Habitability Issues in Long Duration Space Missions Far from Earth

Living in space today means to stay at an altitude of about 400 km above the Earth surface, on the orbital International Space Station (ISS). In the '70s the man reached the Moon but a manned space exploration mission, beyond low Earth orbit and cislunar space, might significantly increase adverse psychophysical effects on human wellbeing. Nowadays, a manned mission to deeper space, such as for example to Mars, is one of the greatest psychological challenge that has never been faced by the humankind. Due to the enormous distance between Earth and Mars, astronauts sent to Mars will be the first human beings who will lose a direct visual link with their Home Planet. Human responses to this and other extreme conditions that might be encountered during long duration missions into deep space are still unknown. In addition, the acute and long term effects of altered gravitational input on the central nervous system and their impact on sensorimotor and cognitive functions need to be clarified to assure maximum performance capabilities during spaceflight and planetary explorations. Our current knowledge on psychological and cognitive effects of orbital spaceflights or analogue environments is not sufficient to reliably assess the specific risks of human mission into outer space. New psychological challenges of mission to Mars will be analyzed with respect to three different areas: individual response and small crew interactions in isolated, confined, and extreme environments (ICE); human adaptation and performance in different gravity environments; concept and methods of psychological countermeasures. The needs of crew members to effectively and safely live and work in space are now referred to missions orbiting around the Earth and have been managed through specific human factors requirements applicable to the ISS. Future manned exploration missions need to reinforce these requirements to design an environment suitable for a safe stay during manned space missions far from Earth. The recommendations of astronauts who have experienced long term stays in space are collected and analyzed to be translated into requirements to be implemented in future space habitats. The analysis of what we have now and what is thought to be relevant to ensure crew wellbeing and performance during long term stays in space is a critical step to assure the success of deep space human missions.