[ RadSafe ] Sickening Solar Flare

[Maury Siskel]

Here is an excerpt from the NASA story about a recent very high energy 
solar flare. The HPs among you can comment on the accuracy of NASAs 
account, but this seems a constructive example of  desirable 
communication with the public which provides meaningful comparisons. 
Additionally, it is, I think, an intrinsically interesting story 
containing a couple neat photos.

http://science.nasa.gov/headlines/y2005/27jan_solarflares.htm

And just for the fun of it, here is another site that some of you will 
enjoy:

http://science.nasa.gov/temp/StationLoc.html

Cheers,
Maury&Dog        maurysis at ev1.net

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The Jan. 20th proton storm was by some measures the biggest since 1989. 
It was particularly rich in high-speed protons packing more than 100 
million electron volts (100 MeV) of energy. Such protons can burrow 
through 11 centimeters of water. A thin-skinned spacesuit would have 
offered little resistance.

"An astronaut caught outside when the storm hit would've gotten sick," 
says Francis Cucinotta, NASA's radiation health officer at the Johnson 
Space Center. At first, he'd feel fine, but a few days later symptoms of 
radiation sickness would appear: vomiting, fatigue, low blood counts. 
These symptoms might persist for days.

Astronauts on the International Space Station (ISS), by the way, were 
safe. The ISS is heavily shielded, plus the station orbits Earth inside 
our planet's protective magnetic field. "The crew probably absorbed no 
more than 1 rem," says Cucinotta.

One rem, short for Roentgen Equivalent Man, is the radiation dose that 
causes the same injury to human tissue as 1 roentgen of x-rays. A 
typical diagnostic CAT scan, the kind you might get to check for tumors, 
delivers about 1 rem [ref 
<http://hps.org/publicinformation/ate/q708.html>]. So for the crew of 
the ISS, the Jan. 20th proton storm was no worse than a trip to the 
doctor on Earth.

On the Moon, Cucinotta estimates, an astronaut protected by no more than 
a space suit would have absorbed about 50 rem of ionizing radiation. 
That's enough to cause radiation sickness. "But it would not have been 
fatal," he adds.

<>To die, you'd need to absorb, suddenly, 300 rem or more. The key word 
is suddenly. You can get 300 rem spread out over a number of days or 
weeks with little effect. Spreading the dose gives the body time to 
repair and replace its own damaged cells. But if that 300 rem comes all 
at once ... "we estimate that 50% of people exposed would die within 60 
days without medical care," says Cucinotta.
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