Human model MATROSHKA for radiation exposure determination of astronauts

Abstract

The exploration of space as seen in specific projects from the European Space Agency (ESA) acts as groundwork for human long-duration space missions. One of the main constraints for long-duration human missions is radiation. The radiation load on space travellers is a factor of ~100 higher than the natural radiation exposure on Earth and it might further increase due to solar particle events should humans travel to Mars. In preparation for long-duration space missions, it is important to evaluate the impact of space radiation in order to secure the safety of astronauts and minimize their radiation risks. To determine the radiation risks on humans one has to measure the radiation doses to vital organs of the human body.

One way to realize this is the utilization of the ESA facility MATROSHKA (MTR), which houses a human phantom and is operated under the scientific project lead of the German Aerospace Center (DLR). The facility was launched in January 2004 and is just performing its fourth experimental phase - now inside the Japanese Experiment Module (JEM). The MATROSHKA project is dedicated determining the radiation load on astronauts when staying within or outside the International Space Station (ISS). The MTR phantom is equipped with over 6,000 radiation detectors to determine the depth dose and organ dose distribution in the body. It is the largest international research initiative ever performed in the field of space dosimetry and combines the expertise of leading research institutions around the world, thereby generating a huge pool of data of potentially immense value for research.

Aiming at optimal scientific exploitation, the FP7 project HAMLET intends to process and compile the data acquired individually by the participating laboratories of the MATROSHKA experiment. Based on experimental input from the MATROSHKA experiment phases as well as radiation transport calculations, a three-dimensional model for the distribution of radiation dose in an astronaut´s body will be set up. Based on a solid experimental and theoretical basis the model is essential for realistic radiation risk estimates for future human interplanetary space exploration. Data received up to now from the MTR experimental phases (MTR-1, -2A and -2B) are already implemented in the database along with relevant experimental and scientific background data.