The ‘Defy Satellite’ link (odd name 🧐) from Bullitt essentially allows any bluetooth paired iOS or Android phone (software standards apply) to send and receive text messages via satellite.
The device also has an SOS function (button on the side) that is not bluetooth connection dependent.
Device costs £99 ish.
Small print: A) Direct-to-satellite messaging requires a Bullitt Satellite Messenger plan. B) Sending a message direct to a satellite requires a clear view of the sky. C) Please refer to the Bullitt website for service coverage maps. D) Has a 600 mAh battery.