Modelling and Simulation of an On-Orbit Experiment for Testing a Novel Engine Technology

The paper describes the design and modelling of an on-orbit mission experiment for testing a novel engine technology in Space. The goal is to assess the novel engine thrust profile through an on-orbit reverse engineering approach. The simulation tool developed at Politecnico di Milano is initially designed to propagate the free attitude dynamics of a spacecraft under the effect of main environment perturbations. Each element of the simulator is validated, prior to the on-orbit experiment, by matching orbit and attitude data from a previous similar mission of the ION spacecraft CubeSat carrier. The novel engine technology is located in one of the ION CubeSat slots and activated in orbit. The simulation tool is adapted to simulate the on-orbit experiments given the information on the attitude engine action and the mass and structure properties of the satellite. The preliminary analysis performed on the in-flight results of the tests highlighted the need of the development of smoothing techniques prior applying the reverse engineering approach. Some uncertain parameters, such as the carrier spacecraft inertias, showed a significant influence on the simulator's performance. Different methods have been applied to characterise the unmodelled dynamics and approximations' effects on the results. Future updates and corrections to the simulator are suggested to deal with the observed problems and improve the detection of the engine thrust magnitude. No end-results of the on-orbit mission experiment are presented in this paper, since the in-space operations are still on-going.