Chuck Bednar for redOrbit.com Your Universe Online

Cosmic radiation from space travel could be less harmful to astronauts than previously believed, data from experiments conducted on board and outside of the International Space Station (ISS) has revealed.

The MATROSHKA experiment, the first comprehensive measurement of long-term exposure of space travelers to cosmic radiation, brought together researchers from the European Space Agency (ESA) and colleagues from other institutions to determine precisely how much radiation astronauts are exposed to during long-term space travel.

The goal was to determine how long astronauts could remain in space without their health being threatened due to exposure to ionizing radiation. To do so, they developed a type of mannequin that was outfitted with several thousand detectors that recorded the doses of cosmic radiation from inside and outside the ISS over the course of several years. The data collected by those sensors has been analyzed, the researchers called the results surprising.

One may say that we found open space to be a bit less hostile to humans than expected. The effective doses, related to the health risk of the astronauts and calculated from measurements with our detectors, were lower than those indicated by dosimeters worn by the astronauts, Dr. Pawe Bilski from the Henryk Niewodniczaski Institute of Nuclear Physics (IFJ PAN), said in a recent statement.

Russian cosmonaut Alexander Skvortsov (left) and Japan Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi, both Expedition 23 flight engineers, work with the European Matroshka-R Phantom experiment in the Kibo laboratory of the International Space Station. Matroshka, the name for the traditional Russian set of nestling dolls, is an antroph-amorphous model of a human torso designed for radiation studies. Credit: NASA

The mannequin, a legless torso described by the researchers as a specially adapted humanoid phantom used in medical research, contained real human bones places inside a plastic shell simulating the shapes and densities of soft tissues and lungs in an astronauts body. It consisted of 33 slices 2.5 cm thickness each, and each of them contained measuring equipment and sets of passive thermoluminescent detectors placed in plastic tubes.

Using a total of six thousand thermoluminescent detectors, the researchers created a three-dimensional rectangular grid of measurement points inside the phantom. The design allowed the authors to accurately determine how much radiation would be absorbed by each of the bodys organs, and to calculate the so-called effective dose, which is considered to be an estimate of the radiation hazard to humans, IFJ PAN explained.

The main hazard to the astronauts health due to exposure to cosmic radiation is the increased probability of developing cancer in his or her body, the institute added. This probability however is quite dependent on the type of radiation the astronaut is exposed to. Most of the natural sources of ionizing radiation on Earth produce electromagnetic radiation of high energy gamma rays. On the other hand, in cosmic rays, energetic protons or heavier ions dominate, which are much more effective in creating cancer cells.

Interior structure of the phantom used in the experiment MATROSHKA. White tubes contain sets of thermoluminescent detectors. Half of these detectors was manufactured by the Institute of Nuclear Physics of the Polish Academy of Sciences in Krakw, Poland. Credit: DLR

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Cosmic Radiation Less Of A Risk To Astronauts Than Previously Thought