Development of the Low-Density Phenolic-Based Fibrous Ablator ZURAM-K

Abstract

ZURAM is an ablative carbon–phenolic thermal protection material, developed by the DLR, German Aerospace Center (DLR) in cooperation with the Institute of Space Systems, University of Stuttgart. In addition to building up a basic competence in the sector of ablative thermal protection materials, an objective of the development was to provide a nonclassified ablative material for university research. ZURAM is comparable to similar low-density ablative thermal protection materials with respect to the material density and general ablative performance. It is based on a rigid, highly porous carbon fiber preform, which is filled with a nano-porous matrix derived from a phenolic resin. In the context of the ongoing material development, possibilities to improve the material were investigated with the aim to lower its thermal conductivity and to enhance the adaptability to varying mission profiles. Preliminary results indicate that by substituting the carbon preform with a phenolic fiber preform, a significant reduction of the thermal conductivity can be achieved while recession rates are comparable to the ones of standard ZURAM. The scope of the present work is the development of ZURAM-K based on phenolic Kynol fibers. Furthermore, results from tests in the arc-heated DLR facilities L2K and L3K, as well as data on the thermal conductivity and heat capacity, will be presented.