Still, the fact that Apple has figured out the weird RF voodoo already makes it seem like a less ridiculous proposition.

Qualcomm is the one who has figured out the weird RF voodoo you speak of. Apple is just consuming that.

Is there any tech manual out there? Would love to see how it works.

I always assumed the main thing with satellite messengers was that they transmit with much higher power. Not that such a system is easy to design, but the “voodoo” mentioned previously was more about achieving compatibility with an existing RF system at much longer ranges than the system was designed for.

it's not rf voodoo. it's a highly spread signal at an extremely low nitrate. this has been common for communications satellites for a very long time.