Question T8B06
From subelement T8 - T8B
Which of the following are inputs to a satellite tracking program?
Why is this correct?
The correct answer is B. Keplerian elements are the fundamental orbital parameters (inclination, eccentricity, argument of perigee, etc.) that mathematically describe a satellite's orbit. These six numerical values are essential inputs that allow tracking programs to predict satellite positions and pass times. Satellite transmitted power (A) and zero Doppler shift timing (C) are not required inputs for orbital calculations—the tracking software uses the Keplerian elements to compute when and where the satellite will be visible.
Memory tip
Look for questions asking about fundamental requirements versus operational measurements. Orbital mechanics requires mathematical descriptions of the satellite's path, not real-time signal characteristics. Keplerian elements are the universal language for describing any orbit in space.
Learn more
Keplerian elements function like a satellite's orbital DNA—six mathematical parameters that completely define its path through space. Named after Johannes Kepler, these elements include semi-major axis, eccentricity, inclination, longitude of ascending node, argument of perigee, and mean anomaly. Amateur satellite operators obtain updated Keplerian elements from AMSAT or NASA to ensure accurate tracking, as atmospheric drag and other forces gradually change orbits over time.
Think about it
Why do you think atmospheric drag would require periodic updates to Keplerian elements for low Earth orbit satellites?