Experimental demonstration of the feasibility of laser communication with reentry spacecraft at 1.55  μm.

It has been demonstrated experimentally for the first time, to the best of our knowledge, that reliable laser communication at 1.55 μm can be established with reentry spacecraft across the entire atmospheric descent trajectory as a way to avoid radio blackout. A plasma sheath with parameters similar to those around the spacecraft is reproduced at the Lomonosov Moscow State University Mechanics Institute Shock Tube Facility.

Investigation of oxygen dissociation and vibrational relaxation at temperatures 4000-10,800 K.

The oxygen absorbance was studied at wavelengths 200-270 nm in Schumann-Runge system behind the front of a strong shock wave. Using these data, the vibrational temperature Tv behind the front of shock waves was measured at temperatures 4000-10,800 K in undiluted oxygen. Determination of Tv was based on the measurements of time histories of absorbance for two wavelengths behind the shock front and on the results of detail calculations of oxygen absorption spectrum.