A Mars Mission's Greatest Challenge: Radiation

daSeiz writes "A New York Times article explores the possible effects of prolonged radiation exposure in deep space. Surprisingly, very little is known about the subject. We'll need to find innovative new ways of shielding spacecraft from fraction-of-lightspeed interstellar rubbish if we're ever to spend much time outside our own magnetosphere."

Moon kooks...

[Threni]

...love all this! they think radiation is what made the lunar landings impossible and therefore obviously faked!

Ways to protect the ship

[Janek Kozicki]

this problem is known, and Mars Society [marssociety.org] already has some solution [marssociety.org]for this problem.

Anyway if you also wanted to know about radiation on the planet Mars, be sure it is not [marssociety.org] dangerous.

Re:Yeah, make fun of it

[Prince_Ali]

Neil Armstrong and Buzz Aldrin would like a "word" with you.

Re:Bone loss

[donnyspi]

I was curious how long it would take to get to mars and back. Here [vanderbilt.edu]'s the answer:

"A mission to Mars would take about three years from launch to reentry, including 6-12 months of travel each way and a lengthy stay on Mars while the planets reach optimum position for beginning a return flight. (NASA)"

Re:Artificial Magnetosphere?

[GileadGreene]

I think you'll find that your questions will be answered by a look at this [washington.edu] site. It's all about Mini-Magnetospheric Plasma Propulsion (M2P2). They do exactly what you are asking for (create an artificial magnetosphere), and supply some nifty propulsion to boot. And no, it doesn't require megatons of molten iron, as some other posters have suggested...

Re:M2P2

[680x0]

This would not do any good unless the particles have a charge,

Well, according to the article, the particles about which they are worrying are mostly ions (as heavy as iron) which are by definition charged. Only gamma rays (which they didn't seem too worried about) and neutrons (which it implied would only be generated when other particles collided with the ships structural components) aren't charged (and are relevant in the context of solar radiation).

but still it could shield the crew and provide propulsion.

Yes, it seems it would do both. This seems like an exceptionally cool idea. The kind of thing that could make the difference between us getting there in the next couple decades, or getting there in another century or two (or never).

Re:Judging

[PhuCknuT]

It's a matter of altitude. Even at the altitude of the space station, there is a very very thin atmosphere which causes drag and lowers the orbit. Putting the station higher would reduce the 'orbital maintenance' but would greatly increase the cost of reaching the station.

Re:How about a

[AKAImBatman]

Even if this was TV, the deflector is the wrong tool for the job. The deflector sweeps particles out of the direct line of travel to prevent major accidents. That's very different from the shielding they obviously employ against radiation. If they didn't use some form of shielding, they would happily roast from their own engines! Most likely, they use some sort of EM field (built into the SIF maybe?) that pushes radiation around and away from the ship.

Now for the crux of the problem. Wouldn't an EM field only protect against some types of radiation? Both Alpha and Beta rays consist of charged particles that can be redirected via electromagnetic means. However, Gamma radiation consists of nuetrons. Nuetrons are inert and won't react to an EM field. (Or will they?) As a result, a significant amount of mass would still be needed as shielding.

Re:Judging

[Charvak]

Though moon is freely falling to earth, its actually moving away from the earth at a very slow rate(due to tidal forces)

Re:Yeah, make fun of it

[SuiteSisterMary]

Are you being serious? Those fine folks went through said radiation belt just fine.

Assuming you are, learn [nasa.gov] from your betters.

Dr. Stern calculated that the solar cells of a satellite passing through the inner Van Allen belt, shielded by only 1 mm of glass, would receive about 25 rad of radiation per pass. Particles in the outer belt are less penetrating. Anything over about 200 rad is dangerous to humans and about 500 rad can be lethal. Fortunately, it doesn't take much shielding to deter the particles, and the shielding doesn't need to be constructed of rare or exotic metals.

Re:Problems Like This

[bravehamster]

just bury them underground. That's hardly what I think Zubrin and company want.

Umm...guess you haven't read his book. That's *exactly* what Zubrin wants, and advocates in his book "A Case For Mars". Just because someone wants something very badly does not mean they are blind to the realities of their dreams.

Re:How about a

[680x0]

However, Gamma radiation consists of nuetrons.

No, actually gamma rays are electromagnetic radiation (if you insist on having a particle, think "photon") of a particular range of frequencies.

Neutrons are neutral particles found in the nucleus of most atoms (hydrogen-1 being the only exception). They are liberated when something else colides with the nucleus, such as another particle (charged or not) or a burst of energy.

Re:Judging

[Anonymous Coward]

Wrong. The moon is increasing its mean distance from earth at a rate of 3.8 cm/year. You can look it up [google.com] yourself.

Re:If the Martians start flying into NY buildings.

[Captain Morgan]

If the Martians start flying spacecraft into buildings on Manhattan Island and mailing anthrax around the US, I'm sure that BOTH parties will agree with you.

This is all rubbish. The 9/11 hijackers were Saudi, there is no evidence that Iraq had anything to do with 9/11 and the anthrax mailings appear to be domestic.

In this case it really does look more worthwhile to have gone to Mars.

Chris

Re:Judging

[fenix down]

The earth's rotation is slowing down (.0000002 seconds a year or whatever) due to the tidal interaction between the moon and us. That energy has to go somewhere, so the moon's orbit is raised (by .000002 meters a year or whatever). If you let it play out over twice the lifetime of the universe or so, the month and the day would eventually equal eachother, for reasons which I used to understand, but couldn't explain for shit.

it's so obvious!

[MOMOCROME]

There is a drive technology called "Mini-Magnetospheric Plasma Propulsion [washington.edu]", or m2p2, that in effect creates a large scale magnetic bubble around a spacecraft.

In the current incarnation, it is intended as a solar-sail like drive for very low-mass probes. However, attached to a larger mass, like an interplanetary vehicle of the scale suitable for human occupancy, it would barely impart momentum at all, which would make it unsuitable as a drive technology.

Though it would work wonderfully to shield the vehicle from the solar wind and other problematic radiation.

The crazy thing is, though a portable magnetosphere is so obviously a crucial requirement for trans-planetary travel, there isn't a single resource available through my above-average googling skills. The technology is either so far removed from mainstream mission planning circles, or...

Shipping food and water to orbit can be CHEAP!

[CSG_SurferDude]

While putting people in orbit is tricky and expensive, there is a way to put food and water into space very cheaply: Superguns! [friends-partners.org]

Re:Not the only issue

[Anonymous Coward]

the combination of the extended stay in low G combined with the other half in zero G will turn most people to jelly. You're probably looking at around 25% bone loss here. Not just the bones you normally think of, but your teeth will rot and fall out as well with these kinds of trips. Even with exercise, muscles, ligaments, and tendons will atrophy significantly.

wtf are you talking about here? you're making all of this up. gravity does not 'magically' keep your bones dense - your body maintains bone density depending on how much impact the bones receive. paraplegics have trouble with bone loss and atrophy in their legs too - but their teeth don't fall out. the parts of the body you use will be fine - muscles, tendons, mouth, etc. The parts that don't get used - legs, long bones, etc will atrophy.

Re:Bone loss

[catfry]

Actually I believe many of the astronauts on the ISS claim that the loss of bone mass has been drastically reduced with the kinds of excercises they are doing on a daily basis. Although the problem hasn't been completely eleminated read for example this letter from expedition 7 crewmember Ed Lu [slashdot.org]. "We have some indications that we may be close to solving the problem. In fact, one of our main goals this mission is to see if we can replicate the very good results obtained by some previous ISS crew members in preventing bone and muscle loss"

BBC article about mars radioation.

[tiger_omega]

Oddly enough there is an article over at the BBC [bbc.co.uk] about how it looks like the radiation levels on mars are low enough to support a human mission.