John A. O'Keefe (1916-2001) was a pioneer in space geodesy and planetary physics, but his passion was his longtime study of tektites. O'Keefe graduated from Harvard University in 1937 with a bachelor's degree in astronomy and received his Ph.D. in astronomy from the University of Chicago in 1941. During World War II, O'Keefe was with the US Army Corps of Engineers, where he spent 13 years heading the research and analysis branch. During his time with the Corps, O'Keefe made significant contributions to geodesy, including his development of the present NATO map coordinate system (UTM) and his initiative to use satellite tracking for geodesy. In 1958, O'Keefe left the Army Map Service to become the assistant chief of the theoretical division at NASA's newly formed Goddard Space Flight Center in Greenbelt, MD. At Goddard, O'Keefe spent the remainder of this career focusing on the study of tektites and the origin of the moon. O'Keefe authored the book, Tektites and Their Origin (1976), in which he presents his belief that tektites were ejected from volcanoes on the moon.