Space travel is a very interesting avenue with the upcoming missions to Moon and Mars. Space tourisms are also increasing drastically in recent years. A major obstacle with space travel is space radiation which space travelers encounter when leaving the protective layer of earth’s atmosphere. This radiation leads to an increased risk, for example for developing dysbiosis in the microbes of the gut or for developing colorectal cancer years later. With The Gut Microbiome Biomarker for Space Radiation Risk (MICROBIAN) project, we aim to unravel a biomarker to assess space radiation risk. Gut microbiome samples from different models are collected throughout the course of the experiment and Next Generation Sequencing (NGS) are employed to investigate the microbial shifts in the gastrointestinal tract (GIT). In addition, the microbiome analysis is linked to various analysis of the GIT samples. We are looking for signatures in the gut microbiome which could serve as ground work for a potential personalized countermeasure for space travelers for their long interplanetary space missions.