John Sisson has an interesting post about space mission simulations carried out by young people during the late 1960s: Books and Ephemera: Kevin Kelly, forgotten space celebrity (1968) – Dreams of Space

One of the most famous junior testing astronauts was a 14 year old boy named Kevin Kelly. He and groups of dedicated  youth tested the limits of survival in a space capsule and led the way to our landing on the Moon.  This October 30, 1968 story in Current Science the outlines these heroic efforts. Unfortunately this coverage was limited to a newspaper distributed in classrooms so few recognize this hero today.

Kevin spent a grueling 336 hours in a test capsule in order to prove that the human body was capable of a flight to the Moon. By locating the expensive test apparatus in the basement of a suburban house they were able to avoid harmful media exposure during the testing.

The Current Science article went on to describe other projects by student teams who simulated multi-day Gemini and Apollo missions.

As described in the HobbySpace Space Simulation section, there are still some schools and organizations who carry out elaborate space simulations with students such as the Columbia Aeronautics and Space Association (CASA)  at Hickman High School in Columbia, Missouri.