"Upgrade your smartphone into a satellite-enabled messenger with the motorola defy satellite link, a Bluetooth accessory that unlocks a whole new world of affordable always-on connectivity."
www.motorola.com
This device is small, waterproof, costs $149 USD, and apparently requires one of several payment plans from Bullitt Satellite Connect for as low as $4.99 USD per month.
Here's the satellite coverage map:
Perhaps members who have other satellite messaging devices could take the time to read up on this device and compare its features and costs to those other devices.

motorola defy satellite link - Motorola
No mobile coverage? No problem. Switch to satellite! Rugged Bluetooth accessory for affordable SOS assist, location tracking and 2-way messaging over satellite. Drop-proof, waterproof and dust-proof.
This device is small, waterproof, costs $149 USD, and apparently requires one of several payment plans from Bullitt Satellite Connect for as low as $4.99 USD per month.

Here's the satellite coverage map:
Perhaps members who have other satellite messaging devices could take the time to read up on this device and compare its features and costs to those other devices.