The goal of this experiment was to determine the experimentally value of accumulated dose resulting from ionizing radiation of space.
Nine dosimeters were placed at different locations in Zvezda while the tenth dosimeter was inserted in the reader permanently for automatic cyclic measurements. The nine dosimeters were collected, read out and relocated roughly monthly while the one in the reader was read out automatically every 90 minutes. During specific events such as extreme SPEs and EVAs two of the dosimeters were used as personal dosimeters. In the latter case a third dosimeter served as a reference one; the extra dose due to EVA was calculated by subtracting the reference dose from the EVA dose of the astronauts.
The average dose rates measured between successive readouts of the nine “Pille-MKS” TLDs distributed throughout the Zvezda module of the station were calculated. The average absorbed dose rates were 6.5µGy/h (Expedition 8), 7.1µGy/h (Expedition 9), and 8.2µGy/h (Expedition 10) while the total average was 7.2µGy/h during the three Expeditions. Various factors contribute to the changing dose rate measured in different locations within the ISS. The ISS altitude affected the overall dose rate as well as changes in the attitude of the ISS relative to its velocity vector also affect the relative particle flux at different locations within the station.