Testing equipment, procedures and even human resilience for future missions to faraway planets requires inventiveness. Volunteer astronauts can spend time in hyperbaric chambers, rollercoaster aircraft, an isolated base in Antarctica, caves, a sealed mockup spacecraft or even stay in bed, depending on the aspect you want to test and rehearse.
In this picture, scientist Lucie Poulet from the DLR German Aerospace Center is taking part in a two-week simulated mission on Mars held in February 2014 at the Mars Desert Research Station in Utah, USA.
Space agencies use simulations like this to research elements of sending humans into stressful environments. In space, help is far away, sunlight irregular, exercise difficult and social life is limited.