Date of Award

Spring 5-5-2023

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Advisor

Justin Lapp

Second Committee Member

Richard Kimball

Third Committee Member

Bashir Khoda

Abstract

Construction material is one crucial need for long-term habitation on the moon. When concentrated for high heat flux, solar radiation can heat lunar soil or regolith until it sinters at temperatures above 900°C. The solid, sintered soil simulant can be used as construction material. This work explores the conditions leading to effective lunar soil sintering for both direct and indirect irradiated sintering. Lunar soil simulants were sintered using concentrated light from a xenon-arc lamp with varying heat flux intensity. During direct sintering of LHS-1, a sintering range of 860°C-1140°C corresponding to a peak heat flux of 105-120 kW/m2 was identified which sinters a 4 mm thick lunar brick. A higher heat flux of up to 225.6 kW/m2 has been experimented with, which melts the top surface of the simulant, but an 8 mm thick lunar brick is achieved. Different direct sintering techniques are experimented with to sinter thick and large lunar soil bricks. A time series experiment is conducted taking LHS-1 and JSC-1A lunar soil simulant to find the sintered mass at different experiment duration. Comparative sintering behavior of LHS-1 and JSC-1A lunar soil simulant is also studied. One exciting thing is the central thickness for JSC-1A is initially higher, but with time, the central thickness of LHS-1 surpasses the central thickness of JSC-1A. Indirect sintering with silicon carbide (SiC) plate is studied by varying input irradiation, which sintered similar thick LHS-1 lunar soil brick without melting at higher irradiation. Indirect sintering increases the size as well. It provides possibility to sinter different shaped lunar bricks using molds. Limited compressive strength data showed higher strength for indirect sintering. Special indirect sintering experiments were conducted to reach the sintering temperature faster with higher incoming irradiation, which reduces processing time. A thermodynamic analysis is also conducted for a closed system furnace to sinter lunar soil and extract byproduct water for oxygen production. The study shows that 0.35 gm of oxygen can be produced from 1 kg of LHS-1 lunar soil simulant, with a hydrogen mole to oxygen mole ratio of four at 2000°C system temperature. The thermodynamic analysis considers all the energy input and output to find the required solar energy to raise the system temperature at a particular operational temperature to sinter lunar soil. It gives a future to develop a model furnace to run the sintering operation at the moon.

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