Search Results

When gas conductance/natural convection plays a major role as heat transfer path, microporous insulations reveal distinct advantages compared to Multi-Layer Insulations (MLI). For re-entry vehicles as e. g. HERMES or capsules silica and ceramic microfiber insulations have been investigated by DASA/ERNO in a temperature range up to 650 °C or, respectively, up to 1200 °C. In the frame of an ESTEC funded study three types of microporous insulations - microfiber, microsphere and polyimide foam - have been analytically and experimentally investigated as candidates for the internal insulation of a MARS-lander in a carbon-dioxide atmosphere for temperatures ranging from - 110 °C to 50 °C. This paper compares the test results with analytical heat transfer calculations and describes methods to improve the thermal insulation performance.

The future deployment of a network of measurement stations on the surface of MARS is presently prepared. The MARS environment is characterised by large daily and seasonal temperature fluctuations in low density atmosphere with carbondioxide as its main constituent. Typical environmental conditions for some locations are presented. Due to geometrical and mass constraints highly efficient and reliable thermal insulations are required for the thermal control of MARS stations which are powered by solar energy. ERNO has investigated the thermal performance of two candidate porous insulations in the frame of an ESTEC technology contract. The paper presents methods to predict the heat transfer modes of both insulations in a Martian environment analytically. Experimental measurements have been performed and evaluated in order to validate the analytical predictions. Based on these results the insulation design concept is reviewed.