[basementcat]

A constellation for SMS-like service need not be as large as a constellation designed for general purpose internet or telephony. The former just requires one (or a small number) of satellites in a Sun-synchronous orbit while the latter may require a large number of satellites in a variety of inclination and "orbital planes".

https://en.m.wikipedia.org/wiki/Sun-synchronous_orbit

[ronaldoCR]

Their goal is to offer full voice capability + enough data throughput to stream youtube.