# EVALUATION OF THE APPROACHING TRAJECTORIES FOR LANDING ON THE ASTEROID 216 KLEOPATRA

## Palavras-chave:

Astrodynamics, Orbital Motion, Orbital Maneuver, Asteroid Kleopatra, Irregular Bodies## Resumo

The goal of this work is to evaluate some orbital trajectories seeking the approaching for

landing on surface of the asteroid 216 Kleopatra. This asteroid, discovered by Johann Palisa in 1880,

has a very irregular shape with approximate dimensions of 217 x 94 x 81 km. Due to its shape, the

gravitational field around the asteroid cannot be considered central. Thus, a spacecraft approaching the

asteroid is subject to orbital perturbations, which can hinder the vehicle to describe the nominal

trajectory. In maneuvers for approach and landing, the trajectory deviations may result in very high

approach velocities, making impossible the soft landing on the surface of the asteroid. In addition, the

rotation of the asteroid is another difficulty for missions aimed at the soft landing. Due to the irregular

shape of the asteroid the relative distance between the surface and the spacecraft varies significantly

depending on the orbital plane adopted for the trajectory. In this work, the intention is to evaluate,

through numerical simulations, orbits of a spacecraft around the asteroid Kleopatra more appropriate

to get closer to the asteroid in order to minimize the relative velocity between the surface and the

spacecraft. For this, was used a polyhedral model of the asteroid's volume, based on radar

measurements from the Arecibo Observatory, to model the non-central gravitational field generated by

the heterogeneous mass distribution of the asteroid. Using the model of the gravitational field and the

simulation environment Spacecraft Trajectory Simulator (STRS), several approach paths were

simulated and compared in order to assist the choice of trajectories, considering the minimum value

for the velocity with respect to the surface at the point of the trajectory with minimum altitude.