Analysis of the Anisotropic Heat-Protective Material Application Effectiveness in the Implementation of Trajectories with Multiple Re-entries into the Atmosphere

In the case of full implementation of the programs of studying and developing the Moon, announced in recent years (“Luna”, Artemis, Chang’e), significant increase in cargo turnover between the Moon and the Earth is expected. Therefore the research and development of appropriate spacecrafts and their structural elements is believed to be promising, especially thermal protection coatings ensuring spacecraft safety during movement (descent) in the dense atmosphere layers. A special characteristic of the trajectory of the spacecraft returning from the Moon’s orbit is the closeness of the speed of its entry into the Earth’s atmosphere to the parabolic one. This circumstance significantly complicates solving the problem of creating thermal protection for such a vehicle, because of higher convective and radiative heat flows compared to those acting on orbital landers. The analysis showed that when implementing the trajectory of the return of spacecraft with multiple re-entries into the Earth’s atmosphere, a trajectory can be selected (at least for cargo flights) so that the intensity of heat exchange on the surface of the coating does not exceed the permissible level. In this case, use of modern and advanced anisotropic heat-protective composite materials can reduce the spacecraft surface temperature to a level that does not cause destruction of the thermal protection coating.

MODIFIED EPOXY COMPOSITION FOR PRODUCTION OF THERMAL PROTECTION COATING

The material summed up in this article is recommended for engineers of aerospace industry, as well as can be of inter-est for the production personnel. The article covers the production of “scale-like” outer thermal protection coatings on the basis of syntactic materials with tumescent characteristics used in the production of special purpose equipment. The research per-formed sums up the results of the practical implementation of the technology adaptative method in the conditions of the real outer thermal protection coatings production. This work describes a typical technological process of “scale-like” outer thermal protection coating production from the panels based on syntactic material, including the stages of separate panels production with the help of shape-generating molding tools and forming of thermal protection coating by laying and molding-on of separate panels on the pressure restraint layer of the aircraft. The author proves the effectiveness of technology adaptative method us-age on the example of modification processes of pattern polymer composition being the basis of syntactic material. The re-search describes the solutions for the production cycle optimization via improvement of technological properties of the materials used. The work also contains the results of the researches, including spectral and thermochemical analyses of polymer compo-sitions modified by polyisocyanates, and describes the research techniques of their properties. Quasi-eutectic compositions of aliphatic and aromatic amines are received, which, being used as curative of reactive epoxiurethane polymers produced on the basis of epoxy-diane oligomers and polyisocyanates, enable to divide the polymerization process into two stages. The method described in the article provides the elimination of panel defects on the stage of molding-on due to implementation of mode separation in polymerization processes, which contributes towards the quality and reliability of thermal protection coating.