Skylab 4, with three astronauts, was launched in 1973. The crew (Commander Gerald P. Carr, Pilot William R. Pogue, and Scientist Edward G. Gibson) spent over 84 days in space, returning to earth on February 8, 1974. Daily life in space is much different from daily life on earth. Marianne J. Dyson wrote a very interesting book, Space Station Science: Life in Free Fall. She provides some easy and fascinating experiments. I like her chapter on space bathrooms.