Capture orbits around asteroids by hitting zero-velocity curves

Abstract

The problem of capturing a spacecraft from a heliocentric orbit into a high parking orbit around binary asteroids is investigated in the current study. To reduce the braking $\Delta V$ , a new capture strategy takes advantage of the three-body gravity of the binary asteroid to lower the inertial energy before applying the $\Delta V$ . The framework of the circular restricted three-body problem (CR3BP) is employed for the binary asteroid system. The proposed capture strategy is based on the mechanism by which inertial energy can be decreased sharply near zero-velocity curves (ZVCs). The strategy has two steps, namely, hitting the target ZVC and raising the periapsis by a small $\Delta V$ at the apoapsis. By hitting the target ZVC, the positive inertial energy decreases and becomes negative. Using a small $\Delta V$ , the spacecraft inserts into a bounded orbit around the asteroid. In addition, a rotating mass dipole model is employed for elongated asteroids, which leads to dynamics similar to that of the CR3BP. With this approach, the proposed capture strategy can be applied to elongated asteroids. Numerical simulations validate that the proposed capture strategy is applicable for the binary asteroid 90 Antiope and the elongated asteroid 216 Kleopatra.