Survival and mutability of Chlorella aboard the Zond vehicles

Space effects on the viability and heredity of the unicellular green alga Chlorella were studied during the Soyuz 5 flight in earth orbit and in Zond 5, 6 and 7 on their earth-moon-earth flight. A culture of strain LARG-1 was exposed aboard the ship on mineral agar medium in the dark. The flight in earth orbit aboard the Soyuz-5 brought about a significant fall-off in cell survival and a gain in their mutability. There was a trend toward the percent growth of anomalies in autosporulation. The results obtained in experiments aboard the automatic stations of the Zond series were rather contradictory. The flight aboard Zond 6, like the earlier Zond 5, led to a statistically significant fall-off in the cell survival (91.9 +/- 0.97% in the control; 80.2 +/- 1.78% in the test). The cell mutability remained unchanged; space had no effect on the cell viability in the experiment aboard Zond 7, but there was a trend toward antimutagenic action of the space factors (0.82 +/- 0.11% in the control; 0.57 +/- 0.06% in the test). Suggestions concerning the causes of these variances of result are reported.