does radiation get to the middle of asteroids?

[cameron marical]

well. the title is kind of my q. and, how does earth stop space radiation? also, hmm, what exactly is space radiation? and how do spacecraft block out that radiation?

[swansont]

You have to be more specific — radiation is any energetic particle emitted by something, and they do not all interact the same way.

 

The earth stops some radiation by absorption in the atmosphere — high and low energy electromagnetic radiation, for example — but lets a lot of visible (and NIR and UV) EM radiation through. Charged particles are deflected by the magnetic field, and lose energy on collisions with the atmosphere. Neutrino radiation mostly goes right through us.

[Martin]

Does radiation get to the middle of asteroids?

 

well. the title is kind of my q. and, how does earth stop space radiation? also, hmm, what exactly is space radiation? and how do spacecraft block out that radiation?

 

I agree that it would be good if you were more specific.

 

 

The space radiation considered a major hazard/obstacle to manned missions and bases on moon/mars etc. is charged particles---protons, electrons.

 

If that is what you are thinking about, the answer to your question is NO, it does not get to the middle of asteroids. A few meters of concrete, or rock, would afford excellent shelter.

 

Ice would also suffice. The largest asteroid is Ceres, if I remember, and it is believed to be covered by a think layer of ice. If people were ever to venture to Ceres they could find refuge from space radiation simply by tunneling down into the ice.

 

There is a lot via google with keywords "space radiation" and "space radiation shielding". A software company that specializes in calculating exposure is:

http://www.spacerad.com/

 

They are mainly concerned with trapped protons/electrons, and solarwind protons, and cosmic rays (which again means mostly protons).

Trapped protons means Van Allen belt stuff---magnetic field lines trap particles which then spiral around and whiz back and forth.

You probably know that solar wind is also largely protons. Spacerad.com talks about heavier ions, neutrons, and other stuff as well.

 

One problem with thin shields is shrapnel. A high energy proton comes in and shatters an atom in the shield and transfers its momentum to a lot of debris that continues on into the ship and can be just as lethal as the original proton. Aluminum is a bad shrapnel producer.

 

Basically you need something thick. Putting the fuel tanks around the crew's cabin. Or some people have proposed schemes using electrostatic deflection.

 

Surface missions on mars would require shielding. Light portable shielding is hard to think up. It is actually an interesting problem.

 

When I think of it, two things come to mind

1. going to Ceres and tunneling down into the ice (but how about shielding during the long trip?)

2. transferring my soul into a robot, so the robot can appreciate beauty, enjoy music, get ideas, solve equations, report impressions.

In other words indepth experience, by a proxy Robo-martin. Then the meat-bag Martin could stay at home in his nice warm wet planet

and let Robo-martin do the honors.

Edited February 14, 2009 by Martin

[cameron marical]

how big is ceres?i thought that eros is biggest. the discription i read stated it was like 5227 miles in diameter. also. how did the appolo block out the radiation?

[Martin]

i thought that eros is biggest. the discription i read stated it was like 5227 miles in diameter.

 

Eros is oblong, about 30 km by 10 km by 10 km.

http://en.wikipedia.org/wiki/433_Eros

Ceres is spherical, about 1000 km in diameter

http://en.wikipedia.org/wiki/Ceres_(asteroid)

 

Apollo mission did not have effective shielding. On the other hand they weren't out there for very long.

 

A more serious question is what about the International Space Station (and things like that) where there is longer occupation.

I don't know the details but I understand that when there is a solar storm

(a brief period of more intense radiation) there is a small central room where all the crew can huddle together. then they can't get any work done. they just crowd in to the small shielded closet and wait there until the radiation storm is over.

Maybe someone who knows more about this could take over and correct me if I am wrong.

Edited February 14, 2009 by Martin

[cameron marical]

that makes sense to me. would it just be like a thicker than other parts of the station outer layer? or something else like some special metal or allow. id guess that its the first. but if radiation in space is just photons, wouldnt anything thats not see through stop it? like any rock or metal out there thats not really thin?

[NowThatWeKnow]

... but if radiation in space is just photons, wouldnt anything thats not see through stop it? ...

 

Different frequencies are very different. X-ray is an electromagnetic radiation you are familiar with that penetrates and then you have gamma rays.

[cameron marical]

what about something like a mirror surrounding it. or at least something shiny. that would reflect everything right?

[NowThatWeKnow]

what about something like a mirror surrounding it. or at least something shiny. that would reflect everything right?

 

I am far from an expert but I did find this. Remember visible light is only a small portion of the EM range.

http://en.wikipedia.org/wiki/Uranium-238

"Uranium-238 is also used as a radiation shield — its alpha radiation is easily stopped by the non-radioactive casing of the shielding and the uranium's high atomic weight and high number of electrons is highly effective in absorbing gamma rays and x-rays. However, it is not as effective as ordinary water for stopping fast neutrons. Both metallic depleted uranium and depleted uranium dioxide are being used as materials for radiation shielding. Uranium is about five times better as a gamma ray shield than lead, so a shield with the same effectivity can be packed into a thinner layer."

[swansont]

what about something like a mirror surrounding it. or at least something shiny. that would reflect everything right?

 

Mirrors only reflect over some limited range of wavelengths.

[cameron marical]

but uranium is radioactive in itself right? along with lead i think, so would this really eliminate it? the iss uses the different things to help sheild it from radation, like the earth itself and aluminum and others. at least thats what the universe now website said.

[Martin]

... but if radiation in space is just photons, ...

 

It is not just photons. Please take another look at my post, Cameron.

I didn't say anything about photons.

 

The radiation they worry about is in large part protons. Very fast moving charged particles. Not photons!

 

There certainly is some electromagnetic (photon) radiation, like ultraviolet, Xray, gammaray, that can hurt you. But that is comparatively easy to shield from and it is not what they primarily worry about.

[cameron marical]

oh, i must have misread. woops. ok. so protons.hmm. thats alot tougher. well, for starters. what stops protons? obviously nothing that effective known to us right now, or wed be using it. hmm. what about electromagnetic waves? what effect do they have on protons? if any.? or antiprotons? do we know how to get them?

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Merged post follows:

Consecutive posts merged

if so, could we use them?

[Baby Astronaut]

what stops protons?

A few meters of concrete, rock, or deep ice.

[cameron marical]

oh, cool. goody. we might not have that on a space ship, but that does mean that no protons get to the middle of asteroids. maybe we could snag a meteor from near us whenever one comes and is at least like 15 meters thick. then we could dig a little tunnel to the very core. leaving an outside few meters of just rock. put some ion engines{or plasma, or other} and life support and all that other stuff spaceships have and use things like this for long distance space travel.[{god, so badly worded, i know, but i dont want to list all the things spaceships have}{like i can}]