A three-channel dosimeter (ELDONET) for continuous monitoring of solar and artificial radiation (UV-B, UV-A, PAR) was developed. More than 30 ELDONET-devices, including terrestrial, aquatic and high altitude stations, have already been installed in a dosimeter network all over Europe and in some other locations of the world. Based on the experience with this ELDONET devices, we developed a microprocessor controlled fully automatic 4 channel dosimeter for measurement of UV-C, UV-B, UV-A and PAR radiation. Additional channels for measurement of cosmic radiation was developed in collaboration with Bulgarian partners. The device will be exposed on the external platform SEBA-EXPOSE on the International Space Station (ISS). Due to the subminiaturized construction the instrument has small spatial dimensions and a weight less than 200 g. Important features of the instrument are an automatic dark current compensation and a wide dynamic range of instrument sensitivity (1:409500), which is realized by means of an electronically adjustable amplifier (1x, 10x , 100x). The instrument has an on-board memory. The data will be transfered to a host computer on the ISS and transmitted to the ground. Tasks of the experiment are the investigation of the global distribution of solar radiation in several wavelength bands and the absorbed dose, dose equivalent and flux and the study of the dose composition of cosmic radiation under normal and disturbed conditions in space (LET-spectroscopy). The experience obtained during the long-time experiment LIULIN on the MIR space station are the basis for the measurement ranges of the R3D-device, because of similar orbit altitudes.