J. Neumann
M. Ernst
P. A. Taschner
N. Gerdes
A. Voss
S. Stapperfend
S. Linke
C. Lotz
J. Koch
P. Weßels
S. Kaierle
E. Stoll
L. Overmeyer

Mobile Selective Laser Melting of Lunar Regolith

Space Resources Week
19.-22. April
Type: Konferenzbeitrag
In-Situ Resource Utilization (ISRU) technologies pave the way for a sustainable colony on the Moon. Above all, the construction of structures using only the available resources is an important factor in reducing costs and logistical effort. The MOONRISE project aims to melt lunar regolith using lasers on mobile platforms for the Additive Manufacturing of structures [1]. This process, working in a non-contact mode, is called Mobile Selective Laser Melting (M-SLM) and has the advantage that only electrical energy and a moving system are required. A payload mainly consisting of a printed circuit board (PCB) for system communication, a fiber coupled diode laser, an electrical diode driver, a beam focusing optics, and an LED illumination was designed. For baseline operation, a laser beam of typically 70 W (up to 140 W) is directed for 6 s to a fixed spot on the lunar surface at a distance of about 25 cm. These parameters were chosen according to previously conducted laboratory experiments with regolith simulant. LED illumination is available for visualization of the molten regolith by external cameras. The payload can be accommodated on a rover or a robotic arm to ensure mobility for the melting experiments. Following that, an Engineering Model (EM) has been built and tested for functionality and under varying environmental conditions. Tests were continued with the EM under vacuum and lunar gravity conditions in the large-scale research device Einstein-Elevator [2] allowing for experiment durations of about 4 seconds. The interior of the samples with a diameter of about 3 mm mainly consists of glass, i.e. amorphous solidified melt of regolith simulant, containing spherical voids of various sizes as analysed by X-ray tomography. In terms of mass and volume, all samples show comparable values. Further, we a ccommodated the EM on a robotic arm to ensure mobility and produce flat rectangular specimens. Solid 2D structures of 2 0 mm x 20 mm x 4 mm in size were reproducibly generated despite the inhomogeneous simulant material (Fig. 1). So, it can be assumed that also larger samples can be manufactured with the process.