Astronauts on board the ISS have been tapping into the opportunity to obtain regenerated water for a long time - for example, from vapours and waste. The European Space Agency has gone several steps further further and offered the much-improved Melissa system - an alternative micro-ecological life-support system. It is designed to process each and every gram of human waste, turning it into oxygen, water and food. The most obvious goal is to save on the delivery of water and necessary products to the orbit. But the most important task of a closed artificial ecosystem development is preparation for long-term space missions: A flight to Mars, or a prolonged stay on the moon.