How much radiation exposure do astronauts get in space?

Here are some numbers for various missions:

Mission.............Dose

Gemini 3        23 millirads
Gemini 4        46 millirads
Gemini 5       176 millirads
Gemini 7       164 millirads
Skylab        2500 millirads
Apollo 11      173 millirads

For orbits at 250 - 300 km at 65 degree inclinations to the equator you get about 10 millirads/day. These numbers are from Volume II of the "Foundations of Space Biology and Medicine" NASA SP-374 published in 1975. Passes through the Van Allen radiation belts give you 10 - 20 rads/hour but most manned flights avoid them, and passages through them last about 10 - 20 minutes.
Copyright 1997 Dr. Sten Odenwald
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