 I'm not familiar with Kosso's work, or at least not off the top of my head. I'd have to research to see if I've read it. I don't remember. But if he was making reference to radiation, radiation is an issue. If you're going to do interplanetary flight, you're going to have to work out some way to protect the humans in that interplanetary spaceship from cosmic rays and from solar wind radiation. You're going to have to protect them.