Cheryl, you have obviously never been in any sort of "pressure cooker" situation or you wouldn't be so narrow minded about this. People have different strengths and weaknesses. Of course he is going to be calm when he traveled to the moon. It was his job, and any sort of screw up in an operation like that could spell disaster. Being calm in those sorts of situations was probably one of the main reasons he was chosen; you can't exactly go apeshit whenever an alarm starts buzzing.
It is comparable to soldiers being diagnosed with "shell shock" after they had already returned from active duty. When you are in the heat of the moment, you aren't thinking about the big picture. Not the repercussions, not the fame of an historic mission, not even whether or not his hot blonde neighbour will sleep with him now that he's famous. He did his job, returned, and finally had time to sit back and think, "Wow, was I really just on the moon?" (Well, assuming all of this actually happened. He could be lying, of course, but this is far from proof).