Space is a very hostile environment: no air, no water, no food, etc. Therefore artificial ecosystem must be developed offering life support to humans living for example on the surface of the Moon or embarked on a long journey to Mars. The creation of such a new ecosystem will allow to recycle waste products and supply essential food, water and oxygen. This is the objective of MELiSSA (Micro-Ecological Life Support System Alternative) which has been conceived as a micro-organisms and higher plants based ecosystem. This is a tool for the development of the technology needed for a future regenerative life support system for long term manned space missions. This story presents this unique pilot plant installed in Barcelona, Spain.