The Delta II began service with its first liftoff from Cape Canaveral’s Space Launch Complex-17 on February 14, 1989, and went on to open a new era in space flight. It launched the Air Force’s first Global Positioning System satellites, NASA’s Earth-observing, science, and interplanetary satellites, including the Mars rovers Spirit and Opportunity, as well as important commercial communication and imaging satellites. Its final launch came on September 15, 2018, closing a twenty-nine-year history that included one hundred fifty-five launches.