Abstract
New data on isotope geochemistry of helium as well as more realistic approach to processes in the upper atmosphere stimulated a revision of the aeronomic problem of helium. If we adopt the maximum values of 3He and 4He fluxes from the solid earth into the atmosphere (which are equal to 80 and 4.106 atoms/cm2 sec, respectively), then a balance of both helium isotopes in the atmosphere can be provided by a mechanism of thermal escape of helium at the average temperature of thermosphere Ta = (1260 ± 40)°K. Possibilities of further study of the problem are discussed.
