High-performance polyimide membranes for use in solar sail propulsion

Solar sailing is a propulsion technology that is capable of driving vehicles and artificial satellites in space without the use of chemical propellants or electrical systems. This propulsion utilizes the solar radiation pressure resulting from the momentum transfer of solar photons reflected off the sail membrane, which is made of an aluminum-coated thin polymer film. The choice of the polymeric material to be used as solar sail membrane is crucial aspect as it influences the correct deployment of the structure and its efficacy as propulsion system during the space mission. In this work, we synthesized several types of polyimides with aromatic chemical structure using different organic solvents, including a greener alternative to traditional toxic solvents such as dimethylacetamide, and tested their properties for potential use in solar sailing. Thin polyimide membranes with thickness below 3 μm were fabricated and their chemical and physical properties investigated using several experimental techniques, from infrared spectroscopy to calorimetry and water contact angle analysis. Results were used to assess the potential use of the in-house-made polyimide membranes for the Helianthus mission, a test study case of the research program on Solar Photonic Propulsion, which is under development jointly between Sapienza University of Rome and the Italian Space Agency (ASI).