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Directly indicating astronaut dosimeter


Since November 2016, a new radiation measurement system that PTB was instrumental in developing has been in use on board the International Space Station (ISS). Depending on the quality of the radiation, the system calculates the impact of the radiation on living tissue and indicates the respective radiation dose for the astronaut without time delay. Previously, it was only possible to evaluate such data after the astronauts had returned to Earth.

French astronaut Thomas Pesquet during his mission on ISS, using a personal dosimeter developed by PTB that immediately indicates the radiation dose. The photo was taken during training (photo: NASA, James M. Blair).

The new dosimeter is called EuCPAD (European Crew Personal Active Dosimeter) and was developed on behalf of the European Space Agency (ESA) and under the direction of the Deutsches Luft- und Raumfahrtzentrum (the national aeronautics and space research center of the Federal Republic of Germany). The dosimeter is not only designed to protect astronauts, but also to provide important information for future aerospace missions. As radiation is one of the limiting factors of long-term missions in space, the following questions have to be clarified: How high is the radiation in the different modules of the ISS, what is the radiation composed of and which fluctuations are there?

EuCPAD consists of a small personal dosimeter and a storage unit. Every week, the data acquired by the dosimeter is stored in this unit. More importantly, however, the storage unit contains a tissue-equivalent proportional counter developed by Seibersdorf Labor GmbH. This counter is an ionization detector that simulates the characteristics of human tissue. Its function is the same as that of the mobile dosimeter worn by the astronaut: to determine the energy dose a human being is exposed to during a space flight. The comparison of the dosimeter data on the one hand and that of the proportional counter on the other verifies the measured data.