Lightweight SSP dynamics due to the beam

In a past note I mentioned that the beam sending energy to Earth
develops perhaps 20-30% of the thrust due to solar pressure and I
didn't know what effect that would have -- a steady force anti-
Earthward.

A friend of mine pointed out the (now) obvious: it effectively makes
gravity a little less strong. Thus, geostationary SSPs will be in a
slightly lower orbit than comsats. How much lower? Haven't done the
calcs, but it should be pretty easy and I'm sure it's not much. In
any case, yet another non-problem.