Mars and Island One

--- In spacesettlers@yahoogroups.com, "Combs, Mike"

> If 2 RPMs turn out to be OK for most people, we could get by with
radii
> significantly below a mile. But even if we're limited to 1 RPM,
the
> first habitats to provide Earthlike levels of gravity might indeed
> require radii of about a mile,

a=v^2/r=4(pi^2)r/t^2 = 9.81 m/s^2 (one gee)
---> r = 9.81t^2/(4pi^2)

at 1 RPM t_ so r = 894.6 m or about 5/9 of a mile

at 2 RPM, r= 223.6 m

at 3 RPM, r = 99.4 m

....................

setting r to 1 mile (1609 m) and a to 9.81, solving for t:

t=sqrt(4 pi^2 r/ a) = 2pi sqrt(r/a) = 80.468 seconds per revolution
(0.75 RPM)

Ed