Six men spend 520 days sealed in a Moscow mock-up
Mars-500 ran a Mars mission at full length with nobody leaving the building. Four of the six crew came out with a sleep or behavioural disorder.
On 3 June 2010 a hatch closed on six men inside windowless steel modules at the Institute of Biomedical Problems in Moscow, and opened again on 4 November 2011. Alexey Sitev, an engineer, commanded; Sukhrob Kamolov was the surgeon and Alexandr Smoleevskiy the physiologist. With them were Romain Charles, a French engineer, Diego Urbina, an Italian-Colombian engineer flying for ESA, and Wang Yue, an instructor from China's astronaut training centre.
Mars-500 remains the only time anyone has run a Mars mission at full duration: roughly 550 cubic metres of sealed volume, all consumables loaded in advance, radio traffic held back to mimic the light-time lag, which ESA stepped up from 8 seconds to a maximum of 736 seconds, just over twelve minutes, on flight day 351. The crew flew out for 250 days and entered simulated orbit. On 14 February 2011 Smoleevskiy and Urbina suited up and stepped into a chamber dressed as the Martian surface; two more Marswalks followed on 18 and 22 February. Then a 240-day cruise home.
Active wakefulness fell 7 percent across the mission, and by the final quarter the crew averaged 1.12 fewer hours a day awake and moving than at the start, with sleep up 8.4 percent. One crewmember's sleep-wake cycle drifted off the 24-hour day, averaging 24.98 hours. Another averaged 6.54 hours a night, rated his sleep quality worst of the six, and accumulated errors on the reaction-time tests. Four of the six finished with a measurable behavioural disturbance or sleep disorder, and one reported depression symptoms in 93 percent of mission weeks.
Over 520 days the crew logged 41 conflicts with mission control against 8 among themselves, two crewmembers accounting for 85 percent of all perceived conflict.
The simulation left out weightlessness, radiation and any possibility of dying, and everyone inside knew the hatch could be opened in minutes. A real crew would have none of those exits and would reach the surface deconditioned. Nobody quit and nobody was pulled out.