When Malaysian Airlines Flight 370 went missing in 2014, it was a reminder that we had a gap in our aviation technology—the global air-traffic-control system lacked the capability to track aircraft over huge areas of the oceans, the polar regions, and remote mountains and deserts. And that adds up to about 70 percent of the planet. Controllers rely on pilots to report their positions, but if the pilot fails to do so, there is no back-up plan. Now that’s about to change as Aireon, which will be provided as a free service managed by the Irish Aviation Authority, will provide global tracking, thanks to a newly deployed network of 66 Iridium NEXT satellites. Aireon calls it “the biggest technological leap since the introduction of radar.” The last of the satellites are scheduled to be deployed by SpaceX by the end of the year, and the system will go live in 2019.