With our recent conversation, this article is very timely.
http://lightyears.blogs.cnn.com/2012/02/10/astronaut-feels-spaces-toll-on-his-body/?hpt=hp_c2
Very good article... NASA does a pretty good job trying to shield astronauts against cosmic radiation, but there's only so much they can do since we really do not understand the long term effects these particles may have in the human body. It is very difficult to even calculate how effective these shielding efforts are.
Our atmosphere filters most of these particles, but in outer space the human body gets bombarded by them. These rays are energy charged subatomic particles, mostly come from our sun and travel well beyond our own solar system. Very interesting article indeed.
On this day 50 years ago (February 20, 1962) John Glenn took a ride on an Atlas rocket built by my union brothers and sisters here in San Diego. Ironically, this launch vehicle was designed not for human space flight, but rather for the extermination of the human race -- the Atlas was a Inter Continental Ballistic Missile designed to carry a thermonuclear warhead capable of destroying a large city. Following his successful launch, he orbited the Earth three times before braving a firey re-entry with a faulty heat sheild and a pack of retro rockets that didn't jettison as planned. He survived and splashed down in the Pacific Ocean 250 miles from his designated landing site. John Glenn today is 90 years old. He commemorated the 50th anniversary of his flight by talking with the astronauts aboard the International Space Station.
Here's a link to a documentary that I can't seem to embed:
http://www.latimes.com/news/nation/nationnow/la-na-nn-john-glenn-anniversary-20120220,0,2152346.story