Synergetic Material Utilization - ISRU developments at the DLR Institute of Space Systems

Introduction Our solar system is full of resources that potentially can be exploited to greatly reduce the material required to be launched from Earth. Among these resources are water ice, hydrates, metals, regolith, rare earths, chemical compounds, volatiles and rare isotopes. Utilizing space resources would enable e.g. propellant production, in-space manufacturing or the construction of large structures which would otherwise be very expensive or not possible at all with material launched from Earth. The 2021-founded research group Synergetic Material Utilization (SMU) at the DLR Institute of Space Systems develops technologies to utilize these resources and also investigates synergies between ISRU and environmental control an life support systems (ECLSS). Research Activities Concrete activities of the SMU research group for the next 3-4 years are technology developments for regolith beneficiation, water extraction and purification for in-situ propellant and consumables production. These developments are complemented by a system study for a shared water-hydrogen-oxygen infrastructure with ISRU and ECLSS elements for a future habitat

Trade-off and optimization for Lunar water extraction

Introduction: Water is an essential resource for space exploration, for both robotic and human exploration. In the future, these resources can be used to produce rocket propellant [1]. This Space Resource Utilisation (SRU) would reduce the cost of spacefaring significantly. Especially considering the development of multiple (commercial) lunar landers currently, the lunar economy will soon become more accessible, which further drives the need for water extraction equipment. Multiple methods to extract water from lunar regolith (e.g. excavating, thermal mining [2], electric arc mining, see examples in figure 1) are already envisioned, and this research aims to select the most promising concept based on the optimization of parameters. This work is embedded in the newly founded research group Synergetic Material Utilization (SMU) at the DLR. Methods: Both a quantitative as well as a qualitative trade-off will be performed, since the fidelity of the designs is likely not enough information to accurately compare them to each other. Also, factors like complexity are hard to define in numbers, but should not be excluded in a selection. For the preliminary design, the following 3 parameters will be initially fixed, and then later varied during a sensitivity analysis; 1.Fixed surface coverage (or volume, in the case of drills) of the heating elements in the system + a sensitivity analysis. 2.Fixed state of the water + a sensitivity analysis (different wt.% of water). 3.Fixed power available in the system + a sensitivity analysis. 3.1.Alternatively, the power could be an output of the design rather than the input, and the power is dependent on the amount of energy required to sublimate the accessible water. The outputs of such a comparison would then be; 1.The mass (an estimate of components, considering the low fidelity of the design). 2.The accessibility of the water extractor to the water-ice. The ability to heat water-ice to the sublimation temperature at sub-surface depth. 3.The time and energy required to get a certain yield. A sensitivity analysis can be performed and the concept of operations to find an optimal scenario. 4.The complexity and the added failure modes, increased risks, and potential losses. The resulting design of this trade-off will be tested in a dedicated TVAC test. References [1] ISECG, In-Situ Resource Utilization Gap Assessment Report (2021) [2] G. F. Sowers and C. B. Dreyer, Ice Mining in Lunar Permanently Shadowed Regions (2019), New Space

Characterisation of Water contaminated by Lunar Regolith and Selection of an associated Water Purification System

In future lunar habitats, the contact between lunar dust and liquid water will be inevitable, as reported in the In-Situ Resource Utilization Gap Assessment Report, 2021 and the Dust Mitigation Gap Assessment Report, 2016. It is therefore necessary to understand and characterise water contaminated by lunar regolith. The experimental results provide a basis for the development of a lunar water simulant and associated water purification system

Design Investigation of Lunar Water Extraction

Water is an essential resource for space exploration, for both robotic and human exploration. It is foreseen that in the future, these resources can be used to produce rocket propellant by electrolyzing water into its components Hydrogen and Oxygen or by astronauts for drinking water and breathable oxygen. This Space Resource Utilisation (SRU) would reduce the cost of spacefaring significantly. Recent discoveries have confirmed the presence of ice at the Lunar south pole. In this work, which is a continuation of the work presented in [1], the design parameters of 4 types of methods for thermal water extraction on the Moon are investigated. These methods are the in-situ surface heating method, the in-situ heated rods method, and the crucible method in different variations, as can be seen in figure 1. The goal is to find the most optimal way to extract water from the lunar surface. Additionally, this poster will present some early results from the EU LUWEX project

Review of Water Capturing Devices for Lunar ISRU

The use of resources present on celestial bodies, known as In-Situ Resource Utilization (ISRU), is becoming more and more important in space exploration due to the high cost of launching mass into orbit. ISRU would enable long-term manned operations and permanent (robotic) presence on extra-terrestrial bodies. Water is considered to be one of the most important resources for further space exploration and is currently investigated for extraction and purification on the future manned Lunar base envisioned around 2025. Previous research focused on the extraction of water from regolith but little work has been done to find ways on how to capture and liquefy the water vapour after its extraction

ISRU technology developments at DLR‘s Institute of Space Systems

Sustainable space exploration requires the development of In-Situ Resource Utilization (ISRU) technologies, which encompass all processes that utilize local resources to generate useful products for robotic and human exploration. This presentation describes the ongoing projects and activities in ISRU technology development at the DLR Institute of Space Systems in Bremen, Germany

Trade-off and optimization for a thermal lunar water extractor

Water is an essential resource for space exploration, for both robotic and human exploration. In the future, these resources can be used to produce rocket propellant. This Space Resource Utilisation (SRU) would reduce the cost of spacefaring significantly. Especially considering the current development of multiple commercial lunar landers, the lunar economy will soon become more accessible, which further drives the need for water extraction equipment. Multiple methods to thermally extract and capture water from lunar regolith (e.g. in-situ thermal extraction, excavation and reaction chamber) are already envisioned, and this research aims to select the most promising concept based on the optimization of parameters. The first step will be to design a set of different concepts which can be compared to each other. Both a quantitative as well as a qualitative trade-off will be performed, since the fidelity of the designs is likely not enough information to accurately compare them to each other by quantitative measures alone. Also, factors like complexity are hard to define in numbers, but should not be excluded in a selection. For the preliminary design, the surface coverage of heating elements in the system, the water ice content of the regolith in wt.% as well as the power available to the system are investigated in a parametric study. Alternatively, the power could be an output of the design rather than the input, and the power is dependent on the amount of energy required to sublimate the accessible water. Multiple criteria will be taken into account to perform the comparison of the extraction methods, the most relevant consisting of: 1) The accessibility of the water extractor to the water ice. The ability to heat water-ice to the sublimation temperature at sub-surface depth. 2) The time and energy required to get a certain yield. A sensitivity analysis can be performed on the time factor and the concept of operations to find an optimal scenario. 3) The complexity and the added failure modes, increased risks, and potential losses. This work is embedded in the research group Synergetic Material Utilisation (SMU) at the German Aerospace Center (DLR)