A novel method for on-orbit measurement of space materials degradation.

The low Earth orbit (LEO) environment is considered hazardous to spacecraft, resulting in materials degradation. Currently, in order to evaluate the degradation of materials in LEO, a retrieval of space exposed samples is required. In this study, a novel approach is proposed to evaluate degradation of materials in LEO without the need of retrieval. The method is utilizing photovoltaic cells (PVCs), an existing component onboard of any satellite. The PVCs are coated by various materials which are sensitive to different LEO constituents, such as atomic oxygen (AO) or ultra-violet (UV) radiation. The method's acronym is ORMADD (on-ORbit MAterials Degradation Detector). The ORMADD's principle of operation is based on measuring the PVC output power which depends on the cell coating material's optical transmission. Erosion of the coating by AO or coloring due to UV radiation affects its optical transmission and, accordingly, the PVC output. The ORMADD performance was tested using different coatings, such as polyimide and amorphous carbon (sensitive to AO), and siloxane based coating which is sensitive to UV radiation. The proposed ORMADD reveals sensitivity to different LEO components and can be used either as material degradation detector or as an AO monitor.