To define and test a MLI for Envision?s aerobraking thermal environment allowing a more aggressive aerobraking regime.

Aerobraking phase of ENVISION is critical in terms of duration and required operations. One limitation during aerobraking is the temperature reached on Multi Layer Insulation (MLI) due to the aerothermal heat flux.MLIs can withstand during short durations (intermittent exposure) higher temperatures than their steady state qualification temperature. Using intermittent temperature limit instead of steady state limit would allow to drastically reduce the duration of the aerobraking phase, resulting in significant cost savings on the operations, without re-design of the existing materials.This requires characterization of materials in conditions representative of the whole aerobraking phase in terms of heat flux, duration (heat load) and thermal cycles (several thousands of atmospheric passes are expected).This activity encompasses the following tasks: - requirements consolidation, including specific Venus environment- selection of candidate materials suitable for MLI under Venus environment- test the materials according to Envision mission requirements in terms of thermal cycling, radiation environment and aerobraking (aerothermal flux and heat load)- Assess MLI performance degradation under realistic aero fluxes conditions, including impact of Venus atmosphere (e.g. degradation due to erosion)- Define, manufacture and test a MLI blanket, in line with EnVision mission requirements.Outcome is a definition of a MLI blanket optimized for ENVISION, including thorough characterization of the materials including the reachable intermittent temperature as a function of relevant parameters such as atmospheric pass duration and total number of atmospheric passes.