United Launch Alliance’s Atlas 5 rocket made its way back to the pad at Space Launch Complex 41 at Cape Canaveral Space Force Station on Thursday morning for a mission carrying national security mission payloads, collectively codenamed Silentbarker. Liftoff has been rescheduled for at 8:47 a.m. EDT (1247 UTC).

Follow the unclassified portion of the Atlas 5 rocket’s ascent to space from Cape Canaveral’s Complex 41 launch pad with the U.S. National Reconnaissance Office’s NROL-61 satellite. Launch is scheduled for Thursday at 8:37 a.m. EDT (1237 GMT).

With as few as 15 more launches on the calendar over the next five years, the rocket name “Delta” that has been serving the U.S. and international customers since 1960 could permanently fade into history.