Investigations on biosatellites of the Cosmos series.

Over the past decade, the USSR has launched six biosatellites of the Cosmos series. The first biosatellite flew 6 d; the remaining five flew 18-21 d. The principal purpose of this investigation was to continue studies on the adaptation of living systems to weightlessness; to investigate the modifying effect of weightlessness on the organism's radiosensitivity; and, to examine the biological effects of artificial gravity. The investigations involved 37 kinds of biological models; rats were the principal test models. It was established that weightlessness induces in the organism symptoms of moderately pronounced stress together with a number of other specific changes. First and foremost are changes in the locomotor system (atrophy of the muscles and lowered mechanical strength of the bones, as examples). An artificial gravity of 1 G employed during space flight helps preserve the "terrestrial" rate of functioning of most physiological systems in the organism. The irradiation of rats during space flight from the Cesium-137 isotope revealed no tangible modifying effect of weightlessness on the course of radiation injuries. No distinct effect of weightlessness on the intracellular processes of vital activity has yet been observed. Contradictory results have been obtained in the growth and development of organisms during weightlessness.