Energetic Feasibility of Redirecting Trans-Neptunian Objects onto Mars-Impacting Orbits: Continuous Thrust and Gravity Assist Trajectories

TL;DR

This study evaluates the energy requirements and feasibility of redirecting trans-Neptunian objects onto Mars-impacting orbits using low-thrust propulsion and gravity assists, demonstrating potential for volatile import with modest energy budgets.

Contribution

It provides a quantitative analysis of the minimum ΔV needed for TNO redirection to Mars, considering optimized trajectories and gravity assists, advancing understanding of outer Solar System resource transfer.

Findings

Optimized steering strategies reduce ΔV to approximately 2.5–3.2 km/s.

Pure inward spiral transfers are highly inefficient, requiring over 22 km/s.

Single Neptune flybys can further lower energy costs in favorable cases.

Abstract

We assess the dynamical feasibility of redirecting small volatile-bearing trans-Neptunian objects (TNOs) onto Mars-impacting orbits using continuous low-thrust propulsion and a single gravity-assist encounter. The study considers two representative dynamical classes: classical Kuiper Belt--like and Scattered Disk--like initial orbits, and determines the minimum characteristic velocity increment $\Delta V$ required to drive the objects onto a Mars-impacting trajectory within a specified transfer time $\Delta T$. The dynamics is modelled in the two-body problem with a fixed maximum low thrust included, allowing the computed $\Delta V$ to represent a dynamical lower bound independent of specific propulsion-technical implementation. Three trajectory classes are investigated: (i) inward spiral transfer, (ii) time-dependent thrust-direction steering optimized via global evolutionary algorithms, and (iii) hybrid transfers combining low thrust with a single Neptune flyby. Pure spiral trajectories yield very high velocity expenditures ($\Delta V \gtrsim 22~\mathrm{km~s^{-1}}$) and millennia durations, confirming that monotonic inward migration is dynamically inefficient for TNO redirection. In contrast, optimized steering strategies systematically increase orbital eccentricity and achieve Mars-impacting geometries with $\Delta V \approx 2.5$--$3.2~\mathrm{km~s^{-1}}$ over 380--540 yr timescales. A single Neptune encounter further reduces the total $\Delta V$ in favourable cases, with minimum values falling below those of direct optimized transfers. These results establish a quantitative lower bound on the energy cost of importing volatiles from the outer Solar System to Mars, showing that controlled redirection is feasible under modest $\Delta V$ budgets when target bodies are chosen from favourable regions of orbital phase space.