Light-trapping helps enhance the light absorption in space solar cells and hence enables their thickness to be reduced to increase the radiation hardness. We have optimised light-trapping structures (LTS) inspired in the diatom frustule and moth’s eyes. As a solar cell reference, we use the commercial 3G30C model from Azure Space Solar Power GmbH. We have developed a physical model to describe the solar cell absorption and derive the efficiency. The optical description relies on the Fourier modal method and the solar cell performance on the detailed balance limit. The LTS are optimised by means of the parallel global multi-objective framework implemented in pygmo. The LTS is placed between the solar cell absorbing layers and the cover glass. Care has been taken to account for and model an interstitial mirror between the middle and bottom junction. Realistic damage introduced in the solar cell is described by the Monte Carlo framework Geant4.