Single Track Deposition of Lunar Regolith Without Substrate Based on Millimeter-Sized Spot

The construction of the lunar base requires the additive manufacturing of lunar regolith bricks using in-situ resources (e.g., lunar regolith and solar energy). Laser or solar powder bed fusion with a large laser spot has the potential to utilize in-situ resources. However, there are difficulties in forming melting tracks with no substrate on the regolith powder bed. This study focused on millimeter-sized spots and processes with no substrate. The continuous deposition of the tracks through wrapping was analyzed through in-situ observation with a highspeed camera. The track discontinuity will occur if the newly formed melting droplet fails to make contact and fuse with the leading edge of the track. The track maintained continuity until the scan velocity increased above a critical value. The critical scan velocity equation of the track discontinuous transition was derived. Finally, a lunar regolith brick measuring 50x50x50 mm was fabricated with track continuity process parameters.