SpaceX has successfully launched 10 satellites for Iridium Communications. This was the first of several such launches in the Iridium satellite replacement program. Many are calling this program a "tech refresh" and it may be the biggest of its kind in history.

This was also a historical event for SpaceX's Falcon 9 rocket, because this is the first launch since an explosion occurred last fall. Iridium has a seven-flight contract with SpaceX to deploy 70 satellites for $468 million.

The new Iridium satellites will assure a continuation of existing telephony services plus several other new functions, including the ability to track airliners anywhere in the world.

Over the next 18 months Iridium will be replacing its first generation constellation with 81 new spacecraft. This includes 66 operational satellites, six on-orbit spares and nine backup units on the ground awaiting assignment as needed. Two of the in-orbit spaces will be launched by a smaller launch vehicle.

Iridium's prime contractor is Thales Alenia Space, with Orbital ATK in charge of assembling, integrating and testing the spacecraft. Orbital ATK is also handling the ground support equipment, payload integration (including hosted payloads), shipping and launch integration services.

Telephony service subscribers can communicate from the ground or an airborne platform at any point on the planet and connect to anywhere else on Earth. NEXT satellites will have an additional payload that can received air traffic data from aircraft flying anywhere over the globe.

The existing constellation of satellites is expected to remain operational until Iridium NEXT is fully operational, with many satellites expected to remain in service until the 2020s. Meanwhile, the new satellites are backward compatible with the current system.