Lunar Regolith Mitigation through Emission of Laser Technology (MELT)
Abstract
Ever since the Apollo Missions, the international scientific community has had the goal of returning to the Moon to establish a base from which to conduct space science research, and as an outpost from which to conduct further space exploration. Mitigation of the ever-present, electrostatically charged lunar regolith has been recognized as a major problem to overcome before any further presence, robotic or human, can be established on the Moon [1,2]. Lunar regolith poses a significant problem to exploration. As was demonstrated during the Apollo Missions, the fine particulate matter, which is electrically charged in the harsh lunar environment, easily enters into sensitive areas on vehicles, including lenses, solar panels, hinges, and joints. Regolith is extremely abrasive, potentially resulting in significant mechanical and electrical failure onboard the lunar vehicle. Among the mitigation strategies which are being investigated by NASA and others, electrostatic methods that separate and remove charged regolith particles (SPARCLE, ELDS, ELDR) show promise [2,3,4]. However, according to the Dust Mitigation Gap Assessment Report (2016), "No single technology completely solves the challenges of dust, but rather a suite of technologies will be required to address them." For dust mitigation on lunar vehicles we propose a method of using a directed energy beam to sinter a path ahead of the vehicle so as to minimize lunar regolith being stirred up and adhering to surfaces. By minimizing the possibility of regolith contamination, laser sintering will limit the amount of technical and mechanical failure of lunar vehicles. MELT is a relatively low-cost and low-mass system, as it does not need to be implemented on every lunar vehicle, and can be successfully implemented with minimal additional parts. Sintering of lunar regolith using solar heating has been proposed as a method of in situ resource utilization (ISRU) for construction of dwellings and roads on the Moon [6,7]. Sintering of lunar regolith has been shown to produce a glass or ceramic with high compressive strength, expected to be one of the strongest materials derived from lunar sources [8]. MELT proposes a two-step laser sintering process which will allow lunar regolith to be sculpted into traversable paths with minimal dust. As a first step, the landing vehicle will be equipped with a high powered laser which will melt successive layers of regolith surrounding the landing craft as it descends. This sintering process will create a solid surface with minimal regolith dust surrounding it. In the second step, robotic lunar rovers will be released from the lander with front-mounted high-powered lasers. We propose a fleet of such rovers which will sinter the lunar regolith into a series of roads and paths before larger vehicles are deployed. Laser sintering will occur as the vehicles move forward, making multiple traverses until the sintered roads are wide enough to accommodate larger vehicles. This process can also be deployed around lunar bases to create low dust surfaces on which humans can walk, minimizing the threat of harmful regolith clinging to their garments, damaging seals, and potentially being tracked inside dwellings. In addition, we are working on using electrostatic precipitation cleaning to attract and trap lunar dust as an additional and synergistic dust mitigation technology. The UCSB Experimental Cosmology Group has already done some research and sample testing to determine the feasibility of this concept. Currently, successful sintering of lunar highland regolith simulant has been performed using a high-flux CW (10 MW/m2) high efficiency (50%) laser at 1 micron wavelength, which produced a glassy surface. We are working on a robotic lunar rover [9], and will front-mount our laser and test MELT with larger quantities of highland and mare lunar regolith simulant. MELT provides a long-term and versatile solution to dust mitigation during lunar landing and travel by creating hard surfaced roads that are relatively dust free. Further cleaning by electrostatic methods may still be required, but with less dust to remove from surfaces, systems such as SPARCLE, ELDS, and other methods will have less wear and tear. References: 1.Dust Mitigation Gap Assessment Report, International Agency Working Group (2016). https://www.globalspaceexploration.org/wordpress/docs/Dust%20Mitigation%20Gap%20Assessment%20Report.pdf, accessed 2020-10-10. 2. Afshar-Mohajer, N., Wua, C-Y., Curtis, J.S., and Gaier, J.R. (2015). Review of dust transport and mitigation technologies in lunar and Martian atmospheres, Advances in Space Research 56 (2015) 1222-1241. 3. Atten, P., Pang, H. L., and Reboud,J. (2009). Study of Dust Removal by Standing-Wave Electric Curtain for Application to Solar Cells on Mars, IEEE Transactions on Industry Applications, vol. 45, no. 1, pp. 75-86, Jan.-feb. 2009, doi: 10.1109/TIA.2008.2009723. 4. Curtis, S.A., Clark, P.E., Minetto, F.A., Calle, C.I., Keller, J., and Moore, M. (2009). SPARCLE: Creating An Electrostatically Based Tool For Lunar Dust Control. 40th Lunar and Planetary Science Conference (2009), Abstract #1128, Lunar and Planetary Institute, Houston, http://www.lpi.usra.edu/meetings/lpsc2009/pdf/1128.pdf 5. Wilson, T. L., and Wilson, K. B.(2005). Regolith sintering: a solution to lunar dust mitigation? 36th Lunar and Planetary Science Conference (2005), Abstract #1422, Lunar and Planetary Institute, Houston, https://www.lpi.usra.edu/meetings/lpsc2005/pdf/1422.pdf 6. Meurisse, A.R.J. (2018). Solar 3D printing of Lunar Regolith, PhD Thesis, accessed at https://publications.rwth-aachen.de/record/723143/files/723143.pdf, 2020-10-10. 7. Meurisse, A., Makaya, A., Willsch, C., Sperl, M. (2018). Solar 3D printing of lunar Regolith. Acta Astronautica 152 (2018) 800-810. 8.Indyk, S. and Benaroya, H., "Structural Members Produced from Unrefined Lunar Regolith Simulant", in 42nd COSPAR Scientific Assembly, 2018, vol. 4 9. Daniel, W., Pedersen, A., Crews-Holloway, C., Chu, S., Burke, I., Jordan, N., Lubin, P. (2020, Proposal Submitted to NASA BIG Ideas 2020 Competition.). Directed Energy Lunar Rover (DELV).
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E.357P