One of the many dangers of space travel for astronauts is exposure to cosmic radiation. And although levels of that radiation were once thought high, a new experiment on the International Space Station (ISS) suggests it is much lower.

It turns out that astronauts are receiving a lot less cosmic radiation exposure, at least in and around the ISS, than initially thought.

The MATROSHKA experiment was an international effort and involved scientists from Germany, Poland, Austria, Sweden and Russia. Researchers outfitted a mannequin with a series of radiation detectors. However, this wasn't an ordinary mannequin: scientists filled it with human bones, as well as objects resembling human organs. This was so the test measured the levels of radiation inside the human body.

From 2004 through 2009, ISS astronauts exposed the mannequin to varying degrees of radiation. It was kept inside the Russian module of the space station for a year, but was also put in a spacesuit and put outside the station for another year. It was outfitted with its own detectors, as well as the dosimeters astronauts use on their bodies for measuring levels of radiation. This is the first time for such an experiment.

Once the mannequin made its way back to Earth, teams of scientists spent weeks studying its data. That data was conclusive: the dosimeters that the astronauts wore on the ISS overestimated the actual dose of cosmic radiation by about 15 percent inside the station. In open space, though, that overestimation was over 200 percent.

"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", says Dr. Paweł Bilski, an associate professor at IFJ PAN.

This suggests that travel to space, at least as far as the ISS and possibly even Mars, is safer for astronauts than we initially thought and that astronauts receive far less exposure to cosmic radiation than expected. However, deep space travel probably still has extremely dangerous levels of cosmic radiation.

"We must remember that measurements within the MATROSHKA experiment were performed at low Earth orbit where the Earth's magnetosphere significantly reduces the number of charged particles from cosmic radiation," says Bilski. "In interplanetary space there is no such shielding."

This also doesn't mean that the radiation levels on the ISS aren't dangerous. Any exposure to cosmic radiation is more likely to cause cancer than any radiation based on Earth.

[Photo Credit: DLR]