Marshall Space Flight Center Research and Technology Report 2019

Today, our calling to explore is greater than ever before, and here at Marshall Space Flight Centerwe make human deep space exploration possible. A key goal for Artemis is demonstrating and perfecting capabilities on the Moon for technologies needed for humans to get to Mars. This years report features 10 of the Agencys 16 Technology Areas, and I am proud of Marshalls role in creating solutions for so many of these daunting technical challenges. Many of these projects will lead to sustainable in-space architecture for human space exploration that will allow us to travel to the Moon, on to Mars, and beyond. Others are developing new scientific instruments capable of providing an unprecedented glimpse into our universe. NASA has led the charge in space exploration for more than six decades, and through the Artemis program we will help build on our work in low Earth orbit and pave the way to the Moon and Mars. At Marshall, we leverage the skills and interest of the international community to conduct scientific research, develop and demonstrate technology, and train international crews to operate further from Earth for longer periods of time than ever before first at the lunar surface, then on to our next giant leap, human exploration of Mars. While each project in this report seeks to advance new technology and challenge conventions, it is important to recognize the diversity of activities and people supporting our mission. This report not only showcases the Centers capabilities and our partnerships, it also highlights the progress our people have achieved in the past year. These scientists, researchers and innovators are why Marshall and NASA will continue to be a leader in innovation, exploration, and discovery for years to come

Flocculation kinetics using Fe(III) coagulant in water treatment: the effects of sulfate and temperature

This research focuses on the use of ferric nitrate as a coagulant to study flocculation kinetics including the fundamental mechanisms of orthokinetic flocculation, the impact of low water temperature, and the effect of sulfate ion. The kinetics of flocculation was studied for systems of kaolin dispersions destabilized by ferric nitrate coagulant in an 18 liter batch reactor under tightly controlled treatment conditions. Detailed measurement of the flocculation kinetics was done by assessing the rate of changes in total particle number concentration with an Automatic Image Analysis (AIA) system and by measuring the degree of turbidity fluctuation in a flowing suspension by a Photometric Dispersion Analysis (PDA) instrument;The overall objective of this research was (1) to investigate the kinetics of flocculating kaolin clay in water suspension under a number of treatment conditions, (2) to assess the effect of temperature on flocculation kinetics, spanning the full range of coagulation domains including the A/D and sweep floc mechanisms of coagulation, and (3) to investigate the role of sulfate ion in flocculation kinetics at two different temperatures;The conclusions of the flocculation kinetics studies using the 18 liter batch reactor are as follows: (1) Both the particle size distribution data obtained from the AIA and the on-line measurement of turbidity fluctuation by the PDA provided reliable and sensitive indications of flocculation kinetics. The AIA at high magnification gave the best indication of the primary particle disappearance, whereas, the PDA ratio values gave the best indication of the larger floc formation. (2) Sulfate ion added to the kaolin suspension played an important role in the flocculation process, not only in improving flocculation kinetics at more acidic pH levels at warm and cold water temperatures, but also in changing the surface charge of the particles. (3) Low water temperature had the pronounced effect on flocculation kinetics, slowing the rate of flocculation and enhancing the charge neutralizing ability of Fe(III) coagulant. The detrimental effect on the rate of flocculation was especially evident in the formation of larger aggregates as revealed by the PDA analysis. (4) The use of constant pOH at 5∘C and/or added sulfate ion was found to be partially effective for reducing the impact of low temperature on flocculation kinetics, but only in the acidic pH range studied (pH 6.0 to 6.8), but even under optimal adjustment of these provisions, the flocculation kinetics did not match the room temperature kinetics

Global optimization of material properties : clusters, solar cells and metal surfaces

Different global optimization tasks have been treated within this thesis. Using an analytic modified embedded atom method (MEAM), a structural-energetic global optimization of lithium and sodium clusters has been performed. With the Aufbau-Abbau procedure we identified up to six most stable isomers for each cluster size N within the size range 2 <= N <= 150, which was followed by a detailed energetic and structural analysis of the obtained Li and Na isomers. For N <= 5 the MEAM partly yields results which are unusual for model potentials, such as planar or linear cluster geometries. Besides the structural optimization of clusters within continuous search spaces, also global property optimizations within discrete search spaces have been performed. Employing a genetic algorithm, a part of our inverse design concept, we optimized organic molecules with respect to their usage within solar cells. Occasionally chemical intuition may help to predict and to understand the substution patterns of the molecules that may be beneficial for solar energy harvesting. Moreover, we extended our inverse design approach to the optimization of the adsorption properties of metal surfaces. The implementation of this project was challenging and associated with several problems. However, also here interesting results could be obtained, which can serve as starting point for further investigations.In dieser Arbeit werden verschiedene globale Optimierungsprobleme behandelt. Unter Verwendung einer analytisch modi fizierten Embedded-Atom-Methode (MEAM), wurden strukturell-energetische globale Optimierungen von Lithium- und Natriumclustern durchgeführt. Für jede Clustergröße N im Bereich 2 <= N <= 150 identi fizierten wir mittels des Aufbau-Abbau-Verfahrens bis zu sechs der stabilsten Isomere, woran sich eine detaillierte energetische und strukturelle Analyse der erhaltenen Li- und Na-Isomere anschloss. Für N <= 5 liefert die MEAM zum Teil, für Modellpotentiale, untypische Ergebnisse, wie flache oder lineare Clustergeometrien. Neben der strukturellen Optimierung von Clustern innerhalb kontinuierlicher Suchräume, wurden auch globale Optimierungen von Materialeigenschaften in diskreten Suchräumen durchgeführt. Unter Verwendung eines genetischen Algorithmus, ein Bestandteil unseres Inverse-Design-Konzeptes, optimierten wir organische Moleküle hinsichtlich ihres Einsatzes in Solarzellen. Chemische Intuition kann vereinzelt hilfreich sein, die für die Nutzung von Sonnenenergie vorteilhaften Substitutionsmuster der Moleküle vorherzusagen und zu verstehen. Zudem erweiterten wir unseren Inverse-Design-Ansatz um die Optimierung der Adsorptionseigenschaften von Metalloberflächen. Die Umsetzung dieses Vorhabens war herausfordernd und mit einigen Problemen verbunden. Jedoch konnten auch hier interessante Ergebnisse erhalten werden, die als Basis weiterer Studien dienen können

Theoretical Investigation of Static and Dynamic Properties of Zeolite ZSM-5 Based Amorphous Material

Results of molecular dynamics simulations on structural, vibrational and relaxational properties of zeolite ZSM-5 based amorphous solids are presented. The effects of extent of amorphization, measured by an energetic criterion, on properties like distribution of coordination numbers, internal surface area, ring statistics and effective pore size are studied. Ring statistics indicates that upon amorphization not only rings with larger size break down to give rings with smaller size, but that for intermediate degree of amorphization also larger rings are generated. The vibrational density of states was determined for different extents of amorphization. The vibrational modes are analyzed by projecting them on those of the SiO4 and Si-O-Si subunits and individual frequency-dependent contributions of stretching, bending and rotation are discussed. Analysis of low-frequency spectrum show that for higher crystallinity the intensity of the boson peak decreases upon amorphization, whereas the opposite behavior is observed for forms with lower crystallinity. These effects are explained in the framework of Maxwell counting of floppy modes. The modes associated with the boson peak for these materials are found to be mainly optic in nature. Relaxations were studied for temperatures below the critical temperature. At low temperatures the relaxations comprise mainly one-dimensional chains of atoms. The dimensionality of the relaxing centers increases with the temperature due to side branching. The possibility of having reversible jumps decreases with increasing temperature due to a strong drop in the potential energy during aging. There exist very prominent peaks in the van Hove correlation functions as a manifestation of the hopping processes. The dynamics of the oxygen atoms is found to be more heterogeneous than those of the silicon atoms. Ab initio many-body calculations on the strain energy ofW-silica, taken as a model system for edge-sharing tetrahedral SiO2-systems with respect to corner-sharing ones as in a-quartz was performed. Correlation contributions are found to play an important role to determine the stability of edge-sharing units. Our calculation reveal that edge-sharing SiO4 tetrahedra in (partially) amorphous silicate systems are possible at a modest energetic expense

Future Transportation

Greenhouse gas (GHG) emissions associated with transportation activities account for approximately 20 percent of all carbon dioxide (co2) emissions globally, making the transportation sector a major contributor to the current global warming. This book focuses on the latest advances in technologies aiming at the sustainable future transportation of people and goods. A reduction in burning fossil fuel and technological transitions are the main approaches toward sustainable future transportation. Particular attention is given to automobile technological transitions, bike sharing systems, supply chain digitalization, and transport performance monitoring and optimization, among others

Recent Experiences in Multidisciplinary Analysis and Optimization, part 2

The papers presented at the NASA Symposium on Recent Experiences in Multidisciplinary Analysis and Optimization held at NASA Langley Research Center, Hampton, Virginia, April 24 to 26, 1984 are given. The purposes of the symposium were to exchange information about the status of the application of optimization and the associated analyses in industry or research laboratories to real life problems and to examine the directions of future developments

An adaptive autopilot design for an uninhabited surface vehicle

An adaptive autopilot design for an uninhabited surface vehicle Andy SK Annamalai The work described herein concerns the development of an innovative approach to the design of autopilot for uninhabited surface vehicles. In order to fulfil the requirements of autonomous missions, uninhabited surface vehicles must be able to operate with a minimum of external intervention. Existing strategies are limited by their dependence on a fixed model of the vessel. Thus, any change in plant dynamics has a non-trivial, deleterious effect on performance. This thesis presents an approach based on an adaptive model predictive control that is capable of retaining full functionality even in the face of sudden changes in dynamics. In the first part of this work recent developments in the field of uninhabited surface vehicles and trends in marine control are discussed. Historical developments and different strategies for model predictive control as applicable to surface vehicles are also explored. This thesis also presents innovative work done to improve the hardware on existing Springer uninhabited surface vehicle to serve as an effective test and research platform. Advanced controllers such as a model predictive controller are reliant on the accuracy of the model to accomplish the missions successfully. Hence, different techniques to obtain the model of Springer are investigated. Data obtained from experiments at Roadford Reservoir, United Kingdom are utilised to derive a generalised model of Springer by employing an innovative hybrid modelling technique that incorporates the different forward speeds and variable payload on-board the vehicle. Waypoint line of sight guidance provides the reference trajectory essential to complete missions successfully. The performances of traditional autopilots such as proportional integral and derivative controllers when applied to Springer are analysed. Autopilots based on modern controllers such as linear quadratic Gaussian and its innovative variants are integrated with the navigation and guidance systems on-board Springer. The modified linear quadratic Gaussian is obtained by combining various state estimators based on the Interval Kalman filter and the weighted Interval Kalman filter. Change in system dynamics is a challenge faced by uninhabited surface vehicles that result in erroneous autopilot behaviour. To overcome this challenge different adaptive algorithms are analysed and an innovative, adaptive autopilot based on model predictive control is designed. The acronym ‘aMPC’ is coined to refer to adaptive model predictive control that is obtained by combining the advances made to weighted least squares during this research and is used in conjunction with model predictive control. Successful experimentation is undertaken to validate the performance and autonomous mission capabilities of the adaptive autopilot despite change in system dynamics.EPSRC (Engineering and Physical Sciences Research Council

Search methods for an autonomous underwater vehicle using scalar measurements

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution July 1996The continuing development of the autonomous underwater vehicle as an oceanographic research tool has opened up the realm of scientific possibility in the field of deep ocean research. The ability of a vehicle to travel to the ocean floor untethered, collect data for an extended period of time and return to the surface for recovery can make precise oceanographic surveying more economically practical and more efficient. This thesis investigates several scalar parameter searching techniques which have their basis in mathematical optimization algorithms and their applicability for use specifically within the context of autonomous underwater vehicle dynamics. In particular, a modified version of the circular gradient evaluation in the simulated environment of a hydrothermal plume is examined as a test case. Using a priori knowledge of the expected structure of the scalar parameter contour is shown to be advantageous in optimizing the search