Regolith Excavation Research Articles

Simulating lunar highlands regolith profiles on Earth to inform infrastructure development and ISRU activities on the Moon

Lunar exploration and infrastructure development near the Moon's south pole, and at other future lunar settlements, demand a detailed understanding of the geotechnical properties, structure, composition, and stratigraphy of the near-surface lunar regolith. Long term exploration and development activities will require the use of regolith as a construction material for multiple structures, and as unrefined material for resource extraction during in situ resource utilization (ISRU) activities. Upcoming robotic and human exploration will be concentrated near the lunar south pole, which has a dominantly feldspathic composition typical of the lunar highlands. Past missions to lunar highlands terrain (Apollo 16, Luna 20) provide valuable “ground truth” data regarding the geomechanical properties of highlands regolith that serve as a guide for future exploration at the lunar south pole. Lunar highlands simulant LHS-1 has well-characterized geotechnical properties and is an appropriate analogue for highlands lunar regolith in terrestrial engineering studies. Cone penetrometer testing (CPT) measurements of LHS-1 reveal a strong exponential correlation between the G slope parameter and bulk density, which allows information to be obtained regarding the density profile of simulated regolith columns directly from CPT stress versus penetration curves. We show that LHS-1 can be used to replicate the near-surface regolith stratigraphy at the Apollo 16 highland landing region in Earth-based laboratories. The ultimate CPT penetration resistance measured in the laboratory under terrestrial gravity is not directly comparable to that measured under lunar gravity, and here we derive an average reduction factor of Rf = 0.29 to scale penetration resistance values to those measured in situ on the lunar surface. Geotechnical measurements of other lunar simulants combined with experiments similar to those described herein, tailored to the terrain type of interest, will provide crucial information to guide future regolith excavation, construction, and ISRU activities on the lunar surface.

From lunar regolith to oxygen and structural materials: an integrated conceptual design

To enable a long-term presence of humans in space, it is essential to use extraterrestrial raw materials to reduce the need for transporting resources or produced materials from Earth. In recent years, a lot of research has been conducted on different ISRU processes, such as regolith excavation, mineral processing and the extraction of oxygen using metallurgical processes. However, it is not sufficient to just focus on a single process but also to focus on how the different processes interact. Therefore, RWTH Aachen’s Integrated Conceptual Design presents a novel concept for the production of oxygen and high-quality metal materials. To meet the challenges of mining in space, selective mining is used to provide the best possible blend based on the original material of the deposit. This process is followed by mineral processing to provide a high-quality ilmenite-rich concentrate, the input material for metallurgical processes. Using the novel MOSARI technique, consisting of molten salt electrolysis and metallothermic reduction, oxygen and metal materials can be recovered. Furthermore, this represents a zero-waste approach for the complete utilization of the material.

Development and test of a Lunar Excavation and Size Separation System (LES3) for the LUVMI‐X rover platform

AbstractFuture sustained human presence on the Moon will require us to make use of lunar resources. This in‐situ resource utilisation (ISRU) process will require suitable feedstock (i.e., lunar regolith) that has been both acquired and prepared (or beneficiated) to set standards. Acquisition of pre‐processed regolith, is an often overlooked engineering challenge in the demanding and low‐gravity environment of the lunar surface. Currently, regolith excavation and size separation are often developed independently of each other. Here, we present the Lunar Excavation and Size Separation System (LES3), which is an engineered one‐system solution to combine the acquisition of lunar regolith as well as separate it into two distinct size fractions, and therefore, can assist to define the quality of the feedstock material for ISRU processes. Intended for use with a lightweight (40–60 kg) lunar rover (LUnar Volatiles Mobile Instrumentation‐X; LUVMI‐X) currently under development, the mechanism utilises vibrations to reduce excavation forces and facilitate size separation. Low excavation forces are crucial for lunar excavators to be deployable on lightweight robotic platforms as limited traction forces are available. The rationale behind the mechanism is explained, its capabilities in the support of science and ISRU are showcased, and results from several laboratory test campaigns, including tests of gravitational dry sieving of different regolith simulants, are presented. The LES3 can excavate up to 100 g in a single charge while maintaining excavation forces of less than 8 N and having a mass of less than 2 kg. Finally, areas of improvement for a second iteration of the design are presented and explained. The LES3 proof of concept shows that combining of regolith excavation and size‐separation in a single mechanism is feasible.

Regolith Excavation Performance of a Screw‐Propelled Vehicle

Excavation of regolith is the enabling process for many of the in situ resource utilization (ISRU) efforts that are being considered to aid in the human exploration of the moon and Mars. Most proposed planetary excavation systems are integrated with a wheeled vehicle, but none yet have used a screw‐propelled vehicle which can significantly enhance the excavation performance. Therefore, CASPER, a novel screw‐propelled excavation rover, is developed and analyzed to determine its effectiveness as a planetary excavator. The excavation rate, power, velocity, cost of transport, and a new parameter, excavation transport rate, are analyzed for various configurations of the vehicle through mobility and excavation tests performed in silica sand. The optimal configuration yields a 30 kg h−1 excavation rate and 10.2 m min−1 traverse rate with an overall system mass of 3.4 kg and power draw of less than 30 W. These results indicate that this architecture shows promise as a planetary excavation because it provides significant excavation capability with low mass and power requirements. An interactive preprint version of the article can be found here: https://doi.org/10.22541/au.162823910.04538641/v1.

Parametric review of existing regolith excavation techniques for lunar In Situ Resource Utilisation (ISRU) and recommendations for future excavation experiments

A high-level overview of current research in the area of lunar regolith excavation and handling for In Situ Resource Utilisation (ISRU) is presented. Thirteen processes are grouped into discrete and continuous excavators. A further differentiation is made between systems with and without connection to a mobility platform – referred to as complete and partial systems. For each group, a set of representative performance parameters has been identified and compared, while special characteristics or limitations are highlighted. The present work identifies a need for high detail research into the development of reliable and efficient excavation systems, due to the high importance of regolith excavation and handling to ISRU. A need for more standardised information and recording of specific data during supporting experimental studies is made apparent. In order to enable easier categorisation, comparison, and evaluation of future concepts, a set of key performance parameters requiring consideration during experimental campaigns is described and the importance of their inclusion underlined.

K3 リッパによる月レゴリス掘削の効率化(宇宙探査)

K3 リッパによる月レゴリス掘削の効率化(宇宙探査)

Measurement of force to excavate extraterrestrial regolith with a small bucket-wheel device

The plans for NASA missions to the moon and mars require excavation of regolith (soil) especially to realize the benefits of in situ resource utilization. Micro-scale excavators might be good candidates for these missions since they will significantly reduce launch mass. Even though the excavator might be small, it still has to be capable, reliable, and power efficient. This paper reports on research to measure the amount of force such a small excavator must generate to be effective. Previous research indicates a bucket-wheel excavator is a good candidate excavator tool; so, we developed a laboratory-scale apparatus to measure the horizontal and vertical forces and power required to excavate simulated regolith with a micro-scale bucket wheel. This paper describes the apparatus and presents the results of measurements along with a comparison with modeled forces, concluding that micro-excavators are feasible candidates for ISRU work.