Arthur T Knackerbracket has processed the following story:
An international team of researchers has conducted a long-term experiment aboard the International Space Station to test the effect of space radiation on mouse embryonic stem cells. Their findings will contribute to helping scientists better assess the safety and risks related to space radiation for future human space flights.
In their study, the team performed a direct quantitative measurement of the biological effect of space radiation by launching frozen mouse embryonic stem cells from the ground to the International Space Station, exposing them to space radiation for over four years, and quantifying the biological effect by examining chromosome aberrations. Their experiment results show, for the first time, that the actual biological effect of space radiation is in close agreement with earlier predictions based on the physical measurement of space radiation.
Ordinary people are now able to travel in space, and the possibility of long-term manned flights to deep space, such as to the moon and Mars, is increasing. Yet space radiation remains a limiting factor for manned exploration. Scientists have been conducting intensive studies to measure physical doses of space radiation to better understand its effect on the human body.
However, since most of the studies until now were conducted on the ground, not in space, the results suffered from uncertainties, given that space radiation consists of many kinds of particles with different energies, and astronauts are continuously irradiated with low-dose rates. The actual space environment cannot be precisely reproduced on the ground.
The team prepared about 1,500 cryotubes containing highly radio-sensitized mouse embryonic stem cells and sent them to space. Their study was complex in its scope, with seven years of work before launch, four years of work after launch, and five years for analysis. "It was difficult to prepare the experiment and to interpret the results, but we successfully obtained quantitative results related to space radiation, meeting our original objective," said Professor Morita.
Looking ahead, the researchers hope to take their studies a step further. "For future work, we are considering using human embryonic stem cells rather than mouse embryonic stem cells given that the human cells are much better suited for human risk assessment, and it is easier to analyze chromosome aberrations," said Professor Morita.
Future studies might also include launching individual mice or other experimental animals to analyze their chromosome aberrations in space. "Such experiments in deep space can further contribute to reducing uncertainties in risk assessments of prolonged human journeys and stays in space," concluded Professor Morita.
More information: Kayo Yoshida et al, Comparison of biological measurement and physical estimates of space radiation in the International Space Station, Heliyon (2022). DOI: 10.1016/j.heliyon.2022.e10266
Journal information: Heliyon
(Score: 5, Informative) by PiMuNu on Friday October 21 2022, @12:26PM
Reading the paper:
Total dose was about 0.5 milliSievert (mSv) per day, to be compared with:
https://www.gov.uk/government/publications/ionising-radiation-dose-comparisons/ionising-radiation-dose-comparisons [www.gov.uk]
They had two sets of embryos - "wild type" and "H2AX heterozygous-deficient" which were "radiation sensitized". I don't know enough biology to know what that means, it looks like the deficincy means chromosonal repair mechanisms are suppressed.
The "wild type" had no observed excess in chromosone abnormalities compared to a sample on earth. The "sensitized" ones did have an excess. Conclusion is that the risk of space travel from radiation is not so severe as previously thought, as the mice embryos are able to self-repair effectively.
(Score: 4, Funny) by looorg on Friday October 21 2022, @01:19PM (7 children)
So is the solution more shielding? Which is more weight. Which I assume makes it more expensive. That or a lot of mice are just going to have to get space cancer for science.
(Score: 3, Interesting) by PiMuNu on Friday October 21 2022, @01:52PM
FTFP:
"Our result suggests that ICRP60 formulas may possibly overestimate the biological effects of higher LET particles when we consider the risks of humans in deep space. "
I read the journalist article, it doesn't look like it is consistent with the paper. The paper says there is not a big effect. Maybe someone who knows biology can comment (I know ionising radiation).
(Score: 3, Insightful) by Immerman on Friday October 21 2022, @03:12PM (1 child)
Depends where you get your shielding.
If you're on the Moon, more shielding is literally dirt cheap. All you need is a shovel.
And once we have a SpinLaunch facility on the Moon (down the road a bit, I'm sure) more shielding in orbit will be almost as cheap, costing less than 1kWh/kg (plus inefficiencies) to launch into co-lunar Earth orbit - like to the L4 and L5 points.
Still gets ferociously expensive for anything that needs to accelerate regularly though. For all their inconveniences, long term my money is on orbital cyclers for any long-range trips humans want to make on the cheap. Even if they end up being nothing more than big concrete shells that ships can park inside for the small part of their cycle they're actually useful for. Maybe deploy some "inflatable tent" habitats in the nice sheltered space as well - give folks some room to stretch their legs. (Zero-g bouncy castles? The months will fly by!)
(Score: 0) by Anonymous Coward on Friday October 21 2022, @08:26PM
Watch out, so will the vomit
(Score: 2) by SomeRandomGeek on Friday October 21 2022, @06:31PM (1 child)
The quantity of shielding needed is proportional to surface area of the vehicle. So, if you have a compact shape, the bigger you make the ship the lower the mass of shielding you need for each unit of volume. Combine that with making the equipment double as shielding by putting it on the outside and wanting a big centrifuge to simulate gravity and you get a space ship design: An air filled spinning drum filled with people surrounded by the engines, storage, etc.
(Score: 2) by Immerman on Friday October 21 2022, @09:07PM
Yeah - I kind of like the idea of big lunar-concrete "bubbles" in orbit, with ships, spinning space stations, etc. inside them. Once you've got protection from radiation and micrometeorites all you need to worry about is holding your air in, and that can be done with impressively little material. Especially valuable for spinning space stations, where every gram of spinning mass translates directly to increased structural support requirements.
(Score: 2) by istartedi on Friday October 21 2022, @07:18PM (1 child)
More but also better shielding. What works best can be counter-intuitive as materials that seem good will actually produce knock-on particles after the initial strike. IIRC, there are some plastics that are not too heavy and may offer better performance than something several times heavier. For extended stays on Mars it has been suggested that an orbital magnetic shield could be deployed to provide some protection. It may also be possible to provide such a solution on the craft, but either way this only protects from ions.
Apollo astronauts reported odd flashes in their field of vision, thought to be from cosmic rays. It hasn't seemed to impact their lifespans, but those were short missions.
This is definitely going to be one of the biggest challenges for long term deep space flight and occupying other bodies.
Appended to the end of comments you post. Max: 120 chars.
(Score: 2) by Immerman on Friday October 21 2022, @09:03PM
Yea, plastics are actually among the best shielding per kg - I think it basically comes down to all the hydrogen. It's collisions (or extremely near misses) with atomic nuclei that stop (or slow via Bremsstrahlung radiation) most high-energy particle radiation. And since cross sections grow slowly with mass (approx. m^(2/3)), but linearly with the number of nuclei, the maximum cross section per unit mass leans heavily towards as much hydrogen as you can hold in one place.
Hydrocarbons are pretty good at that, with 6 amu of carbon per hydrogen being typical, compared to 8 amu of oxygen for water. Ammonia is a little better (4.7amu of Nitrogen/H), but being a toxic, caustic, flammable liquid presents... challenges. Seems like borohydrides may have some great potential (potentially less than 3 amu of boron per H), but I haven't heard much discussion of them as radiation shielding, so perhaps they have other issues. I know Boron is prone to fissioning into He4 under proton bombardment (a.k.a p-B fusion), which might cause it to degrade rapidly and/or contribute to dangerous particle cascades? Though Boron alone is often considered as a fusion shielding material as it doesn't suffer from neutron activation, and the resulting He4 makes good fuel for further fusion.