Anticipating the Dangers of Space Radiation (utexas.edu)

aarondubrow writes: Astronauts and future space tourists face risks from radiation, which can cause illness and injure organs. Researchers from Texas A&M, NASA, and the University of Texas Medical Branch used supercomputers at the Texas Advanced Computing Center to investigate the radiation exposure related to the Manned Orbiting Laboratory mission, planned for the 1960s and 1970s [but never actually flown], during which a dangerous solar storm occurred. They also explored the historical limitations of radiation research and how such limitations could be addressed in future endeavors.
Supercomputers could be "a game-changer" when it comes to predicting the risks of space radiation, allowing NASA to make life-saving decisions in real-time, argues one of the researchers. During that 1972 solar storm, skin and organs would've risked being exposed to radiation in excess of NASA limits, though one of the study's co-authors believes that rather than risking harm to the astronauts, NASA would've promptly terminated that mission.

"Though the study explored the historical missions, the researchers had in mind future commercial space flights, like those proposed by SpaceX or Virgin Galactic, that will likely travel a similar orbit to best show off the beauty of Earth from space."

Comments

Tinpot space-station designs...

[Anonymous Coward]

Do away with them. Big, 1G-simulating spinning space-wheels with nuclear-powered magnetic field generators to redirect all of that solar-shit to enormous lead-lined shields at either end.

Sure, it'll cost a couple of trillion, but just take it from your war-fund. You don't need any more of those.

Mars mission?

[b0s0z0ku]

How will this be dealt with on a Mars mission where trajectory can't be changed much, and abort isn't a practical option? Will surrounding a part of the spacecraft with water tanks for shielding be enough? Will NASA just hope for no solar storms during the mission?

Re:Mars mission?

[tquasar]

Will my lead underwear protect me?

Re:Mars mission?

[K. S. Kyosuke]

It will be dealt with probabilistically. As in, you'll hope the probability of a high exposure event will be reasonably small. Once you're on site, you can burrow into the surface.

Water shield

[AlanObject]

I have wondered about this and haven't found a definitive answer: if you use water for a radiation shield, does it become contaminated and unusable after it absorbs the output of a solar storm?

Even if it does it seems to me the best option.

Re:Water shield

[rtb61]

Probably needs to be more high tech. You are not trying to 'stop' radiation. You are trying to convert high frequency photons into lower frequency photons ie gamma down to infra red. Likely method involving crystalline structures and electron flows, fancy molecular engineering to force that change, rather than simply intervening mass. Even better if you can convert it into electron energy flows, as high frequency photovoltaic panel ie converting a negative into a positive, heh heh.

Re:Water shield

[Rei]

There's nothing to contaminate it with, in the end the electromagnetic radiation might break a few chemical bonds, which can be really bad for DNA strands (i.e. cause cancer), but in the case of water it'll just recombine and warm up a bit

Which is why nuclear reactor core coolant doesn't become radioactive, right? ;)

3H (effectively) doesn't capture neutrons, but both 1H and 2H do. 1H has a pretty high cross section for them, so readily breeds 2H, although 2H has a rather small cross section, 3 orders of magnitude less than 1H (but you still get some tritium over time). 16O has a rather low cross section (similar to deuterium) and only becomes stable 17O, which can capture to stable 18O, so it's not a major threat concerning low-energy neutron capture. Minor water contaminants can have much larger cross sections (overwhelming their low abundances) and/or create hazardous byproducts. For example, the (n, alpha) cross section of 10B is 4 orders of magnitude higher than 1H (minor boron contamination led the Germans in World War II to incorrectly conclude that graphite had too high of an absorption cross section to be used as a moderator). As a general (but not universal) rule, the heavier the isotope, the more likely that neutron capture will lead to dangerous daughter products.

So don't get me wrong, water is excellent from the perspective of not breeding hazardous isotopes. But it's not immune to it

And the short of it is, no, your water supply is not going to get contaminated. But water alone doesn't really make up an optimal shield; an optimal shield is layered. For example, hydrogen-rich materials, while superb neutron moderators and "decent" neutron absorbers in their own right, tend not to be good shields of EM radiation (high-Z materials work best for that). And there are far better candidates for neutron absorbers than water (for example, heavily borated plastics). But with layering you can create a more effective net whole.

Lastly: the heating of water from GCR or solar radiation is utterly irrelevant.

Re:Water shield

[cjameshuff]

"the heating of water from GCR or solar radiation is utterly irrelevant"

Neutron capture is nearly so, as there's no cosmic or solar neutrons to capture. Solar radiation and cosmic rays are composed of charged particle radiation and EM. Only GCRs are capable of inducing radioactivity, and that's by spallation, not neutron capture. The only free neutrons are those produced by spallation, and the contribution is minor.

Your primary concern is bremsstrahlung, electromagnetic secondary radiation, which can be significant from solar protons and electrons striking high-z materials. Water's pretty good at blocking charged particles while limiting bremsstrahlung, as are things like polyethylene.

Radiation is dangerous

[Mister Liberty]

Yeah, we knew that already, in and out of space.
What's the story here anyway, radiaton, supercomputers, NASA's budget, or the ubiquitous Elon Musk?

I'm Surprised

[grep -v '.*' *]

Supercomputers could be "a game-changer" when it comes to predicting the risks of space radiation ... During that 1972 solar storm, skin and organs would've risked being exposed to radiation in excess of NASA limits,

So using a big enough one as a shield would stop the radiation? Supercomputers -- what CAN'T they do? That ECC stuff is actually good for something!

And then really, you've got a timing problem. You discover high incoming radiation but don't have time to get the astronauts back home / out of the way. At some point you've got to block the rays, deflect them, dance between them, outrun them, or suck it up.

Re:I'm Surprised

[groundstone]

I agree your point

The robots wont care

[aberglas]

Humans are already obsolete technology for space travel.