Within the first 10 minutes of NASA's initial Saturn IB flight, the Instrument Unit (IU), nervecenter of America's mightiest launch vehicle, is designed to make more than 7 million calculations, sample vehicle calculations 100 times a minute, telemeter 3 million numbers back to Earth, and measure the performance of 300 pieces of equipment in the IU, S-IB, and S-IVB stages.
Summary: "Based on Lawden's equation, semi-explicit,'iterative' Saturn guidance equations are derived, many were successfully flight tested on Saturn I and analyzed for the main Apollo mission and other applications applications."