Current space missions to Luna and Mars are considering to use the resources, which can be found on‐site at the destination. This strategy named in‐situ resource utilization (ISRU) saves valuable pay‐load capacities during the rocket launch from the earth surface. Specifically, in mars missions it is intended to produce the necessary rocket fuel CH4 for the back‐transit to earth via water electrolysis and subsequent CO2 methanation. The present study elaborates this concept and examines the question if polymeric reactors are feasible for heterogeneously catalyzed reactions in applications beyond earth. The study aims at providing a theoretical backbone for a proof‐of‐concept. The evaluation is conducted theoretically by design considerations and adds experimental results to show the general feasibility of polymeric reactors for applicable reaction conditions. [ABSTRACT FROM AUTHOR]