Iridium has gone through a major transformation since the idea of a worldwide communication system via satellite was first conceived in the late 1980s.
Though it was first thought an interconnected constellation of satellites would require 77 of them for global coverage, engineers later realized that 66 was the number required. Over the next 10 years, over 90 satellites were built and launched into space. Commercial service was launched in 1998. But the company went bankrupt just one year later (due to the expansion and growth of cell phones and cell service that had occurred in the 10 years leading up to this time), which would mean shutting down Iridium for good.
But a group of global investors who signed a service contract with the U.S. Department of Defense saved Iridium just in the nick of time. Iridium would carry on.
Though these first satellites were only expected to have a lifespan of 7 years, they were able to function for much longer. Eventually, it was time for an upgrade. They were finally replaced with 75 next-generation Iridium satellites as part of the Iridium NEXT mission. New satellites were launched into space beginning in 2017. In two years' time, there would be a full revamp of this unique and powerful space technology.
All communication services were transferred from the old fleet of satellites to the new in February 2019.