At the dawn of the 16th century, Johannes Kepler disproved Copernicus's theory of perfectly circular planetary orbits by demonstrating, after years of meticulous calculations, that planets move in elliptical orbits. Despite numerous errors in his calculations, Kepler's persistence led to the groundbreaking realization of elliptical planetary motion. Throughout history, cumbersome calculations were a barrier to scientific advancement until the development of the slide rule, a mechanical device that facilitated complex computations using logarithms, which was essential for significant achievements like Newton's equations of motion and NASA's lunar missions. The slide rule, invented in the 17th century by John Napier with the discovery of logarithms, transformed multiplication into addition, simplifying calculations and extending the capabilities of scientists and engineers for centuries. Despite its eventual obsolescence with the advent of digital computing, the slide rule remains a testament to human ingenuity, having contributed to major technological and scientific milestones before the last one was manufactured in 1976.