A young child thinks about what it would be like to be an astronaut and go out on a mission into space. The book uses actual terminology, such as gravity, orbit, and satellite, in easy to read, simple sentences paired with colorful drawings.

Written by an astronaut, a small but plucky mouse named Mike is sure that he can help the Space Shuttle astronauts, and ends up saving the whole mission. Includes facts about NASA and space travel. His adventures continue in the sequel Mousetronaut Goes to Mars.