[Paper Review] Exploring Potential Environmental Benefits of Asteroid Mining

Andreas M. Hein, Michael Saidani+1 more|arXiv (Cornell University)|Oct 10, 2018

Geochemistry and Elemental AnalysisEarth and Planetary Sciences24 references18 citations

TL;DR

This paper evaluates the environmental benefits of asteroid mining by conducting a first-order life cycle assessment comparing Earth-based and space-based mining for water and platinum. It finds that asteroid water mining is environmentally beneficial once mined water exceeds the mass of the mining spacecraft, and platinum mining is advantageous if 0.3–7% of the spacecraft's mass is returned to Earth, depending on platinum source.

ABSTRACT

Asteroid mining has been proposed as an approach to complement Earth-based supplies of rare earth metals and supplying resources in space, such as water. Existing research on asteroid mining has mainly looked into its economic viability, technological feasibility, cartography of asteroids, and legal aspects. More recently, potential environmental benefits for asteroid mining have been considered. However, no quantitative estimate of these benefits has been given. This paper attempts to determine if and under which conditions asteroid mining would have environmental benefits, compared to either Earth-based mining or launching equipment and resources into space. We focus on two cases: Water supply to cis-lunar orbit and platinum mining. First, we conduct a state-of-the-art of current environmental life cycle assessment for the space domain and platinum mining. Second, a first order environmental life cycle assessment is conducted, including goal and scope definition, inventory analysis, and impact assessment. We compare water supply to cis-lunar orbit with and without asteroid mining and go on to compare terrestrial with space-based platinum mining. The results indicate that asteroid water mining would have environmental benefits, as soon as the amount of water supplied via mining is larger than the mass of the spacecraft used for mining. For platinum mining, we find that by comparing the operations phase of terrestrial and space mining, space mining would have a lower environmental impact, if the spacecraft is able to return between 0.3 to 7% of its mass in platinum to Earth, assuming 100% primary platinum or 100% secondary platinum, respectively. For future work, we propose a more detailed analysis, based on a more precise inventory and a larger system boundary, including the production of the launcher and spacecraft.

Motivation & Objective

• To assess the environmental impact of asteroid mining relative to Earth-based mining and space launches.
• To evaluate whether asteroid mining could offer lower environmental burdens than terrestrial mining for water and platinum.
• To identify threshold conditions under which asteroid mining becomes environmentally preferable.
• To provide a first-order life cycle assessment framework for space-based resource extraction.

Proposed method

• Conducting a state-of-the-art review of existing environmental life cycle assessments in space and for platinum mining.
• Defining the goal and scope of the assessment, including system boundaries for water and platinum mining scenarios.
• Performing an inventory analysis of material and energy inputs for spacecraft, launch vehicles, and mining operations.
• Assessing environmental impacts using standardized life cycle impact assessment methods.
• Comparing the environmental performance of asteroid mining against Earth-based mining and launch-only supply chains.
• Using sensitivity analysis to determine break-even points for environmental benefit based on return mass and efficiency.

Experimental results

Research questions

• RQ1 Under what conditions does asteroid mining for water in cis-lunar orbit yield lower environmental impacts than Earth-based alternatives?
• RQ2 What mass of platinum must be returned from space mining to achieve lower environmental impact than terrestrial mining?
• RQ3 How do the environmental impacts of launching equipment into space compare to in-situ resource utilization via asteroid mining?
• RQ4 What is the threshold mass of water mined relative to spacecraft mass that makes asteroid mining environmentally preferable?
• RQ5 How does the source of platinum (primary vs. secondary) affect the environmental viability of space mining?

Key findings

• Asteroid water mining has environmental benefits when the mass of water extracted exceeds the mass of the mining spacecraft.
• For platinum mining, environmental benefits are achieved if the spacecraft returns between 0.3% and 7% of its mass in platinum to Earth, depending on whether the platinum is primary or secondary.
• The environmental impact of space-based platinum mining is lower than terrestrial mining when return efficiency meets the 0.3–7% threshold.
• The study identifies a critical mass threshold for water mining, indicating that mining must be sufficiently productive to offset launch and in-space operations.
• The results suggest that asteroid mining could be environmentally favorable under realistic mission performance and return rate assumptions.
• Future work should expand the system boundary to include launcher and spacecraft manufacturing for more accurate environmental assessments.