Carbon Phenolic Ablation Testing and Analysis for High Speed Earth Return

Testing of carbon phenolic heatshield materials suitable for the forward heatshield of a high speed Earth return capsule is addressed.

Critical aspects of the testing included thermocouple size, orientation and placement, and heat flux calibration to provide accurate data. Post-test examination provides evidence of char and pyrolysis depth, delamination and cracking.

Analysis indicates the specific heat capacity has a heating rate dependency, this has been accounted for in the correlation of conductivity with temperature. A fissure model to account for delamination of the samples needed to be included.