There are two kinds of radiation here, the solar storms from the sun and the cosmic radiation. The ISS is reasonably well protected from the slower moving particles of the solar storms by the Earth's magnetic field. It's not much protected from cosmic radiation, which is much faster moving and hardly affected by the Earth's magnetic field. But that's more of a steady flux.
There was an intense solar storm in between Apollo 16 and 17. Luckily no astronauts on the way to the Moon or on it at the time. If they had been, beyond the protection of the Earth's magnetic field - well inside the Apollo module they'd have had some shielding, absorbed 35 REM. But if they were caught out of doors in a solar storm in just a spacesuit - they would have got a potentially lethal dose of 400 REM - though their lives could have been saved by medical treatment back on Earth, e.g. bone marrow transplants. NASA - Sickening Solar Flares. If there had been any astronauts on the Moon then they would not have been able to go walking on the lunar surface that day. And would have had to get back into the module as fast as possible if caught out of doors.
That's why you need a solar storm shelter for long term interplanetary flight. It might also be possible to shield against solar storms using magnetic fields in the future.
As for cosmic radiation - it's going to increase your risk of getting cancer by a few percent, and that's true for long term stays on the ISS as well, though you get more cosmic radiation in interplanetary flight. It's also cancer that you could get early in your life, not late in life like smoking.
Cosmic radiation is difficult to shield against. To get down to Earth levels of cosmic radiation you need about 4.5 tons of shielding per square meter of your spaceship. Water and rock are both good at shielding against it.
That's why habitats on the Moon are likely to be underground possibly in underground caves, or covered in thick layers of regolith. And if we have long term space settlements then - the Stanford Torus etc also would be shielded by thick layers in order to shield against cosmic radiation. Luckily there is plenty of rock and regolith around to use for shielding.
For shorter term voyages of a year or two through interplanetary space, you'd shield as much as you can with design of the spacecraft, (water, stores, or rocket fuel arranged to shield the astronauts), and the astronauts just have to accept a somewhat increased risk of cancer, compared to living on Earth for the same period of time, but you keep that as low as you can.
If we ever send humans to Jupiter, then that's a very challenging environment for radiation, in vicinity of Europa then it would be deadly for humans within a day, unprotected.
There was an intense solar storm in between Apollo 16 and 17. Luckily no astronauts on the way to the Moon or on it at the time. If they had been, beyond the protection of the Earth's magnetic field - well inside the Apollo module they'd have had some shielding, absorbed 35 REM. But if they were caught out of doors in a solar storm in just a spacesuit - they would have got a potentially lethal dose of 400 REM - though their lives could have been saved by medical treatment back on Earth, e.g. bone marrow transplants. NASA - Sickening Solar Flares. If there had been any astronauts on the Moon then they would not have been able to go walking on the lunar surface that day. And would have had to get back into the module as fast as possible if caught out of doors.
That's why you need a solar storm shelter for long term interplanetary flight. It might also be possible to shield against solar storms using magnetic fields in the future.
As for cosmic radiation - it's going to increase your risk of getting cancer by a few percent, and that's true for long term stays on the ISS as well, though you get more cosmic radiation in interplanetary flight. It's also cancer that you could get early in your life, not late in life like smoking.
Cosmic radiation is difficult to shield against. To get down to Earth levels of cosmic radiation you need about 4.5 tons of shielding per square meter of your spaceship. Water and rock are both good at shielding against it.
That's why habitats on the Moon are likely to be underground possibly in underground caves, or covered in thick layers of regolith. And if we have long term space settlements then - the Stanford Torus etc also would be shielded by thick layers in order to shield against cosmic radiation. Luckily there is plenty of rock and regolith around to use for shielding.
For shorter term voyages of a year or two through interplanetary space, you'd shield as much as you can with design of the spacecraft, (water, stores, or rocket fuel arranged to shield the astronauts), and the astronauts just have to accept a somewhat increased risk of cancer, compared to living on Earth for the same period of time, but you keep that as low as you can.
If we ever send humans to Jupiter, then that's a very challenging environment for radiation, in vicinity of Europa then it would be deadly for humans within a day, unprotected.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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