It took eight launches over two years to put up 66 satellites plus six spares (with nine more stored on the ground), replacing the original Iridium constellation launched in the 1990s.

When the FAA conceived NextGen as the long-awaited modernization of the U.S. air traffic control system, it hooked its progeny to the Global Positioning System.

In their westward migration from Norway more than 1,000 years ago, the seafaring Vikings navigated their longboats across the treacherous North