#format jsmath
== Centrifuge RPM ==

Centrifugal acceleration and RPM versus radius.  Radius is to body midline for similar head-to-foot hydrostatic pressure compared to 9.8 m/s² gravity).  This neglects subtle long-term Coriolis effects, besides the obvious and well-known vestibular effects of motion in a rotating acceleration field.

$ a = \omega^2 R ~$ so 
$~ R = a (gees) / \omega^2 = 9.8 / ( \pi RPM / 60 )^2 = 3575 / RPM^2 $ meters for one gee

|| '''RPM '''            ||    1 ||   2 ||   3 ||   5 ||  8 || 10 || '''15''' || 20 || 30 ||
|| '''radius (meters)''' || 3575 || 894 || 397 || 143 || 56 || 36 || '''16''' ||  9 ||  4 ||

One paper claims vestibular adaptation to 30 RPM(!) within a week, for a limited range of motion.  A conservative guess is that 15 RPM will suffice for most practical long term needs, assuming training and procedural accomodations.

A cylinder 16 meters radius and 10 meters wide provides 1000 square meters of floor space.  Three meters of polethylene shielding around that is a polyethylene volume of π (16*38² - 10*32²) m³ ≈ 10,000 m³ ≈ 9,000 tonnes of PE.