Semester

Spring

Date of Graduation

2024

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Lane Department of Computer Science and Electrical Engineering

Committee Chair

Dimitris Korakakis

Committee Member

Jeremy Dawson

Committee Member

Parviz Famouri

Abstract

The payload capacity of spacecraft is constrained by the weight of the craft itself, including fuel and electronic systems. The protective measures used to shield onboard electronics from the harsh space environment, characterized by high-energy particles and significant temperature fluctuations, can further diminish the available payload capacity. This thesis explores the potential of naturally radiation-hard alternatives to commonly used electronic materials, such as Silicon, to reduce the need for shielding and other protective measures, thereby decreasing the weight and cost of space missions.

III-V semiconductor materials, such as Gallium Nitride (GaN), are known for their inherent resilience to temperature swings and lattice damage. Despite their successful application on Earth, GaN-based electronics have not been widely adopted in space missions. Most evaluations of GaN materials’ resilience to radiation and temperature have been conducted terrestrially using accelerated lifetime testing approaches. However, there is a lack of studies evaluating GaN materials in actual space environments over timeframes consistent with space missions.

This thesis describes a CubeSat experiment designed to investigate the effects of radiation and temperature on 24 GaN Light Emitting Diodes (LEDs) housed inside a 3U cube satellite in low earth orbit at 500km, as part of West Virginia’s STF-1 mission. Using a custom-designed Low-powered Optoelectronic Characterizer for CubeSat (LOCC), periodic current and voltage measurements were taken to construct the current/voltage (IV) curves of each LED. Additionally, the luminosity and color of the LEDs (designed for 465nm emission) were measured.

Data collected since 2019 has been processed, revealing a likely outcome that the LEDs are still functioning with minimal damage. The data from the MaZET MTCSiCF MCDC04 Analog to Digital Converter (ADC) was interpreted for plotting in a Commission Internationale de l’éclairage (CIE) 1931 X Y Z color space. A correction matrix K was calculated, where K = () * ; T is a reference matrix consisting of reference measurements, and S is the Signal matrix interpreted from the ADC values. The X, Y, and Z ADC values were multiplied by K to obtain the X, Y, and Z CIE colorimetric plot values, which were then plotted on a two-dimensional CIE graph. This study provides valuable insights into the performance of GaN LEDs in space environments, contributing to the development of more efficient and cost-effective space missions.

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