A SpaceX Falcon 9 rocket is scheduled for liftoff from Cape Canaveral Space Force Station with a GPS navigation satellite at 12:09 p.m. EDT (1609 GMT), at the opening of a 15-minute launch window. It is the first time, SpaceX is launching a national security payload for the U.S. military using a previously-flown rocket booster.
Watch live as SpaceX counts down to the launch of a GPS satellite
