Radiation in space – the “nuclear deterrent” against astronauts

there are two things those astronauts have shown us. First, there are genetic changes and damage happening even within the relatively safe confines we’ve traveled thus far. Second, there is a hell of a lot we don’t know about how radiation exposure and risk works in outer space.

How space radiation hurts astronauts, Boing Boing,  Maggie Koerth-Baker, Jan 4, 2013    ”……We know the rates of cancer for survivors of the nuclear bombs dropped on Hiroshima and Nagasaki, but that radiation isn’t really comparable to the stuff in Galactic Cosmic Radiation. In particular, Cucinotta is concerned about particles known as HZE ions.

These particles are very heavy and very fast and we don’t experience them here on the ground. They’re the kind of things that get filtered out and broken down by Earth’s defense systems. But HZE ions can cause more damage, and different kinds of damage, than the radiation scientists are really familiar with. We know this because scientists actually compare samples of astronauts’ blood before and after a spaceflight.

Cucinotta calls this pre-flight calibration. Scientists take a blood sample from an astronaut before the launch. While the astronaut is in space, the scientists divide that blood sample up and expose it to various levels of gamma rays — the kind of damaging radiation we’re used to dealing with on Earth. Then, when the astronaut comes back, they compare those gamma ray-affected samples to what has actually happened to the astronaut while in space. “You see about a two-to-three fold difference across the population of astronauts,” Cucinotta told me.

One example of how HZE ions are different: They seem to be able to affect cells they don’t even touch. In non-human trials, these non-targeted effects can happen in cells up to a millimeter away from the cells that have actually been irradiated and we don’t really know what that means yet. But it definitely changes the way we think about radiation risks, which is a model based on the assumption of a direct, linear connection between dose and risk. With HZE ions, that might not be true….

there are two things those astronauts have shown us. First, there are genetic changes and damage happening even within the relatively safe confines we’ve traveled thus far. Second, there is a hell of a lot we don’t know about how radiation exposure and risk works in outer space….  http://boingboing.net/2013/01/04/how-space-radiation-hurts-astr.html

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