Live coverage: Delta 4-Heavy rocket launches from Cape Canaveral

These narrated videos show the pre-launch preparations that readied the United Launch Alliance Atlas 5 rocket and the Orbital ATK Cygnus commercial cargo-delivery spacecraft for flight and rolling to Complex 41 for liftoff to the International Space Station.

Nine Merlin main engines on a SpaceX Falcon 9 rocket ignited at 12 p.m. EDT (1600 GMT) Friday, April 17, during a hold-down test-firing on launch pad 39A at NASA’s Kennedy Space Center in Florida.

SpaceX rolled out a Falcon 9 rocket Sunday night to pad 39A at NASA’s Kennedy Space Center in Florida for liftoff with the next 60 Starlink internet satellites, but officials have pushed back the launch until Wednesday.