[论文解读] 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 Sciences参考文献 24被引用 18

一句话总结

本文通过首次一级生命周期评估，比较了地球基与空间基开采水和铂的环境效益。研究发现，一旦开采的水质量超过采矿航天器的质量，小行星水采矿便具有环境优势；若航天器将0.3%至7%的质量送回地球，则铂矿开采具有优势，具体取决于铂的来源。

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.

研究动机与目标

• 评估小行星采矿相对于地球基采矿和空间发射的环境影响。
• 评估小行星采矿是否可为水和铂提供低于地球采矿的环境负担。
• 确定小行星采矿在环境上更具优势的临界条件。
• 为基于空间的资源开采提供一级生命周期评估框架。

提出的方法

• 对现有空间领域及铂矿开采的环境生命周期评估开展最先进综述。
• 定义评估的目标与范围，包括水和铂矿开采情景的系统边界。
• 对航天器、运载火箭及采矿作业的材料与能源投入进行清单分析。
• 采用标准化的生命周期影响评估方法评估环境影响。
• 将小行星采矿的环境表现与地球基采矿及仅发射的供应链进行比较。
• 通过敏感性分析，确定基于返回质量与效率的环境效益临界点。

实验结果

研究问题

• RQ1 在何种条件下，小行星轨道内地月空间的水采矿环境影响低于地球基替代方案？
• RQ2 必须从空间采矿中返回多少质量的铂，才能实现低于地球采矿的环境影响？
• RQ3 与通过小行星采矿实现原位资源利用相比，将设备送入空间的环境影响如何？
• RQ4 相对于航天器质量，开采的水质量达到何种临界值时，小行星采矿在环境上更具优势？
• RQ5 铂的来源（原生或再生）如何影响空间采矿的环境可行性？

主要发现

• 当开采的水质量超过采矿航天器质量时，小行星水采矿具有环境效益。
• 对于铂矿开采，若航天器将自身质量的0.3%至7%的铂返回地球，则可实现环境效益，具体取决于铂是原生还是再生来源。
• 当返回效率达到0.3%–7%的阈值时，基于空间的铂矿开采环境影响低于地球采矿。
• 本研究识别出水采矿的关键质量阈值，表明采矿必须足够高效，以抵消发射和在轨操作的环境成本。
• 结果表明，在现实任务性能与返回率假设下，小行星采矿可能具有环境优势。
• 未来工作应将运载火箭与航天器制造纳入系统边界，以获得更准确的环境评估。