There appears to be concern among some people about the possible effects of
cosmic radiation on everyday life. The amount of cosmic radiation that rea
ches the Earth and its environment is a function of solar cycle, altitude a
nd latitude. The possible effect of naturally occurring cosmic radiation on
airplane crews and space flight personal is a subject of current study. Th
is paper discusses the variables controlling the cosmic ray flux in the atm
osphere and describes models and software that have been developed that pro
vide quantitative information about the cosmic radiation exposure at flight
altitudes. The discussion is extended to include the cosmic radiation expo
sure to manned spacecraft.