Cyanobacteria may become central components in biological in situ resources utilization (ISRU) on Mars. Their cultivation will rely on a photobioreactor-based system, whose design and modelling are currently being worked upon. The project proposed here aims at contributing to the development of this system and to the assessment of its cost-efficiency (using equivalent system mass as a main metric) through a model-based systems engineering approach. The overall system will be considered but a higher focus will be given to the gas management subsystem.