EAC-1A: A novel large-volume lunar regolith simulant

Abstract

The European Astronaut Centre (EAC) is currently constructing the European Lunar Exploration Laboratory (LUNA), a large training and operations facility to be located adjacent to EAC at the DLR (German Aerospace Centre) campus in Cologne, Germany. With an estimated representative lunar testbed area of approximately 660 m², a large volume of lunar regolith simulant material is needed for this purpose. In this study, a basanitic sandy silt from a quarry located in the Siebengebirge Volcanic Field is evaluated as a large-volume source of material. The focus of this project has been to conduct a physical and chemical characterisation of the fine-grained material to be used in LUNA; the European Astronaut Centre lunar regolith simulant 1 (EAC-1 A). The physical characterisation tests undertaken include sphericity, density measurements, cohesion and static angle of repose, with mineralogical investigations via petrographical analysis with optical microscope and SEM, XRF, XRD and DSC measurements. The results of the EAC-1A tests are compared to published data on existing widely used lunar regolith simulants, namely JSC-1A, JSC-2A, NU-LHT-3M, DNA and FJS-1.

Figure 1

Grain size distribution curve. The grain size distribution of EAC-1A, DNA and JSC-1A, plotted together with the bulk grain size range of the Apollo samples.

Figure 2

Thin sections under polarised light. To the left, the glomerocryst-containing unit, showing an olivine glomerocryst. On the right, a large pyroxene crystal from the aphanitic unit. Note the similar feldspar and olivine-rich, fine-grained matrix in both units.

Figure 3

Major element compositions. The MgO and TiO₂ compositions of the studied lunar regolith simulants are compared to samples taken during the Apollo 14, 15, 16 and 17 missions. EAC-1 values fall within the range of the Apollo 17 samples.

Figure 4

Total-alkali-silica diagram. NaO₂ and K₂O plotted against SiO₂ illustrates how the lunar samples contain much less alkali minerals than terrestrial materials. The only lunar regolith simulant with a comparable alkali content is NAO-1.

Figure 5

Ternary diagram for the plagioclase and pyroxene endmember compositions. EAC-1 compared to Apollo 12 samples.

Figure 6

Differential scanning calorimetry measurement. The lunar regolith simulants were heated stepwise to determine whether any glass phase was present in the material, and to find the melting point.