 I think the most important evaluation criteria for a trade study are, does it lead where you need to go? Does it solve the problem that you're going to eventually find with enough space for mistakes? Suppose you decide early on, well, we're going to use such a material like Brillium. Does it leave you margin for error? What if the Brillium turns out to be harder to use than you think? Do you have a backup plan? Do you have to build a special factory, which we did? Can you afford the result? You have to be able to anticipate the steps that follow the decision that you're about to make. Nothing is ever finished when you think it's finished. You say, okay, we're going to use Brillium. Well, then there's many, many years in front of you before Brillium is really ready to fly. There's no possible way to anticipate all of that. So part of the decision process has to be, is this a robust decision? Are you protected in case you don't understand everything? Is there any way to go back if you have to? Would those glass mirrors ever be able to meet the requirements if you had to use them? So I think that's one of the most important criteria for a trade study. Is it really a final decision or not?