Publications
2005 |
Saenz-Otero, Alvar; Miller, David W Design and operation of micro-gravity dynamics and controls laboratories Journal Article 2005. BibTeX | Tags: @article{saenz2005design, title = {Design and operation of micro-gravity dynamics and controls laboratories}, author = {Alvar Saenz-Otero and David W Miller}, year = {2005}, date = {2005-01-01}, publisher = {Georgia Institute of Technology}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Chung, Soon-Jo; Kong, Edmund; Miller, David Dynamics and control of tethered formation flight spacecraft using the SPHERES testbed Inproceedings AIAA Guidance, Navigation, and Control Conference and Exhibit, pp. 6089, 2005. BibTeX | Tags: @inproceedings{chung2005dynamics, title = {Dynamics and control of tethered formation flight spacecraft using the SPHERES testbed}, author = {Soon-Jo Chung and Edmund Kong and David Miller}, year = {2005}, date = {2005-01-01}, booktitle = {AIAA Guidance, Navigation, and Control Conference and Exhibit}, pages = {6089}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Chung, Soon-Jo; Kong, Edmund M; Miller, David W SPHERES Tethered formation flight testbed: Application to NASA's SPECS mission Inproceedings UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II, pp. 58990L, International Society for Optics and Photonics 2005. BibTeX | Tags: @inproceedings{chung2005spheres, title = {SPHERES Tethered formation flight testbed: Application to NASA's SPECS mission}, author = {Soon-Jo Chung and Edmund M Kong and David W Miller}, year = {2005}, date = {2005-01-01}, booktitle = {UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II}, volume = {5899}, pages = {58990L}, organization = {International Society for Optics and Photonics}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Saenz-Otero, Alvar; Miller, David W SPHERES: a platform for formation-flight research Inproceedings UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II, pp. 58990O, International Society for Optics and Photonics 2005. BibTeX | Tags: @inproceedings{saenz2005spheres, title = {SPHERES: a platform for formation-flight research}, author = {Alvar Saenz-Otero and David W Miller}, year = {2005}, date = {2005-01-01}, booktitle = {UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II}, volume = {5899}, pages = {58990O}, organization = {International Society for Optics and Photonics}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Saenz-Otero, Alvar; Miller, David W Using ISS to develop telescope technology Inproceedings UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II, pp. 58990J, International Society for Optics and Photonics 2005. BibTeX | Tags: @inproceedings{saenz2005using, title = {Using ISS to develop telescope technology}, author = {Alvar Saenz-Otero and David W Miller}, year = {2005}, date = {2005-01-01}, booktitle = {UV/Optical/IR Space Telescopes: Innovative Technologies and Concepts II}, volume = {5899}, pages = {58990J}, organization = {International Society for Optics and Photonics}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Rodgers, Lennon; Hoff, Nicholas; Jordan, Elizabeth; Heiman, Michael; Miller, David A universal interface for modular spacecraft Journal Article 2005. BibTeX | Tags: @article{rodgers2005universal, title = {A universal interface for modular spacecraft}, author = {Lennon Rodgers and Nicholas Hoff and Elizabeth Jordan and Michael Heiman and David Miller}, year = {2005}, date = {2005-01-01}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Blanc-Paques, Pierre Thruster calibration for the SPHERES spacecraft formation flight testbed Journal Article Master's Thesis, MIT, 2005. BibTeX | Tags: @article{blanc2005thruster, title = {Thruster calibration for the SPHERES spacecraft formation flight testbed}, author = {Pierre Blanc-Paques}, year = {2005}, date = {2005-01-01}, journal = {Master's Thesis, MIT}, publisher = {Citeseer}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Nolet, Simon; Kong, Edmund; Miller, David W Design of an algorithm for autonomous docking with a freely tumbling target Inproceedings Modeling, Simulation, and Verification of Space-based Systems II, pp. 123–135, International Society for Optics and Photonics 2005. BibTeX | Tags: @inproceedings{nolet2005design, title = {Design of an algorithm for autonomous docking with a freely tumbling target}, author = {Simon Nolet and Edmund Kong and David W Miller}, year = {2005}, date = {2005-01-01}, booktitle = {Modeling, Simulation, and Verification of Space-based Systems II}, volume = {5799}, pages = {123--135}, organization = {International Society for Optics and Photonics}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Kwon, Daniel W Electromagnetic Formation Flight of Satellite Arrays PhD Thesis 2005, ISSN: 15710297. Abstract | Links | BibTeX | Tags: 1700, 250-721-8542, adulteration, b, books are developed from symposia sponsored by, c, ca, canada, Capsules, Cascade theory, causality, chemical composition, Chemistry, cointegration, comprehensive books developed, correspondence to, Cultivation, Delayed-Action Preparations, department of economics, Diffusion, dimension, economic growth, Electron, email, from ACS sponsored, functional properties, Gel point, Gelatin, Gelation mechanisms, giles, icle, jgiles, judith a, main products, medicinal uses, Microchemistry, Microchemistry: methods, Microscopy, misspecification, model, Nigella, ot, Percolation theory, Permeability, Physical, Physicochemical Phenomena, po box, Polymers, quality specifications, robustness, Rubber elasticity, Scanning, Sol-gel and gel-sol transitions, Starch gels, telephone, The ACS Symposium Series was first published in 1, The ACS Symposium Series was first published in 19, time series models, toxicity, university of victoria, uvic, v8w 2y2, victoria, we are grateful, Whey protein nanofibril gels @phdthesis{kwonElectromagneticFormationFlight2005a, title = {Electromagnetic Formation Flight of Satellite Arrays}, author = {Daniel W Kwon}, doi = {10.1007/978-1-4614-7990-1}, issn = {15710297}, year = {2005}, date = {2005-01-01}, volume = {12 Suppl 1}, number = {9}, abstract = {This book is an attempt to introduce the enormous amount of literature on solidification heat transfer. Many of the applications have been directed to water/ice soil systems.}, keywords = {1700, 250-721-8542, adulteration, b, books are developed from symposia sponsored by, c, ca, canada, Capsules, Cascade theory, causality, chemical composition, Chemistry, cointegration, comprehensive books developed, correspondence to, Cultivation, Delayed-Action Preparations, department of economics, Diffusion, dimension, economic growth, Electron, email, from ACS sponsored, functional properties, Gel point, Gelatin, Gelation mechanisms, giles, icle, jgiles, judith a, main products, medicinal uses, Microchemistry, Microchemistry: methods, Microscopy, misspecification, model, Nigella, ot, Percolation theory, Permeability, Physical, Physicochemical Phenomena, po box, Polymers, quality specifications, robustness, Rubber elasticity, Scanning, Sol-gel and gel-sol transitions, Starch gels, telephone, The ACS Symposium Series was first published in 1, The ACS Symposium Series was first published in 19, time series models, toxicity, university of victoria, uvic, v8w 2y2, victoria, we are grateful, Whey protein nanofibril gels}, pubstate = {published}, tppubtype = {phdthesis} } This book is an attempt to introduce the enormous amount of literature on solidification heat transfer. Many of the applications have been directed to water/ice soil systems. |
2004 |
Velásquez-García, Luis Fernando The Design, Fabrication and Testing of Micro-fabricated Linear and Planar Colloid Thruster Arrays PhD Thesis 2004. BibTeX | Tags: @phdthesis{LuisFernandoVelasquez-Garcia2004, title = {The Design, Fabrication and Testing of Micro-fabricated Linear and Planar Colloid Thruster Arrays}, author = {Luis Fernando Velásquez-García}, year = {2004}, date = {2004-01-01}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
Jilla, Cyrus D; Miller, David W Multi-objective, multidisciplinary design optimization methodology for distributed satellite systems Journal Article Journal of Spacecraft and Rockets, 41 (1), pp. 39–50, 2004. BibTeX | Tags: @article{jilla2004multi, title = {Multi-objective, multidisciplinary design optimization methodology for distributed satellite systems}, author = {Cyrus D Jilla and David W Miller}, year = {2004}, date = {2004-01-01}, journal = {Journal of Spacecraft and Rockets}, volume = {41}, number = {1}, pages = {39--50}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Chung, Soon-Jo; Miller, David W; de Weck, Olivier L ARGOS testbed: study of multidisciplinary challenges of future spaceborne interferometric arrays Journal Article Optical Engineering, 43 (9), pp. 2156–2168, 2004. BibTeX | Tags: @article{chung2004argos, title = {ARGOS testbed: study of multidisciplinary challenges of future spaceborne interferometric arrays}, author = {Soon-Jo Chung and David W Miller and Olivier L de Weck}, year = {2004}, date = {2004-01-01}, journal = {Optical Engineering}, volume = {43}, number = {9}, pages = {2156--2168}, publisher = {International Society for Optics and Photonics}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Kong, Edmund MC; Kwon, Daniel W; Schweighart, Samuel A; Elias, Laila M; Sedwick, Raymond J; Miller, David W Electromagnetic formation flight for multisatellite arrays Journal Article Journal of spacecraft and Rockets, 41 (4), pp. 659–666, 2004. BibTeX | Tags: @article{kong2004electromagnetic, title = {Electromagnetic formation flight for multisatellite arrays}, author = {Edmund MC Kong and Daniel W Kwon and Samuel A Schweighart and Laila M Elias and Raymond J Sedwick and David W Miller}, year = {2004}, date = {2004-01-01}, journal = {Journal of spacecraft and Rockets}, volume = {41}, number = {4}, pages = {659--666}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Sullivan, Kay Ueda PIC Simulation of SPT Hall Thrusters : High Power Operation and Wall Effects By PhD Thesis 2004. @phdthesis{Sullivan2004, title = {PIC Simulation of SPT Hall Thrusters : High Power Operation and Wall Effects By}, author = {Kay Ueda Sullivan}, year = {2004}, date = {2004-01-01}, abstract = {The fully kinetic Hall Thruster simulation built by [1] and used by [2] is further refined and used to obtain results for the P5 SPT Hall thruster at 3kw and 5kw operation. Performance data agree well with experiments [3], although very low values of anomalous diffusivity must be used for convergence. Particle temperatures and plasma potentials in the chamber are similar to experimental results, although charged particles and peak ionization rates are found further upstream than is observed experimentally. Electron transport mechanisms and the magnetic field configuration are analyzed for their physical consistency and effect on particle placement. Electron mobility rates are found to be physical although the reason for high Hall parameter is still unclear. Strong magnetic mirror effects, that are not reported in experimental data, are found in the simulation. Meanwhile, two sputtering models are added to the simulation and tested. A yield model based on [4]'s theories and implemented with [5]'s functions is found to agree well with experimental yield data for 300eV to 1000eV sources, but produces small yields at thruster operating conditions.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } The fully kinetic Hall Thruster simulation built by [1] and used by [2] is further refined and used to obtain results for the P5 SPT Hall thruster at 3kw and 5kw operation. Performance data agree well with experiments [3], although very low values of anomalous diffusivity must be used for convergence. Particle temperatures and plasma potentials in the chamber are similar to experimental results, although charged particles and peak ionization rates are found further upstream than is observed experimentally. Electron transport mechanisms and the magnetic field configuration are analyzed for their physical consistency and effect on particle placement. Electron mobility rates are found to be physical although the reason for high Hall parameter is still unclear. Strong magnetic mirror effects, that are not reported in experimental data, are found in the simulation. Meanwhile, two sputtering models are added to the simulation and tested. A yield model based on [4]'s theories and implemented with [5]'s functions is found to agree well with experimental yield data for 300eV to 1000eV sources, but produces small yields at thruster operating conditions. |
Whiting, James K Orbital Transfer Trajectory Optimization PhD Thesis 2004. Abstract | BibTeX | Tags: control law, Hamiltonian, low thrust, Optimization @phdthesis{Whiting2004, title = {Orbital Transfer Trajectory Optimization}, author = {James K Whiting}, year = {2004}, date = {2004-01-01}, abstract = {Recent developments in astronautical engineering have led to the adoption of low thrust rocket engines for spacecraft. Optimizing the orbital transfers for low thrust engines is significantly more complicated than optimizing transfers for impulsive engines because a continuous control law must be found and long integrations are necessary to determine whether the control law works or not. Previous work on optimizing low thrust orbital transfers has led to the development of control laws for continuous thrusting including the effects of oblateness, multiple attracting bodies, eclipses, and solar cell degradation. The current work adds to this by developing control laws for optimal coasting and for variable specific impulse at constant power. The Hamiltonian method is used to develop the optimal control laws and physical interpretations are given to each term in the Hamiltonian. Application of the optimal coasting control law to transfers from LEO to GEO indicate that small amounts of coasting can significantly reduce the fuel needed for a transfer.}, keywords = {control law, Hamiltonian, low thrust, Optimization}, pubstate = {published}, tppubtype = {phdthesis} } Recent developments in astronautical engineering have led to the adoption of low thrust rocket engines for spacecraft. Optimizing the orbital transfers for low thrust engines is significantly more complicated than optimizing transfers for impulsive engines because a continuous control law must be found and long integrations are necessary to determine whether the control law works or not. Previous work on optimizing low thrust orbital transfers has led to the development of control laws for continuous thrusting including the effects of oblateness, multiple attracting bodies, eclipses, and solar cell degradation. The current work adds to this by developing control laws for optimal coasting and for variable specific impulse at constant power. The Hamiltonian method is used to develop the optimal control laws and physical interpretations are given to each term in the Hamiltonian. Application of the optimal coasting control law to transfers from LEO to GEO indicate that small amounts of coasting can significantly reduce the fuel needed for a transfer. |
Woffinden, David C On-Orbit Satellite Inspection: Navigation and Delta-V Analysis PhD Thesis 2004. @phdthesis{woffindenOnOrbitSatelliteInspection2004, title = {On-Orbit Satellite Inspection: Navigation and Delta-V Analysis}, author = {David C Woffinden}, year = {2004}, date = {2004-01-01}, volume = {Masters Th}, number = {Massachussetts Institute of Technology}, abstract = {Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004.}, keywords = {★}, pubstate = {published}, tppubtype = {phdthesis} } Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2004. |
Chang, Darren Datong Quantifying Technology Infusion and Policy Impact on Low Earth Orbit Communication Satellite Constellations.Pdf PhD Thesis 2004. BibTeX | Tags: @phdthesis{Chang2004, title = {Quantifying Technology Infusion and Policy Impact on Low Earth Orbit Communication Satellite Constellations.Pdf}, author = {Darren Datong Chang}, year = {2004}, date = {2004-01-01}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
Kong, Edmund M; Saenz-Otero, Alvar; Nolet, Simon; Berkovitz, Dustin S; Miller, David W; Sell, Steve W SPHERES as Formation Flight Algorithm Development and Validation Testbed: Current Progress and Beyond Journal Article 2004. BibTeX | Tags: @article{kong2004spheres, title = {SPHERES as Formation Flight Algorithm Development and Validation Testbed: Current Progress and Beyond}, author = {Edmund M Kong and Alvar Saenz-Otero and Simon Nolet and Dustin S Berkovitz and David W Miller and Steve W Sell}, year = {2004}, date = {2004-01-01}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Deux, Jean-Marie Kinetic Modeling of Electrodynamic Space Tethers PhD Thesis 2004. BibTeX | Tags: @phdthesis{Deux2004, title = {Kinetic Modeling of Electrodynamic Space Tethers}, author = {Jean-Marie Deux}, year = {2004}, date = {2004-01-01}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
Nolet, Simon; Kong, Edmund; Miller, David W Autonomous docking algorithm development and experimentation using the SPHERES testbed Inproceedings Spacecraft Platforms and Infrastructure, pp. 1–16, International Society for Optics and Photonics 2004. BibTeX | Tags: @inproceedings{nolet2004autonomous, title = {Autonomous docking algorithm development and experimentation using the SPHERES testbed}, author = {Simon Nolet and Edmund Kong and David W Miller}, year = {2004}, date = {2004-01-01}, booktitle = {Spacecraft Platforms and Infrastructure}, volume = {5419}, pages = {1--16}, organization = {International Society for Optics and Photonics}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Enright, John; Hilstad, Mark; Saenz-Otero, Alvar; Miller, David The SPHERES Guest Scientist Program: collaborative science on the ISS Inproceedings Aerospace Conference, 2004. Proceedings. 2004 IEEE, IEEE 2004. BibTeX | Tags: @inproceedings{enright2004spheres, title = {The SPHERES Guest Scientist Program: collaborative science on the ISS}, author = {John Enright and Mark Hilstad and Alvar Saenz-Otero and David Miller}, year = {2004}, date = {2004-01-01}, booktitle = {Aerospace Conference, 2004. Proceedings. 2004 IEEE}, volume = {1}, organization = {IEEE}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Kong, Edmund Mun Choong; Hilstad, Mark Ole; Nolet, Simon; Miller, David W Development and verification of algorithms for spacecraft formation flight using the SPHERES testbed: application to TPF Inproceedings New Frontiers in Stellar Interferometry, pp. 308–320, International Society for Optics and Photonics 2004. BibTeX | Tags: @inproceedings{kong2004development, title = {Development and verification of algorithms for spacecraft formation flight using the SPHERES testbed: application to TPF}, author = {Edmund Mun Choong Kong and Mark Ole Hilstad and Simon Nolet and David W Miller}, year = {2004}, date = {2004-01-01}, booktitle = {New Frontiers in Stellar Interferometry}, volume = {5491}, pages = {308--320}, organization = {International Society for Optics and Photonics}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Elias, Laila Mireille Dynamics of Multi-Body Space Interferometers Including Reaction Wheel Gyroscopic Stiffening Effects : By LIBR ARIES PhD Thesis 2004. BibTeX | Tags: @phdthesis{eliasDynamicsMultiBodySpace2004, title = {Dynamics of Multi-Body Space Interferometers Including Reaction Wheel Gyroscopic Stiffening Effects : By LIBR ARIES}, author = {Laila Mireille Elias}, year = {2004}, date = {2004-01-01}, number = {March}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
Howell, Deborah J Multiconfiguration Model Tuning for Precision Optomechanical Systems PhD Thesis 2004, ISSN: 0277786X. Abstract | Links | BibTeX | Tags: @phdthesis{howellMulticonfigurationModelTuning2004, title = {Multiconfiguration Model Tuning for Precision Optomechanical Systems}, author = {Deborah J Howell}, doi = {10.1117/12.551436}, issn = {0277786X}, year = {2004}, date = {2004-01-01}, volume = {5497}, abstract = {High quality multi-disciplinary integrated models are needed for complex opto-mechanical spacecraft such as SIM and TPF in order to predict the system's on-orbit behavior. One major activity in early design is to examine the system's behavior over multiple configurations using an integrated model. A three step procedure for model tuning is outlined that consists of (1) applying engineering insight to the model so that all physical systems are present in the model, (2) using optimization to automatically update system parameters that are uncertain in the model, and (3) evaluating the model at several configurations using the updated parameters. The key contribution of this work is the systematic checking of the validity of the updated parameters by evaluating, both in the model and the experiment, the system at different configurations (step three). It is hypothesized that if the simulation model and experimental data of the additional configurations match well then the tuned system parameters were indeed updated in a way that physically represents the system. This three step process is applied to a testbed at the MIT Space System Laboratory.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } High quality multi-disciplinary integrated models are needed for complex opto-mechanical spacecraft such as SIM and TPF in order to predict the system's on-orbit behavior. One major activity in early design is to examine the system's behavior over multiple configurations using an integrated model. A three step procedure for model tuning is outlined that consists of (1) applying engineering insight to the model so that all physical systems are present in the model, (2) using optimization to automatically update system parameters that are uncertain in the model, and (3) evaluating the model at several configurations using the updated parameters. The key contribution of this work is the systematic checking of the validity of the updated parameters by evaluating, both in the model and the experiment, the system at different configurations (step three). It is hypothesized that if the simulation model and experimental data of the additional configurations match well then the tuned system parameters were indeed updated in a way that physically represents the system. This three step process is applied to a testbed at the MIT Space System Laboratory. |
Lamamy, Julien-Alexandre Enhancing the Science Return of Mars Missions via Sample Preparation , Robotic Surface Exploration , and in Orbit Fuel Production Julien-Alexandre Lamamy , David Miller May 2004 SSL # 7-04 Enhancing the Science Return of Mars Missions via Sample Preparati PhD Thesis 2004. BibTeX | Tags: @phdthesis{Julien-2004, title = {Enhancing the Science Return of Mars Missions via Sample Preparation , Robotic Surface Exploration , and in Orbit Fuel Production Julien-Alexandre Lamamy , David Miller May 2004 SSL # 7-04 Enhancing the Science Return of Mars Missions via Sample Preparati}, author = {Julien-Alexandre Lamamy}, year = {2004}, date = {2004-01-01}, number = {May}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
LoBosco, David M 2004, ISSN: 0277786X. @phdthesis{loboscoIntegratedModelingOptical2004, title = {Integrated Modeling of Optical Performance for the Terrestrial Planet Finder Structurally Connected Interferometer}, author = {David M LoBosco}, doi = {10.1117/12.550929}, issn = {0277786X}, year = {2004}, date = {2004-01-01}, volume = {5497}, number = {May}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
2003 |
Lozano, P Studies on the Ion-Droplet Mixed Regime in Colloid Thrusters PhD Thesis 2003. @phdthesis{lozanoStudiesIonDropletMixed2003, title = {Studies on the Ion-Droplet Mixed Regime in Colloid Thrusters}, author = {P Lozano}, year = {2003}, date = {2003-01-01}, volume = {282}, number = {February}, abstract = {Colloid thrusters working with mixtures of ions and droplets are gradually becoming an alternative technology for space micro-propulsion needs in missions requiring high position controllability, compactness and low power consumption. The mechanics of the colloid thruster emission process are discussed through a theoretical review of its general properties and by means of experimental characterization. Droplets are the most energetic particles in the beam, while ions are emitted with energies that overlap those of the droplets but extend down a few hundreds of volts in comparison. A small fraction of the ion current is emitted from the jet breakup region with considerably lower energies. This energy variety transforms the optical hardware elements into energy filters by taking advantage of the chromatic aberration property of electrostatic lenses. The relatively wide ion energy distribution is conceptually explained as a result of emission from different locations in the cone-jet structure where the normal electric field is most intense and where the convective current produces drastic changes in the local potential. The energy spread of purely ionic emission from EMI-BF4 is measured and is found to be of the order of a few tens of volts. A high-speed electron multiplier detector is used for the first time to analyze the ion component emitted directly from electrospray sources. Ion identification is performed and is found that the most probable degree of solvation is n = 5.1 for (CH3NO)nNa+ ions in formamide doped with NaI for a conductivity of 2.15 siemens per meter. Two ions are observed for the ionic liquid EMI-BF4: EMI+ and (EMI-BF4)EMI+. It is found that these ions are emitted with a small energy differential. The use of 5 micron ID capillary emitters, working with flow rates close to 20 pico-liters per second, is successfully achieved. Under such conditions, highly charged droplets with specific charges in excess of 10 coulombs per gram are obtained, representing the highest charge state obtained so far in experiments of this kind. The applicability of colloid thrusters for space propulsion is discussed in terms of performance parameters in the ion-droplet mixed regime, along with other practical considerations, such as the problem of beam neutralization.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } Colloid thrusters working with mixtures of ions and droplets are gradually becoming an alternative technology for space micro-propulsion needs in missions requiring high position controllability, compactness and low power consumption. The mechanics of the colloid thruster emission process are discussed through a theoretical review of its general properties and by means of experimental characterization. Droplets are the most energetic particles in the beam, while ions are emitted with energies that overlap those of the droplets but extend down a few hundreds of volts in comparison. A small fraction of the ion current is emitted from the jet breakup region with considerably lower energies. This energy variety transforms the optical hardware elements into energy filters by taking advantage of the chromatic aberration property of electrostatic lenses. The relatively wide ion energy distribution is conceptually explained as a result of emission from different locations in the cone-jet structure where the normal electric field is most intense and where the convective current produces drastic changes in the local potential. The energy spread of purely ionic emission from EMI-BF4 is measured and is found to be of the order of a few tens of volts. A high-speed electron multiplier detector is used for the first time to analyze the ion component emitted directly from electrospray sources. Ion identification is performed and is found that the most probable degree of solvation is n = 5.1 for (CH3NO)nNa+ ions in formamide doped with NaI for a conductivity of 2.15 siemens per meter. Two ions are observed for the ionic liquid EMI-BF4: EMI+ and (EMI-BF4)EMI+. It is found that these ions are emitted with a small energy differential. The use of 5 micron ID capillary emitters, working with flow rates close to 20 pico-liters per second, is successfully achieved. Under such conditions, highly charged droplets with specific charges in excess of 10 coulombs per gram are obtained, representing the highest charge state obtained so far in experiments of this kind. The applicability of colloid thrusters for space propulsion is discussed in terms of performance parameters in the ion-droplet mixed regime, along with other practical considerations, such as the problem of beam neutralization. |
McConnell, Josh Technical and Policy Issues Surrounding the Use of Autonomous Manueverable Earth Observing Satellites PhD Thesis 2003. Abstract | BibTeX | Tags: Embedded systems, satellite policy, scheduling, ★ @phdthesis{McConnell2003, title = {Technical and Policy Issues Surrounding the Use of Autonomous Manueverable Earth Observing Satellites}, author = {Josh McConnell}, year = {2003}, date = {2003-01-01}, abstract = {To better respond to transient Earth phenomenon that can cause loss of life or damage to economic assets (tornadoes, mudslides, flash floods, etc.), an increase in the amount and timeliness of information collected on phenomenon is needed. One method for collecting this information is by using groups of Earth observing satellites with the ability to perform autonomous orbital maneuvers and view phenomenon on demand. However, as satellites are very costly, creating a group of satellites large enough to perform this task is currently beyond the abilities of any one organization. One method of gathering a group of satellites that is large enough is by several organizations ``pooling'' their satellite resources together temporarily. In order to pool autonomous maneuverable satellites, several technical and policy problems must be overcome. The technical problem addressed is how to schedule large numbers of satellites to effectively collect critical information on phenomenon, even in the face of unexpected events, such as satellite failures that can prohibit the collection of this information. The policy problem addressed is how to overcome barriers that prevent organizations from temporarily loaning their satellite resources to a pooling system. To overcome the technical problem of effectively scheduling large numbers of satellites, an integrated planner is developed using Draper Laboratory's EPOS 1.0 optimal planner and the ALLIANCE behavioral planning algorithm. The optimal planner efficiently allocates satellite and fuel resources, while the reaction planner modifies the optimal plan if an unexpected event occurs that would decrease the group's ability to collect information. To overcome the policy problem of assembling a large number of satellites, a public-private partnership pooling organization is proposed. As satellites are currently a highly expensive and limited resource, the willingness and ability of organizations with satellite resources to contribute part of their satellite resources is in question. Barriers identified when forming a pooling organization and ways to overcome these barriers are identified. Through the analysis of several simulations it was found that it is possible to achieve the technical results of responding to unexpected events in a timely manner without a substantial increase in fuel usage. Through a policy analysis it was determined that the liability issues associated with satellite pooling and organizational cultural inertia are the primary barriers inhibiting organizations from participating in a pool, but that these are possible to overcome, as there are examples where similar cross organizational relationships have succeeded with great effort. This thesis finds that the critical barriers that must be resolved before creating a group of autonomous maneuverable Earth observing satellites are not technical in nature, but are legal and cultural changes in organizations.}, keywords = {Embedded systems, satellite policy, scheduling, ★}, pubstate = {published}, tppubtype = {phdthesis} } To better respond to transient Earth phenomenon that can cause loss of life or damage to economic assets (tornadoes, mudslides, flash floods, etc.), an increase in the amount and timeliness of information collected on phenomenon is needed. One method for collecting this information is by using groups of Earth observing satellites with the ability to perform autonomous orbital maneuvers and view phenomenon on demand. However, as satellites are very costly, creating a group of satellites large enough to perform this task is currently beyond the abilities of any one organization. One method of gathering a group of satellites that is large enough is by several organizations ``pooling'' their satellite resources together temporarily. In order to pool autonomous maneuverable satellites, several technical and policy problems must be overcome. The technical problem addressed is how to schedule large numbers of satellites to effectively collect critical information on phenomenon, even in the face of unexpected events, such as satellite failures that can prohibit the collection of this information. The policy problem addressed is how to overcome barriers that prevent organizations from temporarily loaning their satellite resources to a pooling system. To overcome the technical problem of effectively scheduling large numbers of satellites, an integrated planner is developed using Draper Laboratory's EPOS 1.0 optimal planner and the ALLIANCE behavioral planning algorithm. The optimal planner efficiently allocates satellite and fuel resources, while the reaction planner modifies the optimal plan if an unexpected event occurs that would decrease the group's ability to collect information. To overcome the policy problem of assembling a large number of satellites, a public-private partnership pooling organization is proposed. As satellites are currently a highly expensive and limited resource, the willingness and ability of organizations with satellite resources to contribute part of their satellite resources is in question. Barriers identified when forming a pooling organization and ways to overcome these barriers are identified. Through the analysis of several simulations it was found that it is possible to achieve the technical results of responding to unexpected events in a timely manner without a substantial increase in fuel usage. Through a policy analysis it was determined that the liability issues associated with satellite pooling and organizational cultural inertia are the primary barriers inhibiting organizations from participating in a pool, but that these are possible to overcome, as there are examples where similar cross organizational relationships have succeeded with great effort. This thesis finds that the critical barriers that must be resolved before creating a group of autonomous maneuverable Earth observing satellites are not technical in nature, but are legal and cultural changes in organizations. |
Kong, Edmund MC; Miller, David W Optimal spacecraft reorientation for earth orbiting clusters: applications to Techsat 21 Journal Article Acta Astronautica, 53 (11), pp. 863–877, 2003. BibTeX | Tags: @article{kong2003optimal, title = {Optimal spacecraft reorientation for earth orbiting clusters: applications to Techsat 21}, author = {Edmund MC Kong and David W Miller}, year = {2003}, date = {2003-01-01}, journal = {Acta Astronautica}, volume = {53}, number = {11}, pages = {863--877}, publisher = {Elsevier}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Sou, Kin Cheong; de Weck, Olivier Fast Time Domain Simulation for Large-Order Linear Time Invariant Systems Inproceedings pp. 471-476, 2003. @inproceedings{deWeck03fastTime, title = {Fast Time Domain Simulation for Large-Order Linear Time Invariant Systems}, author = {Kin Cheong Sou and Olivier de Weck}, doi = {10.2514/6.2003-1532}, year = {2003}, date = {2003-01-01}, journal = {44th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference}, volume = {2}, pages = {471-476}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Scialom, U Optimization of Satellite Constellation Reconfiguration PhD Thesis 2003. BibTeX | Tags: @phdthesis{Scialom2003, title = {Optimization of Satellite Constellation Reconfiguration}, author = {U Scialom}, year = {2003}, date = {2003-01-01}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
Smith, Bryan K Definition , Expansion and Screening of Architectures for Planetary Exploration Class Nuclear Electric Propulsion and Power Systems by Master of Science in Engineering and Management Massachusetts Institute of Technology PhD Thesis 2003. BibTeX | Tags: @phdthesis{Smith2003, title = {Definition , Expansion and Screening of Architectures for Planetary Exploration Class Nuclear Electric Propulsion and Power Systems by Master of Science in Engineering and Management Massachusetts Institute of Technology}, author = {Bryan K Smith}, year = {2003}, date = {2003-01-01}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
Warner, N Z Performance Testing and Internal Probe Measurements of a High Specific Impulse Hall Thruster PhD Thesis 2003. @phdthesis{Warner2003, title = {Performance Testing and Internal Probe Measurements of a High Specific Impulse Hall Thruster}, author = {N Z Warner}, year = {2003}, date = {2003-01-01}, abstract = {The BHT-1000 high specific impulse Hall thruster was used for performance testing and internal plasma measurements to support the ongoing development of computational models. The thruster was performance tested in both single and two stage anode configurations. In the single stage configuration, the specific impulse exceeded 3000s at a discharge voltage of 1000V while maintaining a thrust efficiency of 50 percent. Two stage operation produced higher thrust, specific impulse and thrust efficiency than the single stage configuration at most discharge voltages. The thruster thermal warmup was characterized using a thermocouple embedded in the outer exit ring, and the magnetic field topology was investigated using a Gaussmeter. The single stage thruster configuration was outfitted with a series of axially distributed Langmuir probes to determine plasma properties inside the discharge channel. Probe data were taken at discharge voltages between 300-900V. Axial profiles of electron temperature, electron density, and plasma potential were measured and compared to results of a previously developed two dimensional particle-in-cell simulation of the BHT-1000 thruster. The experimental data matched the simulation results well, particularly in profiles of electron temperature and plasma potential at low discharge voltages. The peak electron temperature was shown to depend on discharge voltage through a power law relationship in both the experimental and simulated data. The greatest discrepancies between experimental data and simulation results were found to be in comparisons of electron density, where it appears that the simulation may be "smearing" the plasma over too wide of an axial region. Hypotheses for this behavior were discussed along with recommendations for future work.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } The BHT-1000 high specific impulse Hall thruster was used for performance testing and internal plasma measurements to support the ongoing development of computational models. The thruster was performance tested in both single and two stage anode configurations. In the single stage configuration, the specific impulse exceeded 3000s at a discharge voltage of 1000V while maintaining a thrust efficiency of 50 percent. Two stage operation produced higher thrust, specific impulse and thrust efficiency than the single stage configuration at most discharge voltages. The thruster thermal warmup was characterized using a thermocouple embedded in the outer exit ring, and the magnetic field topology was investigated using a Gaussmeter. The single stage thruster configuration was outfitted with a series of axially distributed Langmuir probes to determine plasma properties inside the discharge channel. Probe data were taken at discharge voltages between 300-900V. Axial profiles of electron temperature, electron density, and plasma potential were measured and compared to results of a previously developed two dimensional particle-in-cell simulation of the BHT-1000 thruster. The experimental data matched the simulation results well, particularly in profiles of electron temperature and plasma potential at low discharge voltages. The peak electron temperature was shown to depend on discharge voltage through a power law relationship in both the experimental and simulated data. The greatest discrepancies between experimental data and simulation results were found to be in comparisons of electron density, where it appears that the simulation may be "smearing" the plasma over too wide of an axial region. Hypotheses for this behavior were discussed along with recommendations for future work. |
Weck, Olivier De L Enhancing the Economics of Satellite Constellations via Staged Deployment and Orbital Reconfiguration Mathieu Chaize PhD Thesis 2003. BibTeX | Tags: @phdthesis{Weck2003, title = {Enhancing the Economics of Satellite Constellations via Staged Deployment and Orbital Reconfiguration Mathieu Chaize}, author = {Olivier De L Weck}, year = {2003}, date = {2003-01-01}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
Wehowsky, Andreas Frederik Safe Distributed Coordination of Heterogeneous Robots through Dynamic Simple Temporal Networks PhD Thesis 2003. @phdthesis{Wehowsky2003, title = {Safe Distributed Coordination of Heterogeneous Robots through Dynamic Simple Temporal Networks}, author = {Andreas Frederik Wehowsky}, year = {2003}, date = {2003-01-01}, abstract = {Research on autonomous intelligent systems has focused on how robots can robustly carry out missions in uncertain and harsh environments with very little or no human intervention. Robotic execution languages such as RAPs, ESL, and TDL improve robustness by managing functionally redundant procedures for achieving goals. The model-based programming approach extends this by guaranteeing correctness of execution through pre-planning of non-deterministic timed threads of activities. Executing model-based programs effectively on distributed autonomous platforms requires distributing this pre-planning process. This thesis presents a distributed planner for model-based programs whose planning and execution is distributed among agents with widely varying levels of processor power and memory resources. We make two key contributions. First, we reformulate a model-based program, which describes cooperative activities, into a hierarchical dynamic simple temporal network. This enables efficient distributed coordination of robots and supports deployment on heterogeneous robots. Second, we introduce a distributed temporal planner, called DTP, which solves hierarchical dynamic simple temporal networks with the assistance of the distributed Bellman-Ford shortest path algorithm. The implementation of DTP has been demonstrated successfully on a wide range of randomly generated examples and on a pursuer-evader challenge problem in simulation.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } Research on autonomous intelligent systems has focused on how robots can robustly carry out missions in uncertain and harsh environments with very little or no human intervention. Robotic execution languages such as RAPs, ESL, and TDL improve robustness by managing functionally redundant procedures for achieving goals. The model-based programming approach extends this by guaranteeing correctness of execution through pre-planning of non-deterministic timed threads of activities. Executing model-based programs effectively on distributed autonomous platforms requires distributing this pre-planning process. This thesis presents a distributed planner for model-based programs whose planning and execution is distributed among agents with widely varying levels of processor power and memory resources. We make two key contributions. First, we reformulate a model-based program, which describes cooperative activities, into a hierarchical dynamic simple temporal network. This enables efficient distributed coordination of robots and supports deployment on heterogeneous robots. Second, we introduce a distributed temporal planner, called DTP, which solves hierarchical dynamic simple temporal networks with the assistance of the distributed Bellman-Ford shortest path algorithm. The implementation of DTP has been demonstrated successfully on a wide range of randomly generated examples and on a pursuer-evader challenge problem in simulation. |
Azziz, Y Plasma Measurements on a 200-Watt Hall Thruster Plume PhD Thesis 2003. @phdthesis{Azziz2003, title = {Plasma Measurements on a 200-Watt Hall Thruster Plume}, author = {Y Azziz}, year = {2003}, date = {2003-01-01}, abstract = {The Electric Thruster Environmental Effects Verification (ETEEV) experiment consists of in-space diagnostics of a hall thruster plume. The ETEEV experiment will be mounted on a Hitchhiker-pallet on board the shuttle. The purpose of ETEEV is to provide recommendations with respect to the effluent-spacecraft interactions and provide design parameters for future missions. The objective of this project is to design and test instruments at the MIT Space Propulsion Laboratory to obtain plume measurements for the ETEEV experiment. The designed diagnostic instruments include a faraday cup, an emissive probe, and a Langmuir probe. Performance measurements of the 200-Watt Busek Hall thruster will be presented. Furthermore, the design of the diagnostic instruments will be described and the results of the in-laboratory testing will be shown. Measurements of current density using a faraday cup will be presented. The existence of various faraday cup designs causes variability of current density measurements for a given hall thruster plume. Therefore, a faraday cup will be designed such that the current density measurements will be comparable to the computer simulation results developed at MIT. Thus, this will ensure the validation of the ETEEV experiment. Also, measurements plasma potential using a floating emissive probe will be presented. The floating emissive probe will be used to map the plasma potential of the plume by increasing the heating current and measuring the floating potential. In addition, measurements of electron density and electron temperature using a single-Langmuir probe will be presented. Finally, contamination and erosion studies will be performed using Quartz Crystal Microbalances (QCM) and the results will be shown.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } The Electric Thruster Environmental Effects Verification (ETEEV) experiment consists of in-space diagnostics of a hall thruster plume. The ETEEV experiment will be mounted on a Hitchhiker-pallet on board the shuttle. The purpose of ETEEV is to provide recommendations with respect to the effluent-spacecraft interactions and provide design parameters for future missions. The objective of this project is to design and test instruments at the MIT Space Propulsion Laboratory to obtain plume measurements for the ETEEV experiment. The designed diagnostic instruments include a faraday cup, an emissive probe, and a Langmuir probe. Performance measurements of the 200-Watt Busek Hall thruster will be presented. Furthermore, the design of the diagnostic instruments will be described and the results of the in-laboratory testing will be shown. Measurements of current density using a faraday cup will be presented. The existence of various faraday cup designs causes variability of current density measurements for a given hall thruster plume. Therefore, a faraday cup will be designed such that the current density measurements will be comparable to the computer simulation results developed at MIT. Thus, this will ensure the validation of the ETEEV experiment. Also, measurements plasma potential using a floating emissive probe will be presented. The floating emissive probe will be used to map the plasma potential of the plume by increasing the heating current and measuring the floating potential. In addition, measurements of electron density and electron temperature using a single-Langmuir probe will be presented. Finally, contamination and erosion studies will be performed using Quartz Crystal Microbalances (QCM) and the results will be shown. |
Chung, Seung H A Decomposed Symbolic Approach To PhD Thesis 2003. BibTeX | Tags: @phdthesis{chungDecomposedSymbolicApproach2003, title = {A Decomposed Symbolic Approach To}, author = {Seung H Chung}, year = {2003}, date = {2003-01-01}, number = {June}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
de Blonk, Brett Optical-Level Structural Modelling of Membrane Mirrors for Spaceborne Telescopes By PhD Thesis 2003. BibTeX | Tags: @phdthesis{deblonkOpticalLevelStructuralModelling2003, title = {Optical-Level Structural Modelling of Membrane Mirrors for Spaceborne Telescopes By}, author = {Brett {de Blonk}}, year = {2003}, date = {2003-01-01}, number = {1993}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
Berkovitz, Dustin System identification of the SPHERES autonomous rendezvous and docking testbed Inproceedings AIAA Space 2003 Conference & Exposition, pp. 6385, 2003. BibTeX | Tags: @inproceedings{berkovitz2003system, title = {System identification of the SPHERES autonomous rendezvous and docking testbed}, author = {Dustin Berkovitz}, year = {2003}, date = {2003-01-01}, booktitle = {AIAA Space 2003 Conference & Exposition}, pages = {6385}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } |
Miller, David W; Kong, Edmund MC; Saenz-Otero, Alvar Overview of the SPHERES autonomous rendezvous and docking laboratory on the international space station. Journal Article Advances in the Astronautical Sciences, 113 , pp. 155–169, 2003. BibTeX | Tags: @article{miller2003overview, title = {Overview of the SPHERES autonomous rendezvous and docking laboratory on the international space station.}, author = {David W Miller and Edmund MC Kong and Alvar Saenz-Otero}, year = {2003}, date = {2003-01-01}, journal = {Advances in the Astronautical Sciences}, volume = {113}, pages = {155--169}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Saenz-Otero, Alvar; Miller, David The SPHERES ISS laboratory for rendezvous and formation flight Journal Article EUROPEAN SPACE AGENCY-PUBLICATIONS-ESA SP, 516 , pp. 217–224, 2003. BibTeX | Tags: @article{saenz2003spheres, title = {The SPHERES ISS laboratory for rendezvous and formation flight}, author = {Alvar Saenz-Otero and David Miller}, year = {2003}, date = {2003-01-01}, journal = {EUROPEAN SPACE AGENCY-PUBLICATIONS-ESA SP}, volume = {516}, pages = {217--224}, publisher = {EUROPEAN SPACE AGENCY}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Ferguson, Philip Andrew Distributed Estimation and Control Technologies for Formation Flying Spacecraft PhD Thesis 2003. @phdthesis{Ferguson2003, title = {Distributed Estimation and Control Technologies for Formation Flying Spacecraft}, author = {Philip Andrew Ferguson}, year = {2003}, date = {2003-01-01}, abstract = {Many future space missions, such as space-based radar, earth mapping, and inter- ferometry, will require formation flying of multiple spacecraft to achieve their very advanced science objectives. While formation flying offers many performance and op- erational advantages, there are several challenges that must be addressed, including navigation, control, autonomy, distributed data management, efficient inter-vehicle communication, and robustness. One of the key issues with formation flying of large fleets is selecting the overall system architecture, because it drives the distribution of the various algorithms and the extent to which data must be transmitted. These challenges are particularly evident with the relative navigation. While carrier-phase differential GPS can be used as a highly accurate sensor for LEO for- mations, it is not sufficient as the sole sensor for missions beyond LEO. If local ranges and range rates are used to augment or replace the GPS measurements, precise es- timation can continue into MEO and beyond. However these new measurements complicate the estimator decentralization by coupling the vehicles' state estimates. This thesis explores solutions to many of these challenges within the context of the Orion microsatellite formation flying mission. It also presents the Formation Fly- ing Information Technology testbed, developed to evaluate the communication and computational requirements associated with various system architectures when using augmented GPS. Several architectures and their associated estimation algorithms are also analyzed and compared in terms of performance, computation, and communica- tion requirements. This analysis clearly shows that the decentralized reduced-order filters provide near optimal estimation without excessive communication or computa- tion requirements. Embedding these reduced-order estimators within the hierarchic architecture presented should also permit scaling of the relative navigation to very large fleets. Thesis}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } Many future space missions, such as space-based radar, earth mapping, and inter- ferometry, will require formation flying of multiple spacecraft to achieve their very advanced science objectives. While formation flying offers many performance and op- erational advantages, there are several challenges that must be addressed, including navigation, control, autonomy, distributed data management, efficient inter-vehicle communication, and robustness. One of the key issues with formation flying of large fleets is selecting the overall system architecture, because it drives the distribution of the various algorithms and the extent to which data must be transmitted. These challenges are particularly evident with the relative navigation. While carrier-phase differential GPS can be used as a highly accurate sensor for LEO for- mations, it is not sufficient as the sole sensor for missions beyond LEO. If local ranges and range rates are used to augment or replace the GPS measurements, precise es- timation can continue into MEO and beyond. However these new measurements complicate the estimator decentralization by coupling the vehicles' state estimates. This thesis explores solutions to many of these challenges within the context of the Orion microsatellite formation flying mission. It also presents the Formation Fly- ing Information Technology testbed, developed to evaluate the communication and computational requirements associated with various system architectures when using augmented GPS. Several architectures and their associated estimation algorithms are also analyzed and compared in terms of performance, computation, and communica- tion requirements. This analysis clearly shows that the decentralized reduced-order filters provide near optimal estimation without excessive communication or computa- tion requirements. Embedding these reduced-order estimators within the hierarchic architecture presented should also permit scaling of the relative navigation to very large fleets. Thesis |
Ferry, Jean Benoit Electron Collection by a Tether at High Potential in a Magnetized Plasma PhD Thesis 2003, ISBN: 9781624100987. Abstract | Links | BibTeX | Tags: @phdthesis{ferryElectronCollectionTether2003, title = {Electron Collection by a Tether at High Potential in a Magnetized Plasma}, author = {Jean Benoit Ferry}, doi = {10.2514/6.2003-4948}, isbn = {9781624100987}, year = {2003}, date = {2003-01-01}, abstract = {In tethered satellites, it is very important to be able to estimate the electron current collected by the tether. However, this analysis is very difficult because of the presence of the geomagnetic field. We are developing a Particle-In-Cell model. The model uses a boundary condition based on quasi-neutrality, very similar to the one T. Onishi used in his Ph.D Thesis (2002), in order to solve for the local potential at the points of the computational boundary. This condition imposes ne = ni at the boundary. Moreover the motion of particles is computed analytically in a domain close to the tether - inside the sheath. This calculation is made possible by neglecting the space charge effect, which is very small in comparison with the tether potential, and therefore allowing the Laplace equation to be solved. The goal of this analytical domain is to provide a better accuracy in the region where electrons can reach high velocity. Although a similar approach was used by T. Onishi, the goal of this model is to experiment higher voltages for the tether, with bias ratio of the order of 1000 to 2500. Indeed such voltages are the ones of interest for space tethers. In order to be able to reach these voltages, we first conducted a precise analysis of the quiescent un-magnetized case. This analysis allowed us to successfully compare the model with established probe theory results. Moreover it gives a good foundation to explore the more complicated case of a magnetized flowing plasma. textcopyright 2003 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } In tethered satellites, it is very important to be able to estimate the electron current collected by the tether. However, this analysis is very difficult because of the presence of the geomagnetic field. We are developing a Particle-In-Cell model. The model uses a boundary condition based on quasi-neutrality, very similar to the one T. Onishi used in his Ph.D Thesis (2002), in order to solve for the local potential at the points of the computational boundary. This condition imposes ne = ni at the boundary. Moreover the motion of particles is computed analytically in a domain close to the tether - inside the sheath. This calculation is made possible by neglecting the space charge effect, which is very small in comparison with the tether potential, and therefore allowing the Laplace equation to be solved. The goal of this analytical domain is to provide a better accuracy in the region where electrons can reach high velocity. Although a similar approach was used by T. Onishi, the goal of this model is to experiment higher voltages for the tether, with bias ratio of the order of 1000 to 2500. Indeed such voltages are the ones of interest for space tethers. In order to be able to reach these voltages, we first conducted a precise analysis of the quiescent un-magnetized case. This analysis allowed us to successfully compare the model with established probe theory results. Moreover it gives a good foundation to explore the more complicated case of a magnetized flowing plasma. textcopyright 2003 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. |
Galabova, Kalina Architecting a Family of Space Tugs Based on Orbital Transfer Mission Scenarios PhD Thesis 2003, ISBN: 9781624101038. @phdthesis{galabovaArchitectingFamilySpace2003, title = {Architecting a Family of Space Tugs Based on Orbital Transfer Mission Scenarios}, author = {Kalina Galabova}, isbn = {9781624101038}, year = {2003}, date = {2003-01-01}, number = {2001}, abstract = {The potential benefit from extending satellite lifetimes or correcting the orbits of stranded satellites drives the need for architecting and designing a space tug vehicle. The main goal of this paper is to analyze various realistic mission scenarios and discuss the potential for creating a family of tugs, possibly using a common platform. In contrast to previous special-purpose tugs, a more exible, reusable vehicle that could serve various types of missions is considered. The paper illustrates a mission-driven concurrent engineering methodology that provides an eficient quantitative assessment of tug system architectures. First, the current on-orbit satellite population was examined and several most populated areas, referred to as "target orbital zones," were identified. Two case studies describe the establishment of one geosynchronous (GEO) and four low Earth orbit (LEO) satellite groups, inhabiting these zones. The "optimal" architecture for each of these five target orbital zones was obtained by varying the propellant type, parking location as well as the tugs's hardware and software complexity. The mapping to the utilities of response time, capability, and delta-v shows that promising tug designs are located below the "knee" in the cost-versus-utility tradeofi that is mainly dictated by the rocket equation. It is shown that while the GEO mission tug uses electrical propulsion, a conventional bipropellant tender with a wet mass of approximately 4,100 kg could accomplish any of the considered LEO missions. A family of tugs could potentially be developed by selectively reusing grappling, bus or propulsion modules. textcopyright 2003 by the American Institute of Aeronautics and Astronautics, Inc.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } The potential benefit from extending satellite lifetimes or correcting the orbits of stranded satellites drives the need for architecting and designing a space tug vehicle. The main goal of this paper is to analyze various realistic mission scenarios and discuss the potential for creating a family of tugs, possibly using a common platform. In contrast to previous special-purpose tugs, a more exible, reusable vehicle that could serve various types of missions is considered. The paper illustrates a mission-driven concurrent engineering methodology that provides an eficient quantitative assessment of tug system architectures. First, the current on-orbit satellite population was examined and several most populated areas, referred to as "target orbital zones," were identified. Two case studies describe the establishment of one geosynchronous (GEO) and four low Earth orbit (LEO) satellite groups, inhabiting these zones. The "optimal" architecture for each of these five target orbital zones was obtained by varying the propellant type, parking location as well as the tugs's hardware and software complexity. The mapping to the utilities of response time, capability, and delta-v shows that promising tug designs are located below the "knee" in the cost-versus-utility tradeofi that is mainly dictated by the rocket equation. It is shown that while the GEO mission tug uses electrical propulsion, a conventional bipropellant tender with a wet mass of approximately 4,100 kg could accomplish any of the considered LEO missions. A family of tugs could potentially be developed by selectively reusing grappling, bus or propulsion modules. textcopyright 2003 by the American Institute of Aeronautics and Astronautics, Inc. |
How, Jonathan P Real-Time Trjaectory Design for Unmanned Aerial Vehicles Using Receding Horizion Control PhD Thesis 2003. @phdthesis{How2003, title = {Real-Time Trjaectory Design for Unmanned Aerial Vehicles Using Receding Horizion Control}, author = {Jonathan P How}, year = {2003}, date = {2003-01-01}, keywords = {★}, pubstate = {published}, tppubtype = {phdthesis} } |
Liu, Kuo-Chia Stochastic Performance Analysis and Staged Controller Designs for Space Interferometry Systems PhD Thesis 2003, ISSN: 0277786X. @phdthesis{liuStochasticPerformanceAnalysis2003, title = {Stochastic Performance Analysis and Staged Controller Designs for Space Interferometry Systems}, author = {Kuo-Chia Liu}, doi = {10.1117/12.460877}, issn = {0277786X}, year = {2003}, date = {2003-01-01}, volume = {4852}, number = {May}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } |
2002 |
Makins, Brian J; Miller, David W Interferometer Architecture Trade Studies for the Terrestrial Planet Finder Mission PhD Thesis 2002. Abstract | BibTeX | Tags: architecture, GINA, TPF, trade studies @phdthesis{Makins2002, title = {Interferometer Architecture Trade Studies for the Terrestrial Planet Finder Mission}, author = {Brian J Makins and David W Miller}, year = {2002}, date = {2002-01-01}, abstract = {A process, based on a quantitative systems engineering methodology, is developed and then used to conduct trade studies for NASA's Terrestrial Planet Finder (TPF) Mission. A software tool, which automates this process, was built to rapidly analyze competing system architectures, including the structurally connected (SCI), tethered spacecraft (TSI), and separated spacecraft interferometers (SSI). This tool, the TPF Mission Analysis Software (TMAS), consists of six macro-modules that take the top-level design variables; namely the number, size, and shape of the apertures, orbit of operation, interferometer baseline, and observational wavelength; and outputs a system design that best meets the mission requirements. Each macro-module consists of sub-modules which parametrically design the spacecraft subsystems. This approach provides many advantages, most notably, is the ability to refine the model components as the mission evolves. Ultimately, the designs are evaluated with the Generalized Information Network Analysis (GINA) performance module. GINA, uses the fundamentals of aperture physics, network theory, and accepted cost estimating relationships, to compute the metrics used to compare the architectures - the design's capability in each of TPF's operational modes, its cumulative performance in the presence of failures, and lifecycle cost. After TMAS was benchmarked, it was used to evaluate nearly 9000 different mission architectures. On the basis of the costperformance metrics, the relative advantages of the SCI, TSI, and SSI, as well as the toplevel design variables, were identified. The results provide insight into the trade space, which can be used to identify cost-effective architectures worth investigating in the latter design stages for TPF.}, keywords = {architecture, GINA, TPF, trade studies}, pubstate = {published}, tppubtype = {phdthesis} } A process, based on a quantitative systems engineering methodology, is developed and then used to conduct trade studies for NASA's Terrestrial Planet Finder (TPF) Mission. A software tool, which automates this process, was built to rapidly analyze competing system architectures, including the structurally connected (SCI), tethered spacecraft (TSI), and separated spacecraft interferometers (SSI). This tool, the TPF Mission Analysis Software (TMAS), consists of six macro-modules that take the top-level design variables; namely the number, size, and shape of the apertures, orbit of operation, interferometer baseline, and observational wavelength; and outputs a system design that best meets the mission requirements. Each macro-module consists of sub-modules which parametrically design the spacecraft subsystems. This approach provides many advantages, most notably, is the ability to refine the model components as the mission evolves. Ultimately, the designs are evaluated with the Generalized Information Network Analysis (GINA) performance module. GINA, uses the fundamentals of aperture physics, network theory, and accepted cost estimating relationships, to compute the metrics used to compare the architectures - the design's capability in each of TPF's operational modes, its cumulative performance in the presence of failures, and lifecycle cost. After TMAS was benchmarked, it was used to evaluate nearly 9000 different mission architectures. On the basis of the costperformance metrics, the relative advantages of the SCI, TSI, and SSI, as well as the toplevel design variables, were identified. The results provide insight into the trade space, which can be used to identify cost-effective architectures worth investigating in the latter design stages for TPF. |
Masterson, Rebecca Development and Validation of Reaction Wheel Disturbance Models: Empirical Model PhD Thesis 2002, ISSN: 0022460X. Abstract | Links | BibTeX | Tags: @phdthesis{mastersonDevelopmentValidationReaction2002, title = {Development and Validation of Reaction Wheel Disturbance Models: Empirical Model}, author = {Rebecca Masterson}, doi = {10.1006/jsvi.2001.3868}, issn = {0022460X}, year = {2002}, date = {2002-01-01}, volume = {249}, number = {3}, abstract = {Accurate disturbance models are necessary to predict the effects of vibrations on the performance of precision space-based telescopes, such as the Space Interferometry Mission (SIM). There are many possible disturbance sources on such spacecraft, but mechanical jitter from the reaction wheel assembly (RWA) is anticipated to be the largest. A method has been developed and implemented in the form of a MATLAB toolbox to extract parameters for an empirical disturbance model from RWA micro-vibration data. The disturbance model is based on one that was used to predict the vibration behaviour of the Hubble Space Telescope (HST) wheels and assumes that RWA disturbances consist of discrete harmonics of the wheel speed with amplitudes proportional to the wheel speed squared. The MATLAB toolbox allows the extension of this empirical disturbance model for application to any reaction wheel given steady state vibration data. The toolbox functions are useful for analyzing RWA vibration data, and the model provides a good estimate of the disturbances over most wheel speeds. However, it is shown that the disturbances are under-predicted by a model of this form over some wheel speed ranges. The poor correlation is due to the fact that the empirical model does not account for disturbance amplifications caused by interactions between the harmonics and the structural modes of the wheel. Experimental data from an ITHACO Space Systems E-type reaction wheel are used to illustrate the model development and validation process.}, keywords = {}, pubstate = {published}, tppubtype = {phdthesis} } Accurate disturbance models are necessary to predict the effects of vibrations on the performance of precision space-based telescopes, such as the Space Interferometry Mission (SIM). There are many possible disturbance sources on such spacecraft, but mechanical jitter from the reaction wheel assembly (RWA) is anticipated to be the largest. A method has been developed and implemented in the form of a MATLAB toolbox to extract parameters for an empirical disturbance model from RWA micro-vibration data. The disturbance model is based on one that was used to predict the vibration behaviour of the Hubble Space Telescope (HST) wheels and assumes that RWA disturbances consist of discrete harmonics of the wheel speed with amplitudes proportional to the wheel speed squared. The MATLAB toolbox allows the extension of this empirical disturbance model for application to any reaction wheel given steady state vibration data. The toolbox functions are useful for analyzing RWA vibration data, and the model provides a good estimate of the disturbances over most wheel speeds. However, it is shown that the disturbances are under-predicted by a model of this form over some wheel speed ranges. The poor correlation is due to the fact that the empirical model does not account for disturbance amplifications caused by interactions between the harmonics and the structural modes of the wheel. Experimental data from an ITHACO Space Systems E-type reaction wheel are used to illustrate the model development and validation process. |
Masterson, Rebecca A; Miller, David W; Grogan, Robert L Development and validation of reaction wheel disturbance models: empirical model Journal Article Journal of Sound and Vibration, 249 (3), pp. 575–598, 2002. BibTeX | Tags: @article{masterson2002development, title = {Development and validation of reaction wheel disturbance models: empirical model}, author = {Rebecca A Masterson and David W Miller and Robert L Grogan}, year = {2002}, date = {2002-01-01}, journal = {Journal of Sound and Vibration}, volume = {249}, number = {3}, pages = {575--598}, publisher = {Elsevier}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Schweighart, Samuel A; Sedwick, Raymond J High-fidelity linearized J model for satellite formation flight Journal Article Journal of Guidance, Control, and Dynamics, 25 (6), pp. 1073–1080, 2002. BibTeX | Tags: @article{schweighart2002high, title = {High-fidelity linearized J model for satellite formation flight}, author = {Samuel A Schweighart and Raymond J Sedwick}, year = {2002}, date = {2002-01-01}, journal = {Journal of Guidance, Control, and Dynamics}, volume = {25}, number = {6}, pages = {1073--1080}, keywords = {}, pubstate = {published}, tppubtype = {article} } |