Dynamical structure of the motion around asteroids with uncertain gravity and solar radiation pressure

Abstract

For a rendezvous space mission to a small body, the gravity field is usually modeled with large uncertainty in the preliminary mission design. Consequently, the orbital motion in the vicinity of the body cannot be predicted accurately. In this research, the automatic domain splitting (ADS) method is applied as an indicator to characterize the dynamical structure and nonlinearity of the orbital motion from a new perspective, which is instrumental in robust mission design. The uncertainties of the C20 and C22 terms in the gravitational potential are considered as these harmonic terms are usually dominant. Asteroid Steins is taken as an example. The relation among the required accuracy, the expansion order and the integration time by applying ADS is firstly investigated. Then the effects of the uncertainties of both the gravity and the solar radiation pressure (SRP) perturbation on orbits with different geometries are studied. The orbital motion is found to be more sensitive to the uncertainty of the C22 term than that of the C20 term. SRP has a significant effect on the high-altitude motion. Moreover, the bounds of the state flow over the uncertainties are also evaluated along with the propagation. The results are validated against numerical integrations and Monte Carlo simulations.