Satellite is different from other forms of communications in terms of its reach. VHF and SSB rely on a line of sight signal or radio waves bouncing within the atmosphere to determine range. Satellite relies upon getting a signal up to a repeater that is orbiting in space.
The drawback with satellite is that it can be insanely expensive. There are stories of luxury yachts that spend over $100,000 on regular satellite access. Most of these fees relate to constant internet access,
There are systems where the device sends a very small "batch" of information to the satellite (such as an email or text). Message delivery may take a minute or two as the device finds a satellite but, the message can be delivered anywhere in the world. Through Iridium the fees for this service are very modest., We intend to have this as backup to our general communications system.
Satellite phones and terminals help users stay connected when travelling to remote areas out of standard GSM coverage.