Aachen PK 2003 – scientific programme

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P: Plasmaphysik

P 19: Plasma Physics

P 19.2: Talk

Friday, March 21, 2003, 10:50–11:10, FO2

Silicon erosion behaviour of coated and uncoated C/C-SiC heat shielding materials for the re-entry process into the earth atmosphere — •Ronnie Stirn, Hirsch K., Lindner P., Roth B., and Schumacher U. — Institut für Plasmaforschung, Universität Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart

Reusable space vehicles entering the atmosphere ask for excellent heat resistant and low erosion materials for the tiles covering the spacecraft surface. Compound materials on the basis of C/C-SiC in combination with surface protection layers are an important basis for developments of such low erosion tiles.The re-entry of the space craft into the earth atmosphere leads to the formation of a plasma in front of the tiles. The investigations are performed by simulating the interaction of the plasma with the material target in a plasma wind tunnel.

The interaction zone of the plasma with the target is investigated by a spectroscopic diagnostic method using emission and self-absorption of the spectral lines of the erosion products. The silicon ground state density is obtained from the optical depth inferred from the intensity ratios of the lines of this multiplet.

The silicon ground state density increases by more than one order of magnitude from 1600 K to 2050 K surface temperature of the target; it levels into saturation beyond temperatures of about 2050 K. Permanent protection against erosion was obtained by applying TiO₂ as surface protection material. Details of the recent spectroscopic measurements and their interpretations as well as of the results of the low erosion material and protection layer development will be presented in this contribution.