Radiation in Space:

A Quick Overview

There are three main sources of radiation in space: the Van Allen Belts, galactic cosmic radiation (GCR), and solar particle events (SPEs). All three of these contribute significantly to the radiation that astronauts are exposed to in space.

This radiation can affect astronauts in several ways: through immediate illness (radiation sickness) or through long-term effects (cancer, genetic disorders). Radiation sickness is not a large concern in missions that do not take the craft outside the Earth?s magnetic field. It is, in fact, only a significant problem during SPEs, and even then it is most likely to severely affect only crewmembers who happen to be outside the craft at the time of the SPE. Exposure levels are not likely to reach the fatal level for this type of exposure.

Long-term effects from prolonged exposure are the more serious concern. Cancer, genetic disorders, and sterility can all be cause by long exposure to radiation. For this reason, NASA has instituted exposure limits for astronauts. These limits are meant to reduce both the risks of radiation sickness (30 day and annual limits) and cancer (career limits).

In order to accurately determine how much radiation astronauts have been exposed to, various measurement devices are used, and a standard support procedure is followed, beginning before the astronauts leave the Earth and ending after they return.

Much is (as of yet) unknown about the effects of space radiation on astronauts, and further research is required (and is being conducted) in several areas, including the improvement of measuring devices.

Here are some links to other sites that have more detailed information on this topic, and on space travel in general.