Spotted: US-based Iridium has completed a $3 billion dollar satellite system that could make flying safer. The system includes 66 operational satellites (plus nine spares) and is mainly intended for global telecommunications. Each satellite includes a special receiver, made by Aireon, a US manufacturer of global aircraft tracking and surveillance systems. The receiver uses technology, which eventually could make it possible to track every plane in the sky, no matter where on earth, the company says.

Today airplanes are tracked using radar and something called automatic dependent surveillance-broadcast (ADS-B) receivers. But air traffic control can only receive signals via towers on the ground. There are more than 600 of these towers, but they can only receive signals from roughly 250 miles away. This leaves large areas of the planet unmonitored, including some oceans and countries with fewer receivers.

The new system could change the ways planes are tracked because the receivers are in space. The system will be able to pick up the ADS-B signal from a plane wherever it is flying. That could help airlines keep track of planes and find better routes. In emergency situations, it could make it easier to locate the plane quickly.

Aireon is currently running tests on the system in space. It plans to go live in the spring.