Abstract
Exposure to cosmic radiations in airflights and space missions are discussed. First, physical properties of the cosmic radiations including origins, compositions and energy spectra of galactic cosmic rays as well as solar particles are outlined, and main factors which influence the cosmic ray strength like solar activity and geomagnetism are presented. Structures along with formation mechanisms of the magnetosphere and Van Allen belt (radiation belt) are also mentioned. Second, exposure data measured in air and space vehicles are presented, and countermeasures to protect crews of foreign flights are introduced. Lastly, exposure control on space activities which is temporarily suggested is briefly mentioned in relation to the coming international experimental station in space.
