Launching the secretive NROL-61 payload for the U.S. National Reconnaissance Office, a United Launch Alliance Atlas 5 rocket thundered away from Cape Canaveral today at 8:37 a.m. EDT (1237 GMT).

Two days after lifting off aboard a SpaceX Falcon 9 rocket from the Complex 40 launch pad at Cape Canaveral Air Force Station, a commercial Dragon supply ship loaded with more than 4,800 pounds of supplies and experiments arrived Sunday at the International Space Station. Capture of the robotic cargo craft occurred at 5:57 a.m. EST (1057 GMT).

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).