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

TL;DR

The paper tackles designing low-energy spacecraft trajectories to study potentially hazardous asteroids by leveraging Venus gravity assists to place the spacecraft on resonant orbits near Venus. It combines a patched-conic framework solving Lambert transfers with a two-stage global-local optimization, and supplements this with a rapid resonance-based asteroid-target search to assemble multi-asteroid flyby sequences. Key findings show that (i) many feasible Earth–Venus–Asteroid–Venus trajectories exist within realistic launch windows, often using 1:1 resonant orbits, (ii) multi-asteroid schemes can achieve impulse-free or near-impulse-free asteroid flybys with modest total impulses, and (iii) high-fidelity n-body simulations validate the理念 while revealing challenges near $\,\pi$- or $\,\pi$-resonances that benefit from multiple shooting refinements. Overall, the work demonstrates the feasibility and design strategies for Venus-centered asteroid tours, expanding the scientific return of inner-Solar-System missions and offering practical pathways for PHAs reconnaissance and planetary-defense demonstrations.

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.

Figures (18)

• Figure 1: SC asymptotic velocity at Venus flyby in the $\xi \zeta \eta$ coordinate system
• Figure 2: The geometric interpretation of the proposed technique
• Figure 3: Comparison of the AMOID, MOID curves and the minimum distance between the SC and the asteroid as a function of the 1:1 resonant orbit, as a function of the parameter $\gamma$.
• Figure 4: Distribution of orbital parameters for selected asteroids, showing semi-major axis versus eccentricity of their heliocentric orbits.
• Figure 5: Distribution of uncertainties in orbital parameters for the selected asteroid group.