If I spend one day beyond the Van Allen belt in an unshielded craft/spacesuit how much radiation will I be exposed to?

Question

I am guessing it's about the same as having a medical X-ray each day, is this about right?

Answer 1

This must relate to real-time solar conditions. e.g.

• a quiet day
• a storm day
• some mission time weighted average

Any of these could be misleading without specifying the assumptions. Note that the latter has to account for the fact that large events occur on longer time-scales than a year or two to Mars and back hence it is a probabilistic problem.

An interesting way of looking at this is that near polar aircraft flights are very much more sensitive to radiation than at lower latitudes. This link says:

• Air crew are classed as radiation workers
• The dose during one particular storm corresponded to 12% of the normal yearly limit (note, limit, not normal dose).

Anecdotally, I have heard there have been rather worse storms in this respect where the single flight does exceeded the yearly limit, if I find a reference I will post it.

Hence, back to the question, it could be very much worse beyond the protection of the Earth's magnetosphere.

The question is related to this one. On of the linked references gives two interesting figures, which I have reproduced below. As a caution, out of context they are not so meaningful, and even look rather cavalier.

Answer 2

From this answer on Travel.SE

a flight from New York to Tokyo is probably about 150 μSV. For comparison, natural background radiation is about 2,000-7,000 μSv per year, a chest x-ray is about 50 μSv.

By contrast, outside the Van Allen belt, say on a trip to Mars, you are looking at around 1.84 mSv per day.

That's about 37 times as much as a medical X-Ray each day!