[Optimal isotope composition of biogenic chemical elements on board of manned spacecrafts].

Isotope composition of biogenic chemical elements (BCE) is discussed. A hypothesis is offered that biochemical and biomedical processes must be influenced as by the isotope composition of hydrogen and oxygen, so by the composition of stable isotopes of all the BCE constituting plants, animals, and humans. Biochemical, toxicological and other biomedical analyses should be performed to determine the best BCE isotope composition. These must be followed by development of methods, technologies, and life support systems to form and maintain the best isotope composition inside spacecraft habitable modules.