subject:(LEO Low Earth Orbit)

1. Gurgenburan, Goksel. A Methodology to Repair or Deorbit LEO Satellite Constellations.

Degree: MS, Mechanical & Aerospace Engineering, 2011, Old Dominion University

URL: https://digitalcommons.odu.edu/mae_etds/318

► In this thesis, mitigation of space debris is addressed by examining an approach for repair or de-orbit of a specific population of non-functional Low… (more)

Subjects/Keywords: Low Earth Orbit satellites; LEO; Clohessy-Wiltshire equations; Orbital mechanics; Aerospace Engineering

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APA (6^th Edition):

Gurgenburan, G. (2011). A Methodology to Repair or Deorbit LEO Satellite Constellations. (Thesis). Old Dominion University. Retrieved from https://digitalcommons.odu.edu/mae_etds/318

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Gurgenburan, Goksel. “A Methodology to Repair or Deorbit LEO Satellite Constellations.” 2011. Thesis, Old Dominion University. Accessed March 04, 2021. https://digitalcommons.odu.edu/mae_etds/318.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Gurgenburan, Goksel. “A Methodology to Repair or Deorbit LEO Satellite Constellations.” 2011. Web. 04 Mar 2021.

Vancouver:

Gurgenburan G. A Methodology to Repair or Deorbit LEO Satellite Constellations. [Internet] [Thesis]. Old Dominion University; 2011. [cited 2021 Mar 04]. Available from: https://digitalcommons.odu.edu/mae_etds/318.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Gurgenburan G. A Methodology to Repair or Deorbit LEO Satellite Constellations. [Thesis]. Old Dominion University; 2011. Available from: https://digitalcommons.odu.edu/mae_etds/318

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

KTH

2. Staniscia, Giada. Development of a Low Earth Orbit Mission Preliminary Analysis Tool.

Degree: Space Technology, 2019, KTH

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265613

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The objective of this project is the development of a mission analysis tool for the nanosatellite company GomSpace Sweden. Although there are many existing software, they… (more)

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The objective of this project is the development of a mission analysis tool for the nanosatellite company GomSpace Sweden. Although there are many existing software, they can be quite complicated and time consuming to use. The goal of this work is to build a simple app to be used at the earliest stages of space missions in order to obtain key figures of merit quickly and easily. By comparing results, assessing the feasibility of customer needs, analysing how various parameters affect each other, it enables immediate deeper understanding of the implications of the main design decisions that are taken at the very beginning of a mission. The tool shall aid the system engineering process of determining orbit manoeuvre capability specifically for CubeSat electric propulsion systems taking into account the most relevant factors for perturbation in Low Earth Orbit (LEO), i.e. atmospheric drag and Earth’s oblateness effects. The manoeuvres investigated are: orbit raising from an insert orbit to an operating orbit, orbit maintenance, deorbiting within the space debris mitigation guidelines and collision avoidance within the 12 to 24 hours that the system has to react. The manoeuvres cost is assessed in terms of Delta v requirements, propellant mass and transfer times. The tool was developed with MATLAB and packaged as a standalone Linux application.

Målet med detta examensarbete var att utveckla ett verktyg för missionsanalys för nanosatellitföretaget GomSpace Sweden. Det finns många andra mjukvaror för att nå samma mål men de är ofta komplicerade och tidskrävande. Det specifika målet var således att skapa en enkel applikation som kan användas i de tidiga stegen av utformning av rymduppdrag för att snabbt och enkelt få fram viktiga parametrar. Genom att jämföra resultat, uppskatta genomförbarheten av kundbehov och analysera hur olika parametrar påverkar varandra kan omedelbar förståelse erhållas rörande påverkan av designbeslut som tas i början av rymduppdragen. Verktyget ska stödja systemingenjörsprocessen genom att uppskatta banförflyttningskapacitet för elektriska framdrivningssystem för CubeSats och ta i beaktande de mest relevanta faktorerna gällande störningar i låg jordbana (LEO), i.e. atmosfäriskt motstånd och effekterna av Jordens form. De undersökta manövrarna är: banhöjning från injektionsbana till operationell bana, banunderhåll, bansänkning som följer riktlinjerna för rymdskrot och kollisionsundvikande inom de 12 till 24 timmar som systemet har på sig att reagera. Kostnaden för manövrarna är uppskattade genom DeltaV-krav, massan av bränslet och förflyttningstider. Verktyget utvecklades med MATLAB och paketerades som en fristående applikation i Linux.

Subjects/Keywords: Mission analysis; CubeSat; Propulsion; Low Earth Orbit (LEO); Perturbations; Atmospheric drag; Earth oblateness.; Aerospace Engineering; Rymd- och flygteknik

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APA (6^th Edition):

Staniscia, G. (2019). Development of a Low Earth Orbit Mission Preliminary Analysis Tool. (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265613

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Staniscia, Giada. “Development of a Low Earth Orbit Mission Preliminary Analysis Tool.” 2019. Thesis, KTH. Accessed March 04, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265613.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Staniscia, Giada. “Development of a Low Earth Orbit Mission Preliminary Analysis Tool.” 2019. Web. 04 Mar 2021.

Vancouver:

Staniscia G. Development of a Low Earth Orbit Mission Preliminary Analysis Tool. [Internet] [Thesis]. KTH; 2019. [cited 2021 Mar 04]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265613.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Staniscia G. Development of a Low Earth Orbit Mission Preliminary Analysis Tool. [Thesis]. KTH; 2019. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-265613

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Université de Grenoble

3. Castaings, Thibaut. Catalogage de petits débris spatiaux en orbite basse par observations radars isolées : Cataloguing small LEO objects using a narrow-fence type radar.

Degree: Docteur es, Signal, image, paroles, télécoms, 2014, Université de Grenoble

URL: http://www.theses.fr/2014GRENT001

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Les débris spatiaux sont devenus une menace considérable pour la viabilité des satellites opérationnels en orbite basse. Afin de pouvoir éviter des collisions accidentelles, des… (more)

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Les débris spatiaux sont devenus une menace considérable pour la viabilité des satellites opérationnels en orbite basse. Afin de pouvoir éviter des collisions accidentelles, des systèmes de surveillance de l'espace existent mais sont limités en performances de détection pour les objets de petite taille (diamètre inférieur à 10cm), ce qui pousse à l'étude de nouvelles solutions. Cette thèse a pour objectif d'appuyer la faisabilité d'un système radar au sol utilisant un champ de veille étroit pour le catalogage de petits débris en orbite basse. Un tel système fournirait en effet des observations dites « isolées », c'est-à-dire qu'une orbite n'est pas immédiatement déductible de chacune d'entre elles. Le grand nombre combinaisons nécessaires est alors prohibitif en termes de temps de calcul pour la résolution de ce problème de pistage. Nous proposons dans ces travaux une nouvelle méthode pour initialiser les pistes, c'est-à-dire associer des observations isolées avec une faible ambiguïté et en déduire des orbites précises. Les pistes ainsi obtenues sont combinées et filtrées grâce à un algorithme de pistage multicible que nous avons adapté aux particularités du problème. Avec un taux de couverture de plus de 80 % obtenu en temps réel sur 3 jours pour des scénarios de 500 à 800 objets en plus d'un fort taux de fausses alarmes, les performances de la méthode proposée tendent à prouver la faisabilité du système envisagé. Afin d'extrapoler les résultats obtenus à de plus fortes densités d'observations, nous proposons un modèle de complexité combinatoire calibré sur les performances de l'algorithme aux faibles densités. L'apport d'un second capteur identique est également étudié et met en évidence un point de compromis entre réactivité et complexité combinatoire, ce qui offre un degré de liberté supplémentaire dans la conception d'un tel système.

Space debris have become a significant threat to the viability of operational satellites in Low-Earth-Orbit. In order to avoid accidental collisions, space surveillance systems exist but their detection performance is limited for the small debris (less than 10cm). New solutions are then at study. This thesis aims at supporting the feasibility of a ground-based radar sensor with a narrow-fence type field of regard for the cataloging of the small space debris. Such a system would produce “isolated” observations, that is to say that an orbit is not directly available from each one of them. The large number of potential combinations is then computationally prohibitive for solving this tracking problem. In this work, we propose a new method for track initiation, i.e. associating isolated observations with little ambiguity and deduce accurate orbits. The obtained set of tracks are combined and filtered using an multitarget tracking algorithm that we have adapted to the peculiarities of the problem. With a coverage rate of more than 80% in real-time on 3 days for 500 to 800-objects scenarios in addition of a high false alarm rate, the performance of the proposed method supports the…

Advisors/Committee Members: Rombaut, Michèle (thesis director), Pannetier, Benjamin (thesis director).

Subjects/Keywords: Pistage; Low earth orbit; Apprentissage statistique; MHT; Catalogue; Observabilité; Tracking; LEO; Machine Learning; MHT; Catalog; Observability; 620

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Castaings, T. (2014). Catalogage de petits débris spatiaux en orbite basse par observations radars isolées : Cataloguing small LEO objects using a narrow-fence type radar. (Doctoral Dissertation). Université de Grenoble. Retrieved from http://www.theses.fr/2014GRENT001

Chicago Manual of Style (16^th Edition):

Castaings, Thibaut. “Catalogage de petits débris spatiaux en orbite basse par observations radars isolées : Cataloguing small LEO objects using a narrow-fence type radar.” 2014. Doctoral Dissertation, Université de Grenoble. Accessed March 04, 2021. http://www.theses.fr/2014GRENT001.

MLA Handbook (7^th Edition):

Castaings, Thibaut. “Catalogage de petits débris spatiaux en orbite basse par observations radars isolées : Cataloguing small LEO objects using a narrow-fence type radar.” 2014. Web. 04 Mar 2021.

Vancouver:

Castaings T. Catalogage de petits débris spatiaux en orbite basse par observations radars isolées : Cataloguing small LEO objects using a narrow-fence type radar. [Internet] [Doctoral dissertation]. Université de Grenoble; 2014. [cited 2021 Mar 04]. Available from: http://www.theses.fr/2014GRENT001.

Council of Science Editors:

Castaings T. Catalogage de petits débris spatiaux en orbite basse par observations radars isolées : Cataloguing small LEO objects using a narrow-fence type radar. [Doctoral Dissertation]. Université de Grenoble; 2014. Available from: http://www.theses.fr/2014GRENT001

4. Coelho, Milca de Freitas. Estimação robusta de órbitas de Satélites LEO baseada na fusão multissensorial de dados.

Degree: 2014, RCAAP

URL: https://www.rcaap.pt/detail.jsp?id=oai:ubibliorum.ubi.pt:10400.6/5271

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A estimação de órbitas é um processo delicado, pois a extração incorreta do vetor de estado do satélite origina uma análise errada da sua trajetória,… (more)

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A estimação de órbitas é um processo delicado, pois a extração incorreta do vetor de estado do satélite origina uma análise errada da sua trajetória, induzindo a que haja uma remodelação desnecessária da sua posição. Desta forma, tanto a fonte utilizada para obter as medições como todo o processo de estimação são de grande importância. Neste trabalho, determina-se a órbita de um satélite LEO (Low Earth Orbit) com base num conjunto de medições efetuadas por dois satélites geostacionários. Este estudo foi realizado com o intuito de contribuir para um melhoramento nos processos atualmente utilizados na determinação de órbitas de satélites artificiais. Tendo consciência da presença inevitável de incertezas, ruídos e erros, computacionais e físicos, provenientes tanto dos modelos matemáticos como dos próprios instrumentos utilizados, todas as medições realizadas pelos satélites geostacionários foram filtradas. Devido á dinâmica não linear do sistema, o filtro aplicado foi o de Kalman estendido. Após a implementação do filtro, verificou-se que o ruído existente é praticamente eliminado. Assim, os resultados obtidos são fiáveis e satisfatórios, sendo possível manter a estabilidade e controlo da órbita LEO com medições efetuadas por satélites geostacionários.

Orbit estimation is a delicate process, since the incorrect extraction of the satellite state vector provides a wrong analysis of its trajectory, inducing to a pointless remodeling of its position. For that reason, the source used for the measurements and the entire estimation process are very important. In this work, the orbit of a LEO satellite (Low Earth Orbit) is determined based on a set of measurements performed by two geostationary satellites. This study was realized with the intention of contributing to an improvement on the orbit determination problem. Towards the unavoidable presence of uncertainties, noise and errors, both from the mathematical models as well in the instruments used, all measurements made by geostationary satellites were filtered. Due to non-linear dynamics of the system, the filter applied was the extended Kalman filter. After the implementation of the filter, the noise is virtually eliminated. So, the results obtained are reliable and satisfactory, being possible to maintain the stability and control of the LEO’s orbit with these measurements.

Advisors/Committee Members: Bousson, Kouamana.

Subjects/Keywords: Determinação de Órbitas; Dinâmica Não Linear; Filtro de Kalman Estendido; Low Earth Orbit; Satélite Leo; Satélites Geostacionários; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Coelho, M. d. F. (2014). Estimação robusta de órbitas de Satélites LEO baseada na fusão multissensorial de dados. (Thesis). RCAAP. Retrieved from https://www.rcaap.pt/detail.jsp?id=oai:ubibliorum.ubi.pt:10400.6/5271

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Coelho, Milca de Freitas. “Estimação robusta de órbitas de Satélites LEO baseada na fusão multissensorial de dados.” 2014. Thesis, RCAAP. Accessed March 04, 2021. https://www.rcaap.pt/detail.jsp?id=oai:ubibliorum.ubi.pt:10400.6/5271.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Coelho, Milca de Freitas. “Estimação robusta de órbitas de Satélites LEO baseada na fusão multissensorial de dados.” 2014. Web. 04 Mar 2021.

Vancouver:

Coelho MdF. Estimação robusta de órbitas de Satélites LEO baseada na fusão multissensorial de dados. [Internet] [Thesis]. RCAAP; 2014. [cited 2021 Mar 04]. Available from: https://www.rcaap.pt/detail.jsp?id=oai:ubibliorum.ubi.pt:10400.6/5271.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Coelho MdF. Estimação robusta de órbitas de Satélites LEO baseada na fusão multissensorial de dados. [Thesis]. RCAAP; 2014. Available from: https://www.rcaap.pt/detail.jsp?id=oai:ubibliorum.ubi.pt:10400.6/5271

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

5. Fugett, Daniel A. Atomic Oxygen Considerations For LEO De-Orbit Trajectories Using Solar Sails.

Degree: MS, Aerospace Engineering, 2017, Cal Poly

URL: https://digitalcommons.calpoly.edu/theses/1756 ; 10.15368/theses.2017.47

► Solar sails have the potential to benefit many future space exploration missions, but they lack the heritage required for present-day use. To grow confidence… (more)

▼ Solar sails have the potential to benefit many future space exploration missions, but they lack the heritage required for present-day use. To grow confidence in solar sail technology, they could be deployed on LEO satellites higher than 600 km to help de-orbit the satellite within 25 years upon mission termination. To determine how atomic oxygen would affect the solar sail, material from Lightsail-2 was tested in a thermal-energy, isotropic, atomic oxygen vacuum chamber based in the space environments laboratory in California Polytechnic State University. The sail material, aluminized Mylar, was tested for its survivability on both the coated and uncoated side, as well as tested for the optical degradation of the coated side. The uncoated side was found to be completely eroded after a fluence of 2.27 x10²⁰ atoms/cm², or ~40 days in International Space Station orbit. The coated side experienced no mass loss, but signs of significant undercutting were found with a fluence of 1.19 x10²¹ atoms/cm², or ~200 days at station orbit. The stitches present on the coated side, meant to prevent tear propagation, eroded before the sample experienced a fluence of 4.13 x10²⁰ atoms/cm², or ~70 days at station orbit. The average total reflectivity of the material dropped by ~5% after atomic oxygen exposure, however no correlation with fluence was found. Average specular reflectivity remained unchanged after atomic oxygen exposure. The reflectivity results were impacted by wrinkling in the material, which was found to have a much larger impact than atomic oxygen exposure. These results were paired with an optimal de-orbit trajectory algorithm, developed in this thesis, to determine how atomic oxygen would affect a solar sail deployed to de-orbit an 800 km LEO satellite with a ballistic coefficient of 0.1. Using a simplified 2D orbit case, it was found that the satellite would de-orbit within 12-18 years, depending primarily on the solar activity level. The measured worst-case for optical degradation increased de-orbit time by ~6 months. Additionally, assuming that the sail material was perfectly reflecting decreased de-orbit time by 2-4 years. The amount of fluence required to erode the uncoated Mylar, and the amount required to erode the stitches, were both reached long before the satellite re-entered. It is therefore recommended that the solar sail minimize uncoated side exposure to atomic oxygen, and a more atomic oxygen-resistant stitch material be found. The fluence required to produce significant material undercutting was reached only once the satellite’s orbit had degraded to below 400 km. But the undercutting was observed to structurally compromise the material; thus, future LEO solar sail mission designers must take care when balancing added performance with higher failure risk when considering the tension in the deployed sail. Advisors/Committee Members: Kira Jorgensen Abercromby.

Subjects/Keywords: atomic oxygen; solar sails; low earth orbit; LEO; AO; Other Aerospace Engineering

…solar sails to help de-orbit LEO objects. NASA and ESA have a requirement that every satellite… …implement solar sails to help de-orbit LEO satellites. The Gossamer De-Orbit Sail has been… …solar sails are to be used in LEO de-orbit missions, this gap in atomic oxygen knowledge must… …that can be applied to a LEO satellite at 800 km in altitude to help the satellite de-orbit… …48 Table 7. Survival Time of Uncoated Side of Solar Sail at Station Orbit…

10 more images…

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APA (6^th Edition):

Fugett, D. A. (2017). Atomic Oxygen Considerations For LEO De-Orbit Trajectories Using Solar Sails. (Masters Thesis). Cal Poly. Retrieved from https://digitalcommons.calpoly.edu/theses/1756 ; 10.15368/theses.2017.47

Chicago Manual of Style (16^th Edition):

Fugett, Daniel A. “Atomic Oxygen Considerations For LEO De-Orbit Trajectories Using Solar Sails.” 2017. Masters Thesis, Cal Poly. Accessed March 04, 2021. https://digitalcommons.calpoly.edu/theses/1756 ; 10.15368/theses.2017.47.

MLA Handbook (7^th Edition):

Fugett, Daniel A. “Atomic Oxygen Considerations For LEO De-Orbit Trajectories Using Solar Sails.” 2017. Web. 04 Mar 2021.

Vancouver:

Fugett DA. Atomic Oxygen Considerations For LEO De-Orbit Trajectories Using Solar Sails. [Internet] [Masters thesis]. Cal Poly; 2017. [cited 2021 Mar 04]. Available from: https://digitalcommons.calpoly.edu/theses/1756 ; 10.15368/theses.2017.47.

Council of Science Editors:

Fugett DA. Atomic Oxygen Considerations For LEO De-Orbit Trajectories Using Solar Sails. [Masters Thesis]. Cal Poly; 2017. Available from: https://digitalcommons.calpoly.edu/theses/1756 ; 10.15368/theses.2017.47

North Carolina State University

6. Bjerkaas, James Kevin. Modeling Ground Sensor Acquisitions of Low Earth Orbit Objects.

Degree: MS, Operations Research, 2010, North Carolina State University

URL: http://www.lib.ncsu.edu/resolver/1840.16/6345

► The United States Strategic Command (STRATCOM) utilizes a sensor network to accomplish several of its missions. These missions include missile defense, missile warning, intelligence collection,… (more)

Subjects/Keywords: low earth orbit; simulation; space surveillance; phased array radars

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APA (6^th Edition):

Bjerkaas, J. K. (2010). Modeling Ground Sensor Acquisitions of Low Earth Orbit Objects. (Thesis). North Carolina State University. Retrieved from http://www.lib.ncsu.edu/resolver/1840.16/6345

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Bjerkaas, James Kevin. “Modeling Ground Sensor Acquisitions of Low Earth Orbit Objects.” 2010. Thesis, North Carolina State University. Accessed March 04, 2021. http://www.lib.ncsu.edu/resolver/1840.16/6345.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Bjerkaas, James Kevin. “Modeling Ground Sensor Acquisitions of Low Earth Orbit Objects.” 2010. Web. 04 Mar 2021.

Vancouver:

Bjerkaas JK. Modeling Ground Sensor Acquisitions of Low Earth Orbit Objects. [Internet] [Thesis]. North Carolina State University; 2010. [cited 2021 Mar 04]. Available from: http://www.lib.ncsu.edu/resolver/1840.16/6345.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bjerkaas JK. Modeling Ground Sensor Acquisitions of Low Earth Orbit Objects. [Thesis]. North Carolina State University; 2010. Available from: http://www.lib.ncsu.edu/resolver/1840.16/6345

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Virginia Tech

7. Dhar, Saurav. Ionospheric Simulator (IonSim): Simulating Ionospheric conditions in a vacuum chamber.

Degree: MS, Electrical Engineering, 2013, Virginia Tech

URL: http://hdl.handle.net/10919/23931

► Understanding and improving ionospheric models is important for both military and civilian purposes. This understanding improves prediction of radio propagation used for communication and GPS… (more)

Subjects/Keywords: Ion source; Ionosphere; vacuum chamber; Low Earth Orbit

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APA (6^th Edition):

Dhar, S. (2013). Ionospheric Simulator (IonSim): Simulating Ionospheric conditions in a vacuum chamber. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/23931

Chicago Manual of Style (16^th Edition):

Dhar, Saurav. “Ionospheric Simulator (IonSim): Simulating Ionospheric conditions in a vacuum chamber.” 2013. Masters Thesis, Virginia Tech. Accessed March 04, 2021. http://hdl.handle.net/10919/23931.

MLA Handbook (7^th Edition):

Dhar, Saurav. “Ionospheric Simulator (IonSim): Simulating Ionospheric conditions in a vacuum chamber.” 2013. Web. 04 Mar 2021.

Vancouver:

Dhar S. Ionospheric Simulator (IonSim): Simulating Ionospheric conditions in a vacuum chamber. [Internet] [Masters thesis]. Virginia Tech; 2013. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/10919/23931.

Council of Science Editors:

Dhar S. Ionospheric Simulator (IonSim): Simulating Ionospheric conditions in a vacuum chamber. [Masters Thesis]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/23931

University of Illinois – Urbana-Champaign

8. Ghosh, Alexander. Multi-CubeSat mission planning enabled through parallel computing.

Degree: PhD, 4048, 2013, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/45554

► Small CubeSat-class satellites are opening up new avenues for science and technology development within the space industry. What was once a purely educational tool has… (more)

▼ Small CubeSat-class satellites are opening up new avenues for science and technology development within the space industry. What was once a purely educational tool has quickly become the newest international exploration platform for low earth orbit missions. These sub-10 kg satellites ride into space as tertiary payloads, kicked out of their launch vehicles after all other satellites have reached their target orbit, and are left to survive in whatever ride-share provided orbit they are deposited into. Due to their small mass and volume, it has been infeasible until very recently to put any form of on-board propulsion on these spacecraft without a significant sacrifice of the science objectives. Current research at the University of Illinois and other institutions will soon lead to the flight of CubeSat-class low thrust, low-power, yet low-specific impulse propellant systems. This technology should enable CubeSats to acquire new orbits from their launch positions, to rendezvous and dock together, or to reconfigure their constellations within orbit. Because of the atypical combination of low-thrust with high propellant mass consumption, a new toolset is needed to assist with planning of both single and cooperative multi-satellite missions. This work contributes a new framework for the calculation of high-fidelity trajectories in low Earth orbit. A shooting method is reformulated as a non-linear programming problem, and wrapped by a novel mesh refinement algorithm, which updates the time discretization based on a cumulative thrust density function. The states are propagated using a higher order explicit Dormand-Prince integrator with an error-adaptive step size. The necessary derivatives and Jacobian are developed in real time using algorithmic differentiation, which allows for significantly higher accuracy over traditional finite difference methods. This framework is tested against analytical methods developed by Wiesel for in-plane, and Edelbaum and Kechichian for out of plane, and is shown to match or surpass their results. This work further contributes to the field by developing an extended framework that allows the simultaneous integration of multiple satellites using parallel processing on a super computer, and lays out the necessary constraints to define cooperative intercept, rendezvous and orbit reconfiguration problems. Finally, this dissertation develops a new approach to parallel algorithmic differentiation, allowing the concurrent calculation of multiple derivatives in a user-transparent manner, simultaneously while propagating multiple satellites. This is accomplished by using a Cartesian processor grid and a new parallel communication scheme to maintain the most data locality per processor, enabling orders of magnitude speedup by comparison to both serial, and the previously developed parallel processing approach. This new parallel algorithmic differentiation technique is demonstrated with a series of test cases, developing cooperative maneuvers for from two to four satellites experiencing… Advisors/Committee Members: Coverstone, Victoria L. (advisor), Coverstone, Victoria L. (Committee Chair), Conway, Bruce A. (committee member), Burton, Rodney L. (committee member), Swenson, Gary R. (committee member).

Subjects/Keywords: satellite; trajectory; trajectory optimization; optimization; cubesat; picosatellite; earth orbit; Orbit; low thrust; low-thrust; automatic differentiation; algorithmic differentiation; parallel processing

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APA (6^th Edition):

Ghosh, A. (2013). Multi-CubeSat mission planning enabled through parallel computing. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/45554

Chicago Manual of Style (16^th Edition):

Ghosh, Alexander. “Multi-CubeSat mission planning enabled through parallel computing.” 2013. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed March 04, 2021. http://hdl.handle.net/2142/45554.

MLA Handbook (7^th Edition):

Ghosh, Alexander. “Multi-CubeSat mission planning enabled through parallel computing.” 2013. Web. 04 Mar 2021.

Vancouver:

Ghosh A. Multi-CubeSat mission planning enabled through parallel computing. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/2142/45554.

Council of Science Editors:

Ghosh A. Multi-CubeSat mission planning enabled through parallel computing. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/45554

University of Technology, Sydney

9. Aboutanios, Elias. Frequency estimation for low earth orbit satellites.

Degree: 2002, University of Technology, Sydney

URL: http://hdl.handle.net/10453/43211

► Low Earth Orbit (LEO) satellites have received increased attention in recent years. They have been proposed as a viable solution for remote sensing, telemedicine, weather… (more)

▼ Low Earth Orbit (LEO) satellites have received increased attention in recent years. They have been proposed as a viable solution for remote sensing, telemedicine, weather monitoring, search and rescue and communications to name a few applications. LEO satellites move with respect to an earth station. Thus, the station must be capable of tracking the satellite both spatially and in frequency. In addition, as the spectrum becomes more congested, links are being designed at higher frequencies such as Ka band. These frequencies experience larger attenuations and therefore the system must be capable of operating at low signal to noise ratios. In this dissertation we report on the research conducted on the following problems. Firstly, we study the estimation of the frequency of a sinusoid for the purpose of acquiring and tracking the frequency of the received signal. Secondly, we propose the use of the frequency measurements to assist the spatial tracking of the satellite. The highly dynamic environment of a LEO system, combined with the high Ka band frequencies result in large Doppler rates. This limits the available processing time and, consequently, the fundamental resolution of a frequency estimator. The frequency estimation strategy that is adopted in the thesis consists of a coarse estimator followed by a fine estimation stage. The coarse estimator is implemented using the maximum of the periodogram. The threshold effect is studied and the derivation of an approximate expression of the signal to noise ratio at which the threshold occurs is examined. The maximum of the periodogram produces a frequency estimate with an accuracy that is Ο(N⁻¹), where N is the number of data samples used in the FFT. The lower bound for the estimation of the frequency of a sinusoid, given by the Cramer-Rao bound (CRB), is Ο(N⁻³⁄²) . This motivates the use of a second stage in order to improve the estimation resolution. A family of new frequency estimation algorithms that interpolate on the fractional Fourier coefficients is proposed. The new estimators can be implemented iteratively to give a performance that is uniform in frequency. The iterative algorithms are analysed and their asymptotic properties derived. The asymptotic variance of the iterative estimators is only 1.0147 times the asymptotic CRB. Another method of refining the frequency estimate is the Dichotomous search of the periodogram peak. This is essentially a binary search algorithm. However, the estimator must be padded with zeroes in order to achieve a performance that is comparable to the CRB. An insight into this is offered and a modified form that does not require the zero-padding is proposed. The new algorithm is referred to as the modified dichotomous search. A new hybrid technique that combines the dichotomous search with an interpolation technique in order to improve its performance is also suggested. The second research mm was to study the possibility of applying the frequency measurements to obtain spatial tracking information. This is called the frequency…

Subjects/Keywords: Low Earth Orbit (LEO) satellites.; Earth station.; High Ka band frequencies.; Low signal to noise ratios.; Spatial tracking.; Large Doppler rates.; Frequency assisted spatial tracking (FAST) concept.; Extended Kalman Filter (EKF).

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Aboutanios, E. (2002). Frequency estimation for low earth orbit satellites. (Thesis). University of Technology, Sydney. Retrieved from http://hdl.handle.net/10453/43211

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Aboutanios, Elias. “Frequency estimation for low earth orbit satellites.” 2002. Thesis, University of Technology, Sydney. Accessed March 04, 2021. http://hdl.handle.net/10453/43211.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Aboutanios, Elias. “Frequency estimation for low earth orbit satellites.” 2002. Web. 04 Mar 2021.

Vancouver:

Aboutanios E. Frequency estimation for low earth orbit satellites. [Internet] [Thesis]. University of Technology, Sydney; 2002. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/10453/43211.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Aboutanios E. Frequency estimation for low earth orbit satellites. [Thesis]. University of Technology, Sydney; 2002. Available from: http://hdl.handle.net/10453/43211

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

10. Ramakrishnan S. Development of critical parameterEstimator models for space batteries;.

Degree: Development of critical parameterEstimator models for space batteries, 2014, Anna University

URL: http://shodhganga.inflibnet.ac.in/handle/10603/30141

►

In the space battery arena there is a continuous drive towards newlinedesigning and producing lighter more robust reliable longer lasting cycle newlinelife and calendar life… (more)

▼

In the space battery arena there is a continuous drive towards newlinedesigning and producing lighter more robust reliable longer lasting cycle newlinelife and calendar life higher energy density batteries with smart battery newlinemanagement system Power requirement and life time requirement of the newlinesatellites are also increasing Traditionally Nickel Cadmium and Nickel newlineHydrogen batteries were used in space applications Significant improvements newlinehave been made in NiCd and NiH2 batteries to meet the need and they have newlinereached their technological limit Cadmium has been the object of growing newlineconcern among environmentalists These trends dictate use of Lithiumion newlinebatteries which satisfy most of the space battery requirements including high newlineenergy density longer life low self discharge etc newlineTypical Low Earth Orbit LEO spacecrafts batteries have to newlineundergo 15 charge discharge cycles in a day The pattern will repeat year after newlineyear There will be roughly 5500 cycles in a year The life time of the newlinebatteries in LEO will be 5 to 8 years Since larger number of cycles involved newlinethe allowed Depth of Discharge DOD will be generally 205 Lower newlinethe DOD longer the cycle life The discharge will be for 35 minutes and the newlinecharge duration will be around 65 minutes In LEO orbits the batteries are newlineused continuously without rest newlineThough the number of charge discharge cycles is less in Geo newlinesynchronous orbit GEO the life time is 15 to 20 years There will be two newlineeclipse seasons in a year extending for 45 days each During solstices periods newlinethe battery is dormant Even during the 45 days eclipse the eclipse duration newlineincreases from 10 minutes to a maximum of 72 minutes and falls back again newlineIn a 15 year period the batteries will undergo a maximum of 1350 charge newlinedischarge cycles So we go for DOD of 60 to 80 in GEO In GEO newlinespacecrafts battery degrades both due to cycling as well as storage when the newlinebatteries are not at all used newline newline newline newline newline newline newline newline newline

appendix p239-240, reference p241-245.

Advisors/Committee Members: Ebenezer jeyakumar A.

Subjects/Keywords: Depth of Discharge; Geo synchronous orbit; Low Earth Orbit; Traditionally Nickel Cadmium and Nickel Hydrogen batterie

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

S, R. (2014). Development of critical parameterEstimator models for space batteries;. (Thesis). Anna University. Retrieved from http://shodhganga.inflibnet.ac.in/handle/10603/30141

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

S, Ramakrishnan. “Development of critical parameterEstimator models for space batteries;.” 2014. Thesis, Anna University. Accessed March 04, 2021. http://shodhganga.inflibnet.ac.in/handle/10603/30141.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

S, Ramakrishnan. “Development of critical parameterEstimator models for space batteries;.” 2014. Web. 04 Mar 2021.

Vancouver:

S R. Development of critical parameterEstimator models for space batteries;. [Internet] [Thesis]. Anna University; 2014. [cited 2021 Mar 04]. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/30141.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

S R. Development of critical parameterEstimator models for space batteries;. [Thesis]. Anna University; 2014. Available from: http://shodhganga.inflibnet.ac.in/handle/10603/30141

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

RMIT University

11. He, C. Precise thermospheric mass density modelling for orbit prediction of low earth orbiters.

Degree: 2019, RMIT University

URL: http://researchbank.rmit.edu.au/view/rmit:162808

► The steady increase in the number of space objects near the Earth has raised critical security concerns for the low Earth orbit (LEO) space environment… (more)

▼ The steady increase in the number of space objects near the Earth has raised critical security concerns for the low Earth orbit (LEO) space environment where most of the near-Earth satellites missions operate. Orbit prediction (OP) is the foundation of many space missions and applications in LEO, e.g., space situational awareness, re-entry prediction and debris removal. However, the precision of OP is limited due to the accuracy of thermospheric mass density (TMD) prediction. In the past few decades, more atmospheric data sets have been inferred from different techniques such as the Global Navigation Satellite System, satellite laser ranging and two-line-element catalogue. However, accurately predicting TMD is still a challenging task due to the limited knowledge of thermospheric dynamics and the lack of measurements with sufficient temporal and spatial resolution. In this research, a precise OP platform for the analysis and prediction of the orbital motion of satellite and and space debris is developed. It consists of various precise perturbation models of gravitational and non-gravitational forces. This includes the high-order Earth gravitational acceleration with the effect of solid and ocean tides, third-body perturbations from other celestial bodies in the solar system, the general relativity effects, aerodynamic acceleration, direct solar radiation pressure, and Earth's albedo and infrared radiation pressure. Coordinate transformation is established on the precise time systems and the measured Earth orientation parameters. The developed OP platform is validated against the historical precise orbits of LEO satellites. In order to evaluate the most representative classes of empirical TMD models, a comprehensive comparison of 12 models is performed. The vertical variability, horizontal scale and the capability to capture the physics-based features of the selected models are investigated. Various validations against the TMD estimated from on-board accelerometer measurements of the GRACE satellites have been conducted. The performance of these models in the OP of the GRACE-A satellite is assessed under different solar and geomagnetic conditions. Also discussed is the coupling effect between the TMD and ballistic coefficient that measures the impact of atmospheric friction on the space object. The impact of TMD variations on orbit dynamics of LEO objects is an important focus in this thesis, which has not been well-quantified in previous studies. Intra-annual, intra-diurnal and horizontal TMD variations are reproduced using the empirical model DTM-2013. Also evaluated are physics-based variations including the equatorial mass density anomaly (EMA) and midnight mass density maximum (MDM), which exhibit both temporal and spatial variations and are simulated by the Thermosphere Ionosphere Electrodynamics General Circulation Model. The analysis is based on the one-day OP simulation at 400 km. The result show that TMD variations have a dominant impact on the predicted orbits in the along-track direction.…

Subjects/Keywords: Fields of Research; Thermospheric Mass Density; Empirical Thermospheric Mass Density Model; Low Earth Orbit; Orbit Prediction; Artificial Neural Network

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

He, C. (2019). Precise thermospheric mass density modelling for orbit prediction of low earth orbiters. (Thesis). RMIT University. Retrieved from http://researchbank.rmit.edu.au/view/rmit:162808

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

He, C. “Precise thermospheric mass density modelling for orbit prediction of low earth orbiters.” 2019. Thesis, RMIT University. Accessed March 04, 2021. http://researchbank.rmit.edu.au/view/rmit:162808.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

He, C. “Precise thermospheric mass density modelling for orbit prediction of low earth orbiters.” 2019. Web. 04 Mar 2021.

Vancouver:

He C. Precise thermospheric mass density modelling for orbit prediction of low earth orbiters. [Internet] [Thesis]. RMIT University; 2019. [cited 2021 Mar 04]. Available from: http://researchbank.rmit.edu.au/view/rmit:162808.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

He C. Precise thermospheric mass density modelling for orbit prediction of low earth orbiters. [Thesis]. RMIT University; 2019. Available from: http://researchbank.rmit.edu.au/view/rmit:162808

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Manchester

12. Macario Rojas, Alejandro. DESIGN CONSIDERATIONS FOR LEO NANOSATELLITE PROPULSION TECHNOLOGIES.

Degree: 2018, University of Manchester

URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313667

► In recent years the space industry has seen significant growth in numbers of sub 10kg satellite platforms now known more broadly in the industry as… (more)

▼ In recent years the space industry has seen significant growth in numbers of sub 10kg satellite platforms now known more broadly in the industry as nanosatellites. Nanosatellites potential applicability is driven by flourishing technologies miniaturisation in the consumer electronics market and commercialisation of space. Currently nanosatellite mission operations are limited in both lifetime and manoeuvrability due to limitations in on board propulsion technologies. Further enhancement of mission operations relies on more effective integration of current reaction-mass-based propulsion technologies and further development of miniaturised propulsion systems. Paradoxically, the compact spacecraft size and mass that facilitate nanosatellite access to space is presently a drawback in terms of acceptable systems performance and propulsion systems capacity. Moreover characteristic power density and vulnerability to the space environment is already high in nanosatellites in contrast to major satellites, rendering the design, inclusion, and optimisation of propulsion technologies a challenging task. This thesis focuses on techniques to support mission planning and characterisation of propulsion technologies for nanosatellites. Acknowledging the outweighing significance of solar activity modulating space environment perturbations and particularly atmospheric drag, a robust solar forecast method is proposed to support lifetime estimations. Complementing the pivotal framework information for propulsion system design and management, the vulnerability to atmospheric drag is assessed to identify the profile of the current vaguely defined drag coefficient of standard nanosatellites. Finally, addressing a crucial task on emerging propulsion technologies for nanosatellite systems, a method to improve low thrust characterisation via in-orbit manoeuvres using standard elementary attitude determination resources is devised. The robust solar activity forecast is carried out using observed historic and reconstructed Sunâ€™s polar magnetic field, to define the initial state of an up-to-date solar magnetohydrodynamics computational model; the method successfully reproduces recent solar cycles activity, anticipating moderate-to-low activity during the next 25th cycle. The identification of the drag coefficient profile in standard nanosatellites is enabled by the statistical assessment of observed orbital decay through an iterative fitting process of propagated orbits; the profile is physically consistent and descriptive mostly in orbits below 350km during moderate-to-high solar activity. Finally, the devised thrust characterisation method exploits the regular geometry and mass distribution of standard nanosatellites to identify low thrust actuation via actuated body angular rotation rates in an intermediate axis spinner; precise computer simulations show that it is possible to improve low thrust estimations from weak and noisy sensor signals using the proposed method against typical methods using body angular acceleration. Advisors/Committee Members: Smith, Katharine.

Subjects/Keywords: Nanosatellite; Propulsion; Atmospheric interaction; Solar activity; Manoeuvre; Thrust characterisation; Low Earth Orbit

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Macario Rojas, A. (2018). DESIGN CONSIDERATIONS FOR LEO NANOSATELLITE PROPULSION TECHNOLOGIES. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313667

Chicago Manual of Style (16^th Edition):

Macario Rojas, Alejandro. “DESIGN CONSIDERATIONS FOR LEO NANOSATELLITE PROPULSION TECHNOLOGIES.” 2018. Doctoral Dissertation, University of Manchester. Accessed March 04, 2021. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313667.

MLA Handbook (7^th Edition):

Macario Rojas, Alejandro. “DESIGN CONSIDERATIONS FOR LEO NANOSATELLITE PROPULSION TECHNOLOGIES.” 2018. Web. 04 Mar 2021.

Vancouver:

Macario Rojas A. DESIGN CONSIDERATIONS FOR LEO NANOSATELLITE PROPULSION TECHNOLOGIES. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2021 Mar 04]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313667.

Council of Science Editors:

Macario Rojas A. DESIGN CONSIDERATIONS FOR LEO NANOSATELLITE PROPULSION TECHNOLOGIES. [Doctoral Dissertation]. University of Manchester; 2018. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313667

13. Macario Rojas, Alejandro. Design considerations for LEO nanosatellite propulsion technologies.

Degree: PhD, 2018, University of Manchester

URL: https://www.research.manchester.ac.uk/portal/en/theses/design-considerations-for-leo-nanosatellite-propulsion-technologies(b5c1458b-b026-462b-b220-0420d00e564b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.740391

► In recent years the space industry has seen significant growth in numbers of sub 10kg satellite platforms now known more broadly in the industry as… (more)

▼ In recent years the space industry has seen significant growth in numbers of sub 10kg satellite platforms now known more broadly in the industry as nanosatellites. Nanosatellites potential applicability is driven by flourishing technologies miniaturisation in the consumer electronics market and commercialisation of space. Currently nanosatellite mission operations are limited in both lifetime and manoeuvrability due to limitations in on board propulsion technologies. Further enhancement of mission operations relies on more effective integration of current reaction-mass-based propulsion technologies and further development of miniaturised propulsion systems. Paradoxically, the compact spacecraft size and mass that facilitate nanosatellite access to space is presently a drawback in terms of acceptable systems performance and propulsion systems capacity. Moreover characteristic power density and vulnerability to the space environment is already high in nanosatellites in contrast to major satellites, rendering the design, inclusion, and optimisation of propulsion technologies a challenging task. This thesis focuses on techniques to support mission planning and characterisation of propulsion technologies for nanosatellites. Acknowledging the outweighing significance of solar activity modulating space environment perturbations and particularly atmospheric drag, a robust solar forecast method is proposed to support lifetime estimations. Complementing the pivotal framework information for propulsion system design and management, the vulnerability to atmospheric drag is assessed to identify the profile of the current vaguely defined drag coefficient of standard nanosatellites. Finally, addressing a crucial task on emerging propulsion technologies for nanosatellite systems, a method to improve low thrust characterisation via in-orbit manoeuvres using standard elementary attitude determination resources is devised. The robust solar activity forecast is carried out using observed historic and reconstructed Sunâs polar magnetic field, to define the initial state of an up-to-date solar magnetohydrodynamics computational model; the method successfully reproduces recent solar cycles activity, anticipating moderate-to-low activity during the next 25th cycle. The identification of the drag coefficient profile in standard nanosatellites is enabled by the statistical assessment of observed orbital decay through an iterative fitting process of propagated orbits; the profile is physically consistent and descriptive mostly in orbits below 350km during moderate-to-high solar activity. Finally, the devised thrust characterisation method exploits the regular geometry and mass distribution of standard nanosatellites to identify low thrust actuation via actuated body angular rotation rates in an intermediate axis spinner; precise computer simulations show that it is possible to improve low thrust estimations from weak and noisy sensor signals using the proposed method against typical methods using body angular acceleration.

Subjects/Keywords: 620; Nanosatellite; Propulsion; Atmospheric interaction; Solar activity; Manoeuvre; Thrust characterisation; Low Earth Orbit

10 more images…

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Macario Rojas, A. (2018). Design considerations for LEO nanosatellite propulsion technologies. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/design-considerations-for-leo-nanosatellite-propulsion-technologies(b5c1458b-b026-462b-b220-0420d00e564b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.740391

Chicago Manual of Style (16^th Edition):

Macario Rojas, Alejandro. “Design considerations for LEO nanosatellite propulsion technologies.” 2018. Doctoral Dissertation, University of Manchester. Accessed March 04, 2021. https://www.research.manchester.ac.uk/portal/en/theses/design-considerations-for-leo-nanosatellite-propulsion-technologies(b5c1458b-b026-462b-b220-0420d00e564b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.740391.

MLA Handbook (7^th Edition):

Macario Rojas, Alejandro. “Design considerations for LEO nanosatellite propulsion technologies.” 2018. Web. 04 Mar 2021.

Vancouver:

Macario Rojas A. Design considerations for LEO nanosatellite propulsion technologies. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2021 Mar 04]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/design-considerations-for-leo-nanosatellite-propulsion-technologies(b5c1458b-b026-462b-b220-0420d00e564b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.740391.

Council of Science Editors:

Macario Rojas A. Design considerations for LEO nanosatellite propulsion technologies. [Doctoral Dissertation]. University of Manchester; 2018. Available from: https://www.research.manchester.ac.uk/portal/en/theses/design-considerations-for-leo-nanosatellite-propulsion-technologies(b5c1458b-b026-462b-b220-0420d00e564b).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.740391

University of Surrey

14. Sun, Wei. Improving Low Earth Orbit digital communications by optimising CPFSK/MSK modulations in single band-limited UHF channels using DSP techniques on-board microsatellites.

Degree: PhD, 1995, University of Surrey

URL: http://epubs.surrey.ac.uk/856640/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308475

► There is growing interest in networks of small satellites in Low Earth Orbit (LEO) to provide a variety of communications services in conjunction with very… (more)

▼ There is growing interest in networks of small satellites in Low Earth Orbit (LEO) to provide a variety of communications services in conjunction with very small terminals. Communications satellites in LEO offer certain potential advantages when compared with conventional geostationary satellite communications systems, but LEO systems exhibit very different and demanding characteristics. A search of the literature has shown that the practical characteristics of the LEO VHF/UHF communications environment are poorly understood and thus optimised communications techniques have not yet been developed for these new services. This research programme investigates communications techniques suitable for the 'little-LEO' class of small (50kg) low-cost ‘microsatellites’ which provide non-real-time (store-&-forward) narrow-band digital communications services at VHF/UHF. Specifically, the study aims to improve the communications throughput achievable to-and-from the microsatellite, as it transits the groundstation horizon, by optimising the constant-envelope CPFSK/MSK modulation schemes that are imposed by the practical constraints dictated by the use of the microsatellite's non-linear RF systems. In order to provide a highly flexible in-orbit research test-bed, a Digital Signal Processing Experiment (DSPE) payload was designed, built and incorporated into two LEO microsatellites (KITSAT-1 & PoSAT-1) during the course of this study. The PoSAT-1 DSPE payload was first used to investigate and improve the current non-coherent CPFSK communications system through the design and implementation of Nyquist pulse shaping and equalisation filters using a time-domain waveform forcing technique. The use of coherent MSK was then proposed in order to take advantage of the potential 3dB improvement in link BER performance achievable when compared with non-coherent. CPFSK techniques. Coherent MSK, however, has not yet been employed in LEO systems because of the difficulty of practical implementation and the sensitivity of classical (de Buda) coherent demodulators to the effects typical of the LEO communications environment. To overcome these effects, a novel implementation of the robust ‘Hodgart-Massey’ coherent MSK demodulator/decoder was developed and compared rigorously with the ‘de Buda’ demodulator under typical LEO conditions through a sequence of computer simulations. These showed that synchronisation problems cause the main difficulty in the demodulation of coherent MSK. Comprehensive laboratory bench tests of a DSP implementation of the ‘Hodgart-Massey’ coherent MSK demodulator/decoder were carried out and were able to quantify a practical 2dB (Eb/No) improvement compared with noncoherent CPFSK whilst also exhibiting considerable tolerance to both frequency and amplitude variations. In-orbit FM (remote) channel measurements and equalisation using the DSPE identified a previously unknown and severe non-linearity in the PoSAT-1 RF modulator, however the critical synchronisation characteristics of the coherent MSK demodulator/decoder were…

Subjects/Keywords: 621.382; Low earth orbit satellite networks

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sun, W. (1995). Improving Low Earth Orbit digital communications by optimising CPFSK/MSK modulations in single band-limited UHF channels using DSP techniques on-board microsatellites. (Doctoral Dissertation). University of Surrey. Retrieved from http://epubs.surrey.ac.uk/856640/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308475

Chicago Manual of Style (16^th Edition):

Sun, Wei. “Improving Low Earth Orbit digital communications by optimising CPFSK/MSK modulations in single band-limited UHF channels using DSP techniques on-board microsatellites.” 1995. Doctoral Dissertation, University of Surrey. Accessed March 04, 2021. http://epubs.surrey.ac.uk/856640/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308475.

MLA Handbook (7^th Edition):

Sun, Wei. “Improving Low Earth Orbit digital communications by optimising CPFSK/MSK modulations in single band-limited UHF channels using DSP techniques on-board microsatellites.” 1995. Web. 04 Mar 2021.

Vancouver:

Sun W. Improving Low Earth Orbit digital communications by optimising CPFSK/MSK modulations in single band-limited UHF channels using DSP techniques on-board microsatellites. [Internet] [Doctoral dissertation]. University of Surrey; 1995. [cited 2021 Mar 04]. Available from: http://epubs.surrey.ac.uk/856640/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308475.

Council of Science Editors:

Sun W. Improving Low Earth Orbit digital communications by optimising CPFSK/MSK modulations in single band-limited UHF channels using DSP techniques on-board microsatellites. [Doctoral Dissertation]. University of Surrey; 1995. Available from: http://epubs.surrey.ac.uk/856640/ ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308475

University of Colorado

15. Kampmeier, Jennifer Lauren. Continuous Solar Observation from Low Earth Orbit with a Two-Cubesat Constellation.

Degree: MS, 2018, University of Colorado

URL: https://scholar.colorado.edu/asen_gradetds/204

► The goal of this work is to assess the feasibility of using a two-CubeSat constellation to make continuous solar science measurements from low Earth orbit.… (more)

Subjects/Keywords: constellation; cubesat; differential drag; low earth orbit; mission design; solar science; Aerospace Engineering; Atmospheric Sciences

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Kampmeier, J. L. (2018). Continuous Solar Observation from Low Earth Orbit with a Two-Cubesat Constellation. (Masters Thesis). University of Colorado. Retrieved from https://scholar.colorado.edu/asen_gradetds/204

Chicago Manual of Style (16^th Edition):

Kampmeier, Jennifer Lauren. “Continuous Solar Observation from Low Earth Orbit with a Two-Cubesat Constellation.” 2018. Masters Thesis, University of Colorado. Accessed March 04, 2021. https://scholar.colorado.edu/asen_gradetds/204.

MLA Handbook (7^th Edition):

Kampmeier, Jennifer Lauren. “Continuous Solar Observation from Low Earth Orbit with a Two-Cubesat Constellation.” 2018. Web. 04 Mar 2021.

Vancouver:

Kampmeier JL. Continuous Solar Observation from Low Earth Orbit with a Two-Cubesat Constellation. [Internet] [Masters thesis]. University of Colorado; 2018. [cited 2021 Mar 04]. Available from: https://scholar.colorado.edu/asen_gradetds/204.

Council of Science Editors:

Kampmeier JL. Continuous Solar Observation from Low Earth Orbit with a Two-Cubesat Constellation. [Masters Thesis]. University of Colorado; 2018. Available from: https://scholar.colorado.edu/asen_gradetds/204

University of Surrey

16. Paffett, John. VHF band interference measurement, analysis and avoidance.

Degree: PhD, 2000, University of Surrey

URL: http://epubs.surrey.ac.uk/2105/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322464

Subjects/Keywords: 621.382; Satellites; Low earth orbit satellite

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APA (6^th Edition):

Paffett, J. (2000). VHF band interference measurement, analysis and avoidance. (Doctoral Dissertation). University of Surrey. Retrieved from http://epubs.surrey.ac.uk/2105/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322464

Chicago Manual of Style (16^th Edition):

Paffett, John. “VHF band interference measurement, analysis and avoidance.” 2000. Doctoral Dissertation, University of Surrey. Accessed March 04, 2021. http://epubs.surrey.ac.uk/2105/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322464.

MLA Handbook (7^th Edition):

Paffett, John. “VHF band interference measurement, analysis and avoidance.” 2000. Web. 04 Mar 2021.

Vancouver:

Paffett J. VHF band interference measurement, analysis and avoidance. [Internet] [Doctoral dissertation]. University of Surrey; 2000. [cited 2021 Mar 04]. Available from: http://epubs.surrey.ac.uk/2105/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322464.

Council of Science Editors:

Paffett J. VHF band interference measurement, analysis and avoidance. [Doctoral Dissertation]. University of Surrey; 2000. Available from: http://epubs.surrey.ac.uk/2105/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322464

17. Hawe, Benjamin. Analysis of Passive Attitude Stabilisation and Deorbiting of Satellites in Low Earth Orbit.

Degree: Electrical and Space Engineering, 2016, Luleå University of Technology

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60323

► Orbital debris poses a serious threat to ongoing operations in space. Recognising this threat, the European Commission has funded the three-year Technology for Self… (more)

▼ Orbital debris poses a serious threat to ongoing operations in space. Recognising this threat, the European Commission has funded the three-year Technology for Self Removal (TeSeR) project with the goal of developing a standard scalable Post Mission Disposal (PMD) module to remove satellites from orbit following the completion of their mission. As the project coordinator and key member of the TeSeR Project, Airbus Defence and Space Germany will invest significant resources in achieving this goal over the course of the project. This thesis details the initial analysis of potential PMD module designs conducted by the author during an internship within the AOCS/GNC department of Airbus Defence and Space Friedrichshafen between 1 April 2016 and 31 August 2016. Three main concepts, drag sails, drag balloons and Electrodynamic Tethers (EDTs), were evaluated during this time with an emphasis on determining the ability of each design to permit passive attitude stabilisation of the satellite during PMD. Following the required modification of a pre-existing MATLAB/Simulink model, several key findings were made for each device concept. It was found that no drag sail designs investigated permitted passive aerodynamic attitude stabilisation at orbit heights above 550 km. When deorbiting from 800 km, however, the lack of the desired and stable attitude was not found to have a significant increase on the deorbit time or the area‑time product. Drag balloon designs were predicted to be comparatively unstable and less mass efficient for deorbiting purposes, with area‑time products up to approximately 50 per cent higher than the equivalent mass drag sail designs. In spite of this, unstable drag balloons were found to provide shorter deorbit times than stable balloons due to the contribution of the satellite body and solar array to the total frontal area of the satellite. This indicated that attitude stabilisation is not required for satellites equipped with drag balloon devices. Modelling of bare EDTs suggested that tethers with lengths of 1000 metres or more would not permit passive attitude stabilisation at an orbit height of 800 km. Simulation of a 500 metre EDT, however, indicated that passive attitude stabilisation can be achieved with EDT devices and proved that EDTs can generate significantly higher drag forces than aerodynamic devices while possessing a significantly lower device mass. Following the analysis of these results, a recommendation was made for future work to be aimed at improving the EDT model used in this investigation.

Subjects/Keywords: electrodynamic; electrodynamic tether; EDT; drag augmentation; drag sail; drag balloon; passive attitude stabilisation; passive; attitude; stability; low earth orbit; LEO; deorbit; de-orbit; Post Mission Disposal; TeSeR; Aerospace Engineering; Rymd- och flygteknik

…Earth; and ℎ is the orbit height. The total deorbit time between the upper and lower orbit… …Smith Beazley Group University of Strathclyde Universität der Bundeswehr München D-Orbit… …the author’s internship within the Attitude and Orbit Control Systems/Guidance Navigation… …of the orbited body, and the y-axis is defined by the negative orbit normal vector, i.e… …satellite and therefore decrease its orbit height. The drag force developed by the interaction of…

12 more images…

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APA (6^th Edition):

Hawe, B. (2016). Analysis of Passive Attitude Stabilisation and Deorbiting of Satellites in Low Earth Orbit. (Thesis). Luleå University of Technology. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60323

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Hawe, Benjamin. “Analysis of Passive Attitude Stabilisation and Deorbiting of Satellites in Low Earth Orbit.” 2016. Thesis, Luleå University of Technology. Accessed March 04, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60323.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Hawe, Benjamin. “Analysis of Passive Attitude Stabilisation and Deorbiting of Satellites in Low Earth Orbit.” 2016. Web. 04 Mar 2021.

Vancouver:

Hawe B. Analysis of Passive Attitude Stabilisation and Deorbiting of Satellites in Low Earth Orbit. [Internet] [Thesis]. Luleå University of Technology; 2016. [cited 2021 Mar 04]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60323.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hawe B. Analysis of Passive Attitude Stabilisation and Deorbiting of Satellites in Low Earth Orbit. [Thesis]. Luleå University of Technology; 2016. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-60323

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Surrey

18. Aziz, Hafeez Mohammad. Band sharing between CDMA based non-geostationary satellite personal communication networks (S-PCN).

Degree: PhD, 2000, University of Surrey

URL: http://epubs.surrey.ac.uk/843165/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340419

► During the past few years, a worldwide interest and unanimous consensus has arisen on personal communication services (PCS), where satellites can play a crucial role… (more)

▼ During the past few years, a worldwide interest and unanimous consensus has arisen on personal communication services (PCS), where satellites can play a crucial role in a global scenario for the provision of PCS's all over the world. While for maritime and aeronautical communication services, the mature technologies of geostationary earth orbit (GEO) satellite systems seem the most suitable for present and future enhanced systems, other orbital configuration such as low earth orbit (LEO) and medium earth orbit (MEO) are being considered for the provision of satellite personal communication services to hand-held mobile terminals. One of the main objectives of personal communication services is the capability to provide personal (or continuous) mobility, communication anytime, anywhere. In general, satellite systems can provide a limited capacity with respect to terrestrial networks, nevertheless they are particularly suited in order to cover large terrestrial areas offering a scarce amount of traffic. The problem of radio frequency management for mobile applications has been addressed by World Administrative Radio Conference (WARC-92). One of the most relevant decisions taken at WARC-92 was to allocate the radio determination satellite system (RDSS) 1610-1626.5 MHz (L-Band) and 2483.5-2500 MHz (S-Band) slots to LEO satellite services on a worldwide, primary basis. This enables "big LEO's" to have a reasonable amount of spectram (i.e. capacity) to serve a substantial number of subscribers. However, the available amount of spectrum at L-band and S-band out of WARC-92 appears hardly sufficient to permit several systems to operate. Hence, to enable all the systems to operate and fulfil the capacity demand, S-PCNs need to share the limited available frequency spectrum. In this thesis we have proposed and evaluated a new fully overlapped band sharing scheme for mobile satellite systems operating in a land mobile satellite channel environment. The results show that the mobile satellite systems can share the limited available bandwidth. However, the overall system capacity of the MSS has been reduced due to excess intersystem interference. In order to reduce the excess inter-system interference a new enhanced overlapped band sharing protocol is proposed. The performance of this optimised band sharing scheme outperforms the conventional band segmentation scheme. Thus, achieving superior overall system capacity.

Subjects/Keywords: 629.46; Low earth orbit; Medium; Mobile; Radio frequency

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APA (6^th Edition):

Aziz, H. M. (2000). Band sharing between CDMA based non-geostationary satellite personal communication networks (S-PCN). (Doctoral Dissertation). University of Surrey. Retrieved from http://epubs.surrey.ac.uk/843165/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340419

Chicago Manual of Style (16^th Edition):

Aziz, Hafeez Mohammad. “Band sharing between CDMA based non-geostationary satellite personal communication networks (S-PCN).” 2000. Doctoral Dissertation, University of Surrey. Accessed March 04, 2021. http://epubs.surrey.ac.uk/843165/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340419.

MLA Handbook (7^th Edition):

Aziz, Hafeez Mohammad. “Band sharing between CDMA based non-geostationary satellite personal communication networks (S-PCN).” 2000. Web. 04 Mar 2021.

Vancouver:

Aziz HM. Band sharing between CDMA based non-geostationary satellite personal communication networks (S-PCN). [Internet] [Doctoral dissertation]. University of Surrey; 2000. [cited 2021 Mar 04]. Available from: http://epubs.surrey.ac.uk/843165/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340419.

Council of Science Editors:

Aziz HM. Band sharing between CDMA based non-geostationary satellite personal communication networks (S-PCN). [Doctoral Dissertation]. University of Surrey; 2000. Available from: http://epubs.surrey.ac.uk/843165/ ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340419

KTH

19. Wikman, John. Software based memory correction for a miniature satellite in low-Earth orbit.

Degree: Computer Science and Communication (CSC), 2017, KTH

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-208496

►

The harsh radiation environment of space is known to cause bit flips in computer memory. The conventional way to combat this is through error… (more)

▼

The harsh radiation environment of space is known to cause bit flips in computer memory. The conventional way to combat this is through error detection and correction (EDAC) circuitry, but for low-budget space missions software EDAC can be used. One such mission is the KTH project Miniature Student Satellite (MIST), which aims to send a 3U CubeSat into low-Earth orbit. To ensure a high level of data reliability on board MIST, this thesis investigates the performance of different types of EDAC algorithms. First, a prediction of the bit flip susceptibility of DRAM memory in the planned trajectory is made. After that, data reliability models of Hamming and Reed-Solomon (RS) codes are proposed, and their respective running times on the MIST onboard computer are approximated. Finally, the performance of the different codes is discussed with regards to data reliability, memory overhead, and CPU usage. The findings of this thesis suggest that using an EDAC algorithm would greatly increase the data reliability. Among the codes investigated, three good candidates are RS(28,24), RS(196,192) and RS(255,251), depending on how much memory overhead can be accepted.

Rymdens strålningsmiljö är känd för att orsaka bitflippar i datorminnen.Vanligtvis motverkas detta genom att felrättande hårdvara installeraspå satelliten, men för lågkostnadssatelliter kan rättningen iställetskötas i mjukvaran. Ett exempel på en sådan satellit är KTH-projektetMiniature Student Satellite (MIST), vars mål är att skicka upp en 3UCubeSat i låg omloppsbana. Den här uppsatsen undersöker hur olika felrättningsalgoritmer kananvändas för att skydda data ombord på satelliten från att bli korrupt. Först görs en uppskattning av hur strålningskänsliga DRAM minnenär i den planerade omloppsbanan. Därefter föreslås datakorruptionsmodellerför Hamming- och Reed-Solomonkoder (RS) tillsammans meden uppskattning av deras respektive körtider på satellitens omborddator. Slutligen diskuteras de föreslagna koderna med hänsyn till datakorruptionsskydd,minnesanvändning och processoranvändning. Uppsatsens slutsats indikerar att användandet av felrättningsalgoritmerkraftigt minskar risken för datakorruption. Bland de kodersom undersökts framstår RS(28,24), RS(196,192) och RS(255,251) somde bästa alternativen, beroende på hur mycket extra minnesanvändningsom är acceptabelt.

Subjects/Keywords: Software based memory correction; DRAM; Reed-Solomon; Hamming; CubeSat; Low-Earth Orbit; MIST; Computer Sciences; Datavetenskap (datalogi)

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APA (6^th Edition):

Wikman, J. (2017). Software based memory correction for a miniature satellite in low-Earth orbit. (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-208496

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Wikman, John. “Software based memory correction for a miniature satellite in low-Earth orbit.” 2017. Thesis, KTH. Accessed March 04, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-208496.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Wikman, John. “Software based memory correction for a miniature satellite in low-Earth orbit.” 2017. Web. 04 Mar 2021.

Vancouver:

Wikman J. Software based memory correction for a miniature satellite in low-Earth orbit. [Internet] [Thesis]. KTH; 2017. [cited 2021 Mar 04]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-208496.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wikman J. Software based memory correction for a miniature satellite in low-Earth orbit. [Thesis]. KTH; 2017. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-208496

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Delft University of Technology

20. Pascarella, Alex (author). Low-energy transfers from GTO to lunar Halo orbits: rideshare options and sensitivities.

Degree: 2020, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:cfd66067-2d95-499d-abbc-55566c7bcabd

►

In this research project, the design of a smallsat mission to a Halo orbit around the Earth-Moon second libration point (EML-2) using a rideshare launch… (more)

Subjects/Keywords: Orbit Design; Low-energy Transfers; Invariant Manifold Theory; Dynamical Systems Theory; Ridesharing; Earth-Moon System; GTO; Smallsats

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APA (6^th Edition):

Pascarella, A. (. (2020). Low-energy transfers from GTO to lunar Halo orbits: rideshare options and sensitivities. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:cfd66067-2d95-499d-abbc-55566c7bcabd

Chicago Manual of Style (16^th Edition):

Pascarella, Alex (author). “Low-energy transfers from GTO to lunar Halo orbits: rideshare options and sensitivities.” 2020. Masters Thesis, Delft University of Technology. Accessed March 04, 2021. http://resolver.tudelft.nl/uuid:cfd66067-2d95-499d-abbc-55566c7bcabd.

MLA Handbook (7^th Edition):

Pascarella, Alex (author). “Low-energy transfers from GTO to lunar Halo orbits: rideshare options and sensitivities.” 2020. Web. 04 Mar 2021.

Vancouver:

Pascarella A(. Low-energy transfers from GTO to lunar Halo orbits: rideshare options and sensitivities. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2021 Mar 04]. Available from: http://resolver.tudelft.nl/uuid:cfd66067-2d95-499d-abbc-55566c7bcabd.

Council of Science Editors:

Pascarella A(. Low-energy transfers from GTO to lunar Halo orbits: rideshare options and sensitivities. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:cfd66067-2d95-499d-abbc-55566c7bcabd

Utah State University

21. Shuster, Simon P. A Survey and Performance Analysis of Orbit Propagators for LEO, GEO, and Highly Elliptical Orbits.

Degree: MS, Mechanical and Aerospace Engineering, 2017, Utah State University

URL: https://digitalcommons.usu.edu/etd/6510

► On-orbit targeting, guidance, and navigation relies on state vector propagation algorithms that must strike a balance between accuracy and computational efficiency. To better understand… (more)

Subjects/Keywords: orbit propagators; leo; geo; highly elliptical orbits; Aerospace Engineering

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APA (6^th Edition):

Shuster, S. P. (2017). A Survey and Performance Analysis of Orbit Propagators for LEO, GEO, and Highly Elliptical Orbits. (Masters Thesis). Utah State University. Retrieved from https://digitalcommons.usu.edu/etd/6510

Chicago Manual of Style (16^th Edition):

Shuster, Simon P. “A Survey and Performance Analysis of Orbit Propagators for LEO, GEO, and Highly Elliptical Orbits.” 2017. Masters Thesis, Utah State University. Accessed March 04, 2021. https://digitalcommons.usu.edu/etd/6510.

MLA Handbook (7^th Edition):

Shuster, Simon P. “A Survey and Performance Analysis of Orbit Propagators for LEO, GEO, and Highly Elliptical Orbits.” 2017. Web. 04 Mar 2021.

Vancouver:

Shuster SP. A Survey and Performance Analysis of Orbit Propagators for LEO, GEO, and Highly Elliptical Orbits. [Internet] [Masters thesis]. Utah State University; 2017. [cited 2021 Mar 04]. Available from: https://digitalcommons.usu.edu/etd/6510.

Council of Science Editors:

Shuster SP. A Survey and Performance Analysis of Orbit Propagators for LEO, GEO, and Highly Elliptical Orbits. [Masters Thesis]. Utah State University; 2017. Available from: https://digitalcommons.usu.edu/etd/6510

Cal Poly

22. Stoker, Kyle. Initial Orbit Determination Error Analysis of Low-Earth Orbit Rocket Body Debris and Feasibility Study for Debris Cataloguing from One Optical Facility.

Degree: MS, Aerospace Engineering, 2020, Cal Poly

URL: https://digitalcommons.calpoly.edu/theses/2153 ; 10.15368/theses.2020.41

► This paper is predicated on determining the effectiveness of angles-only initial orbit determination (IOD) methods when limited observational data is available for low-Earth orbit… (more)

▼ This paper is predicated on determining the effectiveness of angles-only initial orbit determination (IOD) methods when limited observational data is available for low-Earth orbit (LEO) rocket body debris. The analysis will be conducted with data obtained from Lockheed Martin Space’s Space Object Tracking (SpOT) facility, focusing on their observational data from 2018 that contains tracking of rocket body debris for less than one minute per overhead pass. After the IOD accuracies are better understood, a feasibility study will follow that investigates the possibility of cataloguing LEO orbital debris from a single optical observation facility with similar observational capabilities as that of the SpOT facility. The IOD accuracy analysis will investigate nine different rocket bodies, with a total of 50 orbital passes of data included in the research. Three main IOD approaches will be tested for each data set to determine the best method in achieving high levels of IOD accuracy: a traditional three-point method, an iterative method, and an assumed-circular orbit method. Application of the iterative approach results in increased accuracy for the resultant initial orbit determination as compared to the three-point IOD method, and an assumed-circular orbit assumption allows for a further increase in accuracy, especially for observed objects in near-circular orbits. The feasibility of cataloguing debris from a singular optical facility shows promise, as subsequent target acquisition after an object’s initial observation is determined to be achievable under the correct circumstances. By choosing a correct telescope pointing angle based on the IOD results from one pass of data, an observed rocket body debris object would pass through the field of view of SpOT’s spotter scope (0.7-degrees) during its next overhead pass for two different test cases. An increase field of view would increase both the likelihood of acquiring the target object and the amount of time the object is visible by the telescope. Advisors/Committee Members: Kira Abercromby.

Subjects/Keywords: initial orbit determination; debris; LEO; accuracy; optical observation; SpOT; Astrodynamics

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APA (6^th Edition):

Stoker, K. (2020). Initial Orbit Determination Error Analysis of Low-Earth Orbit Rocket Body Debris and Feasibility Study for Debris Cataloguing from One Optical Facility. (Masters Thesis). Cal Poly. Retrieved from https://digitalcommons.calpoly.edu/theses/2153 ; 10.15368/theses.2020.41

Chicago Manual of Style (16^th Edition):

Stoker, Kyle. “Initial Orbit Determination Error Analysis of Low-Earth Orbit Rocket Body Debris and Feasibility Study for Debris Cataloguing from One Optical Facility.” 2020. Masters Thesis, Cal Poly. Accessed March 04, 2021. https://digitalcommons.calpoly.edu/theses/2153 ; 10.15368/theses.2020.41.

MLA Handbook (7^th Edition):

Stoker, Kyle. “Initial Orbit Determination Error Analysis of Low-Earth Orbit Rocket Body Debris and Feasibility Study for Debris Cataloguing from One Optical Facility.” 2020. Web. 04 Mar 2021.

Vancouver:

Stoker K. Initial Orbit Determination Error Analysis of Low-Earth Orbit Rocket Body Debris and Feasibility Study for Debris Cataloguing from One Optical Facility. [Internet] [Masters thesis]. Cal Poly; 2020. [cited 2021 Mar 04]. Available from: https://digitalcommons.calpoly.edu/theses/2153 ; 10.15368/theses.2020.41.

Council of Science Editors:

Stoker K. Initial Orbit Determination Error Analysis of Low-Earth Orbit Rocket Body Debris and Feasibility Study for Debris Cataloguing from One Optical Facility. [Masters Thesis]. Cal Poly; 2020. Available from: https://digitalcommons.calpoly.edu/theses/2153 ; 10.15368/theses.2020.41

University of Florida

23. Werremeyer, Mark R. Design of Subsystems for a Representative Modern LEO Satellite.

Degree: MS, Aerospace Engineering - Mechanical and Aerospace Engineering, 2013, University of Florida

URL: https://ufdc.ufl.edu/UFE0045534

► This thesis discusses the design of subsystems for a representative modern low Earth Orbit (LEO) satellite. Specifically, the subsystems presented were designed for inclusion on… (more)

Subjects/Keywords: Aluminum; Artificial satellites; Composite materials; Low earth orbits; Magnetism; Nadir; Plumbing; Propulsion; Satellite design; Thrusters; attitude – debris – debrisat – hypervelocity – impact – leo – modern – orbital – propulsion – representative – satellite – structure – subsystems – test – thermal

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APA (6^th Edition):

Werremeyer, M. R. (2013). Design of Subsystems for a Representative Modern LEO Satellite. (Masters Thesis). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0045534

Chicago Manual of Style (16^th Edition):

Werremeyer, Mark R. “Design of Subsystems for a Representative Modern LEO Satellite.” 2013. Masters Thesis, University of Florida. Accessed March 04, 2021. https://ufdc.ufl.edu/UFE0045534.

MLA Handbook (7^th Edition):

Werremeyer, Mark R. “Design of Subsystems for a Representative Modern LEO Satellite.” 2013. Web. 04 Mar 2021.

Vancouver:

Werremeyer MR. Design of Subsystems for a Representative Modern LEO Satellite. [Internet] [Masters thesis]. University of Florida; 2013. [cited 2021 Mar 04]. Available from: https://ufdc.ufl.edu/UFE0045534.

Council of Science Editors:

Werremeyer MR. Design of Subsystems for a Representative Modern LEO Satellite. [Masters Thesis]. University of Florida; 2013. Available from: https://ufdc.ufl.edu/UFE0045534

KTH

24. Henriques, Johan. Digitalization of forest management : Next generation unsupervised monitoring using Internet of Things and Blockchain.

Degree: Industrial Economics and Management (Dept.), 2020, KTH

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278191

►

The forest industry is a fundamental cornerstone of the Swedish economy employing over 70 000 workers on a national scale. In recent years, the… (more)

▼

The forest industry is a fundamental cornerstone of the Swedish economy employing over 70 000 workers on a national scale. In recent years, the industry has seen increased efforts to digitalize operations and management of forestry to reap economical rewards, improve efficiency and gain competitive advantages. Due to living nature of trees, forest-management is a critical activity within the industry; trees and forests maintained properly will reward the owner with not only greater quality and greater quantity of wood, but also a shorter realization of cash flow. Fully realized, data from UPM Skog suggests that proper forest management has the potential to increase forest returns with up to 50 percent. This thesis studies forest management in the context of digitalization with the aim of making forest monitoring more digital and intelligent. In particular, it studies unsupervised monitoring in detail, a subset of remote sensing. Applications and effects of unsupervised monitoring include but are not limited to; enable real-time management of forest inventory, improved planning, time logging to market-fluctuations and enhanced biodiversity. There are a multitude of technologies that could be utilized and applied to achieve unsupervised monitoring and the startingpoint for discussion are the technologies Internet of Things and Enterprise Blockchain. The research is carried out as a case-study utilizing qualitative semi-structured interviews as primary data collection tool combined with a rigorous literature study in the relevant technological areas. The findings of this thesis portray a trade-off between infrastructure, maintainability, precision and latency on the choice of communication technology. Further, it discusses various ways to work around the different drawbacks of specific technology choices and in what contexts they be more or less suitable. Blockchain technology can act as an enabler for multiple novel industrial applications due to is properties of immutability, transparency and trust; however, not critical for unsupervised monitoring applications in the short run. This research serves as a first step in exploring the area of Internet of Things and Blockchain applied to unsupervised monitoring of forestry. In doing so, the thesis addresses infrastructural considerations, economic feasibility as well as key implications in terms of change management.

Skogsindustrin är en hörnsten för svensk ekonomi och sysselsätter fler än 70 000 arbetare på en nationell skala. De senaste åren har industrin sett ökade satsningar mot att digitalisera förvaltning och operation av skog med syftet att nå ekonomisk avkastning, ökad effektivitet och förbättrad konkurrenskraft. Till följd av trädens levandenatur är skogsförvaltning en kritisk aktivitet inom industrin; trä och skog som underhålls på rätt sätt belönar ägaren med både höjd kvalitet på virke och högre kvantitet av virke samt snabbare realisering av kassaflöden. Data från UPM Skog uppskattar att god skogsförvaltning har potential att medföra upp till 50…

Subjects/Keywords: internet of things; blockchain; unsupervised monitoring; enterprise blockchain; forest monitoring; forest management; 5g; low power wide arena network; lidar; low earth orbit satellite; "internet of things"; "blockchain"; "unsupervised monitoring"; "enterprise blockchain"; skogsövervakning; skogsförvaltning; 5g; "low power wide arena network"; lidar; "low earth orbit satellite"; Economics and Business; Ekonomi och näringsliv

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APA (6^th Edition):

Henriques, J. (2020). Digitalization of forest management : Next generation unsupervised monitoring using Internet of Things and Blockchain. (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278191

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Henriques, Johan. “Digitalization of forest management : Next generation unsupervised monitoring using Internet of Things and Blockchain.” 2020. Thesis, KTH. Accessed March 04, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278191.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Henriques, Johan. “Digitalization of forest management : Next generation unsupervised monitoring using Internet of Things and Blockchain.” 2020. Web. 04 Mar 2021.

Vancouver:

Henriques J. Digitalization of forest management : Next generation unsupervised monitoring using Internet of Things and Blockchain. [Internet] [Thesis]. KTH; 2020. [cited 2021 Mar 04]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278191.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Henriques J. Digitalization of forest management : Next generation unsupervised monitoring using Internet of Things and Blockchain. [Thesis]. KTH; 2020. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-278191

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Delft University of Technology

25. Claes, Jochem (author). Thermosphere Modelling using Machine Learning: Artificial Neural Networks to forecast thermospheric densities and generalise beyond the properties of an acceleration data set using the Swarm satellites as study case.

Degree: 2019, Delft University of Technology

URL: http://resolver.tudelft.nl/uuid:85cbb07a-d1dc-44de-833d-a8a8f984a0e3

►

The Low Earth Orbit (LEO) region has been attractive to many space agencies and organisations because of its ease of access and the ideal opportunity… (more)

▼

The Low Earth Orbit (LEO) region has been attractive to many space agencies and organisations because of its ease of access and the ideal opportunity for remote sensing. Due to the low altitudes, a satellite's orbital state is highly affected by the atmospheric drag force acting on the satellite's body. The largest variation in this drag force is caused by the changes in thermospheric density due to the complex interactions of the Sun with the Earth's thermosphere. In order to properly forecast the orbital state of a LEO satellite, the thermospheric densities need to be predicted as accurately as possible. The thermospheric density values can be estimated by using for example empirical atmospheric density models, such as the DTM2013 (Drag Temperature Model). During this thesis study it has been investigated whether the highly researched field of machine learning models could be used to develop a predictor for the along-track density values for the Swarm satellite constellation. This constellation has an abundant amount of trajectory-based time series of thermospheric density values from Precise Orbit Determination (POD) data. This research has focused on the development of Multi-layer Perceptron (MLP) models which are a type of Feed-Forward Neural Network. These MLP models have been trained and tested on past acceleration and solar activity data sets provided by the Swarm satellite mission and space weather observatories, respectively. The performance of these MLP models was then compared to two baseline models, namely a Calibrated Persistence Model (CPM) and the density values modelled by DTM2013. The results in this research led to the conclusion that a three-layer MLP model performed best when it was trained on data of the same spacecraft like the one it was supposed to perform along-track density forecasts for. The forecasting accuracy increased the most when the model was trained on long periods of training data characterised by high solar and low geomagnetic activity. When trained on these data sets, the MLP model has shown to outperform the baseline models when making predictions up until two days into the future during periods of high solar activity. The DTM2013 seems the best option to forecast density values during low solar activity. As an alternative to the DTM2013, the CPM seems a suitable model when one needs to quickly implement a forecasting model with decent performance irrespective from the presence of geomagnetic storms.

Aerospace Engineering

Advisors/Committee Members: van den IJssel, Jose (mentor), Doornbos, Eelco (graduation committee), Delft University of Technology (degree granting institution).

Subjects/Keywords: DTM2013; Thermosphere; POD-derived Densities; Machine Learning; Neural Networks; Multi-layer Perceptron; Tensorflow; Python; Time Series Forecasting; Swarm Satellite Constellation; Low Earth Orbit

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APA (6^th Edition):

Claes, J. (. (2019). Thermosphere Modelling using Machine Learning: Artificial Neural Networks to forecast thermospheric densities and generalise beyond the properties of an acceleration data set using the Swarm satellites as study case. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:85cbb07a-d1dc-44de-833d-a8a8f984a0e3

Chicago Manual of Style (16^th Edition):

Claes, Jochem (author). “Thermosphere Modelling using Machine Learning: Artificial Neural Networks to forecast thermospheric densities and generalise beyond the properties of an acceleration data set using the Swarm satellites as study case.” 2019. Masters Thesis, Delft University of Technology. Accessed March 04, 2021. http://resolver.tudelft.nl/uuid:85cbb07a-d1dc-44de-833d-a8a8f984a0e3.

MLA Handbook (7^th Edition):

Claes, Jochem (author). “Thermosphere Modelling using Machine Learning: Artificial Neural Networks to forecast thermospheric densities and generalise beyond the properties of an acceleration data set using the Swarm satellites as study case.” 2019. Web. 04 Mar 2021.

Vancouver:

Claes J(. Thermosphere Modelling using Machine Learning: Artificial Neural Networks to forecast thermospheric densities and generalise beyond the properties of an acceleration data set using the Swarm satellites as study case. [Internet] [Masters thesis]. Delft University of Technology; 2019. [cited 2021 Mar 04]. Available from: http://resolver.tudelft.nl/uuid:85cbb07a-d1dc-44de-833d-a8a8f984a0e3.

Council of Science Editors:

Claes J(. Thermosphere Modelling using Machine Learning: Artificial Neural Networks to forecast thermospheric densities and generalise beyond the properties of an acceleration data set using the Swarm satellites as study case. [Masters Thesis]. Delft University of Technology; 2019. Available from: http://resolver.tudelft.nl/uuid:85cbb07a-d1dc-44de-833d-a8a8f984a0e3

Oklahoma State University

26. Gaza, Ramona. Space Radiation Dosimetry: an Optically Stimulated Luminescence Radiation Detector for Low-earth Orbit.

Degree: Department of Physics, 2004, Oklahoma State University

URL: http://hdl.handle.net/11244/6891

► The purpose of this study was to investigate Al2O3:C as a potential optically stimulated luminescence (OSL) radiation detector for Low-Earth Orbit. The OSL response of… (more)

▼ The purpose of this study was to investigate Al2O3:C as a potential optically stimulated luminescence (OSL) radiation detector for Low-Earth Orbit. The OSL response of Al2O3:C was characterized in terms of its luminescence efficiency for a variety of heavy charged particles (HCPs) with features similar to those found in space. The HCP irradiations were performed using the HIMAC accelerator at Chiba (Japan), the proton facility at Loma Linda (CA) and the NSRL facility at Brookhaven (NY). The OSL curves were further investigated to obtain information about the 'mean efficiency' and 'mean LET', parameters that needed to assess the absorbed dose and the dose equivalent. This analysis was applied for simulated mixed radiation fields (ICCHIBAN) and actual space radiation exposures (i.e., STS-105, BRADOS, and TRACER). In parallel, the thermoluminescence response of dosimetry materials LiF:Mg,Ti and CaF2:Tm was also studied. The OSL efficiency of Al2O3:C exposed to HCPs was found to decrease with increasing linear energy transfer (LET) for the investigated LET range (i.e., from keV/μm to keV/μm). For simulated mixed radiation fields with a strong low-LET component, the results indicated that the OSL calibration methods (i.e., τ method and R method) can be used with good accuracy to obtain information about the absorbed dose and the dose equivalent. Nevertheless, for mixed fields with a strong high-LET component these methods will give larger errors when estimating the absorbed dose and the dose equivalent. For actual space radiation exposures, the results indicated that different materials/calibration methods (i.e., the LiF:Mg,Ti/HTR method and the CaF2:Tm/ peak peak method) give different results in terms of 'mean efficiency' and 'mean LET'. This was explained by suggesting that none of the above calibration methods can give information about the true average LET of the incident radiation, but rather about the 'mean LET' weighted by the dosimeter efficiency. Advisors/Committee Members: McKeever, Stephen W. S. (advisor), Anderson, Bruce J. (committee member), Arena, Andrew S. (committee member), Rosenberger, Albert T. (committee member), Westhaus, Paul A. (committee member).

Subjects/Keywords: space radiation dosimetry; optically stimulated luminescence; radiation detector; low-earth orbit

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APA (6^th Edition):

Gaza, R. (2004). Space Radiation Dosimetry: an Optically Stimulated Luminescence Radiation Detector for Low-earth Orbit. (Thesis). Oklahoma State University. Retrieved from http://hdl.handle.net/11244/6891

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Gaza, Ramona. “Space Radiation Dosimetry: an Optically Stimulated Luminescence Radiation Detector for Low-earth Orbit.” 2004. Thesis, Oklahoma State University. Accessed March 04, 2021. http://hdl.handle.net/11244/6891.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Gaza, Ramona. “Space Radiation Dosimetry: an Optically Stimulated Luminescence Radiation Detector for Low-earth Orbit.” 2004. Web. 04 Mar 2021.

Vancouver:

Gaza R. Space Radiation Dosimetry: an Optically Stimulated Luminescence Radiation Detector for Low-earth Orbit. [Internet] [Thesis]. Oklahoma State University; 2004. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/11244/6891.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Gaza R. Space Radiation Dosimetry: an Optically Stimulated Luminescence Radiation Detector for Low-earth Orbit. [Thesis]. Oklahoma State University; 2004. Available from: http://hdl.handle.net/11244/6891

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Universitetet i Tromsø

27. Aarud, Vebjørn Orre. Wire Gear for Small Rotary Actuator intended for Low Earth Orbit Applications.

Degree: 2018, Universitetet i Tromsø

URL: http://hdl.handle.net/10037/13471

► In this master thesis, a small rotary actuator with wire driveline intendent for space solutions is developed and tested. The replication of the environment with… (more)

Subjects/Keywords: VDP::Teknologi: 500::Industri- og produktdesign: 640; VDP::Technology: 500::Industrial and product design: 640; Space; Low Earth Orbit; Space X; Small Rotary Actuator; Testing; Mechanical; Zylon; Wire Gear; Driveline

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Aarud, V. O. (2018). Wire Gear for Small Rotary Actuator intended for Low Earth Orbit Applications. (Masters Thesis). Universitetet i Tromsø. Retrieved from http://hdl.handle.net/10037/13471

Chicago Manual of Style (16^th Edition):

Aarud, Vebjørn Orre. “Wire Gear for Small Rotary Actuator intended for Low Earth Orbit Applications. ” 2018. Masters Thesis, Universitetet i Tromsø. Accessed March 04, 2021. http://hdl.handle.net/10037/13471.

MLA Handbook (7^th Edition):

Aarud, Vebjørn Orre. “Wire Gear for Small Rotary Actuator intended for Low Earth Orbit Applications. ” 2018. Web. 04 Mar 2021.

Vancouver:

Aarud VO. Wire Gear for Small Rotary Actuator intended for Low Earth Orbit Applications. [Internet] [Masters thesis]. Universitetet i Tromsø 2018. [cited 2021 Mar 04]. Available from: http://hdl.handle.net/10037/13471.

Council of Science Editors:

Aarud VO. Wire Gear for Small Rotary Actuator intended for Low Earth Orbit Applications. [Masters Thesis]. Universitetet i Tromsø 2018. Available from: http://hdl.handle.net/10037/13471

28. Schaefer, Glen Allen. Ultrathin metallic coatings for silver surfaces: Function and utilization in low Earth orbit.

Degree: PhD, Materials Science and Engineering, 1993, Case Western Reserve University School of Graduate Studies

URL: http://rave.ohiolink.edu/etdc/view?acc_num=case1060351586

► Silver is a material for space-based mirror technologies operating within the visible spectrum of solar radiation and for electrical contacts utilized in space power transmission… (more)

▼ Silver is a material for space-based mirror technologies operating within the visible spectrum of solar radiation and for electrical contacts utilized in space power transmission applications. However, in spacecraft operating in the low Earth orbit environment, structures utilizing silver components are susceptible to attack from incident atomic oxygen. The structures require protective coatings against atomic oxygen to shield silver surfaces from the environment in order to provide durability. The focus of this research centers on modifying thin film silver surfaces with ultrathin protective coatings of gold and aluminum to provide resistance to a low Earth orbit, atomic oxygen environment. A physical vapor deposition process involving electron beam evaporation produced the thin film coatings in a high vacuum at 3 × 10^-7 torr. The coatings were characterized for reflectance with a Perkin Elmer UV-VIS-NIR Spectrophotometer, for thickness with a quartz crystal monitor and for microstructural features with SEM, TEM, AES and ESCA. The samples were oxidized in a modified barrel asher which utilized quartz crystal technology to monitor the plasma process and in the University of Toronto Institute for Aerospace Studies atomic oxygen directed beam facility. A low Earth orbit exposure aboard Atlantis on STS-46 in the Center for Materials for Space Structures LDCE-1 experiment concluded the environmental testing. The silver layer was highly susceptible to plasma oxidation at the thin film grain boundaries. The grain boundary oxidation rate was ten times faster than the bulk silver oxidation process. Aluminum coatings with thicknesses of 80-100 A (30-40 monolayers) wet these silver surfaces and grain boundary regions, thus providing protection from the atomic oxygen. The gold coatings did not protect these sensitive regions and failed in the high energy atomic oxygen environments. The aluminum-silver coatings equalled pure aluminum coatings in the total solar reflectance criteria and the oxidation resistance criteria. The 80 A aluminum layer underwent complete conversion to aluminum oxide in the low Earth orbit exposure. This conversion process was modelled by the inverse logarithmic solution to the Mott-Cabrera rate equation originally proposed by M. J. Dignam. The particular 450°C solution to this rate equation resulted in a linear relationship between oxide thickness and the environmental potential. The aluminum oxide thickness was verified in the UTIAS beam facility at 2 eV and in the low Earth orbit at 5 eV atomic oxygen species. These thin boundary layer aluminum coatings offer protection for silver surfaces which must operate in harsh oxygen environments and present a new candidate material system worthy of additional study Advisors/Committee Members: Wallace, John (Advisor).

Subjects/Keywords: Engineering, Metallurgy; Silver surfaces, ultrathin metallic coatings; Low earth orbit

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Schaefer, G. A. (1993). Ultrathin metallic coatings for silver surfaces: Function and utilization in low Earth orbit. (Doctoral Dissertation). Case Western Reserve University School of Graduate Studies. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=case1060351586

Chicago Manual of Style (16^th Edition):

Schaefer, Glen Allen. “Ultrathin metallic coatings for silver surfaces: Function and utilization in low Earth orbit.” 1993. Doctoral Dissertation, Case Western Reserve University School of Graduate Studies. Accessed March 04, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1060351586.

MLA Handbook (7^th Edition):

Schaefer, Glen Allen. “Ultrathin metallic coatings for silver surfaces: Function and utilization in low Earth orbit.” 1993. Web. 04 Mar 2021.

Vancouver:

Schaefer GA. Ultrathin metallic coatings for silver surfaces: Function and utilization in low Earth orbit. [Internet] [Doctoral dissertation]. Case Western Reserve University School of Graduate Studies; 1993. [cited 2021 Mar 04]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=case1060351586.

Council of Science Editors:

Schaefer GA. Ultrathin metallic coatings for silver surfaces: Function and utilization in low Earth orbit. [Doctoral Dissertation]. Case Western Reserve University School of Graduate Studies; 1993. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=case1060351586

Ohio University

29. Sangal, Rahul. Performance analysis of the transmission control protocol over low earth orbit satellite communication systems.

Degree: MS, Electrical Engineering & Computer Science (Engineering and Technology), 1999, Ohio University

URL: http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1175629275

► There has been a proliferation in the development of Low Earth Orbit(LEO)satellite networks to provide seamless global access to Internet. The effect of the… (more)

Subjects/Keywords: Low Earth Orbit satellite networks; Transmission Control Protocol; Round Trip Time

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sangal, R. (1999). Performance analysis of the transmission control protocol over low earth orbit satellite communication systems. (Masters Thesis). Ohio University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1175629275

Chicago Manual of Style (16^th Edition):

Sangal, Rahul. “Performance analysis of the transmission control protocol over low earth orbit satellite communication systems.” 1999. Masters Thesis, Ohio University. Accessed March 04, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1175629275.

MLA Handbook (7^th Edition):

Sangal, Rahul. “Performance analysis of the transmission control protocol over low earth orbit satellite communication systems.” 1999. Web. 04 Mar 2021.

Vancouver:

Sangal R. Performance analysis of the transmission control protocol over low earth orbit satellite communication systems. [Internet] [Masters thesis]. Ohio University; 1999. [cited 2021 Mar 04]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1175629275.

Council of Science Editors:

Sangal R. Performance analysis of the transmission control protocol over low earth orbit satellite communication systems. [Masters Thesis]. Ohio University; 1999. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1175629275

30. GANESAN, GAUTHAM. Accessibility Studies of Potentially Hazardous Asteroids from the Sun-Earth L2 Libration Point.

Degree: Space Technology, 2020, Luleå University of Technology

URL: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81630

► A newly proposed F-class mission by the European Space Agency (ESA) in 2019,Comet Interceptor, aims to dynamically intercept a New Solar System Objectsuch as… (more)

Subjects/Keywords: Near-Earth Objects; Potentially Hazardous Asteroids; Halo Orbit; Invariant Manifolds; Analytical construction; Palermo Scale; Low-Energy transfer; Aerospace Engineering; Rymd- och flygteknik

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APA (6^th Edition):

GANESAN, G. (2020). Accessibility Studies of Potentially Hazardous Asteroids from the Sun-Earth L2 Libration Point. (Thesis). Luleå University of Technology. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81630

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

GANESAN, GAUTHAM. “Accessibility Studies of Potentially Hazardous Asteroids from the Sun-Earth L2 Libration Point.” 2020. Thesis, Luleå University of Technology. Accessed March 04, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81630.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

GANESAN, GAUTHAM. “Accessibility Studies of Potentially Hazardous Asteroids from the Sun-Earth L2 Libration Point.” 2020. Web. 04 Mar 2021.

Vancouver:

GANESAN G. Accessibility Studies of Potentially Hazardous Asteroids from the Sun-Earth L2 Libration Point. [Internet] [Thesis]. Luleå University of Technology; 2020. [cited 2021 Mar 04]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81630.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

GANESAN G. Accessibility Studies of Potentially Hazardous Asteroids from the Sun-Earth L2 Libration Point. [Thesis]. Luleå University of Technology; 2020. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81630

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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Open Access Theses and Dissertations