 Not enough data to know for sure how long term they'll last. Now, the word damage attracts me. I've avoided it, but here it is. DNA damage. What does that mean? Isn't DNA damage part of living? It is. DNA damage, I agree. We wouldn't want to say that when you go to space, you're assaulted with damage. But it is true that you do get radiated, and radiation can lead to DNA damage. And there's more radiation, so it's not surprising.