NASA Wants Revolutionary Radiation Shielding Tech 160
coondoggie writes "Long term exposure to radiation is one of the biggest challenges in long-duration human spaceflights, and NASA is now looking for what it calls 'revolutionary' technology that would help protect astronauts from harmful exposure. 'It is believed that the best strategy for radiation protection and shielding for long duration human missions is to use electrostatic active radiation shielding while, in concert, taking the full advantage of the state-of-the-art evolutionary passive (material) shielding technologies for the much reduced and weaken radiation that may escape and hit the spacecraft.'"
Have they considered Denial? (Score:5, Funny)
Seems to be the first line of defence for many...
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How much water? (Score:3)
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What does Egypt have to do with Radiation?
Water, of course, is a great shielding material, if you have enough of it. Hence, de Nile.
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So, the (Score:2)
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Tinfoil Hat thing didn't play out?
I was fascinated to find wood is effective in blocking a stream of neutrons - how about not so much Revolutionary as trying what you have, first.
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I was fascinated to find wood is effective in blocking a stream of neutrons
Most plastics are awesome neutron shields, so if you think of wood as "naturally made plastic" then it shouldn't be too surprising.
Carbs would make a decent neutron shield, plenty of H and low Z atoms. A giant caramel or taffy would make a decent shield. Plus you could eat it.
Deflectors to full? (Score:4, Insightful)
Re:Deflectors to full? (Score:4, Funny)
Yeah, don't forget the ability for it to be reconfigured to emit a tachyon pulse. That can be very useful in many situations.
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Fast forward to the first season of Voyager (using a tachyon pulse, of course), and it would be useful in ALL situations.
8*)
Re:Deflectors to full? (Score:4, Informative)
Active shielding will only work for Alpha, Beta, and high energy Protons. It will do nothing for Neutron, Gamma, Xrays, and so on. For Neutron you could us a material with lots of Boron in it but I am not sure if Boron only captures some energies of Neutrons effectively or all of them. If it only captures thermal neutrons then you could combine it with carbon and have pretty efective material. But when you are talking about high energy Photons the only thing that I know works is mass.
So pick your radiation and there will be a different way to shield it.
Re:Deflectors to full? (Score:4, Informative)
Well, not to put too fine a point on it, but NASA wants active shielding for the sorts of natural radiation astronauts encounter in space. Cosmic rays, solar flares, and the Van Allen radiation belts. All of which are charged particles.
As a general rule, one only encounters neutrons, gamma rays, and x-rays from artificial sources, such as nuclear weapons and nuclear power plants.
So unless NASA is contemplating starting a space war with alien invaders from another solar system, they will be well served by active shielding.
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As a general rule, one only encounters neutrons, gamma rays, and x-rays from artificial sources, such as nuclear weapons and nuclear power plants.
What do you think is going to be powering these space vehicles?
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Hamsters. On wheels. Many, many hamsters.
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What do you think is going to be powering these space vehicles?
Aneutronic fusion power plants, assuming Bussard was on to something. *Fingers crossed*
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What do you think is going to be powering these space vehicles?
Solar power arrays. The insane Luddite activists went absolutely ballistic about the Cassini space probe with its piddling 72 pounds of plutonium in a sub-critical RTGs. Do you seriously believe that the activists and the politicians they control are going to allow NASA to put an actual full-scale nuclear reactor on a booster rocket?
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Wait, no Gamma in space? What about the gamma ray bursts? Too far away?
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Wait, no Gamma in space? What about the gamma ray bursts? Too far away?
You might say that. Gamma ray burst occur in other galaxies. Way to far away to be harmful.
Such a burst inside our galaxy would probably be strong enough to cause a mass-extinction event on the entire Earth, so any astronauts who were killed would have plenty of company.
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last time i checked our sun put out a fairly decent amount of gamma and x-rays .. and i don't think it is artificial
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last time i checked our sun put out a fairly decent amount of gamma and x-rays ..
and i don't think it is artificial
Jeez, I suppose you think they really landed men on the moon too? And that JFK wasn't an alien lizard?
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Sorry i believe in Science not Scientology
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So unless NASA is contemplating starting a space war with alien invaders from another solar system, they will be well served by active shielding.
You mean like an ant hill would be well served by putting up a layer of leaves and debris? Cuz it would be about the same thing I think.
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True the majority are charged particals but you do also have hard X-Ray as well. Some of which could be caused by your own shielding.
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There is no need to pick, mass works for everything.
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Actually Mass can make it worse. Comic rays can cause more radiation when they hit a high mass shield then when there is no shielding. That is unless you have a LOT of mass.
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640km should be enough for everybody
Simple (Score:3)
Just move the Earth wherever you want to go.
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The Best Solution Ironically is Nuclear Rockets (Score:3, Insightful)
The reason, even 1st generation ones will be able to lift 2 to 3 times as much weight in orbit as the chemical rockets we have now. This is the difference between orbiting the earth with substantial protection in an overbuilt craft and orbiting with tin foil.
The simple act of wrapping the crew quarters with water tanks for one. Water, when exposed to vacuum, freezes. It expands when it freezes, sealing any holes made by micro meteorites or space junk. It absorbs radiation somewhat readily, meaning you'd have to purify it before putting it to its most common use - drinking it.
But building a spacecraft or spaceship with such a concept in place will take a monumental increase in lifting capacity. We've taken chem rockets about as far as they are going to go - nuclear is the way if we can ever get over our irrational fear of the stuff.
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Re:The Best Solution Ironically is Nuclear Rockets (Score:5, Interesting)
The one downside of nuclear rockets is that if we had another Challenger-esque disaster, this time with, say, plutonium fuel, the repercussions would be much, much, much more immense. Just to be sure, we'd have to launch all rockets from tiny little atolls in the middle of the ocean.
Except you wouldn't use plutonium for fuel.
When NASA were planning to launch NERVA rockets the flight path would have been south from California so that any launch failure would either dump the NERVA into the ocean or the Antarctic. And since it would have been boosted by a conventional Saturn V, there wouldn't be any really nasty radioactivity until the NERVA started firing late in the launch.
That said, using nuclear fission rockets for launch from Earth still seems pretty optimistic to me.
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[...] the flight path would have been south from California so that any launch failure would either dump the NERVA into the ocean or the Antarctic.
And it's not like anything we eat actually comes from the ocean, so it's a great place to dump stuff.
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And it's not like anything we eat actually comes from the ocean, so it's a great place to dump stuff.
The impact on sea life of a few tons of uranium on the seabed would be practically zero.
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See, the thing about the ocean is that in general, it's very, very deep, while our nets are very, very small, and the fish we eat tends to stay relatively near the surface.
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I wasn't thinking NERVA - but Gaseous Diffusion rockets which use Uranium Hexafluoride gas as the reactant. A lot more kick to those, but admittedly if we start today they're still 30 years away.
And yes, it is overly optimistic. Even the educated public here is scared of the things not to mention the 4th grade reading level challenged common public that believes the lies CNN and Faux News cook up for them. When such a rocket goes bad (it will happen, Murphy's law) the radiation release would be on par wi
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if we had another Challenger-esque disaster, this time with, say, plutonium fuel, the repercussions would be much, much, much more immense
Oh, we've had one. The vehicle blew up (a Titan, if I recall correctly) shortly after launch, and the plutonium fuel canister (in an RTG, for the space probe) fell into the ocean ... where it was recovered, cleaned off, and used in the backup spacecraft.
Want to argue that that was an RTG and not a NERVA-type engine? Okay. Rocket engines are designed to withstand thousa
Huh? (Score:5, Insightful)
With the exception of Project Orion, all of the nuclear propulsion concepts I've read about, and even the actual trials made in the 1960s, have much lower thrust than chemical fueled rockets. In the case of ion and plasma thrusters, vanishingly little thrust. Even in the case of fission/thermal rockets (e.g., NERVA), only about a third of the thrust of chemical rockets. They are less suitable for getting stuff into orbit than chemical rockets.
Once you're in orbit (or beyond), thrust counts for much less than exhaust velocity.
And as for Project Orion: Yeah, some of the proposed designs could heave a pretty damn big ship into orbit, But the fear of fallout from hundreds of little atomic bombs going off in the atmosphere is anything but irrational. One of the principles of the project, Freeman Dyson, specifically stated that the risk wasn't worth it. (I mean, maybe if there was a big asteroid on the way . . .)
And . . . jeeze:
"Water, when exposed to vacuum, freezes."
No, it evaporates.
Re:Huh? (Score:5, Informative)
And . . . jeeze: "Water, when exposed to vacuum, freezes."
No, it evaporates.
Or to be more precise, it evaporates, and the loss of heat due to the latent heat of vaporization results in cooling, which in turn results in freezing when the temperature gets sufficiently low (after which point you will still have some cooling due to sublimation of solid ice)..
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Even in the case of fission/thermal rockets (e.g., NERVA), only about a third of the thrust of chemical rockets. They are less suitable for getting stuff into orbit than chemical rockets.
The thrust is lower, but so is the mass of the engine and fuel. When used in second or subsequent stages this means you can be carrying a bigger payload and still be traveling faster after the first-stage burn, meaning less thrust is needed from subsequent stages to reach orbit.
However it's hardly a revolution in lift capacity given the revolution in power source. Doubling the payload is an impressive gain, but is it impressive enough to actually build and operate and fight the political battles when inst
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Water, when exposed to vacuum, freezes. It expands when it freezes, sealing any holes made by micro meteorites or space junk.
Water freezes. Ice sublimates. Water would make a very poor hull material because it would quickly evaporate into space. Having it fill small holes may work, or it may just allow the precious water supply to leak through those tiny holes.
I also thought of keeping the water on the outside, but the question I have is whether the water will become radioactive itself. The coolant used in nuclear plants becomes radioactive. I haven't looked into the process, but if your water supply became radioactive, the
Re:The Best Solution Ironically is Nuclear Rockets (Score:4, Informative)
The coolant in nuclear power plants is radioactive *mainly* because it has small amounts of insoluble stuff (commonly called "crud") suspended in it and soluble stuff dissolved in it that are radioactive, mostly Na-24 and Cl-38. Just a teeny little bit of cobalt from alloys in valves and pumps getting into the coolant and getting activated to Co-60 contributes a majority of the long-lived radioactivity of reactor coolant. There are some water activation products but they are smaller contributors and have short half-lives.
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Yes, ice sublimates. But it's a relatively slow process, one that allows for patching. If the hull breach leads straight to air on the other hand you have explosive decompression. So which would you rather have, a slow sublimating ice leak that will leak out your water supply in about 7 days or an explosive decompression that kills you in 7 seconds unless you're fortunate enough to have a bulkhead between you and the strike?
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Yes there are other options. How many are as elegant or efficient?
Take a 1 foot thick shell of water around the crew compartment. Water is one of the best radiation deflectors there is, but also a very good insulator. Plus, it will flow to redistribute itself. If the craft doesn't rotate the water nearest the sun will expand and flow away to the dark side of the craft, while that cold water will move back creating equilibrium within the whole.
I don't know the specifics of the radiation uptake of water - i
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But building a spacecraft or spaceship with such a concept in place will take a monumental increase in lifting capacity. We've taken chem rockets about as far as they are going to go - nuclear is the way if we can ever get over our irrational fear of the stuff.
Or we could give up on the idea of lifting entire spacecraft and every component on them in a single launch. Think less like Apollo and more like the ISS. Lift components separately on cheap, commodity rockets, assemble in space, lift water and fuel in separate launches.
It's not as sexy as the giant launcher, but much more flexible. Also more attainable.
We're quite a ways from nuclear rockets even if the environment were politically amenable. I think we'll need quite a while of demonstrating vastly impr
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Well said. I think we should also point out that there are many possible lift technologies that generate acceleration a human could not possibly live through. Those same technologies could be very cheap though.
The idea of one giant rocket pushing the crew and everything they need into space all at once should of been abandoned long ago.
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We had a nuclear rocket, NERVA. It worked quite well, had a number of successful ground tests with no failures IIRC, and was ready for a flight test. It was killed for political reasons in 1972 during the Nixon administration, along with Apollo and all Apollo follow-ons.
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Correct, or almost so. The NERVA rocket did produce thrust, but leaked . The leaks were due to erosion of the pipes at supersonic flow. The system worked by injecting a working fluid (liquid Hydrogen, liquid Helium, or liquid water.) into pipes (nozzles really) that ran through a working reactor. The reactor was designed to be very high temperature. The working fluid was heated to around 2000 degrees C before emerging from the rear of the engine. The system did work, but the thrust levels were not high enou
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Eh, I don't think our fear of radiation poisoning is that irrational. Nuclear powered rockets do sound pretty useful though.
Re:The Best Solution Ironically is Nuclear Rockets (Score:4, Informative)
Check out "Project Pluto" some time. It was a nuclear-powered ramjet cruise missile. At some point they realized that simply flying the dirty engine at low-altitude mach 3 over anything was about as bad as actually bombing the target. The stuff the engine spewed out the back was so bad that there was no safe way to flight test it, and you could never fly it over a friendly nation on its way to a target.
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That's true, but by the time you add the weight of a heat exchanger to a nuclear ramjet, I suspect the best you'll do is a nuclear-ramjet-powered car or boat.
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Unless the idea was that the water should be frozen to begin with, I don't get this. To remain liquid in order to later be frozen, it would have to be kept pressurized and heated, right? Exposing it to vacuum would then at least involve a short period of boiling?
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It would absorb the same types of radiation as other organic matter (Like human tissue), and as a bonus the radiation would tend to kill off any lurking pathogens.
Passive shielding has diminishing returns. (Score:2)
Shielding is primarily used to take care of the low-hanging fruit when dealing with space radiation. There are some really high energy particles out there which are simply impractical to completely block with passive shielding.
Furthermore, energetic particles do the most damage when they are low-enough energy that object they hit can just barely stop them (at the Bragg Peak [wikipedia.org]), whereas very high energy particles are more likely to pass right through without interacting. If you have a relatively uniform distri
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At the Target NEO [targetneo.org] meeting, "thermal nuclear" was one of the propulsion types on the table. It's only been
By the way, "primordial" asteroids contain water, and one of the ideas we discussed at lunch at that meeting was to stick down a pipe to get water to fill those shielding tanks, which would really cut down on the lift required. This would make a very interesting target for a NEO mission.
It's only been 39 frakking years since NERVA was canceled.
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Actually, it does both, at the same time!
You lose some water to evaporation, until the ice forms and blocks the hole. After that, you lose some to sublimation, until it passes the lower temperature limit for that process (around -60 degrees C.). The the losses stop. That's why comets can form and keep intact in the outer solar system.
To work well in a spacecraft, you would want to have a high reflectance outer surface. Letting the water freeze before any hole formed would also help limit water losses, but m
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Without knowing how you would build a nuclear powered rocket, there is no way to know how much radioactive fallout would be generated.
The NERVA system would have lost around a half pound of uranium mixed with 5% plutonium on a single launch. spread out over the hemisphere, it isn't really much. Since the Uranium is naturally occurring anyway, there is always some uranium dust in the air anyway.
The Orion system, on the other hand would have left several tons of plutonium in the atmosphere after each launch.
T
ICE (Score:2)
IIRC there was an SF story by A.C. Clark where a space craft used a huge block of ice as a radiation shield.
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IIRC there was an SF story by A.C. Clark where a space craft used a huge block of ice as a radiation shield.
Probably work great until the thing has totally sublimated.
They'll probably develop something which captures it in a magnetic envelope or has a game of kick about with particles and nano-tubes, then find the composite material of a standard childrens rain coat works just as well.
Radiation is funny that way.
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IIRC there was an SF story by A.C. Clark where a space craft used a huge block of ice as a radiation shield.
Probably work great until the thing has totally sublimated.
I've followed most of this whole freeze vs. sublimate thread thus far, but your comment raises what should be an obvious question: if ice sublimates so readily and quickly in space that it's not considered suitable as a shielding material, how do things like the rings of Saturn continue to exist? Last I heard, the rings are thought to be composed of various ices, some of which is likely water ice.
The rings have been there a long, long, *long* time and haven't sublimated away, yet they don't appear to be c
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The Songs of Distant Earth, 1986
http://en.wikipedia.org/wiki/The_Songs_of_Distant_Earth [wikipedia.org]
Blocks of ice were frozen on-planet and then lifted with a space elevator to create a shield. The shield was there to protect against micrometeorites and other space debris though, not radiation.
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I believe you're referring to _Songs of a Distant Earth_.
Personally, I'm more amused by _A Prelude to Space_, in which Clarke directly asserted that a chemical rocket could never reach the moon.
As a matter of interest, why do you use underscore characters instead of quotation marks or italics to enclose book titles?
Harness the energy (Score:3)
Is it possible that an active magnetic envelope could be devised that would capture radiation and particles at the front of the craft and accelerate it to the rear. There is not a lot of interplanetary debris, but what is there would be devastating as the craft approaches a significant fraction of c. Shielding would be necessary for both radiation and particulate matter. If the particles and ionized radiation could be harnessed, the craft could move through space much like a jelly fish.
Ion deflection (Score:3)
The other issue is generating magnetic fields is non-trivial and usually requires heavy equipment, i.e. permanent magnets, coils and iron cores. Any workarounds on this?
I think gamma rays might still be a significant problem.
BTM
Random thought from an ignorant person (Score:2, Insightful)
What if there was a superconductor that was saturated with electrons, would that be effective at blocking electromagnetic radiation? I'm asking at more of a theoretical level, and I am ign
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Radiation consisting of heavier particles, such as protons or nu
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then the cold vacuum of space would keep things cool
Correct me if i'm wrong but I thought space, while being cold, was relatively shitty at cooling things, since the only way to transfer heat in the relative absence of atoms was radiation which is very slow?
Russian technology! (Score:2)
The good old MIR had a much better shielding than the Internationale Space Station. The simple reason: It was so massive with so much junk around the module. Now they want to be fancy, light, and efficient.
Fools, I say!
Once the space elevator is finally running, we might be able to go back to nice and heavy, with a lead, paraffin, moon-rock mixture.- Who knows, the first interplanetary cruiser might look like Red Dwarf.
In other news ... (Score:2)
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I'm pretty sure people that live here [hell2u.com] get plenty of iced water. It tends to freeze over every single year, actually.
Can't they just...?? (Score:2)
(a) Polarize the hull plating
(b) If that doesn't work, I recommend bypassing the quantum phase-modulator arrays in the plasma conduits, thereby frequency-limiting the gravimetric fluctuations in the warp nacelles and hopefully inducing a soliton static-warp shield-harmonic attenuation grid over the triassic subresonance field.
Obligatory Simpsons (Score:2)
Rad-Away (Score:2)
Just supply the crew with enough Rad-X and Rad-Away.
And don't forget some extra water chips, just in case.
Re:Japan (Score:5, Informative)
Nope. Completely different type of radiation.
In space, the main problem (unless your spacecraft is nuclear-powered) are high energy cosmic rays.
In Japan, the issue is with radionuclide contamination.
Also, NASA's looking for a way to keep external radiation out - in Japan they're trying to contain radioactive substances within a vessel that contains superheated water that is pressurizing it, water which is unfortunately radioactive (resulting in the steam being radioactive if they vent it)
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If they could remove the heavier elements out of the steam (perhaps by forcing it through a distillation column as it escapes?) the H2O wouldn't be an issue.
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As far as I remember the biggest threat to astronauts is from cosmic rays, which are charged particles and require shedloads of shielding if you want to stop them with a passive shield.
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Neutron radiation is neutrons. The #1 neutron-stopper in use is water (or other stuff high in hydrogen).
Re:Am I being naieve... (Score:4, Informative)
Alpha particles are blocked by a thin sheet of paper, so no risk to astronautics as long as the alpha particle producers stay outside the craft
Secondary gammas release on impact. Ouch.
Beta particles are neutrons
No electrons.
Gamma rays are an electromagnetic wave, like light, and hence also can't be deflected by an electric field.
There are other types of radiation, but I got the feeling they were rare (ie. not found except in particle accelerators) - can someone correct me?
Not really. nuke radiation is pretty much defined as alpha beta and gamma "waves/particles" plus our mostly artificially generated pal, the neutron. If we could make muons or other particles in bulk we'd probably add those. Delta waves and stuff are only found in star trek technobabble.
The concept of "rare" is kind of vague in particle physics.
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Not really. nuke radiation is pretty much defined as alpha beta and gamma "waves/particles" plus our mostly artificially generated pal, the neutron. If we could make muons or other particles in bulk we'd probably add those. Delta waves and stuff are only found in star trek technobabble.
The concept of "rare" is kind of vague in particle physics.
Don't forget the odd decay by positron emission. (and subsequent annihilation radiation when that hits your passive shielding)
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I think what they are really worried about are very high energy cosmic rays, can be protons, but also can be atomic nuclei (I believe that Iron nuclei have been detected in UHECR's, for example). If these hit shielding, they will cause a shower of secondaries that would be quite dangerous (on the Earth, this happens many km up, so it's not dangerous here on the ground). It might be possible to use multiple shield with a gap, but that make for a big structure. Deflecting these away from the spacecraft would
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The universe is a big particle accelerator. Cosmic rays are one of the biggest dangers and they're mostly protons or helium nuclei, which can certainly be deflected by electric or magnetic fields. Likewise, the solar wind is mostly protons and electrons, both of which are charged and can be deflected.
Not nuclear radiation (Score:3)
I'm taking a course right now about how to predict and mitigate space radiation effects in electronics. We may have skipped over radiation that harms humans but not electronics, but here is what I know.
The radiation you are talking about are the all result of nuclear decay. In science/engineering the word radiation can refer to any type of electromagnetic or energetic particle which is radiating from an object. Nuclear radiation generally isn't a concern in the space environment (unless you are carrying som
huh? (Score:2)
Alpha particles = helium nucelus
Beta particles = electrons and positrons (not neutrons)
Gamma rays being EM waves, might be deflected by electro magnetics...
Some others common forms of ionizing radiation...
Neutron radiation = neutrons (you got that mixed up with beta), basically how current fission nuclear reactors chain and how C14 carbon dating works.
Proton radiation = mostly cosmic rays, but also used for cancer treatment
The problem with cosmic rays which are mostly proton radiation (but also include all
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Gamma rays being EM waves, might be deflected by electro magnetics...
F
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And how do you suppose they'd see where they are going then? Ha? Ha? Have you thought about that?
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Just crew the ship(s) with Japanese astronauts. ...
What? Too soon?
Yes, this rare situation is much to serious to be made light of.
Wait till it's well done before making such jokes!
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... plus 40 miles of gaseous envelope to trap what gets through, and secondary particles ...
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This is Slashdot!
How dare you not want to send humans as soon as possible for Star Trekful fapworthy adventures despite the fact they are useless for actually "exploring" space since their function is still to operate remote systems?
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Well, the "telerobotics" would be an issue on Mars when you figure that there will be a delay between 4 and 20 minutes. So the whole "Wait, stop! That looks interesting!" part becomes a bit trickier.
Yes, it's not like they could just turn round once and go back once they received the instruction twenty minutes later or anything.
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Creates a few, too. Ever tried using a mouse that took a second to start working and a second to stop?
Yes, TF2 has been laggy today... but anyway, it won't be such a problem if one can endow the robot with an intelligence on the order of, say, a mouse.
Re:Taking advantage of the situation(says a moron) (Score:4, Insightful)
Your mindless trashing of NASA is revolting. The people at NASA are dedicated professionals. I doubt you have the qualifications to mow the lawn at a NASA facility, given the shear ignorance of your statement. I assume that you trash talk you betters because you are both stupid and vile. You are most likely incapable of tying you own shoes, so your only response is to slander people who have real accomplishments.