Conference Paper

Analysis of the Aerothermal and Material Performance During the Exomars Schiaparelli Descent

Authors:
  • UK Space Agency
  • Fluid Gravity Engineering Ltd
  • ESA, European Space Agency
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Abstract and Figures

The ability to send telemetry during the descent of the ExoMars Schiaparelli Descent Module (ESDM) has given the community a unique set of validation data. In this paper, the flight aerothermal and material response data has been used by Fluid Gravity Engineering (FGE) to critically assess the aerothermodynamic approach taken in the design phases of the ExoMars 2016 project. The key objective was to highlight what lessons can be learnt for future missions from the ExoMars data. During the ESDM entry, the temperature response of the thermocouples was found to be significantly lower than inferred from the design-level assumptions, owing to their conservatism. The data indicated that boundary layer transition and significant dust storm erosion did not occur. In this work, the significant conservatism present in the aerothermal design database was removed and a front shield performance database has been generated using FGE's thermal and chemical non-equilibrium Navier-Stokes solver, TINA. A decrease of over a factor of 6 at the edge thermocouple was found from the design-level heat fluxes when compared with the performance heat fluxes derived by TINA. This analysis has highlighted the importance of considering both the aerothermal and material response models in assessing the vehicle's performance. Lessons learnt from this analysis have been used to develop a more balanced margins policy for the thermal protection system (TPS). This approach has been demonstrated to lead to a reduction in heat shield mass while remaining conservative. The information gathered from the ESDM, as well as the analyses performed can be used to inform future mission design studies.
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... This limits what other post-flight analyses can achieve (Portigliotti, 2017). E.g., improved estimates of the parameters mentioned would help studies that assess the aerodynamic database (Johnstone, 2019a). The velocity, atmospheric conditions, and the flow angles must be known to study the temperature and heat flux measurements from the front shield and the backshell Pinaud, 2019;Brandis, 2018). ...
... As it stands, the corrected state at EIP and the resulting flow angles during entry are useful to inform and update other studies. For example, the entry simulations by (Johnstone, 2019a) focusing on aerodynamics, and the post-flight EDL simulations by (Bonetti, 2018). ...
... The consolidated flow angles are useful input for other studies. For example, the aerodynamic trajectory simulations by (Johnstone, 2019a) and the COMARS+ aerothermal analysis by . The corrected initial state at EIP can also be used to update the post-flight trajectory simulations from (Bonetti, 2018). ...
Conference Paper
The EXOMARS 2016 mission was the first (of two) join European-Russian mission aiming at searching the evidence of past extra-terrestrial life on Mars. After a successful launch of the Russian Proton rocket on the 14th of March, 2016, from Baikonour, and several liberation maneuvers while orbiting the Earth, the BreezeMupper stage carrying the Trace Gas Orbiter (TGO) and the Schiapparelli Entry Descent and Landing module started a long journey to Mars. Seven months later, on the 16th of October 2016, the space probe was released on a direct entry path to the red Planet [1]. After a nominal entry and an expected aerodynamic breaking, saturation of the GNC algorithm during the highly dynamic deployment phase of the parachute, leaded to a final free fall of the module and a destructive impact on ground [2]. However, telemetry of the entry phase was recorded and enabled a post-flight analysis of the heat shield behavior. This paper provides an initial assessment of the thermal instrumentation data that is comprised of in-depth temperatures in the TPS made ofNorcoat® Liege (a phenolicimpregnated cork based ablator [3]). In addition to an ablation scheme sensitivity analysis and material thermal diffusivity correction, a preliminary inverse analysis is performed where the time-dependent surface heating is estimated from flight-measured subsurface temperature data.
Analysis of the AEDB performance during the ExoMars Schiaparelli descent
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E. Johnstone, F. Willcocks and L. Ferracina, "Analysis of the AEDB performance during the ExoMars Schiaparelli descent," in FAR Conference, Monopoli, 2019.
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