Orbital Mechanics Fundamentals

Abstract Reviews basic statements of the equations of motion, including Kepler's and Newton's laws and the constants of orbital motion. Orbital elements are introduced and the two‐body problem is shown along with conic sections. These relations form the basis for astrodynamic applications and permit many useful studies to be accomplished. Perturbation theory and the major forces affecting satellite motion are discussed, along with the variability of those forces. Graphs are included to show the effect of perturbing forces on typical satellite orbits. The distinction is made between mean and osculating elements, fast and slow variables, and periodic forces. Discussion about the main problems in astrodynamics is included – orbit propagation and orbit estimation – along with definitions of analytical, numerical, and semianalytical propagation. The broad concept of orbit determination is introduced. Some relevant problems in astrodynamics are introduced noting the tie to propagation and orbit estimation. A summary concludes the remarks.