Photos: Atlas 5 on the pad for X-37B launch

An Ariane 5 rocket will fire into the sky from French Guiana Thursday evening and deliver a record heavyweight payload to orbit less than an hour later.

The 721,000-pound United Launch Alliance Delta 4 rocket launches on-time at 2:36 p.m. EDT Wednesday into a deck of low-hanging clouds over Complex 37 at Cape Canaveral Air Force Station carrying the GPS 2F-9 navigation satellite.

Marking United Launch Alliance’s first rocket flight in 2017, beginning its year of national security and science-enabling missions, the Atlas 5 rocket departs Cape Canaveral carrying the SBIRS GEO Flight 3 satellite.