Characterization of thermo-physical Properties using ground testing facilities

Stefan Loehle, Institut fuer Raumfahrtsysteme, Pfaffenwaldring 31, Stuttgart, D-70197, Germany

The investigation of thermo-physical properties is of importance for future observation campaigns as well as for the understanding of the atmospheric entry. For example emissivity measurements can give an information on temperature from observation data of meteorites and the corrseponding clouds. The engineering problem of a re-entering spacecraft from space also requires the knowledge of emissivity, especially for radiation cooled heat shield where the emissivity is a decisive parameter for the choice of a thermal protection system (qrad=ε*σ*T4). At Institut fr Raumfahrtsysteme a facility based on a black body radiator has been set up to measure emissivity of material samples at different temperature levels. Within this talk, an overview over the possibility to measure emissivity is given. Furthermore, with respect to the measured cloud, it is depending on the knowledge of emissivity possible to reduce the measured infrared data to temperature.