What are Keplerian elements?

Keplerian elements are a set of mathematical parameters used to define the exact orbit of a satellite. Named after Johannes Kepler, who discovered the laws of planetary motion, these numbers are essential for satellite tracking software to predict when a spacecraft will be above your horizon. Distractors like phase reversing elements in Yagis, high-emission heater filaments, or spread spectrum encryption codes are completely unrelated to satellite mechanics. Keplerian elements (which include parameters like epoch, inclination, right ascension, and eccentricity) deal purely with orbital mechanics.