Mechanical Concepts on Large Membrane Array Antenna Architectures

Increasing interest from the scientific community to utilize space-borne L- or P-Band radar antennas for remote sensing techniques specifies very large antenna apertures in future. Typical applications are biomass monitoring, measurements of surface displacement due to seismic activity, volcanism, or glacier flow, or the sounding of the ice shields. A common European interest in large antenna developments can be derived from ESA’s Technology Harmonization Mapping activities. A growing trend of antenna sizes is expected for higher sensitivity instruments. Severe constraints on antenna size were identified and very large apertures at around 30m dimension were found to be required. To comply with future requirements of huge space antennas, typical items such as volume constraints of the launcher, system mass, system stiffness, development costs, shape accuracy during operation, and risks must be carefully assessed prior to concept selection. Foldable membrane array antennas are attractive candidates, but since thin gauge films do not provide any stiffness, deployable support structures are required to stretch the large membrane adequately. At DLR, in collaboration with space industries, very light deployment concepts for support structures in space are being developed. Originally intended to span huge membranes for propellant-less solar sails, the concepts are evaluated now to be applied to very large deployable array antennas. The main focus of the present trade-offs aim at strict mass reduction, but membrane flatness and alignment requirements are in consideration as well