Iridium satellite network

Iridium Satellite LLC is a company, based in Bethesda, Maryland, United States which operates the Iridium satellite constellation, a system of 66 active satellites used for worldwide voice and data communication from hand-held satellite phones and other transceiver units. The Iridium network is unique in that it covers the whole Earth, including poles, oceans and airways. The company derives its name from the chemical element iridium. The number of satellites projected in the early stages of planning was 77, the atomic number of iridium, evoking the metaphor of 77 electrons orbiting the nucleus. The satellites are frequently visible in the night sky as satellite flares, a phenomenon typically observed as short-lived bright flashes of light.

Iridium controls the virtual country codes +8816 and +8817, part of the 881 range designated by the ITU for the Global Mobile Satellite System.

Iridium SSC, Iridium communications service was launched on November 1, 1998. The first Iridium call was made by the Vice President of the United States Al Gore. Motorola provided the technology and major financial backing. The logo of the company was designed by Landor Associates, and represents the Big Dipper.

The founding company went into Chapter 11 bankruptcy nine months later, on August 13, 1999. At one stage there was a threat that the Iridium satellites would have to be de-orbited; however, they remained in orbit and operational. Their service was restarted in 2001 by the newly founded Iridium Satellite LLC, which was owned by a group of private investors. Although the satellites and other assets and technology behind Iridium were estimated to have cost on the order of US$6 billion, the investors bought the firm for about US$25 million.

Iridium Satellite LLC has approximately 320,000 subscribers as of the end of December 2008 (compared to 203,000 in July 2007).

The Iridium system requires 66 active satellites in orbit to complete its constellation and spare satellites are kept in-orbit to serve in case of failure. The satellites are in six polar low Earth 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. Most of these satellites were launched in the late 1990s before the company went through bankruptcy. Since the bankruptcy, only seven additional satellites have been launched but an updated constellation of 66 satellites is currently being developed and is planned for launch in 2014.

Each Iridium satellite is cross-linked to four other satellites - two satellites in the same orbital plane and one in each adjacent plane. These links create a dynamic network in space. Calls are routed among Iridium satellites without touching the ground, creating a reliable connection. Iridium's satellites are virtually impervious to natural disasters - such as hurricanes, tsunamis and earthquakes - that can damage ground-based wireless towers and terrestrial wires.

Quellen: wikipedia  Iridium


Weitere Informationen zu unseren Dienstleistungen finden Sie auf unserer facebook-Seite