Your father was an astronaut, one of the ones who went up in a rocket but when he came back he was someone else. Same body, same face, different Daddy. You're certain of it.
"He was one of the best," the head of NASA will say to you during your interview today. "Any child of your father will always have a home at NASA."
Tell the head of NASA that the reason you've decided to become an astronaut is to go out there into space and find whatever it is out there that changed your Daddy into the blank xerox copy of the man that got sent back home.
The head of NASA will nod his head. "You aren't the first. In fact, there's a whole shuttle mission being staffed up with nothing but kids of astronauts who want to find the alien sons of bitches who sent their parents home full of static and dead stares. We want you on board."
The head of NASA will hand you a contract that says you want to sign on for The Mission To Find Out What Happened Up There.
You'll give the contract a quick read. "But you're sending us up there to wipe them out. Not to bring back. Not to study."
The head of NASA will say, "Of course." But he'll look away when he does because he doesn't want you to guess that the only reason you're being sent into space is because the beings who changed your Daddy and all the other Daddies aren't up there in the cosmos, they're RIGHT HERE IN THE NASA OFFICE BUILDING BECAUSE NASA IS RUN BY ALIENS! Also, once you're out of the Earth's orbit they're going to pump a gas into your craft that murders you all in a few breaths. You can't fight NASA, kiddo.