Research projects for the 2007 NASA Glenn Academy.
Group Project: “Design of a Probe Mission to an Earth-like Planet”
“Analyzing MER Image Data to Quantify Mars Atmospheric Dust” – Rebecca Arvanites
Abstract: Understanding the properties of dust devils is important for gaining knowledge of the Martian environment. The goal of this project is to investigate the distribution of dust concentration in dust devils on Mars, using the Navcam images taken by Spirit. The dust concentration of the dust devils is examined by determining the opacity, τ, which is a nondimensionalized parameter describing the amount of dissipation that the dust devil causes to light traveling through it. The distribution of τ was investigated to determine how τ varies with position within the dust devils, and how τ changes with time as the dust devils develop. One challenge was distinguishing the dust devils in the images from the background for the portion of the dust devil in front of the sky. Also of interest is how the optical properties of the dust in the devil compare to those of the dust suspended in the atmosphere; calculations were done first assuming the same optical properties and then more rigorously without these assumptions.
“Genetic Algorithm Optimization for Inlet Bleed Design Systems” – Kyle B. Gaiser
Abstract: A genetic algorithm coupled with computational fluid dynamic software is used to optimize the configuration of an engine inlet at a supersonic speed. The optimization program is written to calculate the pressure recovery of many varying bleed schedules throughout the inlet walls. The goal is to find the best combination of the bleed holes’ locations, diameters, and flow rates such that a high pressure recovery is maintained. Parallel computing using the NAS supercomputer Columbia is used to run the algorithm efficiently. This is the first time a genetic algorithm has been applied to inlet bleed design. A test function is used to evaluate and debug the optimization algorithm. The genetic algorithm and its associated programs are found to work and show strong potential for use in developing more efficient bleed schedules in a hypersonic engine.
“Liquid Propellant Gauging in Low Gravity: the Pressure-Volume-Temperature (PVT) Method” – Jennifer L. Jones
Abstract: Fluids in low gravity are controlled by surface tension. Since cryogenic propellants in spacecraft are not held at the bottom of fuel tanks by the Earth’s gravity, a reliable and accurate gauging method is essential to mission success. Desirable gauging methods are accurate without requiring settling of the fuel tanks. This reduces fuel margins, reducing both the mass and cost of the mission. The Pressure-Volume-Temperature (PVT) method does not use fuel in the gauging process, works with various tank geometries and liquid placement within the tank, and minimizes the amount of additional hardware required. The PVT method uses a noncondensible gas to pressurize a propellant tank. The mass that is transferred from the pressurant gas supply bottle to the propellant tank is determined to find the percentage of liquid volume that is left within the tank. Analytical and experimental work has been performed using helium as the pressurant gas and liquid oxygen (LO2) as the propellant. Tests were performed at propellant tank pressures of 50 psia, 150 psia, and 250 psia to verify the accuracy of the PVT gauging method. The data show accuracies within ±3% of full scale or better, thereby demonstrating PVT as a viable gauging method for cryogenic propellants in low-g.
“Genetic Algorithm Optimization of Inlet Geometry for a Hypersonic Jet Engine with Mode Transition” – Ashley Micks
Abstract: A genetic algorithm (GA) program is developed to simulate the “evolution” of a “population” of hypersonic jet engine inlet geometries over many generations, with “natural selection” favoring better total pressure recovery. The algorithm mimics biological evolution to produce increasingly desirable designs with each generation. The result is an improved design from a small-scale run, plus the functional algorithm, complete with auxiliary scripts for use in future work such as time- and computation-intensive large-scale runs.
“Exploration Life Support – Dust Mitigation and Support” – Larry Bernard Murphy
Abstract: A closed circuit wind tunnel is being designed to test different high efficiency particle aerosol (HEPA) filters and other filtration concepts against lunar dust loadings. ASHRAE and Lawrence Livermore National Laboratory Standards were used to establish regulations for future filtration tests.
“Cryogenic Analysis Tool Applied to LSAM (Lunar Surface Access Module)” – Adam P. Pfendt
Abstract: Storing cryogenic propellants for lunar missions possesses great potential for mass savings over the course of the mission. The Cryogenic Analysis Tool is an analytical model that returns information critical to deciding on the storage scheme for liquid hydrogen, methane, and oxygen fuels. The tool’s current uses in determining which fuel storage system offers the greatest mass savings, newly implemented procedures and functionality, and future applications are discussed herein.
“Resonant Frequencies of Implantable Piezoelectric Generators” – Jessica Snyder
Abstract: Piezoelectric generators are currently being studied in a variety of energy harvesting situations. The goal of this project is to power implanted electronic medical devices with implanted piezoelectric generators, augmenting or replacing the external power supplies or implanted batteries currently used as power sources. Preliminary animal experiments have shown that this may be a viable method of powering internal electrical devices2. This paper covers the procedures used to determine the resonance frequencies of the piezoelectric generators in an effort to maximize the power output of the system.
“Next Generation High Power Multi-frequency Transmitter for Space Borne Doppler Radar Sensing and Precipitation Measurements” – Stephanie Vasicek
Abstract: Data analysis was performed using a Tektronix RSA 3303A Real-Time Spectrum Analyzer with the objective of demonstrating the feasibility of using a single Kaband Traveling Wave Tube (TWT) to amplify two pulses at frequencies 3.5 GHz apart. This approach is being studied as a potential alternative to a current model proposed for use on the Global Precipitation Measurement (GPM) mission using two separate TWTs at two separate frequencies. The applicability of MATLAB, Tektronix, and Agilent software was explored. Using this software, pulse analysis techniques were further investigated and refined. Vector Signal Analysis software was investigated for possible use with an Agilent Performance Spectrum Analyzer in order to observe modulated signals at Ka-band. It is being further investigated to possibly enable more detailed quantitative comparisons. MATLAB Signal Processing Toolbox is also being explored as a possible analysis tool. A staggered pulse method was determined to have advantages over two simultaneous pulses in that full peak power at each frequency can be viewed and intermodulation products can be avoided. Current work includes refining ability to evaluate radar pulse modulations, investigating new filtering techniques to minimize intermodulation products, investigating distortion effects and phase modulation due to the TWT, comparing NASA Glenn Research Center findings to NASA Goddard Space Flight Center calculations, and improving ways to quantitatively measure pulse characteristics after passing through the TWT.