A-B-Cs of sun-synchronous orbit mission design

The sun-synchronous-orbit (SS-0) is one of the most commonly used forms of earth orbit for science missions. Historical examples of missions which use the SS-0 include NIMBUS, TIROS, COBE, SME, LANDSAT, and others. More recent earth science missions based on the SS-0 are Terra, EO-1, and Aqua. And even now there are several future missions that will be launched into a SS-0 within the next few years: Aura, Cloudsat, CALIPSO, Aquarius, and OCO. The list of past, present, and future earth orbiting sun-synchronous missions is long and impressive. Given the widespread utility of the SS-0, it is worthwhile to review characteristics that make the SS-0 so useful and therefore desirable for scientific application. It might also be useful to describe the process of how one goes about selecting the mission parameters defining the SS-0 mission design.