Glossary
Space Trajectories. Perturbed Motion

Keplerian; Keplerian

Relating to the motion obtained in the two-body problem.

Osculateur; osculating

Relating to the orbit that would be followed under Keplerian assumptions.

Precession; precession

Rotation of the orbital plane in relation to the polar axis (nodal precession) or of the orbit in its plane (apsidal precession).

Disturbance; disturbance

A force other than central attraction that deviates from the Keplerian trajectory.

Harmoniques sphériques ; spherical harmonics

Gravitational potential development terms as a power of distance.