Cosmic radiation, just how dangerous is it to humans

[sponge]

Hello,<br /><br />Ive been wondering of late just how fatal is cosmic radiation to humans, Its just that with all the talk of interplanetry travel, if and when we get a man to Mars, it seems our only block to achieve this, is the cosmic radiation, could it turn out that maybe it could be beneficial in certain quantities, who knows, but does anyone have any real ideas how to shield it effectively, and how much do we really know about its properties, sorry if this post sounds a little nieve to some of you science buffs, but of what i do know about it is that it can penertrate the normal shielding say of lead or concrete please correct me if Iam wrong. <div class="Discussion_UserSignature"> <p><em><u>SPONGE</u></em></p> </div>

 

[nexium]

Authorities seem to differ over a wide range. My guess is average life expectancy is reduced by 10 years, if you spend 30 years in LEO with little or no radiation protection. If you cower in a tiny shelter during CMEs, perhaps there will be only 2 years of reduced life expectancy. The hazard at least doubles in the ionized layers at a few thousand kilometers altitude. Then drops off a little beyond GEO altitude = 36,000 kilometers. Even so an occasional person will survive to age 90 or age 100. The consensus seems to be a centimeter of aluminum shielding = to about a millimeter of lead shielding is a waste of mass as the very energetic particals produce a shower of particles which are more destructive to humans than the original very energetic particle. A centimeter of aluminum does, however, stop nearly all the the alpha, beta, ultra violet and X rays. Much thicker is needed to stop gamma rays. By weight, water is about as good as other mass but has the advantage that we may need the water at our destination. The radiation is beneficial very long term as it occasionally produces a useful DNA change, but for the trip to Mars, no benefits at all. Please comment, refute and/or embellish. Neil

 

[docm]

Perhaps the strongest "cosmic ray" (a misnomer since they're particles, not photons) was the legendary "Oh My God" particle. It was a proton with an energy of >10^20 electron-volts, that of a tennis ball traveling at 53+ miles per hour. Since then about 16 other such events have been detected with similar energies, probably related to massive black holes. Thankfully they're scarce. <div class="Discussion_UserSignature"> </div>

 

[ashish27]

Can't spacesuits cut off cosmic rays?

 

[MeteorWayne]

Not at all.<br />For cosmic rays (which are actually particles) a spacesuit it thinner than tissue paper.<br />It's like it's not even there. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[kyle_baron]

On the program Mars Rising (Science Channel) cosmic rays are a top priority beyond LEO. They test materials for repulsion of the rays. A simple plastic (polyethelene) did a satisfactory job. Aluminum, which most space craft are made from actually INCREASES THE INTENSITY of the cosmic rays, within the spacecraft. An intense magnetic field surrounding the outside of the ship, seems to be the best choice. It is similar to Earth's magnetic field, only more concentrated. <div class="Discussion_UserSignature"> <p><font size="4"><strong></strong></font></p> </div>

 

[willpittenger]

Unfortunately, a strong enough field is going to wreck havoc on the electronics. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[billslugg]

The configuration of the shielding magnets will be such that the field in the crew compartment will be zero.<br /> <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[willpittenger]

Are we capable of generating a suitable field with the power available on a spacecraft? What about the mass requirement? <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[billslugg]

The field would be 5 Teslas, and would be generated by superconductors. I do not believe that any iron would be required. There is no need to concentrate the field into a small workspace. Quite the opposite, we are interested in the field configuration outside of the coils. Once the current flow is established there is no need to introduce additional power. The only power requirement would be to condense the boiloff. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[sponge]

I have too wondered about a magnetic field, in one of my very first posts on this forum, i mentioned it and was told that it would have little effect, as most of the radiation from cosmic rays collide with our upper atmosphere, hence having little effect on life once it reaches the ground, please correct me if Im wrong <div class="Discussion_UserSignature"> <p><em><u>SPONGE</u></em></p> </div>

 

[docm]

<font color="yellow">The field would be 5 Teslas</font><br /><br />And as a point of comparison the magnetic field in a medical MRI scanner runs 0.3 - 3.0 Tesla, and it too is typically generated by superconducting magnets....very often niobium-titanium. Some research devices run 20+ Tesla.<br /><br />How big? You can fit a medium sized MRI into a semi trailer and have enough room to maneuver around the machine for working and repairs, have an isolated control room and a bunch of accessories. <div class="Discussion_UserSignature"> </div>

 

[sponge]

heres an iea, is it possible to take a radioactive source as a form of protection, ie emitting a source directly at the cosmic radiation and some what making a compound of particles that cold be better sheilded by a common protective material.<font color="orange"> Im sure ill find out fairly soon if this is a dumb question haha)</font> <div class="Discussion_UserSignature"> <p><em><u>SPONGE</u></em></p> </div>

 

[willpittenger]

But what about the mass? The dimensions are of no help if it is too heavy to put into orbit or assemble there. <div class="Discussion_UserSignature"> <hr style="margin-top:0.5em;margin-bottom:0.5em" />Will Pittenger<hr style="margin-top:0.5em;margin-bottom:0.5em" />Add this user box to your Wikipedia User Page to show your support for the SDC forums: <div style="margin-left:1em">{{User:Will Pittenger/User Boxes/Space.com Account}}</div> </div>

 

[kelvinzero]

<font color="yellow">heres an iea, is it possible to take a radioactive source as a form of protection..</font><br /><br />No, this would be even less effective than using a machine gun to intercept the bullets of a bunch of people trying to machine gun you. The particles are too tiny and spread out. However the link below mentions one way of using charged particles to counteract others, by using them to conduct a current in a massive loop. The goal here is to interact with a large number of particles for propulsion though.<br /><br />Mini-magnetospheric plasma propulsion

 

[docm]

Above I noted that an MRI scanner produces a field of about 0.3 and 3.0 Tesla, with 1 Tesla being equal to 10,000 gauss. <br /><br />Care to guess how strong the Earths dipole field is? Just 30,000-60,000 <i><b>nano</b></i>teslas (nT) <i>at the surface</i>. Above the surface it weakens inverse to the distance. <br /><br />Create a field at least that strong that extends beyond the boundaries of the ship then inject plasma into it and you have an artificial magnetosphere plus a plamasphere, basically one helluva shield. <div class="Discussion_UserSignature"> </div>

 

[billslugg]

docm<br />Suppose we were make a shield around our ship that had the same deflection ability as the Earth's magnetic field.<br />Take the Earth's field strength times height. (60000E-9 T times say 1000 miles high) The result is 300 T-Ft. <br /><br />We would have to make our 3 Tesla shield about 100 feet thick. Difficult but not impossible. <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[ashish27]

So as I understand this, in the ISS the aluminium hull is only providing partial protection to astronauts? And when they are out spacewalking, there is no protection at all?<br /><br />What if an accidental Gamma Ray burst strikes? Astronauts are gonna die then?

 

[MeteorWayne]

The hull of the ISS or an EVA suit provide no protection from cosmic rays.<br />The earth's magnetic field (which the ISS is well under) provides some protection.<br /><br />A single cosmic ray hit won't kill anyone.<br /><br />A much greater threat is a piece of orbital debris (~90%) or a micrometeoroid (~10%) as far as causing fatal damage.<br /><br />Now a year or ten down the road, that cosmic ray may cause a cancer that leads to the demise of an astronaut (A risk they are all aware of, I suspect),<br />But in the short term, the risks are far higher from an impact of plain old "stuff", i.e. matter. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[sponge]

The shielding is needed for say when we go to the moon or another body in the solar system, thats when we get full exposusure from the cosmic radiation, as we are not protected by the magnosphere, there has been a couple of interesting ideas on this thread already, but one way or another, no space agency will risk a human to mars without adequate protection, normal sources of radiation , say cesium 137 and cobalt 60 use a lead lined pig for shielding , which has to swab tested regularly for leaks , as well as geiger counter test. The other forms of protection for earth based sources are Time - Distance - Shielding, this can be managed effectively here on earth, but in space you only have one you can rely on, and thats shielding. <div class="Discussion_UserSignature"> <p><em><u>SPONGE</u></em></p> </div>

 

[nexium]

Most of you are familliar with the mag loop space craft = a super conducting loop with a diameter of about 100 kilometers. It would function with Earth's magnetic field as a linear motor, producing a tiny, but useful accelleration. It would also propel with the aid of solar wind of particles, but not photons. It would also shield the crew from most of the particles in space. With smaller dimentions it is doubtful the shielding would sufficient. <br />Another similar proposed space craft, uses a giant bubble of ionized gas for similar propulsion. It also produces significant radiation protection for the crew. The latter is believed testable near term.<br />The super conducting loop is awaiting space rated superconductors that can tolerat very strong magnetic fields at licquid nitrogen temperatures or warmer. CNT with excellent specs is also needed to keep a reasonably strong ring from being too heavy. Neil

 

[sponge]

HiNeil, <br />Do you have any links for the ionized gas bubble, this sounds like a very interestng idea, id be keen to see how it works. <div class="Discussion_UserSignature"> <p><em><u>SPONGE</u></em></p> </div>