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Previous research has demonstrated the operational benefits of supplementing unmanned aircraft systems (UAS) with solar power. With limits to energy storage based on aircraft cost and weight, supplementing aircraft power systems with solar technology can meet modern requirements with current technology. The focus of this research is to determine the potential increase in the range and endurance of the AeroVironment Switchblade 300 unmanned aerial vehicle (UAV) through the inclusion of advanced thin-film flexible solar cells. In lieu of a fully operational test aircraft, the research developed a prototype solar enhanced Switchblade 300 using comparable components and a production Switchblade 300 airframe to conduct real world experimentation in the feasibility of solar enhancement. The research also extrapolated empirical data to estimate the effects of solar enhancement on similar Group 1 UAS. A 23.7% increase in endurance was achieved on the prototype solar enhanced Switchblade 300 and a more than 83.3% increase is feasible using higher efficiency solar cells. More than a 108% increase is theoretically feasible for the Switchblade 600 UAV based on scaled empirical data. These findings indicate that current production small electric tube-launched UAS have significant potential for improvement and could leverage future advances in solar technology to gain significant technological advantages for the warfighter. Captain, United States Marine Corps Approved for public release. Distribution is unlimited.

As technology and spacecraft design advance, the demand for power is ever more prevalent. Photovoltaic cells continue to be the industry standard for space power, and their efficiencies have progressed significantly. However, as spacecraft become more exquisite, modest solar arrays are scaling into massive booms, and time spent in eclipse is becoming increasingly problematic. Tuning photovoltaic cells to the infrared region, coupled with a thermal source, removes the requirement for sunlight and allows the spacecraft to generate electricity even in complete eclipse. Thermophotovoltaic (TPV) cells also allow a spacecraft to operate at great distances from the sun so long as a heat source is present. This thesis explores the possibility of incorporating TPVs coupled with nuclear power systems into spacecraft design for future Earth-bound and interplanetary missions. DoD Space Lieutenant, United States Navy Approved for public release. Distribution is unlimited.

Interdigitated back surface contact (IBC) and copper indium gallium diselenide (CIGS) solar cells have been explored by multiple former Naval Postgraduate School (NPS) students with mutual independence. This thesis marries IBC and CIGS into a single cell to explore its optical parameters before introducing a novel cell design to reduce recombination in the absorber by establishing a vertical electric field. Implementing the novel design established up to a 7.5kV/cm electric field in the absorber to promote the separation of charge carriers, resulting in significant increases in short circuit current and I-V curve knee extension to raise cell efficiency to 24.32% at 300 K. Comparing this cell to optimal designs of prior theses, our cell boasts a 79.45% reduction in cell thickness and relative efficiency increase of 5.74%. Modeling of this cell demonstrates its potential for use in low weight, high power equipment such as UAVs, satellites, and solar blankets used by warfighters. Lieutenant, United States Navy Approved for public release. Distribution is unlimited.

Though studies and experimentation have been done regarding solar UAVs, it appears that these studies have been primarily focused on the development of futuristic prototypes or proof-of-concept vehicles used under very controlled conditions and without regard to extensive practical applications. On the other hand, in this research we seek to examine the flying endurance benefits that may be achieved by equipping the Nimbus Pro VTOL small unmanned aerial aircraft with commercially available thin film photovoltaic cells. Typical miniature and micro UAVs that run on battery power have an endurance of thirty minutes to two hours, after which time they need to be retrieved so that the batteries can be recharged, or so that another single-use battery can be installed. The retrieve-prepare-relaunch cycle can be greater than the on-station time for the UAV, and greatly reduces the utility of these systems to the intelligence gatherer or war fighter. The focus of this research is to determine the estimation of the power consumption of the Nimbus Pro VTOL and the power generated from an array of solar cells installed on the wing of the aircraft. With that information, we can approximate the additional flight time gained by the installation of the solar array. LTJG, Peruvian Navy Approved for public release. Distribution is unlimited.

The purpose of this research is to document further research into the optimization techniques investigated by James Walsh and applied to Multi-junction Solar Cells. Walsh performed his research with the Near Orthogonal Latin Hypercube (NOLH) in order to optimize the design specifications for each layer of solar cell thickness and doping concentration. Walsh at the same time evaluated cell performance under the radiation effects of the space environment. This research performed a similar analysis, except for the radiation effects, but focused more on producing an algorithm that could be executed from single user input and significantly reducing the selected design space. This research produced an efficient program that seamlessly operates between Ruby, MATLAB, and Silvaco ATLAS in order to produce an optimal designed dual-junction solar cell for space applications, in a much smaller design space than the technique utilized by Walsh. http://archive.org/details/optimizationofmu1094564137 Captain, United States Marine Corps Approved for public release; distribution is unlimited.

Silicon (Si) and gallium arsenide (GaAs) solar cells have shown success in back-contact designs. However, solar cells with back contacts have not been implemented on copper indium gallium diselenide (CIGS). To show the advantages of using this type of solar cell on unmanned aircraft, data from the Puma 3 AE was used. Our objective was to model 144 staggered back contact (SBC) CIGS cells onto a Puma and prove that it would extend the flight time, all at a minimal cost to the U.S. military. There are four tasks to achieving this objective: calculate maximum efficiency the solar cell could achieve, simulate a real CIGS cell, simulate the SBC CIGS cell, and model 144 SBC CIGS cells on a Puma while doing a cost analysis. Using a MATLAB script, this research calculated the ideal efficiency for a CIGS cell to be 26.72%. Using Silvaco, an accurate CIGS cell was simulated, based on a 3% difference in output performance from the real cell. A simulated SBC CIGS cell was successfully designed, which had a 23% efficiency. The new design had an 18% increase in power output from the real NREL model. Modeling 144 SBC CIGS cells on the Puma improved its standard 1–2 hour flight time to 8–17 hours, depending on location and temperature. To install 144 cells and equipment, the total cost was estimated at $926. This thesis determined that a simulated SBC CIGS cell can be made to help extend the Puma flight time, at minimal cost to the U.S. military. Lieutenant, United States Navy Approved for public release; distribution is unlimited.

A ground force commander (GFC) is in a constant fight to maintain complete situational awareness of his or her respective area of operations (AO). This means being aware of all friendly and enemy movement in his AO, and being able to quickly identify new threats and neutralize them efficiently. One of the greatest tools at an AO's disposal for achieving these objectives is the utilization of intelligence, surveillance, and reconnaissance (ISR) aerial platforms. While these platforms are incredible assets, they are often remotely controlled by a higher headquarters, and sensor coverage time is usually shared between multiple ground units spread across numerous AOs. This means that the GFC rarely has access to the sensor as often and for as long as desired. Therefore, the impetus of this thesis is to design, build, and test an ISR platform, controlled by a team on the battlefield, which is capable of virtually uninterrupted sensor coverage due to utilization of a photovoltaic solar array as a power supply. This study includes computer-assisted design, 3D printing, multirotor technology, solar energy absorption, maximum power point tracking, energy storage, and full-motion video relays to achieve the objective. http://archive.org/details/designconstructi1094561373 Lieutenant, United States Navy Approved for public release; distribution is unlimited.

In this research, we focus on quantifying the flight endurance gains possible for a variety of flight profiles and environments by adding commercially available thin film photovoltaic cells and power electronics hardware to the RQ-20 Puma small unmanned aerial vehicle. We use a combination of precise aircraft sub-component power utilization measurements, in-flight performance data, and precise calculations of solar azimuth, elevation, and intensity. The result of our analysis is a novel computer model of the aircraft and photovoltaic system that accounts for geographic location, altitude, and time of year, and then predicts minute-by-minute battery charge over the course of a dynamic flight profile. We conclude that substantial flight endurance gains are possible in the most favorable environments, and modest but worthwhile gains are even possible with little sunlight. Based on our findings and a favorable cost-benefit analysis, we recommend that the Navy and Marine Corps pursue full-flight testing in support of fielding this technology across the RQ-20 inventory. http://archive.org/details/increasingperfor1094560447 Major, United States Marine Corps Approved for public release; distribution is unlimited.

Dual junction solar cells are used in space applications for their high efficiency. In this thesis, we model an indium gallium phosphide/gallium arsenide dual-junction solar cell. The solar cell is modeled using Silvaco ATLAS software. Solar cell layer thicknesses and doping concentrations were varied to find optimum efficiency parameters for the solar cell under a variety of radiation conditions. These radiation conditions mimic the damage done at various orbits around Earth for an arbitrary mission length of 12 years. The optimization process resulted in an improved efficiency of 15.1% to 22.4%. http://archive.org/details/optimizationofmu1094559615 Lieutenant, United States Navy Approved for public release; distribution is unlimited.

The electrical power supplied to satellites will continue to be provided by solar cells for the foreseeable future and new technologies and better methods of production for these cells will continue to be developed. Additionally, the space environment within the Earth’s radiation belts and the effect of the radiation on solar cells within this environment is well documented. The effects of radiation on solar cells outside this environment with the use of an 8-MeV electron beam was investigated. Thin-film high-efficiency gallium arsenide test devices were characterized, and an analysis of the thin-film devices’ performance post-irradiation was conducted via illuminated DC current-voltage and external quantum efficiency measurements. The results of this analysis showed a drastic reduction in device short circuit current of over 95% by a total electron fluence of 1016 cm-2. http://archive.org/details/highenergyelectr1094559561 Lieutenant, United States Navy Approved for public release; distribution is unlimited.

Gallium Arsenide (GaAs) solar cells are proven lightweight and high power density photovoltaic devices that offer significant performance improvements over conventional silicon solar cells; however, only a handful of commercial companies currently produce GaAs cells due to manufacturing costs. The objective of this thesis is to investigate the combined performance of several uncommonly used methods of fabricating thin-film GaAs solar cells, which show promise in reducing the cost of cell fabrication. Using Silvaco ATLAS Technology Computer Aided Design (TCAD), we simulated and optimized the performance of back-side contact thin-film solar cells. In such a design, both anode and cathode contacts are placed on the same side of a device, resulting in no shadowing of incoming light. The replacement of the AlGaAs emitter with a Schottky junction was simulated and evaluated and compared to the original back-side contact design. Finally, a method of improving the Schottky barrier height of the Schottky design was simulated and evaluated. http://archive.org/details/modelingschottky1094559575 Lieutenant, United States Navy Approved for public release; distribution is unlimited.

This research is part of a continued effort to simulate the effects of total dose radiation on the performance of single and composite operational amplifiers using PSPICE. This research provides further verification that the composite operational amplifier has a superior performance to the single operational amplifier while operating in a radiation flux. In this experiment, a single and composite op amp were constructed in PSPICE and implemented in a finite gain amplifier circuit. The effects of ionizing radiation were simulated by varying the parameters of the components that made up the op amps. These component parameters were varied in ways that would mimic the response of the actual components that were irradiated in previous research. The simulations were incrementally run to simulate an increasing radiation dose. The results of these simulations were then compared with the results of an actual study conducted at Naval Postgraduate School where similar circuits were irradiated using the school's LINAC. This procedure proved to be an improved method for predicting the effects of total dose radiation for radiation hardened devices and provided additional confirmation of the superior performance of the composite op amp over the single op amp. http://archive.org/details/improvedmethodfo109451161 Lieutenant, United States Navy Approved for public release; distribution is unlimited.

This thesis reports on three procedures and the associated numerical results for obtaining semiconductor majority carrier concentrations when subjected to a temperature sweep. The capability of predicting the exhaustion regime boundaries of a semiconductor is critical in understanding and exploiting the full potential of the modern integrated circuit. An efficient and reliable method is needed to accomplish this task. Silvaco International's semiconductor simulation software was used to predict temperature dependent majority carrier concentration for a semiconductor cell. Comparisons with analytical and numerical MATLAB-based schemes were made. This was done for both Silicon and GaAs materials. Conditions of the simulations demonstrated effect known as Bandgap Narrowing. http://archive.org/details/comparisonofnaly109454558 Lieutenant, United States Navy Approved for public release; distribution is unlimited.

In this research, the design and VLSI implementation of a digitally programmable active analog filter, based on the Generalized Immittance Converter (GIC) circuit, are presented. The programmable features include the filter type (bandpass, high pass, low pass or notch), the center or cut off frequency, and the quality factor. Switched capacitor networks are used to implement resistances. The design was first simulated and then implemented on a wire wrap board and tested. The circuit was then modeled and re-simulated using the Cadence Design Tools software package. Once the modeled circuit passes all design rule checks the final chip design was then submitted for fabrication. This research project will help provide a knowledge base for using Cadence software for VLSI CMOS design. Once the chip has been fabricated and tested it will provide a base for further development of stray insensitive VLSI design of analog circuits. http://archive.org/details/thevlsiimplement109459151 Lieutenant, United States Navy Approved for public release; distribution is unlimited.