Thermomechanical qualification tests of complex CMC re-entry structures

Abstract

In the last years a lot of international effort has been invested in high temperature resistant ceramic structures. Especially the outer thermal protection system (TPS) of the X-38 re-entry vehicle was regarded for all participants as a great challenge to both the technological progress and international cooperation of the involved companies respectively. Several German companies, MAN-T, Astrium and DLR, were directly involved in the responsibility of sufficient TPS structures of the vehicle in particular for the nose cap and within the body flap development. During the development work of the fully ceramic body flaps (two symmetrical body flaps are located in parallel at the lower rear position of the X-38 vehicle, figure 1;2), which was carried out by MAN-T in Augsburg, two mentionable qualification test campaigns were necessary and conducted at DLR Stuttgart focussed on two important bearing parts of the flap system (Fig. 2), the so called EMA = electromechanical actuator -bearing and the hinge bearing attachment system. Under contract of MAN-T and coordinated by ESA (European Space Agency) DLR Stuttgart tested the EMA bearing first in the summer of 2000 and one year later the hinge bearing attachment system. Both components have completely been made of C/SiC materials and developed, manufactured and delivered by MAN-T. Within the two exciting and also perception rich test campaigns the re-entry conditions were simulated thermally, mechanically and in an oxidizing atmosphere according to the X-38 re-entry trajectory close to reality as possible.