The Exocube experiment is designed to address fundamental questions in exobiology concerning the response of microorganisms and biologically relevant molecular systems to space and planetary conditions. Biological processes and molecular mechanisms are investigated at the interface between biology, chemistry and physics, with particular emphasis on radiation-induced changes, microbial survival and adaptation, and the stability of biomolecules and membrane structures.

Exocube is part of the European Space Agency's ExoBio facility on the exterior of the International Space Station (ISS). It combines two complementary experimental investigations, ExocubeBio and ExocubeChem, which allow biological and chemical changes to be monitored in situ during space exposure.

ExocubeBio investigates the responses of microorganisms to the space environment using a miniaturized microfluidic system with in-situ optical density and fluorescence measurements. These measurements enable the monitoring of microbial activity and growth responses during the mission. Complementary ground reference experiments and detailed post-flight analyses of returned samples will provide further insights into microbial survival, stress responses and adaptation under space conditions.

ExocubeChem focuses on the stability and chemical evolution of biologically relevant molecules, including lipids and membrane-associated systems. Using in-situ Fourier-transform infrared (FTIR) spectroscopy, ExocubeChem investigates changes in molecular structures and functional groups during space exposure, complemented by laboratory simulations and post-flight sample analyses.

Building on the heritage of earlier space exposure experiments, including O/OREOS and OREOcube, Exocube combines time-resolved in-situ measurements with the recovery of samples for detailed investigations on Earth. Launch to the ISS is currently planned for 2027, followed by approximately six months of space exposure.

The results will contribute to our understanding of microbial responses to space conditions, the stability of potential biosignatures, and radiation-induced changes in biologically relevant molecular systems. These findings are relevant to astrobiology, life-detection strategies, planetary protection and future space exploration missions.