Photos: Atlas 5 rocket soars from West Coast

An official weather outlook issued by U.S. Air Force meteorologists Thursday calls for partly cloudy skies on Florida’s Space Coast for liftoff of a SpaceX Falcon 9 rocket just after sunrise Sunday with a clandestine payload for the U.S. government’s intelligence agencies.

SpaceX’s next Falcon 9 rocket arrived at launch pad 39A Thursday for a customary hold-down engine firing. Liftoff from Florida’s Space Coast is targeted for Sunday, weather permitting.

The United Launch Alliance Atlas 5 rocket, standing 194 feet tall and and weighing 950,000 pounds, unleashes 1.5 million pounds of thrust from its main engine and two side-mounted boosters at 8:37 a.m. EDT today to launch the National Reconnaissance Office’s NROL-61 satellite from Cape Canaveral.