They have travelled 70 million miles through space to Mars and back without ever leaving a warehouse in Moscow.
Today the six crew members of the Mars 500 project will “land” back on Earth after 520 days in isolation on a simulated flight that aimed to test the psychological impact of a journey to the Red Planet.
Mission controllers at the Moscow Institute of Biomedical Problems have monitored their progress since the men — three Russians, one Chinese, a Frenchman and an Italian — were sealed inside a narrow complex of three windowless steel capsules on June 3 last year.
The hatch of their module is due to open at 2pm Moscow time (10am GMT) allowing the crew their first physical contact with their families