From the late 1950s to 1976, the U.S. human spaceflight program advanced as it did largely due to the extraordinary efforts of Austrian immigrant George M. Low. Described as the "ultimate engineer" during his career at NASA, Low was a visionary architect and leader from the agency's inception in 1958 to his retirement in 1976. As chief of manned spaceflight at NASA, Low was instrumental in the Mercury, Gemini, and Apollo programs.