CAPE CANAVERAL, Fla.—NASA’s next-generation moon rocket began a highly anticipated, slow-motion journey out of its assembly plant en route to the launch pad in Florida on Thursday for a final round of tests in the coming weeks that will determine how soon the spacecraft can fly. Rollout of the 32-story-tall Space Launch System (SLS) rocket and its Orion crew capsule marks a key milestone in U.S. plans for renewed lunar exploration after years of setbacks, and the public’s first glimpse of a space vehicle more than a decade in development. The process of moving the 5.75-million-pound SLS-Orion spacecraft out of its Kennedy Space Center Vehicle Assembly Building began shortly after 5:30 p.m. EDT under clear skies at Cape Canaveral. A nearly full moon rose about 90 minutes later. The SLS-Orion, which cost some $37 billion to develop including ground systems, constitutes the backbone of the NASA’s Artemis program, aimed at …