A computer-triggered abort halted the countdown of a Falcon 9 rocket Sunday at NASA’s Kennedy Space Center in Florida, pushing back the next mission in SpaceX’s launch surge until at least Monday.

An early bird rocket launch from the Florida spaceport will take to the skies before dawn Thursday when an Atlas 5 lofts a classified U.S. government satellite.

Teams working at the Kennedy Space Center in Florida last week connected a U.S.-built Orion crew module with its European-made power and propulsion element for the first time, a significant accomplishment ahead of the spacecraft’s shipment to Ohio this fall for testing inside the world’s largest vacuum chamber.