Live coverage: Atlas 5 countdown and launch journal

The launch of five commercial Iridium message relay satellites and a pair of U.S.-German orbiting geophysics probes on a Falcon 9 rocket from California has been delayed three days to May 22, and a week-long schedule slip to May 31 is expected for the next SpaceX flight from Cape Canaveral with an SES communications payload.

The United Launch Alliance Atlas 5 rocket, standing 194 feet tall and and weighing 720,000 pounds, generates 860,000 pounds of thrust from its main engine to launch the Orbital ATK Cygnus cargo ship on the OA-7 mission to the International Space Station.

A SpaceX Falcon 9 rocket successfully lifted off from Cape Canaveral at 10:29 a.m. EDT (1429 GMT) Wednesday with two Boeing-built communications payloads for Eutelsat and Asia Broadcast Satellite. A secondary objective to recover the first stage offshore in the Atlantic Ocean failed.