Another interesting point about pursuing the more southern orbit of
ISS.

The Van Allen 'South Atlantic Anomaly' isn't getting itself any
smaller. Supposedly this dips to nearly 155 miles (250 km) off the
deck, and in recent years this dip zone has grown measurably, of which
the likes of ISS can't afford the luxury of repeat encounters of such
radiation hits without their crew exceeding their individual career TBI
factor. Although, perhaps foods should stay a bit fresher and a good
number of germs shouldn't stand a chance, thus they might not have to
die while having a nasty cold or from the likes of food poisoning.

QUESTIONS:
How much of an orbit shift can be safely accommodated while avoiding
the "South Atlantic Anomaly"?

Before going to serve onboard ISS, are any of these ISS crew currently
banking their bone marrow?

I believe 1.25 Sv is about maximum dosage if you've got that stash of
banked bone marrow standing by, although that's not reassuring of all
body pars, including the eyes and brain that would become somewhat of
an unknown. Thus perhaps 0.5 Sv is a safe career red-line.

Regards, Brad GUTH / GASA~IEIS
http://guthvenus.tripod.com/lunar-space-elevator.htm