The DOSIS and DOSIS 3D project on-board the ISS — Current status and scientific overview

Abstract

The radiation environment encountered in space differs in nature from that on Earth, with contributions of protons and high energetic ions up to iron, resulting in radiation levels far exceeding the ones present on Earth and what is allowed for occupational radiation workers. Accurate knowledge of the physical characteristics of the space radiation field in dependence on the solar activity, the orbital parameters and the different shielding configurations of the International Space Station (ISS) is therefore important. For the investigation of the spatial and temporal distribution of the radiation field inside the European Columbus module the experiment “Dose Distribution inside the ISS” (DOSIS), under the project and science lead of DLR, was launched in July 2009 with STS-127 to the ISS. The DOSIS experiment consists of a combination of “Passive Detector Packages” (PDP) distributed at eleven locations inside Columbus for the measurement of the spatial variation of the radiation field and two active DOSimetry TELescopes (DOSTEL) with a the DOSTEL Data and Power Unit (DDPU) in a dedicated Nomex pouch mounted at a fixed location beneath the EPM rack for the measurement of the temporal variation of the radiation field parameters. The DOSIS experiment suite measured during the lowest solar minimum conditions in the space age from July 2009 to June 2011. In July 2011 the active hardware was transferred to ground for refurbishment and preparation for the follow up DOSIS 3D experiment. The hardware for DOSIS 3D was launched with Soyuz 30S in May 2012. The PDPs are replaced with each even number Soyuz flight starting with Soyuz 30S and with each odd number Soyuz flight starting with Soyuz 45S. Data from the active detectors is transferred to ground via the EPM rack which is activated once a month for this action. This paper will give an overview of the DOSIS and DOSIS 3D experiment and focus on the results from the passive radiation detectors from the DOSIS 3D experiment (2012–2016) in comparison to the data of the DOSIS experiment (2009–2011), and what we can learn from that for the future planned interplanetary space missions.