Hetoroporous heterogeneous ceramics for reusable thermal protection systems
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Claudio Badini Politecnico di Torino, Department of Applied Science and Technology, 10129 Torino, Italy
Volker Liedtke Aerospace and Advanced Composites GMBH Viktor-Kaplan-Strasse 2 2700 Wiener Neustadt, Austria
Christian Wilhelmi EADS Innovation Works Dept. IW-MS 81663 Munich, Germany
Claudio D’Angelo SUPSI ICIMSI, Strada Cantonale, Galleria 2, 6928 Manno, Switzerland
Daniele Gaia Erbicol SA, Viale Pereda 22, 6828 Balerna, Switzerland
Wolfgang Fischer Astrium Space Transportation GmbH Airbus-Allee 1, 28199 Bremen, Germany (Received 6 February 2013; accepted 13 March 2013)
Reusable thermal protection systems of reentry vehicles are adopted for temperatures ranging between 1000 and 2000 °C, when gas velocity and density are relatively low; they exploit the low thermal conductivity of their constituent materials. This paper presents a new class of light structural thermal protection systems comprised of a load bearing structure made of a macroporous reticulated SiSiC, filled with compacted short alumina/mullite fibers. Their manufacturing process is very simple and does not require special devices or ambient conditions. The produced hetoroporous heterogeneous ceramics showed high radiations shielding capabilities up to 2000 °C in vacuum. Even after repeated exposures at higher temperatures, a significant degradation of the SiSiC scaffold was not observed.
I. INTRODUCTION
The thermal protection system (TPS) is a barrier that shields the heat produced by the friction of the atmospheric gasses against the outer surface of a space vehicle during the atmospheric entry. Since vehicle speed is hypersonic, gasses immediately turn into a superheated plasma causing high thermo-chemical loads1,2 around the spaceship surface which must be protected by engineered materials. TPS can be grouped into two categories.3 The first is the reusable TPS (RTPS). RTPS are adopted for relatively low temperatures (;1000 °C), when gas velocity and density are low; they account on the low thermal conductivity, reflectivity, and opacity of their constituent materials. The second, named ablative TPS (ATPS), dissipates the incoming heat with endothermic chemical reactions of its polymer matrix constituent material. ATPS are adopted when gas velocity, density, and thus temperatures are extremely high. The concept proposed in this paper falls within RTPSs. a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2013.70 J. Mater. Res., Vol. 28, No. 17, Sep 14, 2013
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Beside the above mentioned thermal requirements, TPSs should comply with other design and operational constraints: structure smoothness (to avoid stress concentrations), low areal weight, low costs, low maintenance, mechanical, and thermal compatibility with the primary aluminum structure. The space shuttle orbiter gave a great impulse to the RTPS development. To protect its aluminum alloy airframe, four types of RTPS have been used: a structural carbon-carbon material; a high-temperature reu
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