Aerobraking manoeuvres make use of upper atmosphere passes to decelerate a spacecraft. While this technique can considerably reduce delta-v requirements and allow for increased S/C dry mass, aerobraking subjects external spacecraft surfaces to intense thermal loads. Detailed analysis of the spacecraft thermal behaviour is therefore critical to ensure effective braking manoeuvres while safely avoiding damage to the spacecraft due to overheating.
Typically, maximum allowable peak heat fluxes and total aerobraking pass heat loads are calculated from CFD analyses. However, this calculation technique is decoupled from the spacecraft thermal model. To analyse the impact of aerobraking fluxes under different S/C angles of attack for ESA’s EnVision mission to Venus, an aerobraking flux was directly integrated into the spacecraft orbital thermal simulation. Aerobraking fluxes were applied to the spacecraft using UV emitter shells, harnessing the ray-tracing capabilities of ESATAN.
This method allows for a much faster simulation of aerobraking orbital temperatures compared to a full mapping aerothermal fluxes from CFD. Compared to conservatively applying the maximum expected aerobraking flux to all exposed surfaces, this method captures key physical phenomena like angular dependence of aerobraking fluxes and self-shadowing phenomena which are characteristic of the flow regime in the upper atmosphere of Venus.