Life cycle assessment of proposed space elevator designs

Abstract The cost and design requirements for transporting satellites and payloads to space using existing orbital technology remain prohibitively high. Yet, quantitative sustainability assessments to evaluate system costs and impacts of existing and proposed orbital transportation systems have been rare. Space elevators are a proposed orbital transportation system intended to safely, gently, and inexpensively transport satellites and other payloads to and from space on a routine daily basis. This life cycle assessment (LCA) was completed to quantify, assess, compare, and suggest improvements to the potential environmental and financial performance of three proposed space elevator system designs, namely i) a One-Tether Initial Space Elevator (the base design) ii) a Two-Tether Initial Space Elevator iii) an Additional One-Tether Space Elevator. A sensitivity analysis to compare the impact of reduced utilization capacity of the space elevator system was also performed. Results indicated the Additional One-Tether Space Elevator scenario had the lowest environmental impact, while the Two-Tether Initial Space Elevator scenario had the lowest production cost per unit mass delivered to orbit. This LCA identified system elements for targeted impact reduction, e.g. operational impacts could be significantly reduced by improving the sustainability of terrestrial transportation delivery systems to the space elevator port. Sensitivity analysis results showed producer cost to be the only impact category with a direct inversely correlated response to reduced capacity; all other impacts showed less sensitivity to utilization reduction. Ultimately, the proposed space elevator design was found to be an environmentally and financially sustainable option for orbital transportation. Further application and refinement of such sustainable engineering and quantitative sustainability assessment methodologies to spacecraft, rocket, and other existing and proposed orbital transportation systems and industries is highly recommended.