Emileigh S Shoemaker Thackston

Planetary Analog Field Work

Geological and geophysical investigations are performed from orbit and from the surfaces of planetary bodies in order to study the processes that have shaped and reshaped their surfaces and subsurfaces. Dr. Thackston uses analogous terrains and environments on Earth to test hypotheses about processes observed from orbit or by rovers on the surfaces of terrestrial planets. Dr. Thackston also studies how geophysical instrumentation can be best deployed by orbiters, rovers, or one day astronauts to study geologic processes and search for crucial resources like water ice.

Planetary Volcanism

Volcanism reshapes the surfaces and crusts of rocky planets. Dr. Thackston studies volcanic regions of Mars using remote sensing instruments to understand the volcanic history of major volcanic regions there. On Earth, Dr. Thackston studies studies the interplay of volcanic and cryospheric activity to understand how these geologic processes work together and how they may play a large role on the surfaces of planets like Mars.

Ground-Penetrating Radar Studies of Sea Ice

Sea Ice

Saline ice has unique electromagnetic properties that can hinder accurate estimates of its thickness using radar. This project seeks to characterize the unique radar properties of sea ice collected with a ground-penetrating radar system during an expedition to the Beaufort Sea near the coast of Alaska. The results of this investigation have implications for radar investigations of Icy Ocean Worlds such as Europa and Enceladus, which likely possess briny oceans beneath their ice shells.

SESAR-LITE

Remote Sensing

SESAR-LITE (Space Exploration Synthetic Aperture Radar - Lunar Investigations Targeted Experiment) is a compact P-band (70 cm wavelength, 435 MHz) polarimetric synthetic aperture radar designed to fly on a smallsat orbital lunar missions. Dr. Thackston is participating as a member of the science team for this instrument development project.

Radar Scattering Modeling of Heterogeneous Subsurface Media

Geophysics

This project uses a combination of electromagnetic forward modeling (finite-difference time-domain) and machine learning approaches to understand the scattering behavior of radar waves in a heterogeneous subsurface. Similar to seismic waves, returned subsurface signals produced through ground-penetrating radar surveying techniques acquire similar characteristics as they propagate through geologic media. Classical analyses of these returned signals using power spectra yield ambiguous results. The approach developed in this study attempts to quantify the frequecy content of the scattered wave field as well as the timescale of which features with a particular frequency content cluster.

Analog Field Work: Pore-Filling Ice at Hekla Volcano, Southwest Iceland

Planetary surfaces

Intermixed ice and regolith likely exist at low concentrations at the Lunar poles. The low concentration of water ice presents a challenge for unambiguous detection using geophysical instrumentation. This goal of this analog field work is to determine the vertical and horizontal distribution and concentration of a pore-filling ice deposit discovered preserved within volcanic tephra on the slopes of the Hekla volcano in southwest Iceland. This site is one of several volcanic edifices across Iceland at high elevation where ice is preserved by volcanic ash and tephra, which has insulating properties. The low-density tephra with pore-filling ice at Hekla is potentially analogous to the intermixed ice and regolith at the Lunar poles and presents an accessible target to test detectability with ground-penetrating radar, currently targeted as an exploration tool for the Moon.