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AO-7's solar elevation from 2007 to 2010

These charts show how AO-7's solar elevation will change over the next few years. Solar elevation is a cheap and cheerful way of estimating the illumination of satellites in near-circular orbits. The dotted red lines show the maximum and minimum angular radius of Earth as seen from the satellite. Above the dotted lines means the satellite is in continuous sunlight; below them every orbit will at some time take the satellite into eclipse, the lower the elevation the longer the eclipses. Between the dotted lines the satellite may be eclipsed depending on the orientation of its perigee relative to the sun.

AO-7 is in a relatively stable orbit, but this model looks so far into the future that it is sure to be affected by decay and other perturbations. However the indication that AO-7 is moving into a period (until about 2018) of long summers is unlikely to be off the mark.