Doctor of Philosophy in Physics

School of Physics Thesis Dissertation Defense

Advik Vira

Advisor: Dr. Phillip First, School of Physics, Georgia Institute of Technology

Radiation Effects, Dust Dynamics, and Petrology of Lunar Materials: Insights from Computational Modeling and Electron Microscopy

Date: Friday, January 9, 2026 

Time: 1:00 p.m.

Location: Howey N201/202

Virtual: Join the meeting now / Meeting ID: 257 608 916 303 99 /  Passcode: EU3d59hS

Committee Members: 

Dr. Zhigang Jiang, School of Physics, Georgia Institute of Technology

Dr. Thomas M. Orlando, School of Chemistry and Biochemistry, Georgia Institute of Technology

Dr. Frances Rivera-Hernandez, School of Earth and Atmospheric Sciences, Georgia Institute of Technology

Dr. Shaheen A. Dewji, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology

Abstract: 

The Artemis missions are a bold return to the Moon—not as fleeting explorers, but as long-term residents. Establishing a sustained lunar presence introduces both new scientific opportunities and engineering challenges, demanding innovative solutions to problems first identified during the Apollo era. Protection against the harsh radiation environment and mitigation of dust adhesion are critical for survival on the Moon, necessitating the use of robust radiation shielding and electrodynamic dust shields. This thesis focuses on two fundamental questions. First, what is the optimal distribution of thermalization and capture elements within a shielding material to shield astronauts from relentless radiation? Second, what are the physical processes that govern the accumulation of charge on lunar grains, leading to the pervasive lunar dust that threatens both equipment and human health? We address these questions through Monte Carlo simulations of particle transport in materials, ultimately identifying an optimal configuration for thermalization and capture elements and characterizing charge accumulation within the microcavities that form in dust grains.

Additionally, over 50 years have passed since the last Apollo missions, and modern instrumentation now enables a far more detailed re-examination of Apollo samples. Such analyses will not only deepen our understanding of the Moon’s geological history but also directly inform the selection of samples returned in upcoming missions. Using high-resolution electron microscopy and electron energy loss spectroscopy, we investigate a lunar mare basalt and find that the ilmenite is enriched in Ti, beyond the end member of the conventional solid solution series. This requires a change in the oxidation state of Ti,  confirming a longstanding hypothesis regarding the Moon’s highly reducing environment and allowing us to estimate the oxygen fugacity during crystallization. Our work underscores how carefully selected lunar specimens can provide critical constraints on the geological formation and evolution of the Moon.