On Tuesday, the U.S. Air Force will launch its first next-generation GPS satellite.
The satellite is the first of 32 planned GPS III satellites, which will replace an older GPS system. They'll reportedly be harder to jam and will also interface better with other countries' navigation satellites.
The new satellite is two and a half years behind schedule, but a ground control unit meant to pair with the new system is even further behind — it isn't expected to be ready until at least 2022.
The GPS III satellite will launch from Cape Canaveral, Florida, aboard a SpaceX Falcon 9 rocket on Tuesday.