Lifting off from Kazakhstan in March 2016, the joint Europe-Russian ExoMars 2016 begins its seven-onth journey to Mars. Picture: ESA–Stephane Corvaja RADIATION sickness. Brittle bones. Alzheimers. None of these will deter explorers in their quest to establish a foothold on Mars, says Apollo 11 hero Buzz Aldrin. “Most people will say the big problem...