At long last, the final journey of the last space shuttle ever built, Endeavour, and its giant orange external tank are expected to begin this month — the capstone to a historic journey to an ambitious museum exhibit in Los Angeles. It’ll be a momentous occasion for the California Science Center, the state-run museum just south of downtown L.A., which is building the 20-story Samuel Oschin Air and Space Center to house Endeavour. Anticipation has been building for more than a decade for the new...