Formation-of-arrays (FoA) distributed antenna technologyFormation-of-arrays (FoA) distributed antenna technologyhas recently been proposed to provide 5G-like mobile satellitesservices in the context of the integration of non terrestrialwith terrestrial networks. This large distributed arrayconfiguration (resulting from the formation of many satelliteseach carrying its own small antenna) must be carefullyengineered to provide the desired benefits. In this paper,we tackle the issue of optimal formation configuration toimprove the performance in terms of system power generationand beamforming design. To this aim, we proposean algorithm based on a formation thinning approach withsparse random placement of satellites on a grid, to optimizeboth beamforming and power generation.