Trip To Mars Could Damage Astronauts' Brains

Hugh Pickens writes writes "Alex Knapp reports that research by a team at the Rochester Medical Center suggests that exposure to the radiation of outer space could accelerate the onset of Alzheimer's disease in astronauts. 'Galactic cosmic radiation poses a significant threat to future astronauts... Exposure to ... equivalent to a mission to Mars could produce cognitive problems and speed up changes in the brain that are associated with Alzheimer's disease' says M. Kerry O'Banio. Researchers exposed mice with known timeframes for developing Alzheimer's to the type of low-level radiation that astronauts would be exposed to over time on a long space journey. The mice were then put through tests that measured their memory and cognitive ability and the mice exposed to radiation showed significant cognitive impairment. It's not going to be an easy problem to solve, either. The radiation the researchers used in their testing is composed of highly charged iron particles, which are relatively common in space. 'Because iron particles pack a bigger wallop it is extremely difficult from an engineering perspective to effectively shield against them,' says O'Banion. 'One would have to essentially wrap a spacecraft in a six-foot block of lead or concrete.'"

Comments

Re:Not that big a problem.

[timeOday]

Wikipedia's entry lists asteroids among several other options:

Several strategies are being studied for ameliorating the effects of this radiation hazard for planned human interplanetary spaceflight:

1. Spacecraft can be constructed out of hydrogen-rich plastics, rather than aluminum.[31] Unfortunately, "[S]ome 'galactic cosmic rays are so energetic that no reasonable amount of shielding can stop them,' cautions Frank Cucinotta, NASA's Chief Radiation Health Officer. 'All materials have this problem, including polyethylene.'"[32]
2. Material shielding has been considered:
   • Liquid hydrogen, which would be brought along as fuel in any case, tends to give relatively good shielding, while producing relatively low levels of secondary radiation. Therefore, the fuel could be placed so as to act as a form of shielding around the crew. However, as fuel is consumed by the craft, the crew's shielding decreases.
   • Water, which is necessary to sustain life, could also contribute to shielding. But it too is consumed during the journey unless waste products are utilized.[32]
   • Asteroids could serve to provide shielding.[33][34]

   Magnetic deflection of charged radiation particles and/or electrostatic repulsion is a hypothetical alternative to pure conventional mass shielding under investigation. In theory, power requirements for the case of a 5 meter torus drop from an excessive 10 GW for a simple pure electrostatic shield (too discharged by space electrons) to a moderate 10 kW by using a hybrid design.[30] However, such complex active shielding is untried, with workability and practicalities more uncertain than material shielding.[30]

Re:Had this conversation a million times...

[dkleinsc]

One of the truly sad stories about Neil Armstrong post moon-walk: Up until 1994, he was carefully fulfilling all the autograph requests and would spend a couple of hours a day signing his own name. The reason he stopped was because people were requesting autographs (which were basically free + postage) and then selling the signed item for big bucks.

irradiation wasn't quite the same as a mars trip

[Anonymous Coward]

From the paper, you noticed that they irradiated the mice very quickly.

"using a foam tube holder positioned at the center of a 20×20 cm beam of iron ions accelerated to 1 GeV/ at a dose rate ranging from 0.1–1 Gy/min. Male mice received total doses of either 10 cGy or 100 cGy. Female mice received only a 100 cGy dose."

1Gy/min is a lot dose in a very short period. So for the female they gave all the dose in a timeframe measured in mins. At lower dose rates, cells repair the DNA damage better. I think that lower dose rates would be more likely to occur in a mars trip.

For those without much radiation background, 100cGy delivered in 1 min isn't the same as 100cGy delivered over 6 months.

It's more complicated than tat

[slew]

The moon is still slightly protected by earths magnetic field. The field doesn't just suddenly end; inverse square law, and all that.

Actually, the moon is usually not protected by the earth's magnetic field. The earth's magnetic field is greatly affected by solar wind so that the part of the field projecting towards the sun is squished and the part away from the sun forms a long "tail"

If you look at this website, you can see that the moon only spends about 6 days/month inside the earth's magnetic tail.

Not only that, extremely dilute atmospheric particles have been discovered on the far side of the moon - the moon is technically inside Earth's atmosphere.

I think this is just false. Although some missions have detected traces of an atmosphere on parts of the moon (e.g., Apollo detected Argon, O2, CO2, CH4, etc, and LRO detected H3), these are thought to be from outgassing or sputtering from material inside the moon itself. The reason that some of them are similar to earth atmopheric components are that the earth-moon system may have actually been formed from prehistoric collision

Re:Another reason we're stuck on this blue planet

[g253]

Include a link dude, people are lazy. http://en.wikipedia.org/wiki/NERVA

Re:The Trap, Yourself

[spidercoz]

Trace amounts? The entire northern polar cap of Mars is water ice, not to mention the sizable amount of ice locked up in Martian soil. There is enough water on Mars to fill the Hellas Basin and then some, possibly enough to turn the entire northern hemisphere into a swamp. As for the Moon, there is enough ice hidden in the polar areas to be useful as fuel for spaceships. In neither case is the amount so small as to be "meaningless."