Delta 4-Heavy Launch Rescheduled for Early Thursday.

United Launch Alliance's Delta 4-Heavy rocket is set to launch a classified spy satellite for the National Reconnaissance Office on Thursday from Cape Canaveral Space Force Station. The mission, codenamed NROL-68, was delayed by a day due to a valve problem. The Advanced Orion satellite is believed to intercept telephone calls, data transmissions, and other types of communication by U.S. adversaries. The launch will be the second-to-last flight of the Delta rocket, which is being retired in favor of the new-generation Vulcan launch vehicle.