Physical Prerequisites of the Antimeteoric Net Protection for Spacecraft

The problem of spacecraft protection against the impact effect of meteorites and man-made (technogenous) particles has become especially topical in connection with the necessity of long-duration flights in space. The probability of spacecraft collision with meteoric and technogenous particles has already considerably increased on the widely used, but strongly contaminated near-Earth orbits. Russian specialists (the author included) proposed to use multilayer spaced barriers for spacecraft protection as early as the beginning of the 1960s. However, further studies on decreasing the mass of antimeteoric shields are required nowadays. The safety net application is one promising approach in this respect. This paper outlines the physical prerequisites for using a net (a system of strings) as one of a package of antimeteoric shields. The simplest models of meteoric particle destruction at impact on the safety net are presented. The hydrodynamic models, as most suitable for modeling the process, are mainly analyzed. The role of the interaction of shock waves and of cumulative effects upon meteorite impact with the net is emphasized. The net is shown to play an important part in forming the nonuniform field of stresses in a meteorite even at high impact velocities, which are accompanied by phase transitions and by the generation of plasma. The role of a safety net for retaining and absorbing the momentum of a plasma cloud, formed upon the impact of meteoric particles, is considered. The advisability of applying two (or several) net barriers is substantiated. It is noted that the safety net can also be useful as a means for mitigating the action of shock waves from explosions.