When I've written for Bill Murray - I've written six films for him - people would read it and say, "Oh, that's so perfectly Bill. " He'd read it and say, "Are you kidding? I can't say these words. " So it's all about perception.
You have to be there not for the fame and glory and recognition and being a page in a history book, but you have to be there because you believe your talent and ability can be applied effectively to operation of the spacecraft.