A SpaceX Falcon 9 rocket lofted the final 10 Iridium NEXT satellites into orbit today from Vandenberg Air Force Base. The launch completes a new constellation of 75 Iridium communications satellites and signals an expansion of Iridium services into broadband. The satellites also carry Automatic Dependent Surveillance-Broadcast (ADS-B) payloads for Aireon’s air traffic global surveillance system. This was the eighth SpaceX launch for Iridium over two years.

Iridium is a system of 66 operational satellites, plus spares, in low Earth orbit (LEO). The original system design called for 77, hence the name Iridium, the 77th element on the Periodic Table. Mission developers ultimately concluded they could accomplish the goal of providing global mobile communications with handheld devices — cell phones via satellite — with 66 instead. In the 1990s when the system was proposed and built, that was an astonishing number of satellites for a single system, though in current times it seems modest.

Unfortunately for Iridium, terrestrial cell phone services took hold at lower cost and it failed to find the user base it needed. After spending $5 billion to create the system, the company went bankrupt in 2000 after building and launching the original constellation.

A special feature of the Iridium system is its intersatellite links, which create a very secure system. Signals travel up to a satellite and are passed along from satellite to satellite without needing to make intermediate hops to ground stations. That is especially useful for the military. Operations resumed after the satellite system was bought by private investors for $25 million once DOD signed a two-year $72 million contract in 2000.

The new Iridium Communications signed a contract with Thales Alenia in 2010 for 81 “Iridium NEXT” replacement satellites: 66 operational, 9 in-orbit spares and 6 ground spares. The same year it contracted with SpaceX to launch the satellites, one of that company’s earliest customers. The total cost of the new constellation is $3 billion.

Today’s launch completes the replacement sequence.

Matt Desch, Iridium’s CEO, said that once the satellites are fully operational “our future will be in place.” The updated constellation will inaugurate a new service called Iridium Certus providing “global specialty L-band broadband connectivity, enabling highly mobile internet access using smaller and more cost-effective terminals.”

The satellites are also outfitted with Aireon’s ADS-B payloads. Aireon CEO Don Thomas said the system will provide “the world’s first, real-time, truly global view of air traffic.” Former FAA Administrator Marion Blakey, who serves on Aireon’s U.S. advisory board, said “we are now one step closer to having a clear, accurate and complete picture of the world’s airspace, including over the oceans and remote areas.”

Although DOD may have saved the day for Iridium in 2000, the U.S. government now accounts for only 15.5 percent of the company’s revenue. A company spokeswoman told SpacePolicyOnline.com that five years ago government business was approximately 19.6 percent of revenue compared with 15.5 percent today and it expects it to decline as revenue from hosted payloads and the Iridium Certus services grow. Aireon alone will provide three new revenue streams for the company: $200 million in hosting fees paid up front and recognized into revenue over a 12.5 year accounting life; a total of $34 million in power fees paid annually over 12.5 years; and $20 million annually for data services.