Investigation of radiation sensitivity in mammals under long duration weightlessness.

Preliminary results of the radiobiological experiments carried out on the biosatellite Cosmos 690 with a radiation exposure unit on board are presented. The duration of the satellite flight was 20.5 days. On the tenth day of the flight 35 rats were exposed on board the satellite to 220 or 800 rads of gamma radiation. Comparison of data obtained in test and control groups of animals has shown that under the influence of space flight factors a somewhat more severe radiation injury develops than in on-ground conditions.

Preliminary results of examinations of rats after a 22-day flight aboard the Cosmos-605 biosatellite.

The results of biomedical investigations carried out in flights of the Salyut and Skylab orbital stations give evidence that during prolonged weightlessness cosmonauts and astronauts remain in a good physical and mental condition. They fill specialists with optimism in regards to a further increase of the duration of manned space flights. In order to make reliable plans for such missions, it is necessary to accumulate detailed knowledge about the mechanism of the effect of weightlessness on different functions of the human body. In addition to manned experiments, of great interest are animal experiments. They may yield data that cannot be obtained in human studies, which is obviously very important from the point of view of space medicine. This was the purpose of the experiment carried out in November 1973 on the biosatellite Cosmos-605; 45 rats aboard the biosatellite flew for 22 d. Preliminary results of examinations of rats after a 22-d space flight in the Cosmos-605 satellite demonstrated not only physiological and biochemical but also morphological changes in the animal body due to prolonged weightlessness. These changes were reversible.