Astronauts will use their feces as a radiation shield on 2018 mission to Mars

The Inspiration Mars Foundation’s audacious plan for a primarily private-funded, manned ship to Mars has more than a few challenges to overcome before its 2018 launch date, and it turns out the solution to one problem — dangerous cosmic rays — comes in the form of feces. The current plan calls for the two astronauts aboard the 1166-cubic-foot spacecraft to defecate into bags which would be used to line the walls of the ship (after extracting as much water as possible from the waste for reuse).a