One thing we do know is Gateway and SLS trying to build a town on the Moon will face far more dangerous radiation risk, perhaps Orders of magnitude (radiation)
NASA might start to build and mine on the Moon and Mars, create shelter from Cosmic Ray events or Solar Storms
Some links
Radiation Measurements on Mars
https://www.nasa.gov/jpl/msl/mars-rover … 17600.html
The Radiation Assessment Detector (RAD) instrument on NASA's Curiosity Mars rover monitors the natural radiation environment at the surface of Mars. It can see the radiation from two sources, galactic cosmic rays and solar energetic particles. This graph plots measurements made during the rover's first 10 months on Mars. The vertical axis is in micrograys per day. Micrograys are unit of measurement for absorbed radiation dose. The horizontal axis is time, labelled on the bottom as months from August 2012 to June 2013 and on the top as the number of sols (Martian days) since landing.
The observations have been almost entirely due to galactic cosmic rays, which contribute a slowly varying dose rate of about 210 micrograys per day. Variations are due to day-to-night differences in the shielding provided by the atmosphere. Sudden drops in the radiation, so-called Forbush decreases, such as seen on sols 50, 97, 208 and 259, result from extra shielding provided by interplanetary coronal mass ejections driven by the sun. The longer-term increase and decrease peaking close to Sol 200 is driven by Martian seasonal effects.
NASA Researchers Develop a Technique to Predict Radiation Risk on International Space Station Missions
https://www.nasa.gov/feature/nasa-resea … onal-space
Radiation Exposure Comparisons with Mars Trip Calculation
https://www.nasa.gov/jpl/msl/mars-rover … 17601.html
Exploring How Radiation Exposure Will Affect Life Forms on the Way to Mars
https://science.nasa.gov/technology/tec … ay-to-mars
New Program Office Leads NASA’s Path Forward for Moon, Mars
https://www.nasa.gov/press-release/new- … -moon-mars
Eight things you never knew about mining on Mars, the Moon, and even asteroids
https://phys.org/news/2022-05-knew-mars … roids.html
Moon vs. Mars: NASA's ultimate destination has varied over the decades
https://www.space.com/moon-mars-nasa-exploration-debate
Radiation Levels on the Surface of Mars 74 - NASA
https://spacemath.gsfc.nasa.gov/planets/10Page74.pdf
,
https://web.archive.org/web/20210318234 … Page74.pdf
Problem 4 - Suppose an astronaut took a 180-day journey to Mars, stayed there for
600 days, and then returned on a 180-day trip back. What would the astronauts total
radiation dose be for the entire 960-day trip?
Problem 5 - If an astronaut remained on Earth, the normal background radiation dose
rate is 3 milliSieverts/year. How many equivalent years of normal Earth exposure
would a single trip to Mars produce?
Space MathProblem 4 - Suppose an astronaut took a 180-day journey to Mars, stayed there for
600 days, and then returned on a 180-day trip back. What would the astronauts total
radiation exposure be for the entire 960-day trip?
Answer: 180x0.0013 + 180x0.0013 + 600x0.0007 = 0.88 Sieverts.
Problem 5 - If an astronaut remained on Earth, the normal background radiation dose
rate is 3 milliSieverts/year. How many equivalent years of normal Earth exposure
would a single trip to Mars produce?
Answer: 0.88 Sieverts over 960 days = 338 milliSieverts/year. So it equals 338/3 =
112 years!
How Space Radiation Threatens Lunar Exploration
https://www.smithsonianmag.com/science- … 180981415/
Scientists are studying the possible impacts of the hazard on astronauts who will travel to the moon
Mars radiation a serious risk to astronauts. - Is radiation a surmountable problem?
https://newmars.com/forums/viewtopic.php?id=1748
Discussion about radiation in the old Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) thread
https://newmars.com/forums/viewtopic.php?id=1590
Basic conversions:
https://news.mit.edu/2011/explained-radioactivity-0328
1 gray (Gy) = 100 rad
1 rad = 10 milligray (mGy)
1 sievert (Sv) = 1,000 millisieverts (mSv) = 1,000,000 microsieverts (μSv)
1 sievert = 100 rem
1 becquerel (Bq) = 1 count per second (cps)
1 curie = 37,000,000,000 becquerel = 37 Gigabecquerels (GBq)
There's been no secret about this. This stuff has been known and well-measured since the late 1960's early 1970's. The ESA detectors on Artemis maty or may not see a flare, but might add detail about the nature of the already-known cosmic ray issue. If they see a flare, they may well saturate without getting good data, since the disparity is so large.
Spacecraft hulls to date only offer minimal shielding effects. Orion is no different. Neither will be Gateway. Same for Musk and his Starship (we have seen nothing yet about the purported presence of a "radiation shelter" in his design). They're gonna kill a crew, sooner or later, by not planning for a direct hit by a huge flare event. Simple as that.
GW
]]>edit update 8-29-2022: I misquoted the GCR exposures as milliREM which I have now corrected to REM. 100 REM = 1 Sievert, for you metric guys. Note that 50 REM over a year is not actually more than a 3% increase in cancer late in life. 50 REM in a "short" time, is the the monthly accumulated exposure limit in NASA's old standards. That's well below any lethal dose, but it might make you a bit sick after that month. 50 REM over hours or days will make you very, very ill. NASA old astronaut exposure standards were set at about twice those used for Earthly nuclear workers.
The other source is the erratically-occurring flood of lower-energy particles from the sun. There is always some of this, it's called the solar wind, and it gets caught and concentrated as the radiation belts about Earth and some other planets. But solar flares release a huge flood of these. Synonyms include "coronal mass ejections", but it's just an eruption from the sun. Some are bigger than others There are more of them when sunspot activity is high, but they can occur at any time. The worst of these you can shield fairly effectively with 15-20 cm of water, or any other low molecular weight materials (to reduce secondary scatter effects). The criterion NASA uses for this is whatever thickness gets you 15-20 g/cm2 of shielding material.
These floods of solar particles are the lethal threat. They are actually rather similar to, and as lethal as, the initial fallout from a nuclear ground burst close by. Shielding against these is simply required for operations outside Earth's magnetic field or within its Van Allen radiation belts. That is because sooner or later, one of these will hit you. It is only statistics that this will occur. The longer you are out there, the more likely you will be hit.
Apollo ignored this, and got away with it, because the missions were only 10 days to 2 weeks long. But the biggest radiation event we have ever seen hit between Apollo 16 and Apollo 17 in 1972. Had a crew been out there when it hit, they would have died within hours, the same way you die within hours standing outside in nuclear fallout. We're talking about 10,000 to 30,000 REM in a short time, with events like that. But that 15-20 g/cm2 of passive shielding cuts it to tolerable levels, PRECISELY BECAUSE lower-energy particles are far easier to shield against.
Update 8-29-2022: The old NASA exposure standards claimed that Apollo's hull cut flare radiation exposures by about a factor of 10. What was 5000 REM outside was about 500 REM inside, estimated for the 1972 event. Since this accumulates over hours to at most a couple of days, that's "short", and therefore still a lethal dose for essentially 100% of those so exposed.
THAT picture is what you have to deal with, for humans leaving LEO! And NASA's Gateway station about the moon does NOT deal with it. If they don't add some shielding, then they will eventually kill a crew aboard it. Mark my words! Bigelow's meter of fabric insulation that was in its B-330 design would go a long way toward being the shield that is needed.
Update 8-29-2022: the old NASA exposure standards are still on the internet at
http://srag.jsc.nasa.gov/Publications/T … chmemo.htm, titled Spaceflight Radiation Health Program at JSC.
Go look at this thing for yourself. The newest reference in its reference list is dated 1993. There is no date on the document as published on the internet. This includes shuttle data, but it predates ISS data. It does project exposures for ISS, that being one of its purposes. As far as I know, the actual ISS data are relatively in-line with these predictions.
GW
]]>There are plenty of immediately fatal problems to contend with on Mars that have a much greater likelihood of reducing total life expectancy, as compared to notable but not dramatic increased radiation dose rates relative to Earth sea level. Moreover, we already have simple and highly effective ways of dealing with increased radiation levels.
So... Is radiation a problem? Yes, but relative to all other problems it's more of an annoyance than a showstopper. Short of remaining completely unprotected during a very powerful solar storm, you'd have to deliberately work at injuring or killing yourself via radiation exposure while living on the surface of Mars. I don't think radiation makes the Top 10 List, with respect to the ways you're most likely to die or be seriously injured on Mars. On the moon, radiation from solar storms might break into that list, but such events are (thankfully) pretty rare. It's a non-zero risk that our rovers have quantified over the years, but we should accept that the mitigation strategies actually work and then move on to much more pressing problems.
]]>This works out at 91mSv per year. It is estinated that 1Sv whole body dose raises mortality risk by 5%. If we assume that on average a radiation induced mortality results in 30 years lost life expectancy, then exposure to 1 year of Mars surface dose, results in 50 days loss of life expectancy. Exposure for fifty years would reduce life expectancy by 6.8 years. Other health factors not withstanding, this suggests that life expectancy woukd be measurably reduced if humans were to spend 100% of time exposed to Mars surface radiation levels.
We can compare this to air pollution on Earth. The average Chinese loses about five years of life expectancy due to air pollution. So if we provided no cosmic ray shielding at all on Mars, the health impact would be comparable to air pollution in China. That is a severe enough problem that mitigation deserves considedatiin and long term habitation should be shielded, especially given that it is relatively easy to do.
For early construction on Mars, living in unshielded structures within inflatable domes would not raise catastrophic risks. If one spent ten years living and working in an unshielded structure, loss of life expectancy would be about 1 year, which is in with stastical noise for most people. Likewise, if some time is spent in shielded areas and some time outside, then overall risk begins to look more acceptable. If humans spend two-thirds of time in shielded structures and one third of time exposed to ambient cosmic dose, then total lifetime LLE is reduced to a little over two years, which is comparable to other common environmental hazards on Earth. If a man spent 40 hours a week onnthe Martian surface, 50 weeks a year, for a 40 year career, then LLE woukd be 1.25 years. That about the same as being exposed to air pollution in any urban area in the developed world. There are many hundreds of millions of people that willingly do this.
So whilst we need to be mindful of radiation exposure on Mars, not all structures will need to be shielded. Even if exposed to ambient Mars surface radiation for a significant fraction of time, it is unlikely that Martian life expectancy would be significantly reduced compared to Earth. On the moon or in free space, the situation may be markedly different.
]]>We have known for a while that plastics made with a high hydrogen ration did help in the radiation shielding.
The bismuth trioxide compound is lightweight, effective at shielding against ionizing radiation such as gamma rays, and can be manufactured quickly - making it a promising material for use in applications such as space exploration, medical imaging and radiation therapy.
"Traditional radiation shielding materials, like lead, are often expensive, heavy and toxic to human health and the environment,"
"This proof-of-concept study shows that a bismuth trioxide compound could serve as effective radiation shielding, while mitigating the drawbacks associated with traditional shielding materials."
awarded a $550,000 grant to the Florida Institute of Technology in Melbourne to begin the three-year machine learning project next month.
Florida Tech is one of 14 universities NASA picked in November for funding to study an array of topics under the agency's Space Technology Research Grants program.
Other schools awarded funding are Rensselaer Polytechnic Institute, Troy, N.Y.; Purdue University, West Lafayette, Ind.; Auburn University, Auburn, Ala.; the University of Michigan, Ann Arbor; the University of Alabama-Tuscaloosa, and the University of California-Los Angeles.
Also, the University of Central Florida, Orlando; Florida State University, Tallahassee; University of Texas, El Paso; University of Illinois-Urbana-Champaign; New Jersey Institute of Technology, Newark, and Vanderbilt University, Nashville.
pg 490
lots of items and what happens for mans trip to mars
https://medium.com/the-physics-arxiv-bl … ba6bfdf65d
Galactic cosmic rays (GCRs) consist of high energy protons (85%), helium (14%) and other high energy nuclei (HZE ions).
http://www.buildtheenterprise.org/shielding
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Following up on post #59 about an electrostatic shield, as discussed in T.A. Heppenheimer ...
After thinking about the issue overnight, it occurred to me that at the time of publication of "Colonies in Space" (1977) Heppenheimer recorded the conclusion of the community that was active at the time. 2019 - 1977 >> 23 + 19 >> 42 years have gone by, and surely later thinkers have explored this topic.
The positively charged outer shell Heppenheimer described would (in his report) repel positively charged atom nuclei, if the charge level is about a billion volts.
He argues that electrons would be attracted to this shield.
Surely someone has thought about creating an inner shell that is negatively charged, to balance the charge of the outer shell.
The vulnerable shelter for humans would reside inside this dual shell structure.
SpaceNut, in recognition of your search skills, please see if you can find the argument against this proposal.
It must surely exist, because otherwise we'd have heard about this concept, long ago.
Not too long ago, in this forum, (as I recall) there was discussion of a concept for solar sailing using charged grids.
Edit: There's a lengthy discussion of billion volt speculations in a forum with a science orientation. The majority of the posts were about lightning, and there was one post about Benjamin Franklin's work with lightning. I had not previously read that he used copper cylinders and steel balls in an apparatus to investigate lightning. He charged the cylinders with lightning (according to the post) and then got a satisfying discharge between the steel balls.
There must be a report of that experiment somewhere, because the poster remembered it (assuming it was true, and the memory was accurate).
However, it certainly sounds plausible, from what I've read about Franklin.
(th)
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