After his true identity is revealed, Snoopy must prove his worth to NASA.
Snoopy is crying with Charlie Brown, sad about being kicked out of NASA. Charlie comforts him, by saying how he never has won anything, but it doesn't stop him. Snoopy escapes back into the astronaut training facility, leaving Charlie Brown alone again. Snoopy and Woodstock redo all of the training, and C.A.R.A. is very impressed. She says that he can go on training into the facility.
The final test is to go into a pool, and feel how zero gravity will feel like in space. Woodstock, however decides to hang out in the pool on a floatie. Snoopy waves, but soon realizes that Woodstock will get washed away! Snoopy is stuck on a rope in the air, and swings the rope towards Woodstock. Snoopy has no choice but to take off his disguise to save Woodstock. C.A.R.A. recognizes Snoopy from the security cameras, and he is forced to be kicked out.
Snoopy and Woodstock regroup with Charlie Brown and the others, and they run to see the announcement of the new astronaut. The new astronaut turns out to be Snoopy, due to the fact that he and Woodstock did all the training. C.A.R.A. assigns all the kids a job at the space center, to watch over Snoopy during the flight to the International Space Station. Everyone throws Snoopy into the air, ready for the mission.