In life support systems, nitrogen recovery is a core objective through its valorization as gas, edible microbial or plant protein. In this PhD, the aim is to tackle a couple of Space constraints pivotal to the main nitrogen converting MELISSA compartments III(nitrificationà and IVb (higher plants). The goals are to (a) explore the use of membrane aerated hollow fibre bioreacter as a technology compatible with microgravity conditions, and (b) to implement innovative sensors for flexible yet robust monitoring/control mechanisms in both compartments III and IVb