Sat Messenger is a satellite gateway for encrypted short messages. Once received they are decrypted and sent to the provided email address. Cost for less than 50 signs, can be 0.05 euro, almost like SMS at the beginning.
Sat Messenger as part of the Recovery Base Station, RBS, uses Iridium as gateway.
Sat Messenger is Open Source. To find out more try /tmp/lab wiki at http://www.tmplab.org.