The Feasibility of Potentially Hazardous Asteroids Flybys Using Multiple Venus Gravity Assists

TL;DR

This paper presents a method for designing low-energy spacecraft trajectories using multiple Venus gravity assists to enable flybys of potentially hazardous asteroids, improving mission flexibility and encounter frequency.

Contribution

It introduces a novel trajectory optimization approach incorporating Venus gravity assists and resonant orbits for asteroid flybys, specifically targeting PHAs.

Findings

Trajectories reduce flight time and increase gravity assist opportunities.

Method demonstrates feasibility of periodic Venus gravity assists for asteroid encounters.

Accessible asteroid windows identified for missions between 2029 and 2050.

Abstract

This work develops low-energy spacecraft (SC) trajectories using Venus gravity assists to study asteroids during heliocentric transfer segments between planetary encounters. The study focuses on potentially hazardous asteroids (PHAs) as primary exploration targets. This paper proposes a method for calculating SC trajectories that enable asteroid flybys after a Venus gravity assist. The method involves formulating and solving an optimization problem to design trajectories incorporating flybys of selected asteroids and Venus. Trajectories are calculated using two-body dynamics by solving the Lambert problem. A preliminary search for candidate asteroids uses an algorithm to narrow the search space of the optimization problem. This algorithm uses the V-infinity globe technique to connect planetary gravity assists with resonant orbits. The resonant orbit in this case serves as an initial approximation for the SC's trajectory between two successive planetary flybys. Four flight schemes were analyzed, including multiple flybys of Venus and asteroids, with the possibility of an SC returning to Earth. The proposed solutions reduce flight time between asteroid approaches, increase gravity assist frequency, and enhance mission design flexibility. The use of Venus gravity assists and resonant orbits ensures a close encounter with at least one asteroid during the SC's trajectory between two consecutive flybys of Venus, and demonstrates the feasibility of periodic Venus gravity assists and encounters with PHAs. The developed method was applied to construct trajectories that allow an SC to approach both Venus-resonant asteroids and PHAs via multiple Venus gravity assists. An additional study was carried out to identify asteroids accessible during the Earth-Venus segment in launch windows between 2029 and 2050.