This week in 1966, S-IVB contractor McDonnell Douglas completed factory checkout of the S-IVB-504 flight stage — used on Apollo 9 — in Huntington Beach, California. The S-IVB stage was developed under the direction of NASA’s Marshall Space Flight Center and was powered by one J-2 engine capable of producing 225,000 pounds of thrust. Here, the S-IVB-505 and S-IVB-211 are shown in the McDonnell Douglas S-IVB Assembly and Checkout Tower. Apollo 8 was the first manned flight of the Saturn V vehicle and the first manned lunar orbit mission. Now through December 2022, NASA will mark the 50th anniversary of the Apollo Program that landed a dozen astronauts on the Moon between July 1969 and December 1972, and the first U.S. crewed mission — Apollo 8 — that circumnavigated the Moon in December 1968.The NASA History Program is responsible for generating, disseminating, and preserving NASA’s remarkable history and providing a comprehensive understanding of the institutional, cultural, social, political, economic, technological and scientific aspects of NASA’s activities in aeronautics and space. For more pictures like this one and to connect to NASA’s history, visit the Marshall History Program’s webpage. (NASA)