Rebuilding the Iridium sat-phone network

Ten spacecraft are launching from California to complete the $3bn refurbishment of the original satellite phone network, Iridium. The first system was put up in the late 90s to enable calls to be made anywhere on the planet. The new 66-satellite constellation will continue the same service but with a number of improvements, one of which should transform the surveillance and management of air traffic. Our science correspondent Jonathan Amos spoke with CEO Matt Desch about the company's decade-long effort to overhaul its technology.