Iridium Communications Inc. (formerly Iridium Satellite LLC) is a publicly traded American company headquartered in McLean, Virginia, United States. Iridium operates the Iridium satellite constellation, a system of 80 satellites: 66 are active satellites and the remaining fourteen function as in-orbit spares. Iridium Satellites are used for worldwide voice and data communication from handheld sate Iridium Communications Inc. (formerly Iridium Satellite LLC) is a publicly traded American company headquartered in McLean, Virginia, United States. Iridium operates the Iridium satellite constellation, a system of 80 satellites: 66 are active satellites and the remaining fourteen function as in-orbit spares. Iridium Satellites are used for worldwide voice and data communication from handheld satellite phones, satellite messenger communication devices and integrated transceivers, as well as for two-way satellite messaging service from supported conventional mobile phones. The nearly polar orbit and communication between satellites via inter-satellite links provide global service availability. The Iridium system requires 66 active satellites in low Earth orbit to complete its constellation and 9 spare satellites are kept in-orbit to serve in case of failure. The satellites are in six polar orbital planes at a height of approximately 485 miles (780 km). Satellites communicate with neighboring satellites via Ka band intersatellite links to relay communications to and from ground stations. The original constellation was launched in the late 1990s before the company went through bankruptcy. In January 2017, Iridium began to launch its next-generation satellites through its $3 billion launch campaign, Iridium NEXT. The new satellites were sent into space on SpaceX Falcon 9 launch vehicles from Vandenberg AFB Space Launch Complex 4 in California over the course of eight launches between January 2017 and January 2019. On January 14, 2017, SpaceX launched 10 of the new Iridium sa Iridium Communications Inc. (formerly Iridium Satellite LLC) is a publicly traded American company headquartered in McLean, Virginia, United States. Iridium operates the Iridium satellite constellation, a system of 80 satellites: 66 are active satellites and the remaining fourteen function as in-orbit spares. Iridium Satellites are used for worldwide voice and data communication from handheld satellite phones, satellite messenger communication devices and integrated transceivers, as well as for two-way satellite messaging service from supported conventional mobile phones. The nearly polar orbit and communication between satellites via inter-satellite links provide global service availability. The Iridium system requires 66 active satellites in low Earth orbit to complete its constellation and 9 spare satellites are kept in-orbit to serve in case of failure. The satellites are in six polar orbital planes at a height of approximately 485 miles (780 km). Satellites communicate with neighboring satellites via Ka band intersatellite links to relay communications to and from ground stations. The original constellation was launched in the late 1990s before the company went through bankruptcy. In January 2017, Iridium began to launch its next-generation satellites through its $3 billion launch campaign, Iridium NEXT. The new satellites were sent into space on SpaceX Falcon 9 launch vehicles from Vandenberg AFB Space Launch Complex 4 in California over the course of eight launches between January 2017 and January 2019. On January 14, 2017, SpaceX launched 10 of the new Iridium satellites into orbit. The second launch of Iridium NEXT satellites took place on June 25, 2017 on a SpaceX Falcon 9 rocket out of Vandenberg Space Force Base. This was the second of eight scheduled launches. The third launch of 10 NEXT satellites took place on October 9, 2017. On December 22, 2017, ten additional satellites were deployed after a successful launch on a SpaceX Falcon 9 rocket. On May 22, SpaceX successfully launched an additional five Iridium NEXT satellites from Vandenberg Space Force Base. On January 11, 2019, the final ten satellites were placed in orbit by SpaceX. Iridium offers four satellite handsets: the 9555, 9575A (which is only available to US government customers), the Extreme, and the Extreme PTT. These can be used for data-logging applications in remote areas (as in data collection satellites). Some types of buoys, such as those used for the tsunami warning system, use Iridium satellites to communicate with their base. The remote device is programmed to call or send short burst data (SBD) messages to the base at specified intervals, or it can be set to accept calls in order for it to offload its collected data. The following transceivers have been released over the years: Iridium Core 9523 – Similar to the 9522B, a modular transceiver released in 2012 Iridium 9522B – A transceiver released in late 2008, is smaller than the 9522A and has similar features. It also supports Circuit-Switched Data (CSD), not just SBD. Iridium 9522A – Based on the 9522, some variants have built in GPS and autonomous reporting functions. Supports SBD. Motorola 9522 – Last Motorola transceiver, supports outgoing SMS but no Iridium 9601 – Supports only SBD, several tracking devices and other products have been built around this modem. It was an Iridium manufactured product designed as an OEM module for integration into applications that only use the Iridium Short Burst Data Service. Short Burst Data applications are supported through an RS-232 interface. Examples of these applications include maritime vessel tracking or automatic vehicle tracking. Iridium 9602 – Smaller, cheaper version of 9601 (released in 2010). Iridium 9603 – One-fourth the volume and half the footprint of 9602 Official website Application of Iridium telecommunications to oceanographic and polar research Iridium Data Modem (PDF) Technical success and economic failure (PDF), MIT