Searching for Life on Venus: History of the Problem and Basic Concepts

Abstract

Venus has always been one of the priorities of the space research program in Russia. The history of successful investigations of Venus in the Soviet Union is primarily associated with delivering a whole series of spacecraft to it and implementing the first ever landing on its surface. In the last few years, the study of Venus in astrobiological direction has been rapidly developing. To date, a fairly large number of theoretical papers have been published, the main purpose of which is to estimate the possibility of the existence of living organisms on Venus. The most likely ecosystem, in which Earth-type organisms could develop, is considered to be a dense cloud layer of Venus. It is supposed that, in this layer, hypothetical microbial communities could exist in aerosols being a concentrated aqueous solution of sulfuric acid. Microorganisms in such a specific air habitat are to be exposed to several extreme factors at once, the main among which are very low values of pH and water activity. The principal strategies for survival under these conditions should be the availability of effective biochemical mechanisms of resistance to the impact of adverse environmental factors and the use of all possible ways of extracting energy in such an ecosystem to maintain the biomass of organisms at a level for stable reproduction.