Ah, but an APRS satellite would be one of those silly pointless FM beepsats.
APRS has had an HT global text-messaging tool before the cell phone craze brought it to everyone.
Since 1998, Ham radio has had an HT (the D7) that can text-message any other APRS HT or mobile on the planet in real time by only knowing the receipient's callsign. This is not email, it is live texting HT-to-HT anywhere, anytime.
Too bad most of ham radio still has never even tried it and criticize it when most of billions of people on the planet now embrace texting as a valuable human-to-human communications tool.
We've had HT texting for over a decade. Well ahead of consumers... yet we squander it away rather than learn to use it.
APRS was never primarioy about GPS tracking. It was first a human-to-human work-everywhere comm link on a single national channel. Too many people got distracted by the maps, and never even tried to communicate with it.
Bob, WB4APR