Life Cycle Assessment: A Tool to Help Design Environmentally Sustainable Space Technologies

Abstract

Life cycle assessment (LCA) is a commonly used tool to quantify the environmental impacts of given engineered systems throughout entire life-cycles, starting with raw material acquisition and including manufacture, use, and end-of-life. The International Organization for Standardization (ISO) has published a series of LCA standards: ISO 14040:2006 and ISO 14044:2006. Using LCA enables an engineer, designer, or manager to identify areas of system life-cycles having significant environmental burdens and develop/evaluate alternative designs to reduce those burdens. LCA also enables comparison amongst different final product designs, to competing products, and supply chain options. LCA results typically quantify environmental impacts such as global warming potential, resource depletion, ecotoxicity, acidification, eutrophication, and human health effects, however, many other quantified impact categories such as producer cost can also be included. In this proceeding we review the basic methods for conducting an LCA and describe how these methods can be adapted for use in the design and evaluation of space technologies. Three LCA methodologies we discus and review are process-LCA, economic input-output LCA (EIO-LCA), and hybrid-LCA. We discuss the main challenges facing the use of LCA for space technologies including the need for comprehensive production and supply chain databases and developing and standardizing new life cycle impact assessment categories relevant to current and future space applications (such as orbital debris and satellite orbital volume use, i.e. the volume of space occupied in a given orbit per unit time). As a case study we explore LCA for evaluating and improving the design of a space elevator. The space elevator concept is based on simple space tether mechanics. Instead of swinging a rope in a circle while an ant climbs back and forth, imagine a strong ribbon attached to the equator and counterbalance in high orbit with tether climbers traversing the ribbon. There is a large and growing quantity of designs published in academic and technical literature. We used the most comprehensive space elevator design at the time of the space elevator LCA research was by Swan et al. (2013). Two design options evaluated in that research – the first one-tether space elevator port and subsequent one-tether space elevator ports – demonstrate how LCA can be used in evaluation of proposed and developing space technologies.