Numerous measurements of the composition of the radiation field inside and outside of spacecrafts in low earth orbits are performed during last years. Dose rates, particle fluences and energy deposit (LET) spectra were determined in dependence of altitude, inclination and solar cycle. Variations of fluence and dose rates up to a factor of two were observed inside STS and MIR missions. Based on the measurements dose equivalents were determined which range for International Space Station (ISS) orbits from 576 to 767 μSvd−1. The dependence of dose and fluence rate measurements for the primary components from mission parameters is quite well understood, whereas this dependence could not be shown for measurements of the secondary components. Only limited measurements on the depth dose distribution in the human body exists. Major future activities are therefore the improvement of existing devices, the development of new devices especially for the measurement of the neutron component, environmental and personnel measurements in the new station and depth dose measurements in realistic human phantoms.