Satellite laser communication with Brandon orbits

We estimate worldwide zenith attenuation for 10 micron laser satellite communication systems. The attenuation may be lowered with the aid of switched ground diversity. However, real satellite systems tend to sharply raise the attenuation with low elevation angles and long atmospheric path lengths. Brandon Molniya satellite concepts are expected to give good worldwide laser satellite performance. Four Brandon satellite replacements for geostationary systems are emphasized. The Brandon4 offers relatively low atmospheric attenuation north of 40N, and it allows laser communications to be considered.