Learn about Iridium’s History from the Smithsonian Institute
The Iridium satellite system is the first to provide a truly global satellite voice and data communication including the oceans and the poles. This has earned Iridium a place in the Smithsonian museum of Space and Aviation in Washington D.C. Below are a few photos taken of the Iridium section of the museum along with information on Iridium satellite system and its components.
The above picture is a side view of the satellite and its solar panels The Iridium satellite constellation is a system of 66 communication satellites and spares around the Earth. It allows worldwide voice and data communications using handheld and fixed devices. The Iridium network is unique in that it covers the whole earth, including poles, oceans and airways. The Iridium is the first satellite communications system in low Earth orbit, at altitudes of 480-800 kilometers (300-500 miles) and the first to provide world wide coverage. Iridium have a crucial advantage over geosynchronous satellites, which orbit much higher at 35,680 kilometers (22,300 miles). Iridium satellites transmit and receive radio signals more quickly using less power than geosynchronous satellites.
This picture is a closer side view of the iridium satellite
This picture is the displace case showing the first generation 9500 Iridium hand held satellite phone.
One of the 100 small antennas that receives the calls from the ground and some of the internal components of the satellite which convert the signal from a satellite phone on the ground to a signal that can be sent to a ground station where the call is then send through landlines to its call destination
The above picture is a closer look at one of the 100 small antennas that make up the main mission antenna. These antennas receive signals from ground based satellite phones then the signals are processed by on board computers. Each Iridium satellite contain seven Motorola/FreeScale PowerPC 603E processors running at 200 MHz. Processors are connected by a custom backplane network.
One processor is dedicated to each cross-link antenna, and two processors are dedicated to satellite control one being a spare. After processing the signal is retransmitted to a ground station or another Iridium satellite phone or it is passed through the crosslink antenna to another Iridium satellite.
This is a closer looks at the first generation 9500 Iridium handheld satellite phone. This model has not been in production for a number of years. It was replaced by the second generation Iridium 9505 phone which was half the size of the first generation phone. The Iridium 9505 was replaced with the current production 9505A phone which has the same appearance as the 9505A but it has modern accessory connections. The Iridium phone can place a call from anywhere in the world to another Iridium phone or any earth based telephone or cellular network. The display states the Iridium phone can be modified to be used as a cellular phone which is not an option for the current production 9505A.
The antennas on the bottom are gateway antennas that transmit the signal to and from ground stations that connect to earth based telephone systems. The antenna right above the gateway antennas are the cross link antennas that pass the signal to other satellites on the network when
needed.
Here is a view of the main mission antenna which is made up of many smaller antennas
This picture is a view of the side panel open to some of the internal modems
Here is a display of the Iridium satellite constellation The satellites orbit from pole to pole with an orbit of roughly 100 minutes.
There is a “seam” where satellites in counter-rotating planes next to one another are traveling in opposite directions this is due to the satellites using an over-the-pole orbital constellation design. Cross-seam intersatellite-link handoffs happen very rapidly. Iridium satellites can only provide intersatellite links using their cross-linking antennas between satellites orbiting in the same direction.