Well now I've seen some figures cited that say the Van Allen belts are not the barrier some would have us believe they were. A scientists says that at 35 r is the onset of radiation poisoning symptoms. But that the VA belts would only expose the astronauts to 20 r out and 20 r in, meaning that on their return they'd probably require treatment for radiation.
Meanwhile solar flares leave the sun at about a million miles per hour, so they would have 91 hours beyond earths protective shield to return safely. Thus the only radiation barrier left would be if the levels of background radiation outside earths protection were too high to survive. So far I've seen no one addressing this issue. If they were hit by a solar flare that would be 900 r, impossible to survive. But the timing would be everything.
Meanwhile solar flares leave the sun at about a million miles per hour, so they would have 91 hours beyond earths protective shield to return safely. Thus the only radiation barrier left would be if the levels of background radiation outside earths protection were too high to survive. So far I've seen no one addressing this issue. If they were hit by a solar flare that would be 900 r, impossible to survive. But the timing would be everything.
