Date of Award

January 2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Space Studies

First Advisor

Mike Gaffey

Abstract

In the search for extraterrestrial life, identification of molecular biosignatures is a key technique. Lipids are important molecular biosignatures: they are ubiquitous to terrestrial life, survive for billions of years in the geologic record, can form biotically and abiotically (bearing molecular features indicating biogenicity), and are detected throughout the Solar System. Lipid-based life detection instruments require stringent contamination control to prevent false positives, but traditional decontamination techniques are unlikely to sufficiently remove lipid contamination without compromising instrument materials. This thesis investigates Electron Beam Irradiation (EBI) as a potential decontamination technique; five representative lipid standards, including palmitic acid, oleic acid, heneicosane, 5α-cholestan-3β-ol, and 5-α-cholestane, were subjected to EBI at 0, 50, and 100 kilogray doses, then analyzed with gas chromatography mass spectrometry to determine removal efficiency. No significant degradation of lipids was observed at doses tested, suggesting EBI should not be utilized as a lipid decontamination technique for life detection instruments.

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