Researchers Finally Measured Radiation Levels On the Moon. They're High. (upi.com) 180
Slashdot reader DevNull127 writes: Scientists were able to, for the first time, measure radiation levels on the lunar surface, reports UPI, and nine days ago they published their results: that the radiation levels on the moon are 200 times stronger than on earth — and 2.6 times higher than those on the International Space Station. One of the scientists behind the study calls that exposure level "considerable." On the moon there's radiation from galactic cosmic rays, from solar particle events, and also a third component from the interaction of that radiation with the lunar soil.
"We humans are not really made to withstand space radiation," study co-author Robert Wimmer-Schweingruber, a researcher at Kiel University in Germany, tells UPI. "However, astronauts can and should shield themselves as far as possible during longer stays on the moon, for example by covering their habitat with a thick layer of lunar soil."
Or, as Business Insider puts it, "Scientists say a lunar base should be built underground to protect astronauts." Wimmer-Schweingruber tells them that "If you think about people staying on the moon for extended periods of time — say, on a scientific research station for a year or two — then these levels start getting problematic. Covering your habitat with sufficient amounts of lunar dirt should do the trick.... Ideally you'd like to be under as much material as is equivalent to Earth's atmosphere," Wimmer-Schweingruber said, adding that "an optimal depth is 30 inches of lunar soil."
"We humans are not really made to withstand space radiation," study co-author Robert Wimmer-Schweingruber, a researcher at Kiel University in Germany, tells UPI. "However, astronauts can and should shield themselves as far as possible during longer stays on the moon, for example by covering their habitat with a thick layer of lunar soil."
Or, as Business Insider puts it, "Scientists say a lunar base should be built underground to protect astronauts." Wimmer-Schweingruber tells them that "If you think about people staying on the moon for extended periods of time — say, on a scientific research station for a year or two — then these levels start getting problematic. Covering your habitat with sufficient amounts of lunar dirt should do the trick.... Ideally you'd like to be under as much material as is equivalent to Earth's atmosphere," Wimmer-Schweingruber said, adding that "an optimal depth is 30 inches of lunar soil."
Or a layer of Water (Score:2, Insightful)
You need it anyway, and it might as well sheild you.
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Why did you single out drinking as a way to delete radiation shielding while ignoring other uses?
Because it's the most common assumption. And it was likely a joke, much like this idea. Water sitting in a bladder, protecting me from deadly radiation? Bad enough we have to worry about maintaining air to breathe. Now we have to worry about something that will eventually leak?
Enough of the pressurized space pen solutions. Grab a fucking pencil already and dig a hole in the ground. Simple, and effective.
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Or alternately, just bury your habitat in sand and gravel after construction, which could be a lot easier than building something underground early on, and has the advantages of allowing the floor plan to be level with the surrounding landscape, and allowing for strategically placed windows to let in indirect sunlight.
So long as the primary living space doesn't have line-of-sight with the sky radiation won't be a problem - just don't spend a lot of time in the areas where you can look out the windows, unles
Re: Irradiated doesn't mean Radioactive (Score:4, Interesting)
There are lava tubes on both the Moon and Mars that run for hundreds of kilometers, and because of the lower gravity and other factors can be as much as a couple of kilometers wide. Glassify or otherwise seal the inside of a section, put an airlock on either end, and you have an enormous already prepared radiation-protected home. (Obviously nothing is a easy in real life, but the concept is sound.)
What I would love to see is the winner of the DARPA Underground Challenge have their robots sent to explore lunar lava tubes.
https://www.subtchallenge.com/ [subtchallenge.com]
Let military funding do something useful for a change.
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Looks like the swastika moron found a new brand of copy pasta.
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Safe to drink, but then you don't have shielding anymore.
Those pesky details when you actually build and run something. Cannot be thinking of them now, somebody may accuse us of actually doing halfway competent engineering!
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Safe to drink, but then you don't have shielding anymore.
They could converse water by using low-flow toilets.
At $10k per liter, a 1.6 gal flush would only cost $60k.
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Today's "low-flow" toilets are down to 1.28 gal/flush.
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High there (Score:2)
Re:Or a layer of Water (Score:5, Interesting)
It would be difficult to maintain: the surface temperatures on most of the moon range from 250 degrees Fahrenheit in lunar daylight to less than 200 degrees Fahrenheit during the lunar night. Preventing it from evaporating under zero pressure means enclosing it. I think it would be far safer to store slightly away from the base, in container, and to tap as needed. Digging down even slightly would help with controlling the habitat's temperature during the 4 terran week long lunar day, without the risk of leaks in the habitat ceiling letting in the water supply.
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Forgive me, that should have red "less than -200 degrees Fahrenheit during the lunar night". Temperature extremes on the moon are quite profound.
Re:Or a layer of Water (Score:5, Insightful)
Forgive me, that should have red "less than -200 degrees Fahrenheit during the lunar night". Temperature extremes on the moon are quite profound.
I also hope very much they _finally_ get rid of obsolete non-metric units on the Moon...
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Re:Or a layer of Water (Score:4, Informative)
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I do believe it was a mars orbiter [cnn.com], and not Hubble. Now, Hubble did have a flaw in the mirror, but I've never heard that was caused by imperial/metric conversion issues.
No, that problem resulted from having an incompetent American "Can do!" company doing that mirror. I mean, it was bad enough you could have seen the flaw with the naked eye.
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You can generate energy real cheap on the moon, at the equator, one side in the dark and the other in the light, one really cold and the other really hot, all you need is something to boil within the desired temperature range. Likely best spots the walls of deep craters close to the night time day time horizon, even right on it, so you can look at the earth and out into space at the same time, close by remote equipment. The hole is already dug, you just need to fill it up over your self. Those crater walls
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Did you mean the poles or the terminator rather than the equator? But either way, I can't see how you could have fixed infrastructure stradding the terminator, because Luna is tidally locked to Earth, not to Sol. Or is your dark "side" buried and the light "side" on the surface, and you have various stations spaced along the equator so that some of them are always in sunlight?
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I don't see how the equator has anything special to offer in that regard. Without an atmosphere, every part of the Moon gets the same intensity of light on a surface facing directly at the sun. And the poles offer a few locations that stay in continuous sunlight rather than facing a two week long night every month.
You won't be able to deal with fixed solar collectors since the moon is constantly spinning through a slow day-night cycle, and thus the direction of the sun constantly changes, just like on Ear
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Water is a major life support resource for human survival, and an easily handled way to store oxygen for breathing and hydrogen and oxygen for use as rocket fuel. I'd anticipate that long-term rocket fuel storage would be as water, not as liquid oxygen and liquid hydrogen.
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Re: pressure can be a problem (Score:4, Informative)
Another point is that every gas under normal conditions has a volume of 22.4 liters/mol (Gas constant). For H2 it means, that each two grams of H2 have a volume of 22.4 under 1 bar pressure at 20 degrees Celsius. To store the H2 contained in just 1 liter of liquid water (1000 g) would require more than two cubic meters (and another cubic meter for the oxygen). You could counter that by deep cooling the H2 and putting it under pressure, but that requires energy to keep the temperature low and increases the losses due to diffusion.
No, storing H2 as water makes sense if you really just need the H2 itself.
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>Also is there not a way to store hydrogen under pressure without having it as a liquid?
Certainly, but you had suggested not storing at high pressure. And high pressure means a massively strong container to store it.
Basically your storage options as a gas are (roughly)constrained by the ideal gas law: P(ressure)*V(olume) = n(number of molecules)*R(a constant)*T(emperature)
Assuming your tank temperature is kept as low as possible regardless, that means that P*V is constant for a given amount of hydrogen
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Actually, never mind the volume ratio of liquid-versus-gaseuous hydrogen - I had skimmed the previous post and missed that they said the hydrogen in 1 L of water would occupy 2 cubic meters. Liquid hydrogen would occupy a much smaller volume, so the pressure ratio between liquid and gas at the same volume would be much greater than 2000:1
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Weight is a restriction for any rocket fuel stored on the moon. In the long run, for permanent settlements, I anticipate that solar sails for asteroid or planetary ring harvesting will provide a large scale water source for our interplanetary exploration, though it does require a long-term investment.
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"Weight efficient" is only one factor. Building and maintaining high pressure tanks for liquid hydrogen and oxygen is awkward and likely to leak, especially the hydrogen. Storing it in gaseous forms is possible, and could be stored under only slight pressure, but it would be gaseous and require _much_ larger tanks. Water is a very stable and relatively easy way to manage and transfer it as needed. With the accompanying storage and handling equipment, it's not immediately clear if it will be more weight efic
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For terrestrial storage of oxygen and hydrogen, it leaks. The hydrogen especially leaks, the molecules are _very_ small. It's easily and inexpensively replenished from Earth's plentiful water supply. But where would we find that on the moon? If it's easier and safer and more stable to store it as water, why would we even consider storing more than immediately necessary as oxygen and hydrogen?
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Liquid hydrogen tanks typically leak at roughly 1%/day under ideal conditions. They're just not reliable for long term storage.
Hydrogen is typically produced from bio-mass because it's an very inexpensive by-product. Unfortunately, biomass on Luna will be even more expensive than water, and will not be available without.... wait for it.... a bountiful water supply with which to run an ecology that generates biomass. Extracting hydrogen and/or oxygen from that bio-mass also depletes hydrogen which will need
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> we probably have the capacity for ice mining from planetary rings
What does that have to do with anything? You need the propulsion capacity *on board* at the the end of your journey in order to reach those asteroids or planetary rings. In general when changing between two orbits (e.g. flying between different planets) you need to provide roughly half of the acceleration up front to accelerate from your original circular orbit onto an elliptical orbit that intersects the orbit you're trying to reach, a
Re: Or a layer of Water (Score:3)
Try rethinking your idea.
Water is a nice stable way of storing oxygen and hydrogen. But that very stability makes it useless as a fuel. You have to use a lot of energy to separate the oxygen and hydrogen. And frankly, if you have that energy available, you'd get better results by directly using the H2O as reaction mass in an ion drive.
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Try rethinking your idea. Water is a nice stable way of storing oxygen and hydrogen. But that very stability makes it useless as a fuel. You have to use a lot of energy to separate the oxygen and hydrogen. And frankly, if you have that energy available, you'd get better results by directly using the H2O as reaction mass in an ion drive.
I think you need to consider where the energy and equipment for conversion reside, vs where the resulting fuel gets used.
It's far easier to have a fueling station on the lunar surface that has water for long-term storage, an energy source for conversion, and smaller tanks for short-term storage of separated O and H (fuel). You use energy from a solar farm or nuclear or whatever to split the water into fuel on the surface.
The rocket burns the H and O, but doesn't need to carry the conversion baggage. It's
Re: Or a layer of Water (Score:5, Informative)
Water is an extremely mass efficient radiation shielding material. There are basically three types of radiation. They are:
1. High energy photons. Aka gamma rays. For this, you want electrons. The more the better. ... well neutral. So you want them to physically interact and for that you want targets of about the same mass such as hydrogen atoms. If a neutron hits a hydrogen nucleus, almost all of its energy goes into the nucleus, which then goes shooting off. And since the nucleus is a charged particles, it interacts with the rest of the shielding and stops. But if a neutron hits a heavier nucleus such as lead, it bounces off in a different direction with close to its original energy.
2. Fast charged particles. Aka alpha and beta radiation. For this class of radiation, you want charged particles such as either electrons or protons.
3. Fast neutrons. This type is a problem. For your radiation shield to work, the radiation needs to interact with the shield material and in the process loose energy to the shielding and then have the energy converted to heat. Neutrons are
Looking at the above, it's evident you want a material with a lot of isolated protons and a relatively low percentage of neutrons. Hydrogen is close to 100% protons and electrons. Lighter elements are close to 50% protons and electrons. Heavy elements such as lead are about 30%.
From a mass perspective, water is far better than lead for radiation shielding against all forms of radiation. But from a volume perspective, lead is better than water. But the real winner is what ever you can obtain the cheapest in sufficient quantity, such as keep piling the dirt on your shelter until you have enough shielding
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Calling it soil is inherently confusing because soil is what we grow plants in. At least call it lunar dirt :p
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Radioactive soil (Score:2)
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He's just another one who probably slept through physics at school and doesn't understand the difference between radiation and radioactive.
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Re: Radioactive soil (Score:5, Informative)
Re:Radioactive soil (Score:5, Informative)
Sometimes yes, the danger comes from the particle interacting with the genome, aka atomes in your genome, or electrons in the molecules forming your genome.
If the particle has to high energy, aka is to fast, it has the wrong energy to be able to interact, and is to fast to have time to interact.
However as solar wind also contains alpha particles, that argument is a bit mood, as alpha particles are big enough to compensare for this and interact with everytjing they directly hit.
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It's not particle radiation that is the problem in space. You can defend against those with a single sheet of paper. Literally. And any astronauts would be packed inside containers that would at least contain Earth-like atmosphere, which means they are inherently protected against those.
The problem is gamma radiation.
Gamma radiation (Score:2)
Just don't get them angry.
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If the soil is radioactive, then, no.
That really depends on the radiation type, intensity and energy levels.
Six feet would be even better (Score:2)
But then people might be bothered by the symbolism.
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We will do it in metric (Score:3)
No Inches, no feet.
The people going tere will be chinese, and will do it in meters.
Regarding Water (Score:2)
Shut up (Score:2, Offtopic)
So I was bored waiting on a centrifuge and playing around with diamagnetic levitation (pyrolytic graphite+neodymium magnets) the other day in my lab and thought wouldn't it be cool to be in Shackleton crater on a superconducting maglev track? Seriously, I think that's a possible thing btw. Shackleton crater is consistently below 100 kelvin .. Bi-2223 is superconducting at 108Kelvin .. it should work. All you need is a track of magnets and a cart with BSSCO underneath it. You can probably make other interest
It would be, but not in the way you're thinking (Score:2)
> wouldn't it be cool to be in Shackleton crater on a superconducting maglev track? Shackleton crater is consistently below 100 kelvin.
Yeah it would be *cool* alright.
I've lived in Colorado; that's cold enough. You can have Shackleton.
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So I was bored waiting on a centrifuge and playing around with diamagnetic levitation (pyrolytic graphite+neodymium magnets) the other day in my lab and thought wouldn't it be cool to be in Shackleton crater on a superconducting maglev track? Seriously, I think that's a possible thing btw. Shackleton crater is consistently below 100 kelvin .. Bi-2223 is superconducting at 108Kelvin .. it should work. All you need is a track of magnets and a cart with BSSCO underneath it.
Stick that maglev cart on a banked circle and you've got a higher g habitat for sleeping/exercise/whatever.
Bad idea (Score:5, Funny)
You shouldn't do important scientific work while consuming drugs.
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Um ... 2 nouns, 1 pronoun (Score:5, Funny)
Researchers Finally Measured Radiation Levels On the Moon. They're High.
The researchers or the radiation levels?
High on what? (Score:2)
> Researchers Finally Measured Radiation Levels On the Moon. They're High.
What were/are the researchers high on?
Handy pre-made structures (Score:5, Informative)
Fortunately there already exists massive underground cave systems on the moon.
https://en.m.wikipedia.org/wik... [wikipedia.org]
Presumably these are adequately deep to block the majority of radiation.
quick way to dig a big cavern: Project Gnome (Score:4, Interesting)
https://en.wikipedia.org/wiki/... [wikipedia.org]
Project Gnome created a 28,000 cubic-metre cavern using a 3 kiloton thermonuclear device.
You might think this would defeat the purpose of avoiding radiation, but only 6 months later, scientists were able to enter the cavern, and found only 6 milli-roentgen.
(Remember 3.6 roentgen, was considered "not great, not terrible")
Underground (Score:2)
Or you shovel some dirt on top of your cottage. "Underground" sounds too much like a journey to the middle of the moon.
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Hands up (Score:2)
So it's true that the moon landings were a hoax (Score:3)
First time radiation measurement? Did nobody carry a geiger counter on the crewed lunar landings?
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Seems strange (Score:2)
Moonquakes (Score:3)
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What I learned in Tokyo: in event of an earthquake, underground in a manmade structure is the safest place to be.
Read the book 'Artemis' for the engineering ... (Score:4, Interesting)
... required to live on our moon. Also pretty good story.
Say "No" to drugs (Score:2)
Yeah, it's bad there (Score:2)
Even the sun doesn't go away for half a month.
That's no moon... (Score:2)
(Am I the only one that misses the Slashdot tag of thatsnomoon on every article even vaguely related to the moon?)
Confusing title... (Score:2)
Researchers Finally Measured Radiation Levels On the Moon. They're High.
The researchers, or the radiation levels?
The English language can be quite confusing at times...
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It varies a lot. Six months on the ISS can give you 0.05 to 2 sieverts. Or for we old school boys 5 to 200 rem. And yes, 200 rem is a fucking lot and makes detectable radiation poisoning effects in the body, and chances of cancers are.... pretty certain. 5 on the other hand is the NRC's limit for nuke plant workers, and plants target half of that for their workers. So, it's a lottery.
Poorly worded headline? (Score:2)
Soviet scientists knew it still in 60s (Score:3)
Even now, why fly humans to be irradiated there? To gain some publicity points? First, some robots are to be sent to dig a pit and to construct a safe underground station. And only then humans can fly there more or less safely.
Otherwise it will be like hurting people knowingly, i.e. kind of immoral.
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You spew nonsense. Of course ALL the Apollo missions measured radiation and the exposure of the astronauts was known, freely available online. For Apollo 7 though 15, the rads were:
0.16, 0.16, 0.20, 0.48, 0.18, 0.58, 0.24, 1.14, and 0.30.
All those are well within the limits of any nuke plant worker, and at a level with no detectable medical effects.
Dose equals rad level multiplied by time. Keep time short, dose is low.
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No. Earth is a seismically active planet with a strong magnetosphere. Large portion of radiation is deflected by it. Of the rest, a large portion is absorbed by the atmosphere. We get a tiny fraction of gamma radiation that exists outside Earth's magnetosphere in the upper parts of the atmosphere, and almost none at ground level.
If you want to see just how powerful earth's magnetosphere is and how much energy it deflects in terms of radiation, go beyond the Arctic Circle and watch northern lights.
Moon has n
Re:Cosmic rays are unusual? (Score:4, Interesting)
As the summary says:
the radiation levels on the moon are 200 times stronger than on earth
The amount of background radiation on earth varies quite a bit and the composition of the radiation can be different in different places. I'm just going to assume the reporter took the most extreme number which would be the average background radiation at sea level. Since generally radiation levels are based upon altitude because the amount of atmosphere blocking cosmic radiation is thicker at sea level. So that would make it ~ 20 micro Sieverts/hour. The article uses Grays which is a bitch to convert and really weird choice as its not a measure of absolute radiation but instead a measure of how much radiation would be absorbed by biological material (i.e. flesh). That's quiet a bit but there are small human populations that live in places with that much radiation, however it's mostly alpha and beta radiation which on the Moon there would be gamma radiation so that doesn't tell us as much as we might like. Either way, its a good lesson in how hostile space is and how much the Apollo astronauts really were lab rates.
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+1 Navy insider joke
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The article says 60 microsieverts an hour, which is about half a Sievert a year. So that's around 10 times the limit allowed for radiation workers in the US.
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