Apollo 11: 40 Years

[GeneW]

Originally Posted by camelll

"A satellite shielded by 3 mm of aluminium in an elliptic orbit passing through the radiation belt will receive about 2,500 rem (25 Sv) per year. Almost all radiation will be received while passing the inner belt."

"A dose of under 100 rems is subclinical and will produce nothing other than blood changes. 100 to 200 rems will cause illness but will rarely be fatal. Doses of 200 to 1000 rems will likely cause serious illness with poor outlook at the upper end of the range. Doses of more than 1000 rems are almost invariably fatal"

OMGWTFVANALLENBELTBBQ is correct.

How long do you think those guys were in the Van Allen belt? They were booking at Earth escape velocity, about 25000 miles an hour. Their vector was not in an elliptical orbit but in a wide curve that approximated a straight line towards the Moon. Let's assume that they were in both belts a total of three hours up and down total. That's reasonable when you figure that the belts at their thickest points are about 9,000 miles.

The outer Van Allen belt's thickness varies between 3,600 miles and 6,000 miles, the inner at about 3,000 miles. Their altitude is about 500 miles to about 10,000 miles high. BTW, 500 miles is damned high for an orbit - most manned flight is in Low Earth Orbit, which is about 200 miles high at most. See http://imagine.gsfc.nasa.gov/docs/as...s/970630a.html


We're talking exposure from about an hour to a couple of hours at most. This is versus a good chunk of a year for that poor Satellite (which is Rad Hardened, something we can't yet do with people).

Let's assume a satellite has hard exposure for three months out of the year, which is a generous low figure. The difference between three months (roughly 2160 hours) versus two or three hours is about one thousand to one. The Satellite gets 2,500 REMs per year (in this case I"m saying with three months up and down through the belts).

The astronauts at the same rates get 2.5 rems.... Most of us probably get more radiation damage to our skin from sunshine over several summers.

Gene