Petition to examine space based solar energy

The only way power-beaming from smaller-scale satellites can work is by using laser transmission rather than microwave. That has yet another set of problems. But there are some researchers in Japan doing studies in that direction.

Regards,

Mike Combs

From: spacesettlers@yahoogroups.com [mailto:spacesettlers@yahoogroups.com] On Behalf Of sraj
Sent: Monday, March 25, 2013 9:16 AM
To: spacesettlers@yahoogroups.com
Subject: Re: [spacesettlers] Re: Petition to examine space based solar energy

It appears that a small space based solar power system is not practical??
Do we really need a 1Km dia transmitting antenna??..

Power beaming from geostationary
orbit by microwaves carries the difficulty that the required 'optical aperture'
sizes are very large. For example, the 1978 NASA SPS study required a 1-km diameter transmitting antenna, and a 10 km diameter receiving rectenna, for a microwave beam at 2.45 GHz. These sizes can be somewhat decreased by using shorter wavelengths, although they have increased atmospheric absorption and even potential beam blockage by rain or water droplets. Because of the thinned array curse , it is not possible to make a narrower beam by combining the beams of several smaller satellites. The large size of the transmitting and receiving antennas means that the minimum practical power level for an SPS will necessarily be high; small SPS systems will be possible, but uneconomic.
http://en.wikipedia.org/wiki/Space-based_solar_power

.. I was about to propose that we put into orbit thousands of small and light, standardized and deployable solar arrays, of 100m x 100m typical size, with self contained control systems. By keeping the size small it will be possible to make the structural support relatively light.

Regard,
Selvaraj