Trajectory Design for Asteroid Retrieval Missions: A Short Review

Joan-Pau Sánchez,Rita Neves,Hodei Urrutxua

doi:10.3389/fams.2018.00044

Abstract

In simple terms, an asteroid retrieval mission envisages a spacecraft that rendezvous with an asteroid, lassos it and hauls it back to the Earth’s neighbourhood. Speculative engineering studies for such an ambitious mission concept appeared in scientific literature at the beginning of the space age. This early work employed a two-body dynamical framework to estimate the Δv costs entailed on hauling an entire asteroid back to Earth. The concept however has experienced a revival in recent years, stimulated by the inclusion of a plan to retrieve a small asteroid in NASA’s 2014 budget. This later batch of work is well aware of technological limitations, and thus envisages a much more level-headed space system, capable of delivering only the most minimal change of linear momentum to the asteroid. As a consequence, the design of retrieval trajectories has evolved into strategies to take full advantage of low energy transfer opportunities, which must carefully account for the simultaneous gravitational interactions of the Sun, Earth and Moon. The paper revises the published literature up to date, and provides a short literature survey on the historical evolution of the concept. This literature survey is particularly focused on the design of asteroid retrieval trajectories, and thus the paper provides a comprehensive account for; the endgame strategies used so far, the different dynamical models and the trajectory design methodologies.

Highlights

Our Solar System is crisscrossed by millions of minor bodies, including asteroids and comets
Section Concluding Remarks instead provides a noncomprehensive literature review of a limited number of issues that relate to the trajectory design for asteroid retrieval
It is widely agreed that a level-headed asteroid retrieval mission must use high-power electric propulsion and should target asteroids that are energetically close to the Earth. This implies that the design of low-thrust, low-energy trajectories must both: (1) solve the optimal control problem defined by a lowthrust trajectory; and (2) take into account dynamical models that carefully consider the simultaneous gravitational interaction of multiple bodies (i.e., Sun, Earth, and Moon)

Summary

INTRODUCTION

Our Solar System is crisscrossed by millions of minor bodies, including asteroids and comets. Asteroids present appealing concentrations of potentially valuable resources, as well as a plethora of useful materials [3]; e.g., volatiles, such as water, may be found in carbonaceous chondrite asteroids, while metals, Trajectory Design for Asteroid Retrieval Missions semi-conductors and rare Earth elements are present in metalrich asteroids or ordinary chondrites Amid these trends, asteroid retrieval or capture missions were proposed. It is immediately clear that capturing an asteroid, whose mass may be several orders of magnitude larger than that of a typical interplanetary spacecraft (∼103 kg), will require an extremely powerful propulsion system and/or an extremely low-energy transfer This short paper concerns with the latter topic: the body of literature studying trajectory opportunities to retrieve asteroids has seen a many-fold increase in the last few years. Section Concluding Remarks instead provides a noncomprehensive literature review of a limited number of issues that relate to the trajectory design for asteroid retrieval

TRAJECTORIES TO MOVE AN ASTEROID

Endgame orbit

Optimal direct capture

CONCLUDING REMARKS