A sophisticated combat-ready U.S. military missile warning satellite moved to its launch pad at Cape Canaveral Space Force Station Saturday on top of a United Launch Alliance Atlas 5 rocket, ready for liftoff Monday afternoon.

A Soyuz rocket lifted off Friday from a jungle spaceport in South America with two satellites for Europe’s Galileo navigation network. The four-hour launch sequence began with blastoff at 2146 GMT (5:46 p.m. EDT).

SpaceX’s first Falcon Heavy launch for the U.S. Air Force took a major step closer to liftoff with a hold-down engine firing Wednesday night at launch pad 39A at NASA’s Kennedy Space Center in Florida. Liftoff with a cluster of experimental satellites and weather monitoring craft is set for June 24.