conclusion, was that the relative distribution of reflected radiation between the diffuse and specular components of an actual SPS was likely to be quite different than the 50-50 distribution assumed in the Briefing Document. In particular, the potential hazard to eyesight that the specular reflections may represent will undoubtedly lead to designs specifically tailored to reduce the energy contained in the specular beam. In the opinion of the working group, the most likely solutions to the problem of the specular beam will result in an increase in the diffuse albedo, and the reduction of the total albedo of the individual satellites (diffuse albedo plus specular albedo) is not likely. The solutions will rather be of the kind that make the antenna structure and solar blanket less like a mirror and more like a piece of white paper. Given the optimistic estimate of the diffuse albedo and the likely fate of the large specular reflections, it would not be surprising if the actual diffuse albedo of the satellites reached 10%, two and a half times the Briefing Document estimate. In summary, it was the concensus of the working group that the magnitude of diffuse albedo of the individual satellites is the major factor in determining the effect of the reference SPS on optical astronomy. Intensity Profile of the SPS Brightness Distribution An essential feature of the Briefing Document is that it attempts to provide a method for calculating the distribution of added sky brightness as a result of the SPS. There are limits to the practicality of this approach as described by Stokes in his discussion of the limitations of the Briefing Document characterization. In spite of the fact that the actual brightness distribution around an individual power satellite will depend strongly on physical conditions, several properties of the brightness distribution of the entire system are relatively independent of local physical conditions. As described in the Briefing Document, the area of increased brightness is sharply peaked. In Figure 2 the predicted increase in the sky brightness along the meridian at midnight for Kitt Peak National Observatory has been plotted for a 60-satellite system. While the intensity scale shown in the figure is for a satellite brightness equal to that of Venus, the shape of the
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