Kirchhoff's law of thermal radiation rarefied material such as air, or transparent material, through which observations can be made. The interface is not a material body and can neither emit nor absorb. It is a mathematical surface belonging jointly to the two media that touch it. It is the site of refraction of radiation that penetrates it and of reflection of radiation that does not. As such it obeys the Helmholtz reciprocity principle. The opaque body is considered to have a material interior that absorbs all and scatters or transmits none of the radiation that reaches it through refraction at the interface. In this sense
A-235 anti-ballistic missile system A-235 and the A-135 missile defense system [6]. According to foreign media reports, on November 18, 2015, the first successful launch of the Nudol missile and the third launch in the missile test program of the complex took place. Presumably, the deployment site of the A-235 missile defense system will be the former base area of the A-135 missile defense system near Moscow. According to the plan, the complex will have the capabilities to intercept the warheads of ballistic missiles, as well as spacecraft [4]. In May 2016, system elements were tested as part of the exercises of the Military