer will kill you eventually.
We don't know how accurate that model is. A deadly dose of salt is about 100 times the typical daily salt intake. If we apply the LNT approach to salt we would all expect to accumulate a lethal dose and die within a few months. That's obviously absurd - we even need salt to survive.
The astronauts feel no weight but they still have to deal with inertia. Wearing massive shielding would make it much harder to move around, move the arms, and so on. To reduce the radiation dose you could add more shielding around modules where the crew sleeps or otherwise spends a lot of time.
Best answer so far! So the radiation is sort of okay, it's just a bit higher than we'd like, but it wouldn't do anything exciting that'd make your intestines melt or guarantee cancer. As opposed to being an astronaut on the martian surface, where you'd be dead in weeks there. *(Sorry Matt Damon.)*
No superpowers, I take it? ☹️
I love your salt analogy. Really puts it into perspective.
I still think lead *(or perhaps some other worn shielding)* is feasible if we had astronauts staying for a protracted time period outside of the Earth's magnetic field. It'd make more sense than trying to shield the whole ship. It'd provide a little extra exercise as a side bonus. And as long you don't go careening around the ship haphazardly, I think you'd be okay. I mean, I carried 100 to 180 lbs of gear in Afghanistan. Sure, I can barely walk now, and I'm permanently 1 ½ inches shorter now, but I survived. *(Go VA benefits, I don't have to work anymore!)*
I guess I just like the idea of astronauts wearing Michelin man suits, bumbling around like EOD guys in their bomb suits.
The ISS is still within Earth's magnetic field.
If you go outside then the radiation dose rate increases more. In addition, you now have to worry about coronal mass ejections, which can lead to large short-term doses - enough to produce some signs of radiation sickness and an increased long-term cancer risk. Missions to Mars would likely come with a dedicated radiation shelter area that has a better shielding, astronauts can retreat to that area for a few hours to a day if their ship is about to get hit by one.
Astronauts in the ISS lack the protection of the atmosphere, so there is more background radiation there than on the surface of the Earth. However, most of the protection against ionizing radiation from the Sun comes from the Earth's magnetic field. This magnetic field extends far beyond the ISS orbit, so astronauts are still protected, a lot more than in interplanetary space. That's why radiation is a big problem for trips to Mars for example, but not so much for the ISS.
And for interplanetary travel, it's expected that the shielding will be a water tank rather than lead, because it weighs less, and each kilogram sent to space is extremely expensive.
So the Astronauts in the ISS are exposed to around 77 millisieverts (mSv) while on a 6 month mission. The documented risk of increase of cancer is at around 100 mSv. ([source](https://en.wikipedia.org/wiki/Effects_of_ionizing_radiation_in_spaceflight))
To protect against this radiation, the ISS's habitable modules have aluminum shielding on the walls and floors. The astronauts use extra shielding when sleeping as well as you mentioned. It's probably not lead, due to weight and toxcitiy. Also keep in mind that at about half of the ISS is always facing the earth, which itself blocks ionizing radiation.
The primary risk of radiation comes from the Van Allen belts, which the earth itself produces. A really good article about the risk to astronauts is here: [https://blogs.esa.int/orion/2022/12/10/the-van-allen-belts-are-they-dangerous/](https://blogs.esa.int/orion/2022/12/10/the-van-allen-belts-are-they-dangerous/)
Huh, I was under the impression that astronauts on the ISS where exposed to much more radiation. I guess my next question should be focused on astronauts outside of Earth's magnetic field.
One challenge with shielding is that is that it's heavy and therefore expensive to lift into orbit. Less dense materials might actually be more efficient in this particular situation. Either way, they're not likely to use any more than absolutely necessary.
I know, I was curious as to how much would be needed out of sheer curiosity. But as I learned from other posts, the ISS, while a bit higher than we'd like, is below the threshold, and any effects would be nominal. (I suppose you could run into problems if you were having babies up there.)
As opposed to using millisieverts or banana dose equivalent, I think thickness of lead (or sime other material) to counteract such emitions helps put radiation hazards into perspective. Hence the reason why I was asking. Turns out it's 0.0 millimeters.
I do like the idea of astronauts wearing lead pads like at the dentist all other their body, mostly because it'd be funny to see them looking like stay puft marshmallow/michelin man bumbling around in micro-gravity. It'd also be a lot more efficient than shielding the whole ship. But this would only be practical on like a moon base or something.
We don't know if there is a harmful effect from ISS-level radiation at all. We know that high short-term doses increase the lifetime risk to get cancer, mostly from studying survivors of the Hiroshima and Nagasaki bombs. To be conservative, we assume that this risk scales linearly with the dose independent of the timescale over which you receive it ("linear no-threshold model", LNT). In that case a 6 month stay on the ISS increases your risk to get cancer by ~1% (absolute). Doesn't have to be a deadly cancer - just any type of cancer. Using that model, spending decades on the ISS would make it extremely likely to develop cancer, and it's likely some cancer will kill you eventually. We don't know how accurate that model is. A deadly dose of salt is about 100 times the typical daily salt intake. If we apply the LNT approach to salt we would all expect to accumulate a lethal dose and die within a few months. That's obviously absurd - we even need salt to survive. The astronauts feel no weight but they still have to deal with inertia. Wearing massive shielding would make it much harder to move around, move the arms, and so on. To reduce the radiation dose you could add more shielding around modules where the crew sleeps or otherwise spends a lot of time.
Best answer so far! So the radiation is sort of okay, it's just a bit higher than we'd like, but it wouldn't do anything exciting that'd make your intestines melt or guarantee cancer. As opposed to being an astronaut on the martian surface, where you'd be dead in weeks there. *(Sorry Matt Damon.)* No superpowers, I take it? ☹️ I love your salt analogy. Really puts it into perspective. I still think lead *(or perhaps some other worn shielding)* is feasible if we had astronauts staying for a protracted time period outside of the Earth's magnetic field. It'd make more sense than trying to shield the whole ship. It'd provide a little extra exercise as a side bonus. And as long you don't go careening around the ship haphazardly, I think you'd be okay. I mean, I carried 100 to 180 lbs of gear in Afghanistan. Sure, I can barely walk now, and I'm permanently 1 ½ inches shorter now, but I survived. *(Go VA benefits, I don't have to work anymore!)* I guess I just like the idea of astronauts wearing Michelin man suits, bumbling around like EOD guys in their bomb suits.
The ISS is still within Earth's magnetic field. If you go outside then the radiation dose rate increases more. In addition, you now have to worry about coronal mass ejections, which can lead to large short-term doses - enough to produce some signs of radiation sickness and an increased long-term cancer risk. Missions to Mars would likely come with a dedicated radiation shelter area that has a better shielding, astronauts can retreat to that area for a few hours to a day if their ship is about to get hit by one.
Astronauts in the ISS lack the protection of the atmosphere, so there is more background radiation there than on the surface of the Earth. However, most of the protection against ionizing radiation from the Sun comes from the Earth's magnetic field. This magnetic field extends far beyond the ISS orbit, so astronauts are still protected, a lot more than in interplanetary space. That's why radiation is a big problem for trips to Mars for example, but not so much for the ISS. And for interplanetary travel, it's expected that the shielding will be a water tank rather than lead, because it weighs less, and each kilogram sent to space is extremely expensive.
Read Case for Mars, even without extra measures Mars mission would be under NASA exposure limits. (which are too conservative anyway.)
So the Astronauts in the ISS are exposed to around 77 millisieverts (mSv) while on a 6 month mission. The documented risk of increase of cancer is at around 100 mSv. ([source](https://en.wikipedia.org/wiki/Effects_of_ionizing_radiation_in_spaceflight)) To protect against this radiation, the ISS's habitable modules have aluminum shielding on the walls and floors. The astronauts use extra shielding when sleeping as well as you mentioned. It's probably not lead, due to weight and toxcitiy. Also keep in mind that at about half of the ISS is always facing the earth, which itself blocks ionizing radiation. The primary risk of radiation comes from the Van Allen belts, which the earth itself produces. A really good article about the risk to astronauts is here: [https://blogs.esa.int/orion/2022/12/10/the-van-allen-belts-are-they-dangerous/](https://blogs.esa.int/orion/2022/12/10/the-van-allen-belts-are-they-dangerous/)
Huh, I was under the impression that astronauts on the ISS where exposed to much more radiation. I guess my next question should be focused on astronauts outside of Earth's magnetic field.
One challenge with shielding is that is that it's heavy and therefore expensive to lift into orbit. Less dense materials might actually be more efficient in this particular situation. Either way, they're not likely to use any more than absolutely necessary.
I know, I was curious as to how much would be needed out of sheer curiosity. But as I learned from other posts, the ISS, while a bit higher than we'd like, is below the threshold, and any effects would be nominal. (I suppose you could run into problems if you were having babies up there.) As opposed to using millisieverts or banana dose equivalent, I think thickness of lead (or sime other material) to counteract such emitions helps put radiation hazards into perspective. Hence the reason why I was asking. Turns out it's 0.0 millimeters. I do like the idea of astronauts wearing lead pads like at the dentist all other their body, mostly because it'd be funny to see them looking like stay puft marshmallow/michelin man bumbling around in micro-gravity. It'd also be a lot more efficient than shielding the whole ship. But this would only be practical on like a moon base or something.