"Dr John Stockton" <spam@merlyn.demon.co.uk> wrote:
> JRS:  In article <3F0587AA.E3CBCC50@nbnet.nb.ca>, seen in
> news:sci.space.policy, Dale Trynor <dalet@nbnet.nb.ca> posted at Fri, 4
> Jul 2003 09:54:45 :-
> 
> >I do remember reading that the solar force is something like 5 pounds per
> >square mile if that's of much use. 
> 
> I make it, for total reflection, about 9.6E-7 kgF/m^2, or nearly one
> kilogram per square kilometre; I leave conversion to archaic units as an
> exercise for the reader.

Both of these determinations are wrong, without the
stipulation that they are for a distance from the Sun
of 1 AU.  The "solar force" scales as the inverse 
square of distance from the Sun.  Since Solar Sails
are meant for sailin' it doesn't make a whole lotta 
sense to force the assumption of 1 AU distance into
the measurement of "solar force", as actually *using*
a Solar Sail will change that, hopefully by a lot.