Russian scientists measured secondary radiation at International Space Station
It has been turned out that the secondary radiation ranges from 16 up to 34 percent of total radiation level on board. It should be noted that although an average level of radiation on board of ISS is relatively high if compared to those on the Earth but it is still rather nonhazardous for the human. For example, NASA manifests the limiting radiation dose for its astronauts to be 500 millisieverts in a year which corresponds to approximately 500 days at ISS. This means that it is almost impossible to gather the dose above the limit at ISS as a year consists of only 365 days.