Interview discusses Leo McGrath's early life and schooling in Concord, Massachusetts, entrance to Harvard on scholarship, courses in the sciences, and contact with Fred Whipple and Cecilia Payne Gaposchkin. Impression of moving from the Concord High School to Harvard. Leave from Harvard for military duty in the Army Security Agency. How his military experience may have prepared him for Smithsonian work. Marriage and return to Harvard. Planning for a career. Jobs, and then responds to opening from Smithsonian Astrophysical Observatory (SAO). Excitement after Suptnik. Process of joining the satellite tracking program. Choice of the station in Jupiter, Florida. Tracking Vanguard. Design issues with early telescopic systems, humidity issues. Early failure to capture satellite tracks. Observing methods, synchronizing the clock and the shutter. Training from Joe Tugas. Station teams and assignments. The problem of securing good predictions. Observing practices, hirings, differences in style. Differences with station manager and relieved of duty. Contact with Cambridge headquarters and dismissal of station manager. Move to Cambridge to work for Tillinghast. Takes over management of the photo reduction processing. Part time management work for Bob Davis on Celescope. Comments on complexity of the project and Davis's management style. Description of the Baker-Nunn camera house. Description of the reduction process in Cambridge. Discussion of workload and budgets. Mergers and budget cutbacks in the late 1960s. Recollections of visiting the site at Jupiter and on Whipple's achievements.