Executive Summary : | space economy is projected as the future multitrillion dollar industry with space tourism, interstellar habitats, and space mining. Therefore, space science is a frontier with multitudes of technological and geopolitical opportunities and challenges. This applies to both civilian as well as defence applications. These space transportation vehicles, be it a space shuttle or a missile, with multiple re-entries into earth's atmosphere are necessary which require a durable, ultralow thermal conductivity thermal protection systems (TPs) operating at high temperatures. High performance TPs materials that can also share some structural loads can potentially reduce to a weight reduction of 20 to 30%. Aerogels are more than 95% porous (light weight) and possess a very low thermal conductivity, and therefore are ideal candidate materials for TPs. However, these lack necessary mechanical strength to be used directly. Hence, we propose the fabrication of carbon foam and carbon felt or carbon aerogel composites. The studies includes optimizing the internal micro and mesostructure through controlling the process parameters to achieve low thermal conductivity composites. For oxidation resistance, it is proposed to coat the composite with siC or ZrB2. Carbon foams with different pore sizes will be synthesized through the pyrolysis of commercially available polyurethane foams, while felts are commercially available. The carbon aerogel surrounding the reinforcement phase (C-foam or felt) will be formed by a sol-gel method using resorcinol-formaldehyde along with with sodium carbonate as the catalyst. subsequent to the solvent exchange step, the hydrogel thus formed will be pyrolyzed to obtain carbon aerogel in the pores of carbon foam or felt. Detailed characterization of the composites will be performed using sEM, TEM, Raman, XRD, thermal conductivity measurements, and compression tests to optimize the micro and mesostructures of the composite for optimum thermos-mechanical properties for a durable low thermal conductivity composite material. |
Co-PI: | Prof. Venkataraman sekkar, Cochin University of science And Technology, Kochi, Kerala, Dr. V sivanandan Achari, Cochin University of science And Technology, Kochi, Kerala, Dr. Vijayakrishna Kari, Indian Institute of Technology (IIT) Bhubaneswar, Odisha |