The “magic number” of people needed to create a viable population for multi-generational space travel has been calculated by researchers. It is about the size of a small village – 160. But with some social engineering it might even be possible to halve this to 80.
However, the key to conquering the final frontier is the space toilet
The European Space Agency has started building a recycling system that will convert astronauts’ waste into food, oxygen and water.