Battery-aware contact plan design for LEO satellite constellations: The ulloriaq case study

Power demands of communication technologies between LEO small-satellites are difficult to counterbalance by solar infeed and on-board battery storage, due to size and weight limitations. This makes the problem of battery-powered intersatellite communication a very difficult one. Its management requires a profound understanding as well as techniques for a proper extrapolation of the electric power budget as part of the inter-satellite and satellite-to-ground communication design. We discuss how the construction of contact plans in delay tolerant networking can profit from a sophisticated model of the on-board battery behavior. This model accounts for both nonlinearities in battery behavior as well as stochastic fluctuations in charge, so as to control the risk of battery depletion. We take an hypothetical Ulloriaq constellation based on the GOMX–4 satellites from GomSpace as a reference for our studies.Fil: Fraire, Juan Andres. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universitat Saarland; AlemaniaFil: Nies, Gilles. Universitat Saarland; AlemaniaFil: Gerstacker, Carsten. Universitat Saarland; AlemaniaFil: Hermanns, Holger. Universitat Saarland; Alemania. Institute of Intelligent Software; ChinaFil: Bay, Kristian. GomSpace A/S; DinamarcaFil: Bisgaard, Morten. GomSpace A/S; Dinamarc

Mastering operational limitations of LEO satellites – The GOMX-3 approach

When working with space systems the keyword is resources. For a satellite in orbit all resources are sparse and the most critical resource of all is power. It is therefore crucial to have detailed knowledge on how much power is available for an energy harvesting satellite in orbit at every time – especially when in eclipse, where it draws its power from onboard batteries. This paper addresses this problem by a two-step procedure to perform task scheduling for low-earth-orbit (LEO) satellites exploiting formal methods. It combines cost-optimal reachability analyses of priced timed automata networks with a realistic kinetic battery model capable of capturing capacity limits as well as stochastic fluctuations. The procedure is in use for the automatic and resource-optimal day-ahead scheduling of GOMX-3, a power-hungry nanosatellite currently orbiting the earth. We explain how this approach has overcome existing problems, has led to improved designs, and has provided new insights