This paper presents the principles and application of DNA based biological UV dosimeters developed by Research Group for Biophysics (RGB) for assessing the biological hazard of the living systems on the Earth surface and in different waters (rivers, lakes, seas, etc.). In dosimeters a bacterial virus, bacteriophage T7 and polycrystalline uracil thin layers were used as biological detectors. On the Earth's surface the UV radiation induce dimer formation in phage T7 and uracil detector which was evaluated by loss of viability of the phage particles and by the decrease of the characteristic optical density (OD) of uracil thin layers, respectively. Recently the increasing human space activity has increased the need to measure the biological effect of extraterrestrial solar radiation, too. Originally sample evaluation occurred on ground, while the improved, automated method presented below makes data collection more efficient and makes process dynamic observable also.