L. S. Novikov

Radiation effects on spacecraft materials

Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.

Contemporary state of spacecraft/environment interaction research

Abstract Various space environment effects on spacecraft materials and equipment, and the reverse effects of spacecrafts and rockets on space environment are considered. The necessity of permanent updating and perfection of our knowledge on spacecraft/environment interaction processes is noted. Requirements imposed on models of space environment in theoretical and experimental researches of various aspects of the spacecraft/environment interaction problem are formulated. In this field, main problems which need to be solved today and in the nearest future are specified. The conclusion is made that the joint analysis of both aspects of spacecraft/environment interaction problem promotes the most effective solution of the problem.

Mathematical and experimental simulation of impact of atomic oxygen of the Earth’s upper atmosphere on nanostructures and polymer composites

The article discusses the results of mathematical and experimental simulation of the impact of atomic oxygen of the Earth’s upper atmosphere on carbon and boron nitride nanotubes, graphene, hexagonal boron nitride sheets, and graphene nanoribbons, as well as composites based on polymer matrices with fillers in the form of nanosized particles of various types.

Degradation Testing of Spacecraft Materials for Long Flights in Low Earth Orbit

Results of simulation tests of the influence of the protective and functional coatings on the resistance of polymeric constructional spacecraft materials to the impact of atomic oxygen with fluences up to 3.5 × × 1022 cm−2 are presented. It was demonstrated that oxygen plasma beams can be used in accelerated tests of carbon-based and polymeric material structures (with the exception of filled and fluorinated hydrocarbons) to evaluate their resistance to the atomic oxygen impact in low Earth orbit. For unprotected materials, a sharp fall of mechanical properties and a deterioration of optical characteristics were observed. The application of protective coatings is shown to reduce this degradation.

Erosion of polyimide modified by amorphous silica sol in the stream of oxygen plasma

Polymeric coatings derived from Kapton H polyimide, thermoplastic polyimide (PI), and a composite with amorphous silica sol (PI-SS) were irradiated in a magnetoplasma dynamic accelerator of oxygen plasma simulating the action of atomic oxygen (AO). The volumetric erosion coefficients of polymers were calculated, and the comparative analysis of the stability of coatings was performed. The changes in morphology of polymer surfaces before and after irradiation were studied by means of scanning electron microscopy. It was shown that the PI-SS composite has increased resistance to atomic oxygen. The composition of the PI-SS composite was found at which the particles of silica sol are uniformly dispersed over the polymer volume that explains a better resistance of PI-SS polymeric-inorganic compositions to the action of atomic oxygen. The lowest stability was registered for the coating based on Kapton H polyimide. The surfaces of all coatings after irradiation were found to possess a carpetlike morphology. Each polymer featured a number of distinctive peculiarities of the surface structure caused by the differences in the chemical structure of the polymides under investigation.

RBS and XFA analysis of polyimide films from the mir space station

The elemental composition of polyimide film contamination was studied by the RBS and XFA methods. The films were exposed to the space environment aboard the Mir orbital space station during the KOMPLAST in-flight experiment. It was shown that the prevalent deposit element was silicon, which agrees with measurements performed on other spacecrafts.

Atomic Oxygen Influence on Polymer Nanocomposites with Different Fillers

This paper describes results of ground-based simulation of atomic oxygen influence on samples of polymer composites with different fillers. Polyimide and polyamide-imide were used as matrices, and polyorganosiloxanes, inorganic nanoparticles of Al2O3, TiO2, WC, multiwalled carbon nanotubes, and detonation nanodiamonds were used as fillers. Data on mass loss of composite samples due to atomic oxygen exposure and results of surface morphology analysis are given.

Changes in K-208 glass transmittance spectra under ionizing radiation and molecular fluxes

The effect of 40-keV electron and proton radiation with a flux density of 5 × 10 cm−2 s−1 on the deposition of products of thermostimulated gas release from a polymer composite on a substrate made from protective K-208 glass used for the protection of spacecraft solar panels is experimentally investigated. Analysis of the obtained results shows that, unlike proton radiation, electron radiation results in an increase in the optical density of the glass and stimulates the deposition of gas-release products. It is established that the majority of effects generated as a result of exposure of the substrate to electron radiation are neutralized by protons upon combined irradiation with electrons and protons.

Ab initio study of unzipping processes in carbon and boron nitride nanotubes under atomic oxygen impact

We apply first principles calculations to compare the carbon and boron nitride nanotube unzipping under atomic oxygen impact. We show that the attack of several oxygen atoms can cause bond breaking in nanotubes, but the structure of boron nitride nanotubes is less damaged than the structure of carbon ones. With increasing diameter, the structural damage of nanotubes reduces.

Critical Evaluation of Testing Results for Russian and Western Space Materials in Ground-Based Simulator Facilities and in Space Experiments

A critical evaluation of space flight experiments and ground-based testing results in LEO simulating facilities for Russian space materials and their functional US and European space materials counterparts, as well as predictive performance evaluation are presented and discussed. Results of long-term GEO imitating ground-based testing are presented also for selected advanced thermal control materials.