The Iridium satellite network has 3 primary components:
- The satellite network
- The ground network
- The subscriber products such as the 9555 handsets
and other end-user equipment
The Iridium network is designed to allow voice and data messages to be relayed from one satellite to another, around the planet until they arrive at the satellite above the respective Iridium handset or terminal at which time the signal is transmitted to Earth.
 Learn about Iridium phones how the network can assist a First Responder or aide in GPS asset tracking. Connection quality for all applications on the Iridium network is typically 3x greater than the competition.
When an Iridium subscriber places a call, it connects to whatever satellite is overhead, and is then dispatched among satellites circling the globe to whichever satellite is above the appropriate Earth gateway, which then downlinks the call and transfers it to a standard public voice network or Internet so that it reaches the recipient.
The fleet of satellites is in a near-polar orbit at a height of 485 miles (780 km). The 66 active satellites fly in formation in six orbital planes, evenly spaced around the planet, each with 11 satellites equally spaced apart from each other in that orbital plane.
Any satellite completely orbits the planet every 100 minutes, traveling at a rate of 16,832 m/hr. As a satellite disappears over the horizon and moves out of reach your call will be seamlessly handed-off to the next satellite appearing in the horizon.
As Iridium is a Low Earth Orbit satellite constellation, voice delays may be unnoticeable. Other satellite configurations use Geostationary Earth Orbits (GEOs), are about 22,300 miles above the equator and as a result the call latency can be quite high as speakers talk over one another (if they are from New York:) or have to wait for each other to finish. GEOs are also largely ineffective at the poles due to the curvature of the Earth which disrupts transmissions when attempted at the fringe of a GEO satellite's footprint.
Every Iridium satellite x-links w/4 other satellites:
- 2 satellites in the same orbital plane
- 2 in an adjacent plane
These x-links create a fluid network where calls are routed throughout the satellites w/out requiring ground contact, creating a secure and reliable connection. More specifically this x-linking makes Iridium  resistant to natural disasters that would damage ground-based cell phone towers since x-links are entirely space-based.
The ground control segment and gateways connect into the terrestrial telephone system. A system control segment supplies operational support and control services to the constellation, delivers satellite tracking data to the gateways, and controls the termination of Iridium messaging services.
Gateways are the ground-based equipment providing voice, data, messaging, billing information, as well as some customer service functions. These gateways support and manage mobile subscribers and the interconnection between the satellite and the earth-based phone system. Gateways also manage their own network and linking elements.
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