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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Human Spaceflight Decision-making As A Potential Well Problem

Litwin, Ari 01 January 2012 (has links)
This study investigates funding within the US human spaceflight program in the timeperiod from 2004 to 2012. The approach taken employed the “potential well” model from physical science. The potential well model constrains any physical body trapped within it, and similarly a political “funding well” will constrain all programmatic decision-making. Two potential well models are employed, one represents classical physics while the other represents quantum physics. Since each model results in motion with certain properties, it can be seen if funding decisions also exhibit similar properties. In physics, the bifurcation between the classical world of aggregate bodies and the quantum world of individual particles is an indicator of deeper physical principles. This study seeks to explore whether this bifurcation exists in the political world as well. If so, it would help explain space policy evolution from 2004 to 2012, and provide evidence concerning the usefulness of physical models for discovering further trends in social science, including political science. The study of a bifurcation in space policy political decision-making resulted in an unclear relationship since some properties were found to be similar to their physical counterpart, some were found to be different, and one property, the quantization of funding into discrete increments, was absent from political decision-making. Further studies are required to explore this bifurcation in greater detail. However, the potential well did prove to be a powerful model in explaining the evolution of human spaceflight policy in 2004 to 2012 as it provided a framework to explain dynamics that may have otherwise remained unclear
2

A Simulation-Based Study of Operational Vulnerabilities and Contingency Planning for Smart Extraterrestrial Habitats

Kenneth A Pritchard (16334184) 14 June 2023 (has links)
<p>Although decades of experience in human spaceflight have produced and refined a wealth of operational knowledge, the unique challenges posed to long-term extraterrestrial surface habitats will require new approaches to mission design. The key objectives of this thesis are to develop an understanding of 1) how to use simulation to study these habitats and 2) how to make contingency plans for these habitats under complex, changing conditions. In order to accurately represent the challenges posed, we identify the common qualities of mission architectures that are likely to be present in near-future habitats. These qualities are used to formulate sample crew schedules that contribute to developing realistic models for meaningful research. We discuss the development of such models and demonstrate the suitability of simulation to enable the design and study of resilient space habitats. Simulation can be used as a tool to understand the challenges and consequences associated with decision making, as well as the importance of resilient design choices in a hazard-prone environment. We then identify aspects of vulnerability in space habitat mission operations, the subfactors that influence changes in habitat vulnerability, and the effects of each identified category of vulnerability. These ‘vulnerability factors’ are subsystem availability, environmental conditions, safety control options, and recent events. Each vulnerability factor has several subfactors that influence its change during a mission.</p> <p><br></p> <p>The set of vulnerability factors is significant because each captures some category of behavior in surface habitats that changes over time and impacts the likelihood or consequences of risks to the habitat. We use these vulnerability factors to formulate six research questions which can be addressed via simulation-based research. A simulation set plan is developed to highlight the significant concepts at play in each research question. Finally, we conduct trials and analyses of these questions via simulation by injecting faults into a modular coupled virtual testbed for space habitats. The results of the simulations are used to develop lists of key implications for each vulnerability factor in practice. In addition, the lessons learned over the course of simulation set design and the usage of the simulation tool are discussed to support future simulation-based research efforts. We conclude by summarizing the major findings and potential for future work in the area.</p>
3

The Cost, Politics and Controversy of Human Space Flight in Nigeria or How to Put the First African Astronaut into Space

Winns, Desiree 01 January 2022 (has links)
The most pressing barriers between reality and the dream of the first African astronaut in space are a lack of resources, cooperation, and support. However, Nigeria presently suffers from the threat of famine, intercommunal violence, and population displacement as a result of terrorism and food insecurity. The reliance upon humanitarian aid from countries such as the United States and international NGOs creates a question of whether Nigeria should even be considering exploration of space. It can be said that any investment into space should instead be granted to displaced people, water and food security, and cracking down on terrorism. Why should a developing country go to space? And what benefits would human space flight provide to people struggling on earth? Economically, the benefits of sending an African into orbit reap effects such as a significant return in investment for the space sector of the continent. Socially, cultural and national pride, international respect, and historical reverence are certainly guaranteed by this accomplishment. There is always a risk in human space flight, be it political or economic investment. There is the risk that the country would be scrutinized for looking to the stars instead of to their own conflict-riddled soil. There is the risk that if a mission fails, money will be wasted and lives needlessly lost. There is a risk that success in the sky will be short-lived, or that political corruption may collapse the foundations of this venture. However, where there is risk, there is also opportunity. There is an opportunity to create stronger diplomatic relationships with other space-interested nations who seek to invest in Africa as a launching point for their own expeditions. There is an opportunity to begin an economic and cultural legacy of African-based space exploration, a legacy that provides secure jobs and education to African citizens and invites international investment and interest. And of course, there is opportunity to put the first African astronaut into space. Conclusively, the quickest and most cost-efficient method to launch an African astronaut into space is by international collaboration on a lunar mission, a space station, or low-earth orbit. This, however, is a short-term solution. For a long-lasting investment into space, the true answer is to create a continental space agency for Africa that would permit its countries to embark on space-faring journeys at their own will. Reliance on foreign countries can solidify or promote diplomatic relations, but it will not improve the local situation in Africa. This requires the collaboration of involved African countries as well as a feasible economic plan to maintain such an organization. The ownership of African spaceports, with the provision of access to partnering countries, would give the continent leverage in international affairs, grant jobs to African citizens, and grant a prosperous stake in the future colonization and exploration of space.
4

Information requirements for function allocation during Mars mission exploration activities

Jordan R Hill (7861682) 05 December 2019 (has links)
The desire to send humans to Mars will require a change in the way that extravehicular activity (EVA) is performed; in-space crews (including those within a vehicle or habitat monitoring others conducting EVA) will need to be more autonomous and that will require them to monitor large amounts of information in order to ensure crew safety and mission success. The amount of information to perceive and process will overwhelm unassisted intra-vehicular (IV) crewmembers, meaning that automation will need to be developed to support these crews on Mars while EVA is performed (Mishkin, Lee, Korth, & LeBlanc, 2007). This dissertation seeks to identify the information requirements for the performance of scientific EVA and determine which information streams will need to be allocated to in-space crew and which are the most effective streams to automate. The first study uses Mars rover operations as a homology—as defined by von Bertalanffy (1968)—to human scientific exploration. Mars rover operations personnel were interviewed using a novel method to identify the information requirements to perform successful science on Mars, how that information is used, and the timescales on which those information streams operate. The identified information streams were then related to potential information streams relevant to human exploration in order to identify potential function allocation or automated system development areas. The second study focused on one identified mission-critical information stream for human space exploration: monitoring astronaut status physiologically. Heart rate, respiration rate, and heart rate variability measurements were recorded from participants as they performed field science tasks (potentially tasks that are similar to those that will be performed by astronauts on Mars). A statistical method was developed to analyze this data in order to determine whether or not physiological responses to different tasks were statistically different, and whether any of those differences followed consistent patterns. A potential method to automate the monitoring of physiological data was also described. The results of this work provide a more detailed outline of the information requirements for EVA on Mars and can be used as a starting point for others in the exploration community to further develop automation or function allocation to support astronauts as they explore Mars.
5

Operational scenarios optimization for resupply of crew and cargo of an International gateway Station located near the Earth-Moon-Lagrangian point-2 / Optimisation des scénarios opérationnels d’un véhicule de ravitaillement et de transport d'équipage pour la servitude d’une Station Spatiale située au point de Lagrange EML2

Lizy-Destrez, Stéphanie 15 December 2015 (has links)
Ce projet se place dans le contexte des futures missions habitées d’exploration du système solaire (avec un horizon de 2025), en respect de la feuille de route proposée par l’ISECG (International Space Exploration Coordination Group) [1]. Une nouvelle avancée serait de maintenir, à un des points de Lagrange du système Terre-Lune, en avant-poste, une station spatiale qui faciliterait l’accès vers les destinations telles que la Lune, Mars et les astéroïdes et permettrait de tester certaines technologies, notamment avant de les employer pour des missions plus lointaines. Un des principaux défis sera de maintenir en permanence et de garantir à bord la santé de l’équipage, à l’aide d’un centre médical (SMC) autonome arrimé à cette station. Se pose alors la problématique de la servitude d’une telle station, pendant la phase de déploiement (assemblage des différents modules constitutifs du centre médical) et la phase opérationnelle. Les enjeux résident, d’un point de vue global, dans la construction des scénarios opérationnels et, d’un point de vue local, la sélection de trajectoires, cherchant notamment à minimiser les incréments de vitesse (la dépense énergétique) et les temps de transport (sauvegarde des équipages). Quelles recommandations pourrait-on apporter en terme d’optimisation de trajectoire, satisfaisant des critères de dépense énergétique, durée de transport et sécurité ? Quels sont les verrous technologiques à lever pour permettre la réalisation d’une telle station spatiale? Quelles seraient les performances à viser pour les sous-systèmes critiques impliqués? Les résultats d’une telle étude permettraient d’ouvrir des perspectives de recherche et développement dans le domaine des vols habités, notamment dans le domaine du transport mais également dans l’optique d’une occupation de longue durée. / In the context of future human space exploration missions in the solar system (with an horizon of 2025) and according to the roadmap proposed by ISECG (International Space Exploration Coordination Group) [1], a new step could be to maintain as an outpost, at one of the libration points of the Earth-Moon system, a space station. This would ease access to far destinations as Moon, Mars and asteroids and would allow to test some innovative technologies, before employing them for far distant human missions. One of the main challenges will be to maintain permanently, and ensure on board crew health thanks to an autonomous space medical center docked to the proposed space station, as a Space haven. Then the main problem to solve is to manage the station servitude, during deployment (modules integration) and operational phase. Challenges lie, on a global point of view, in the design of the operational scenarios and, on a local point of view, in trajectories selection, so as to minimize velocity increments (energy consumption) and transportation duration (crew safety). Which recommendations could be found out as far as trajectories optimization is concerned, that would fulfill energy consumption, transportation duration and safety criterion? What would technological hurdles be to rise for the building of such Space haven? What would be performances to aim at for critical sub-systems? Expected results of this study could point out research and development perspectives for human spaceflight missions and above all, in transportation field for long lasting missions.Thus, the thesis project, presented here, aims at from global system life-cycle decomposition, to identify by phase operational scenario and optimize resupply vehicle mission. The main steps of this project consist in:- Bibliographical survey, that covers all involved disciplines like mission analysis (Astrodynamics, Orbital mechanics, Orthography, N-Body Problem, Rendezvous…), Applied Mathematics, Optimization, Systems Engineering….- Entire system life-cycle analysis, so as to establish the entire set of scenarios for deployment and operations (nominal cases, degraded cases, contingencies…) and for all trajectories legs (Low Earth Orbit, Transfer, Rendezvous, re-entry…)- Trade-off analysis for Space Station architecture- Modeling of the mission legs trajectories- Trajectories optimizationThree main scenarios have been selected from the results of the preliminary design of the Space Station, named THOR: the Space Station deployment, the resupply cargo missions and the crew transportation. The deep analysis of those three main steps sorted out the criticality of the rendezvous strategies in the vicinity of Lagrangian points. A special effort has been set on those approach maneuvers. The optimization of those rendezvous trajectories led to consolidate performances (in term of energy and duration) of the global transfer from the Earth to the Lagrangian point neighborhood and return. Finally, recommendations have been deduced that support the Lagrangian points importance for next steps of Human Spaceflight exploration of the Solar system.
6

Augmented Reality in Lunar Extravehicular Activities: A Comprehensive Evaluation of Industry Readiness, User Experience, and the Work Environment

Vishnuvardhan Selvakumar (17593110) 11 December 2023 (has links)
<p dir="ltr">This research explores the potential of AR for lunar missions via the xEMU spacesuit. A market analysis of commercial off-the-shelf AR devices identifies technological trends and constraints that inform the architectural decisions for AR integration with the xEMU. User evaluations in simulated work environments ensure lunar informatics align with crew needs. Drawing insights from human-in-the-loop testing of COTS AR devices, qualitative test results underscore the importance of display optimization, occlusion management, and environmental considerations for enhancing the AR experience during lunar EVAs. Grounded in a task analysis from JETT3 analog testing, crew workflows and communication dynamics are baselined, underscoring the vital role of communication and collaboration. Integrating AR into the EVA work environment holds the potential to streamline decision-making, improve navigation, and enhance overall efficiency, but may come with unintended operational consequences. The human-centered approach prioritizes crew involvement, ensuring that technology remains a facilitator rather than an encumbering element in lunar exploration. The study's significance lies in advancing AR technology for lunar EVAs, guiding hardware design, and enabling seamless integration into the EVA work environment. AR holds promise in reshaping the human-technology relationship, empowering crew members, maximizing science output, and contributing to the next chapter in lunar exploration.</p>
7

A Study of International Space Station Ground/Crew Communication Methods with Applications to Human Moon and Mars Missions

Esper, Jennifer Eileen 05 May 2007 (has links)
The International Space Station utilizes many different forms of written and verbal communication between the flight crews and ground control personnel. This study analyzes the historical use of three regular communication methods, Daily Planning Conferences, Weekly Planning Conferences and written Daily Summaries, as well as specific, science and internal maintenance events for characteristics and perceived effectiveness across eight expeditions (4 ? 11). The results are recommendations for the continued use of, or substitution for, these methods for future long-duration human space missions, specifically to the Moon and to Mars. General conclusions are that most of the conference content could have been relayed through written/electronic methods, and that the Daily Summaries are considered succinct and effective as a communication cornerstone. Conclusions formed from the study of individual events involved the importance of well-written crew procedures, the effective stowage and retrieval of necessary materials and the selection of well-defined science experiments.

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