CNS Damage in Mice Experiencing Mars-Voyage-Like Radiation for Six Months

This is not good news. We should expect that humans undergoing a Mars trip, with selectively vulnerable hippocampi and dependent on complex behaviors for survival, will fare even worse per unit time, and worse still over the closer to twenty-four months for the out and back that such a trip would take. Regardless of air, water and food requirements, this is yet another barrier to even colonizing the rest of our own solar system, much less getting to another star, and another reason why we might never see interstellar civilizations composed of planetary-surface-evolved organisms rather than machines. Paper here, summary here.