Guests attend a ribbon-cutting ceremony for the last United Launch Alliance Delta II rocket as it joins the lineup of historic launch vehicles in the Rocket Garden at the Kennedy Space Center Visitor Complex in Florida, on March 23, 2021. The Delta II rocket was a workhorse for NASA and civilian scientists, the U.S. military, and commercial clients throughout its almost 30 years of service. Since its first launch in 1989, the Delta II has launched 154 successful missions. NASA’s Launch Services Program launched the ICESat-2 spacecraft on the final Delta II launch on Sept. 15, 2018, from Vandenberg Air Force Base in California.