Out-of-this-world pranks: From space apes to sandwich smuggling.

Astronauts are not above a good practical joke, as evidenced by some of the best pranks carried out in space. These include a contraband sandwich smuggled aboard NASA's first crewed Gemini flight, a gorilla suit worn by astronaut Scott Kelly on the International Space Station, and a fake alien encounter orchestrated by Canadian astronaut Chris Hadfield on April Fool's Day. These pranks show the lighter side of space exploration.