A Last-of-Its-Kind Rocket Will Launch a GPS Satellite for the US Military Thursday. How to Watch...

After nearly two decades of work helping the American military accomplish national security missions, United Launch Alliance's Delta IV medium rocket is ready to retire.

Luckily, you have one last chance to watch it launch live, on ULA's YouTube channel or here at Space.com. The Delta IV medium is expected to launch into space on Thursday (Aug. 22) during a 27-minute window that opens at 9 a.m. EDT (1300 GMT), blasting off from Cape Canaveral Air Force Station in Florida.

It will carry the second satellite in a next-generation constellation of the Global Positioning System that supports navigation on Earth's surface and in the air. The new satellites include better accuracy, more resiliency against jamming and a new signal for civilian users, according to ULA.