[Server-sky] Server Sky - ISDC, IEEE, Geodesic Arrays

[Keith Lofstrom]

Server Sky News:

I presented Server Sky at ISDC 2013 in San Diego two weeks ago;
some new technical developments, and some applications.  I will
present server sky at the IEEE Sustainable Technology conference
August 1 to 2 in Portland. 

I stumbled across an interesting way to arrange Server Sky
thinsats, as vertices of a distorted geodesic sphere.  Thinsats
trace ellipses around the central orbit, changing between 
perturbations of radial distance and tangential distance.  Along
with an oscillating NS distance change from the central orbit,
the thinsat arrays appear to rotate and skew. 

Rather than put thinsats in some sort of grid, their orbits are
now designed to follow the surface of an ellipsoid, with spacings
mimicking those of an icosahedral geodesic sphere - distorted by
the rotation and skew.  This increases the number of thinsats in
at a higher radius from center, which helps with focus, and the
triangular grid spacing washes out the unwanted grating lobes in
the primary beam.  The sparse spacing of the thinsats still wastes
most of the transmit power away from the small receiver antenna,
but that waste power is uniformly spread over a hundred thousand
square kilometers, far below the interference threshold of other
receivers, and at levels a trillion times lower than the mW/m²
levels that raise health concerns.

See http://server-sky.com/IEEESustech2013
for a draft of the IEEE paper, and for a flash animation of a
small rotating array of 1002 thinsats formed into a 5kg, 4kW system. 
That is 30% of the power of the largest comsat, with 200 times the
effective antenna aperture area, weighing less than a 2U cubesat.
Typical arrays will be 7842 thinsats with a few hundred nearby spares. 

Keith

P.S. This is a test of the server sky mailing list, which I haven't
used for a while.  Are you folks interested in more mails like this,
or should I put everything on http://server-sky.com instead?

-- 
Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993