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Astrodynamics

Article Title

Non-equatorial equilibrium points around an asteroid with gravitational orbit–attitude coupling perturbation

Keywords

asteroid mission, gravitational orbit–attitude, coupling perturbation, (GOACP), attitude-restricted orbital, dynamics, non-equatorial equilibrium, points

Abstract

A recently proposed orbital dynamics model in the close proximity of an asteroid, whichis called “attitude-restricted orbital dynamics”, includes the perturbation caused by thespacecraft’s gravitational orbit–attitude coupling. This orbital model improves the precisionof classical point-mass orbital model with only the non-spherical gravity. Equatorialequilibrium points have been investigated in the previous paper. In this paper, the in-plane non-equatorial equilibrium points, which are outside the asteroid’s equatorial planebut within its longitudinal principal plane, are further studied for a uniformly-rotatingasteroid. These non-equatorial equilibrium points are more diverse than those in the classicalpoint-mass orbital dynamics without gravitational orbit–attitude coupling perturbation(GOACP). Two families of them have been found. The equatorial equilibrium points studiedbefore and the non-equatorial ones studied here give a complete map of equilibrium pointsin the asteroid’s principal planes. Compared with the classical point-mass orbital dynamicswithout GOACP, the equatorial equilibrium points have extended the longitude range ofequilibrium points around an asteroid, while the non-equatorial ones studied here will extendthe latitude range. These equatorial and non-equatorial equilibrium points provide naturalhovering positions for the asteroid close-proximity operations.

Publisher

Tsinghua University Press

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