text:  Certainly, our post-mission period is following up with questions such as that. I think that those are things, though, that are big questions that will come out of all of these studies. As a scientist, I think that you always kind of think about that. Your experiments always lead to more questions than answers, of course. What were you expecting would be the hardest part of this mission? And I wonder if it was different than what ended up being the hardest part.