A material experiment for small satellites to characterise the behaviour of carbon nanotubes in space – operation and results

The CiREX2 experiment on the nanosatellite SOMP2b provides in-orbit study of carbon nanotube (CNT) and graphene materials under real space conditions. The mission was conceived to complement terrestrial experiments and represents a follow-up publication ( Abbe et al., 2019 ). Launched in January 2021, twenty samples, including single-walled, multi-walled, and composite structures, were exposed to low Earth orbit and electrically monitored. Following commissioning challenges and partial sample loss, measurements from late 2023 revealed clear dependencies of electrical behavior on orbital parameters and temperature variations. Notably, single walled (SW) carbon nanotubes samples exhibited accelerated degradation prior to re-entry, while graphene materials showed greater stability. These results highlight the limitations of ground-based simulations and the necessity of in-orbit validation to capture the combined effects of radiation, plasma, and thermal cycling. CiREX2 establishes an essential basis for the evaluation of CNT-based materials as lightweight, multifunctional candidates for future EMI shielding and structural applications in space systems.