Date of Award:

2016

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Physics

Advisor/Chair:

J. R. Dennison

Abstract

The main cause of spacecraft failures is due to the harsh space environment; therefore, rigorous testing of materials used in modern spacecraft is imperative to ensure proper operation during the life span of the mission. Enhancing the capabilities of ground-based test facilities allows for more accurate measurements to be taken as it better simulates the environment to which spacecraft will be exposed. The range of temperature measurements has been significantly extended for an existing space environment simulation test chamber used in the study of electron emission, sample charging and discharge, electrostatic discharge and arcing, electron transport, and luminescence of spacecraft materials. This was accomplished by incorporating a new two-stage, closed-cycle helium cryostat, which has an extended sample temperature range from 450 K, with long-term controlled stability of -7Pa) that can simulate diverse space environments. These existing capabilities include controllable vacuum and ambient neutral gases conditions (< 10-7 to 10-1 Pa), electron fluxes (5 eV to 30 KeV monoenergetic, focused, pulsed sources ranging from 10-4 to 1010 nA-cm-2), ion fluxes (<0.1 to 5keV monoenergetic sources for inert and reactive gases with pulsing capabilities), and photon irradiation (numerous continuous and pulsed monochromatic and broadband IR/VIS/UV [0.5 to 7 eV] sources). The original sample mount accommodates one to four samples of 1 cm to 2.5 cm diameter in a low-temperature carousel, which allows rapid sample exchange and controlled exposure of the individual samples. Multiple additional sample mounts have been added to allow for standalone use for constant voltage measurements, radiation induced and conductivity tests, as well as extended capabilities for electron-induced luminescent measurements to be conducted using various material sample thickness in the original existing space environment simulation test chamber.

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