 The environment in space, you know, this is one of the big risks, is that you are in an environment that, of course, has the radiation, but even the environment itself is, you know, there are limited structures for protection. You have limited microbial diversity, so you're in basically a mostly somewhat sterile environment. You try to keep it sterile, but bacteria can grow in there. In the environment, you can have micrometeorites that can break through your spacecraft. You know, the environment, also you have changes in circadian rhythm. Instead of every...