3D Ray Tracing Solver for Communication Blackout Analysis in Atmospheric Entry Missions

in Computer Physics Communications (2023)

During the atmospheric entry phase at hypersonic speed, the radio communication from/to a space vehicle can be disrupted due to the formation of a plasma sheath within the surrounding flow field. In order ... [more ▼]

During the atmospheric entry phase at hypersonic speed, the radio communication from/to a space vehicle can be disrupted due to the formation of a plasma sheath within the surrounding flow field. In order to characterize such communication blackout phases, this work presents a numerical methodology combining Computational Fluid Dynamic (CFD) simulations of ionized chemically reacting entry flows by means of Computational Object-Oriented Libraries for Fluid Dynamics (COOLFluiD) and a ray tracing analysis by means of the newly developed BlackOut RAy Tracer (BORAT). The latter is based on the numerical solution of the 3D Eikonal system of equations, offering a fast, efficient and accurate method to analyse the interaction between electromagnetic signals and weakly ionised plasmas. The proposed methodology, and BORAT in particular, is first verified on popular benchmark cases and then used to analyse the European Space Agency (ESA) 2016 ExoMars Schiaparelli entry flight into Martian environment. The corresponding results demonstrate the validity of the proposed ray tracing approach for predicting communication blackout, where signals emitted from the on-board antenna undergo reflection and refraction from the plasma surrounding the entry vehicle, and the advantage of a 3D approach for analysing real flight configuration. [less ▲]

A Magnetohydrodynamic enhanced entry system for space transportation: MEESST

in Journal of Space Safety Engineering (2022)

This paper outlines the initial development of a novel magnetohydrodynamic (MHD) plasma control system which aims at mitigating shock-induced heating and the radio-frequency communication blackout ... [more ▼]

This paper outlines the initial development of a novel magnetohydrodynamic (MHD) plasma control system which aims at mitigating shock-induced heating and the radio-frequency communication blackout typically encountered during (re-)entry into planetary atmospheres. An international consortium comprising universities, SMEs, research institutions, and industry has been formed in order to develop this technology within the MEESST project. The latter is funded by the Future and Emerging Technologies (FET) program of the European Commission’s Horizon 2020 scheme (grant no. 899298). Atmospheric entry imposes one of the harshest environments which a spacecraft can experience. The combination of hypersonic velocities and the rapid compression of atmospheric particles by the spacecraft leads to high-enthalpy, partially ionised gases forming around the vehicle. This inhibits radio communications and induces high thermal loads on the spacecraft surface. For the former problem, spacecraft can sometimes rely on satellite constellations for communicating through the plasma wake and therefore preventing the blackout. On the other hand, expensive, heavy, and non-reusable thermal protection systems (TPS) are needed to dissipate the severe thermal loads. Such TPS can represent up to 30% of an entry vehicles weight, and especially for manned missions they can reduce the cost- efficiency by sacrificing payload mass. Such systems are also prone to failure, putting the lives of astronauts at risk. The use of electromagnetic fields to exploit MHD principles has long been considered as an attractive solution for tackling the problems described above. By pushing the boundary layer of the ionized gas layer away from the spacecraft, the thermal loads can be reduced, while also opening a magnetic window for radio communications and mitigating the blackout phenomenon. The application of this MHD-enabled system has previously not been demonstrated in realistic conditions due to the required large magnetic fields (on the order of Tesla or more), which for conventional technologies would demand exceptionally heavy and power-hungry electromagnets. High-temperature superconductors (HTS) have reached a level of industrial maturity sufficient for them to act as a key enabling technology for this application. Thanks to superior current densities, HTS coils can offer the necessary low weight and compactness required for space applications, with the ability to generate the strong magnetic fields needed for entry purposes. This paper provides an overview of the MEESST project, including its goals, methodology and some preliminary design considerations. [less ▲]

Radio communication blackout analysis of ExoMars re-entry mission using raytracing method

in Radio communication blackout analysis of ExoMars re-entry mission using raytracing method (2021, January)

This work presents a numerical methodology to properly characterize and predict the ommunications blackout phase of the ExoMars Schiaparelli Martian atmospheric re-entry flight. The focus of this work ... [more ▼]

This work presents a numerical methodology to properly characterize and predict the ommunications blackout phase of the ExoMars Schiaparelli Martian atmospheric re-entry flight. The focus of this work lies on the use of an optical ray tracing technique to describe the electromagnetic waves behaviour within the ionized wake flow of the vehicle. Bi-dimensional hypersonic CFD simulations are performed over the ExoMars Schiaparelli module at different trajectory points with the COOLFluiD aerothermodynamics Finite Volume solver coupled with the thermochemistry library PLATO. Subsequently, a ray tracing algorithm is applied to examine the propagation of electromagnetic waves and their interaction with the re-entry wake flow of the ExoMars vehicle. In this work, results are presented at three different trajectory points, characterized by different ionization levels of the flow. The results show how this methodology is suited to analyze blackout re-entry phases providing useful information on electromagnetic waves behaviour in ionized plasma re-entry flows. [less ▲]