Cosmic radiation was discovered successfully in the beginning of the twentieth century by the Austrian Nobel Price winner Victor Hess. Radiation effects to humans are of major concern during human space missions and also due to the increasing aviation altitudes and flight time. ICRP recommendations lead to adaptations of the Basic Safety Standards by the European Council. Beginning in the 1990 s up to now, significant improvements and findings in aviation dosimetry and epidemiology were done word-wide. Five research projects on measurements and modelling cosmic radiation exposure were supported by European Research Framework Programmes. In-flight measurements with remarkable agreement (+/-25%) were carried out to validate calculation codes for routine dose assessment within +/-30% for galactic cosmic radiation. Measurements and improvements of modelling radiation exposure due to solar particle events (SPE) is still an objective for future research projects.