Can Homo sapiens evolve into Homo spatius? For over 50 years now, we have been testing our human nature in our effort to conquer outer space, and still 30 years away from a possible human exploration of Mars, a question remains: Can our body take such travels? Will it ever adapt? Accelerated aging, muscular atrophy, slowed-down brain functions, euphoric hallucinatory spells - as soon as we leave our usual environment towards extra-terrestrial horizons, we face conditions which our bodies are unfit for. However, the pull of exploration is stronger and space medicine is at work to prepare astronauts for travelling to new worlds - in a near or more distant future. Combining human adventure and the exploration of the human body, this film offers unique insights into the physical and psychological effects of space travel on the Astronauts and measures the impact on medical sciences.