Iridium Worldwide Coverage
Standing on the ground, an Iridium satellite will rise from the horizon and stay within line-of-sight view for about 7 minutes. To maintain constant connectivity with the Iridium network, a data handoff is made when one satellite is setting and another is rising from the horizon… this allows for Iridium’s 100% seamless coverage which goes completely unnoticed to the end-user.
Iridium Certus Low-Latency
One future benefit of the Iridium LEO Low-Earth-Orbiting satellites is the potential of low-latency or ping times… these will be far far faster than Geo-Stationary satellites. As of March of 2020 Iridium’s Certus network latency is hovering around 700 to 900 milliseconds but in time it is expected to be 40 to 50 milliseconds with updated infrastructure. A 50 millisecond ping time is a far cry from the Geo-Stationary satellite latency of 600 to 1200 milliseconds.
The reason some satellites are so slow is the speed of light is 186,000 miles per second and Geo-Stationary satellites sit 22,300 miles above the equator and data must travel up and down twice to make a round trip “ping”. In comparison, Iridium satellites orbit about 500 miles above Earth and communicate with each other to reach a land station that may be only a 1,000 or 2,000 miles away reducing ping times to traditional land-based connections.
Many applications such as VPN will operate far better with the low latency benefit of the Iridium Certus network. Voice calls are the a big winner as latency is now so low that talking parties will not notice the delay between speakers.
Interesting Facts On Iridium Satellites
The 2nd generation of the Iridium NEXT constellation consists of 66 operational satellites with 9 orbital spares and 6 more satellites on the ground for a total of 81 satellites… The final launch of 10 satellites was made on January 11, 2019 and all satellites were expected to drift into their respective slots on February 4, 2019. Full operation happened on February 8th, 2019.
Iridium satellites themselves communicate with each other (via Ka-Band) to relay customer data to one of the many strategically placed Iridium teleports that connect to the Internet backbone… a truly elegant solution.
Iridium has been de-orbiting the 1st generation of satellites and as of February 8th 2021, there have been 61 old Iridium satellites de-orbited.