Communication

Iridium Sat Phones

by jacksmith in 12.08.2010 23:40

Iridium Communications Inc. (formerly Iridium Satellite LLC) is a company, based in McLean, VA, 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. 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 2015-2017 on SpaceX Falcon 9 Launch Vehicles from Vandenberg AFB Space Launch Complex 3 in California.

The former Iridium provided phones from two vendors, Kyocera and Motorola. The Motorola 9500 iridium sat phone is a design from the first commercial phase of Iridium, whereas the current Motorola 9555 iridium sat phone model is the most current version of the handset and was released in October 2008.

Until the release of the 9555 the 9505A was the sole handset sold by the company — a functionally identical clone of the Motorola 9505 with some slightly different components.

Kyocera Iridium sat phones models SS-66K and SD-66K are no longer in production but still available in the second-hand and surplus market. The SD-66K phone is a small 900 MHz GSM phone that fitted in a cradle (KI-G100) that included a large antenna and facilitated connection to the Iridium network. The SS-66K is a self contained phone, but featured a rather unusual ball antenna.

All iridium sat phones can receive SMS, but only the 9505, 9505A, 9555 and those based on the 9522 can send them.

Prepaid SIM cards are available from a variety of different outlets as http://www.prepaidsatphone.com. Their values range from 50 to 5,000 minutes; the 50 minute cards have no validity and the 75 minute vouchers are valid for only a month, but the 5,000 minute cards stay valid for two years. Since Iridium charges quite a bit for merely accessing their network without making calls it is possible to extend the validity of such an account by a month for around US$45. It is also possible to refill such an account without purchasing a new SIM card.

The 500 minute card is the most common one, which remains valid for one year and can usually be bought for US$600 to $750, while the 75 minute card can cost up to US$175 and the 5,000 minute card costs around US$4,000.

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