This work investigates the application of highly-curved HAPG analyzer crystals in wavelength-dispersive X-ray fluorescence spectroscopy for the simultaneous analysis of lanthanides in unique extraterrestrial materials and explore its 3D voxel scanning capabilities at low excitation energies. For this a novel analysis technique is proposed to obtain non-destructive, selective volume information of rare earth elements in µm-sized analogues of coarse grain asteroid samples in preparation for the initial analysis of materials from asteroid sample return missions, such as the Hayabusa 2 (JAXA) and Osiris-REx (NASA). The combination of ultra-high cylindrical curvature and a high solid angle of 0.51 sr, is expected to provide higher throughput and collimation as compared to high energy resolution fluorescence detection spectroscopy. In addition, these measurements will contribute to the so-called Sample Analysis Readiness Test in the framework of the Osiris REx initial analysis programme.