Lunar sourcebook. A user's guide to the moon

This paper provides a comprehensive review of the material behaviour for extrusion-based concrete 3D printing spanning from the early age to long-term performance. We begin with a discussion on the recent progress on the understanding of early-age behaviour. Following this, the mechanical response in the hardened state, and the different strategies to introduce reinforcement are reviewed. Finally, we present insights and perspectives on the transport mechanisms in printed concrete to assess the long-term performance, and also discuss the overall impact of construction by concrete 3D printing on sustainability.

Extrusion-based concrete 3D printing from a material perspective : a state-of-the-art review

The production of oxygen and metal from lunar regolith

https://par.nsf.gov/servlets/purl/10166329

3-D printing of concrete: Beyond horizons

Molten oxide electrolysis (MOE) is the electrolytic decomposition of a metal oxide, most preferably into liquid metal and oxygen gas. The successful deployment of MOE hinges upon the existence of an inert anode capable of sustained oxygen evolution. Herein we report the results of a program of materials design, selection, and testing of candidate anode materials and demonstrate the utility of iridium in this application. An electrolysis cell fitted with an iridium anode operating at 0.55 A cm ―2 produced liquid metal and oxygen gas by the decomposition of iron oxide dissolved in a solvent electrolyte of molten MgO―CaO―SiO 2 ―Al 2 O 3 . The erosion rate of iridium was measured to be less than 8 mm y ―1 . The stability of iridium is attributed to a mix of mechanisms including the electrochemical formation and simultaneous thermal decomposition of a surface film of iridium oxide.

/pdf/production-of-oxygen-gas-and-liquid-metal-by-electrochemical-1ewnh9ro7d.pdf

Production of Oxygen Gas and Liquid Metal by Electrochemical Decomposition of Molten Iron Oxide

When considering the construction of a lunar base, the high cost ($ 100,000 a kilogram) of transporting materials to the surface of the moon is a significant barrier. Therefore in-situ resource utilization will be a key component of any lunar mission. Oxygen gas is a key resource, abundant on earth and absent on the moon. If oxygen could be produced on the moon, this provides a dual benefit. Not only does it no longer need to be transported to the surface for breathing purposes; it can also be used as a fuel oxidizer to support transportation of crew and other materials more cheaply between the surface of the moon, and lower earth orbit (approximately $20,000/kg). To this end a stable, robust (lightly manned) system is required to produce oxygen from lunar resources. Herein, we investigate the feasibility of producing oxygen, which makes up almost half of the weight of the moon by direct electrolysis of the molten lunar regolith thus achieving the generation of usable oxygen gas while producing primarily iron and silicon at the cathode from the tightly bound oxides. The silicate mixture (with compositions and mechanical properties corresponding to that of lunar regolith) is melted at temperatures near 1600 C. With an inert anode and suitable cathode, direct electrolysis (no supporting electrolyte) of the molten silicate is carried out, resulting in production of molten metallic products at the cathode and oxygen gas at the anode. The effect of anode material, sweep rate, and electrolyte composition on the electrochemical behavior was investigated and implications for scale-up are considered. The activity and stability of the candidate anode materials as well as the effect of the electrolyte composition were determined. Additionally, ex-situ capture and analysis of the anode gas to calculate the current efficiency under different voltages, currents and melt chemistries was carried out.

/pdf/direct-electrolysis-of-molten-lunar-regolith-for-the-5gdojezkac.pdf

Direct Electrolysis of Molten Lunar Regolith for the Production of Oxygen and Metals on the Moon

https://ntrs.nasa.gov/api/citations/20150018802/downloads/20150018802.pdf

Thermophysical property models for lunar regolith

Development of a Molten Regolith Electrolysis Reactor Model for Lunar In-Situ Resource Utilization”

Previously, we have demonstrated the production of oxygen by electrolysis of molten regolith simulants at temperatures near 1600oC. Using an inert anode and suitable cathode, direct electrolysis (no supporting electrolyte) of the molten silicate is carried out, resulting in the production of molten metallic products at the cathode and oxygen gas at the anode. Initial direct measurements of current efficiency have confirmed that the process offer potential advantages of high oxygen production rates in a smaller footprint facility landed on the moon, with a minimum of consumables brought from Earth. We now report the results of a scale-up effort toward the goal of achieving production rates equivalent to 1 metric ton O2/year, a benchmark established for the support of a lunar base. We previously reported on the electrochemical behavior of the molten electrolyte as dependent on anode material, sweep rate and electrolyte composition in batches of 20-200g and at currents of less than 0.5A. In this paper, we present the results of experiments performed at higher currents (several Amperes) and in larger volumes of regolith simulant (500g) for longer durations of

Recent Advances in Scale-up Development of Molten Regolith Electrolysis for Oxygen Production in support of a Lunar Base

The technology of direct electrolysis of molten lunar regolith to produce oxygen and molten metal alloys has progressed greatly in the last few years. The development of long-lasting inert anodes and cathode designs as well as techniques for the removal of molten products from the reactor has been demonstrated. The containment of chemically aggressive oxide and metal melts is very difficult at the operating temperatures ca. 1600 C. Containing the molten oxides in a regolith shell can solve this technical issue and can be achieved by designing a Joule-heated (sometimes called 'self-heating') reactor in which the electrolytic currents generate enough Joule heat to create a molten bath. Solutions obtained by multiphysics modeling allow the identification of the critical dimensions of concept reactors.

/pdf/joule-heated-molten-regolith-electrolysis-reactor-concepts-484p65m8jb.pdf

Laurent Sibille

Papers

Direct Electrolysis of Molten Lunar Regolith for the Production of Oxygen and Metals on the Moon

Thermophysical property models for lunar regolith

Development of a Molten Regolith Electrolysis Reactor Model for Lunar In-Situ Resource Utilization”

Recent Advances in Scale-up Development of Molten Regolith Electrolysis for Oxygen Production in support of a Lunar Base

Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars