Update: A Delta IV rocket blasted off from Cape Canaveral Air Force Station at 7:38 p.m. into a clear night sky with a high-capacity military communications satellite.
After the on-time liftoff, the early flight was proceeding smoothly, with four solid rocket motors dropping away 100 seconds after lighting, the first stage burning out and separating properly.
The second stage's first of two burns also was completed successfully.
The Defense Department's fourth Wideband Global SATCOM satellite is due to separate from the upper stage about 41 minutes into flight.
The first Cape launch of 2012 was the 18th by a United Launch Alliance Delta IV rocket.
Up next: A ULA Atlas V rocket is targeting a Feb. 16 launch of another military satellite.
IMAGE: By Craig Bailey, FLORIDA TODAY