ULA’s Delta 4-Heavy rocket lifted vertical on pad 37B at Cape Canaveral ahead of launch on the NROL-68 mission. Credit: United Launch Alliance
United Launch Alliance’s second-to-last Delta 4-Heavy rocket is scheduled to blast off from Cape Canaveral April 20 with a classified cargo for the U.S. government’s spy satellite agency, a mission that will mark ULA’s first flight of the year, officials announced this week.