Investigation of Characteristics of Microparticles during Interaction of the Plasma Flow with the Surface of the Spacecraft during the Passage of the Atmosphere

Returning spacecraft, when passing through Earth’s atmosphere, are characterized by intense destruction of the frontal heat shield caused by the impact of a high-speed oncoming gas flow. As a result of ablation, which occurs over several minutes, the products of destruction enter the surrounding plasma layer and partially settle on the surface of the spacecraft. The design features of the Soyuz descent vehicle made it possible to study the results of the interaction between the plasma flow and the surface of the porthole located in the leeward zone. To examine the characteristics of individual particles and their aggregates, both direct imaging of surface relief fragments and various methods of sample preparation were used. The results of experimental studies of the plaque on the porthole were obtained by various methods: optical microscopy, laser scanning confocal microscopy, X-ray diffraction, and electron microscopy. The physicochemical conditions of plasma component deposition on the glass surface are discussed. The obtained data on the phase composition, morphology, and elemental composition of the microparticles are analyzed. A classification of particles formed on the surface of the spacecraft during interaction with the plasma flow while passing through the atmosphere is proposed.