What is Iridium?
Iridium Communications Inc. operates the world's only satellite constellation providing complete pole-to-pole coverage through 66 operational LEO satellites (plus 9 in-orbit spares) at 781 km altitude in 6 polar orbital planes. Iridium is unique in using inter-satellite links connecting each satellite to its four immediate neighbours — two in the same plane, two in adjacent planes — creating a mesh network in orbit that routes calls and data without necessarily touching the ground.
Iridium NEXT constellation
The original Iridium constellation (launched 1997–2002, bankrupt 1999) was replaced by Iridium NEXT: 66 new satellites launched by SpaceX Falcon 9 between 2017 and 2019, all hosted in the same orbital planes as the original constellation. Iridium NEXT satellites are software-upgradable and carry additional payloads including ADS-B receivers (contracted to Aireon, providing global aircraft tracking), AIS receivers, and the NEXT-hosted partner programme.
Services
Iridium Certus: Maritime broadband (352 kbps to 704 kbps) via small low-profile antennas — compliant with GMDSS safety communications. Iridium Short Burst Data (SBD): The standard for global IoT and M2M messaging, used in asset tracking, remote sensing, and logistics. Iridium PTT (Push-to-Talk): Global group voice communications for military and enterprise. Iridium GO!: Consumer satellite communicator for smartphones via Wi-Fi. The combination of global coverage (including both poles), small form-factor devices, and the mature SBD ecosystem makes Iridium the dominant provider for polar operations, aviation safety, and global IoT applications.