United Launch Alliance teams ran through an 11-hour countdown Friday at Cape Canaveral to rehearse procedures before the first flight of a modified Atlas 5 rocket with Boeing’s Starliner crew capsule Dec. 20.

Watch a replay of the Atlas 5 rocket launch with the GOES-S weather satellite from Cape Canaveral, as seen from the Kennedy Space Center press site around 4 miles from the launch pad.

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).