Iridium

The Iridium system is a planned commercial communications network comprised of a constellation of 66 LEO spacecraft. The system will use L-Band to provide global communications services through portable handsets. A total of 125 spacecraft will be built by Lockheed for more than $700M. Commercial service are planned to begin in 1998. Total cost of the project is estimated at $3.45 billion and subscriber fees are estimated at $3 per minute. The system will employ 15-20 ground stations with a master control complex in Landsdowne, VA, a backup in Italy, and a third engineering center in Chandler, AZ.

Spacecraft
3-axis stabilized. Hydrazine propulsion system. Two solar panels with 1-axis articulation.

Payload
The system employs L-Band using FDMA/ TDMA to provide voice at 4.8 kbps and data at 2400 bps with 16 dB margin. Each satellite has 48 spot beams for Earth coverage and uses Ka-Band for crosslinks and ground commanding.

Country of Origin	United States
Customer/User	Iridium Corp. (Motorola commercial venture)
Manufacturer(s)	Motorola, Lockheed-Martin
Size	13 m length, 4 m width
Launch	First Launch in 1997. Launches to use Delta II, Proton, and Long March vehicles
Orbit	LEO, 780 km circular, 75 deg inclination, 6 planes of 11 satellites each
Design Life	8 years
Related Sites	Lloyd Wood's satellite pages