La thèse porte sur le rôle de la rotation planétaire dans la structure globale de l'interaction vent solaire/magnétosphère à partir de simulations magnétohydrodynamiques (MHD). Les magnétosphères planétaires du système solaire présentent une incroyable diversité, et notamment dans leurs configurations respectives de l'inclinaison de leur axe magnétique par rapport à leur axe de rotation. La durée des périodes de rotation par rapport au temps de relaxation de chaque magnétosphère diffère aussi d'une planète à l'autre. On distingue ainsi les rotateurs lents (Mercure et la Terre), pour lesquels le temps de relaxation est plus court que la période de rotation, des rotateurs rapides (Jupiter, Saturne, Uranus et Neptune). Dans le cas du rotateur lent Mercure, on s'intéresse à l'influence des paramètres du vent solaire sur la structure globale du champ magnétique et de l'écoulement. En appui à la mission spatiale BepiColombo, nous présentons des simulations effectuées pour deux modèles différents de champ magnétique herméen. Nous détaillons le rôle des fronts d'onde MHD stationnaires, en particulier les fronts stationnaires de mode lent dans la magnétogaine. Saturne présente la particularité d'avoir un axe magnétique parfaitement aligné avec son axe de rotation. C'est donc un cas de rotateur rapide stationnaire, qui nous permet d'étudier la structure globale du champ magnétique et de l'écoulement pour différentes orientations de l'IMF, mais aussi pour différentes vitesses de rotation de la planète. Enfin, le cas d'une configuration quelconque, avec un grand angle entre l'axe magnétique et l'axe de rotation planétaire, est étudié en présence d'un vent solaire magnétisé en s'inspirant de la configuration d'Uranus au solstice et à l'équinoxe. Dans la configuration « solstice », c'est à dire lorsque l'axe de rotation pointe vers le Soleil, on montre qu'une structure de nature alfvénique se développe en hélice dans la queue de la magnétosphère, et que les zones de reconnexion entre le champ magnétique planétaire et l'IMF, qui forment aussi une double hélice, ralentissent la progression de la structure alfvénique. A l'équinoxe, lorsque l'axe de rotation est toujours dans le plan de l’écliptique mais perpendiculaire à la direction Soleil-Uranus, la structure en hélice disparaît. / The topic of the thesis is the part of planetary rotation in the global structure of the solar wind interaction with planetary magnetospheres using MHD simulations. We discuss the distinction between slow and fast rotators from a MHD point of view. In the case of a non-rotating magnetosphere (as is the one of Mercury), the part of standing MHD modes is studied, along with a method to identify them in simulations. A fast-rotating but stationary magnetosphere (inspired by the case of Saturn) is presented in details and provides a good test to validate the new version of the AMRVAC code allowing for any configuration regarding the respective directions of the planetary spin axis, planetary magnetic axis, solar wind inflow direction, and IMF orientation. Finally, a random configuration, with a large angle between the planetary spin and magnetic axis, is analyzed for the first time in presence of a magnetized solar wind, using configurations inspired from the planet Uranus at solstice and equinox.

Project Upsilon is a proposed NASA Flagship Class, Uranus Orbiter and Probe mission concept to investigate Uranus' planetary magnetic field and atmosphere. Three spacecraft - the Upsilon-0 Propulsion Module, the Upsilon-1 Science Orbiter, and the Upsilon-2 Atmosphere Probe - shall be implemented to meet needs, goals, and objectives as stated by the NASA Solar System Planetary Science Decadal Survey 2013-2022. Upsilon-0 shall be expended in order to complete orbital capture about Uranus. Upsilon-1 shall study Uranus' planetary magnetic field, obtaining real-time measurements for nominally 20 months within the first two years of arrival; and for as long as possible after the first two years, as part of an extended science mission. Upsilon-2 shall be descended into Uranus' cloud tops to obtain physical data and imagery well into the atmosphere's depths. Chemical propulsion is employed in place of solar-electric propulsion, with regard to the interplanetary system-level trade tree. The interplanetary trajectory requires a single un-powered flyby of Jupiter, selected among several flyby node configurations. The science orbit produces nearly repeating latitude-longitude tracks over a rotating Uranus. The statistical estimation method combines an orbit determination model with respect to Uranus' flattening, and a simple magnetic dipole model for field line modeling. A 7-year period is allotted for the technology research and development, and the testing and verification stages of the project life cycle; the interplanetary journey to Uranus requires 21 years; and the nominal in-situ operation lifetime is 2 years. The Project Upsilon spacecraft launch in 2021 to "revolutionize our understanding of ice giant properties and processes, yielding significant insight into their evolutionary history"; contributing to the Planetary Science Decadal Survey's, and NASA's, key planetary science and deep space exploration visions. / text

Submitted by Andre Amarante Luiz null (amarante@feg.unesp.br) on 2018-02-11T19:52:31Z No. of bitstreams: 1 A_Amarante__O_C_Winter__M_Tsuchida.pdf: 9049058 bytes, checksum: a87f695e2060e08b5657bf5c4106d282 (MD5) / Approved for entry into archive by Pamella Benevides Gonçalves null (pamella@feg.unesp.br) on 2018-02-14T10:49:37Z (GMT) No. of bitstreams: 1 amarante_a_dr_guara.pdf: 9049058 bytes, checksum: a87f695e2060e08b5657bf5c4106d282 (MD5) / Made available in DSpace on 2018-02-14T10:49:37Z (GMT). No. of bitstreams: 1 amarante_a_dr_guara.pdf: 9049058 bytes, checksum: a87f695e2060e08b5657bf5c4106d282 (MD5) Previous issue date: 2017-09-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A origem e estabilidade de satélites planetários estão, intimamente ligadas à origem do nosso Sistema Solar e à formação de planetas. Portanto, é apropriado estudar alguns casos peculiares para nossa compreensão atual sobre a formação do Sistema Solar e para entender a criação dos sistemas de satélites. Tendo isso em vista um estudo da estabilidade dos satélites internos de Urano é realizado procurando viabilizar um cenário estável para tal sistema. Nós encontramos um provável cenário que possa nos dar indícios de que o sistema de satélites internos de Urano possa ser estável. Outro cenário importante para compreender a formação de satélite é o estudo de nosso próprio satélite natural, a Lua. O estudo da origem a Lua é realizado através de uma rápida revisão bibliográfica das teorias de origem da Lua e com isso tentamos analisar qual seria o cenário mais provável de colisão dentro da teoria do Grande Impacto que favorece a formação do nosso satélite, levando em conta suas características físicas, químicas e petrológicas. O cenário mais provável foi aquele em que colisões com massas comparáveis são usadas para se originar a Lua. O estudo da estabilidade de coorbitais dos pequenos satélites do sistema binário Plutão-Caronte é importante visto que também é um caso de cenário de formação de satélites peculiares no Sistema Solar. O estudo dessa estabilidade nos levou a indícios de que o sistema não possui coorbitais à suas pequenas luas, fato comprovado até agora pela missão New Horizons. / The origin and stability of planetary satellites are closely linked to the origin of our Solar System and the formation of planets. Therefore, it is appropriate to study some peculiar cases to our current understanding of the formation of the Solar System and to understand the origin of satellite systems. In order to study the stability of the internal satellites of Uranus, in order to provide a stable scenario for such a system. We have found a probable scenario that allows the internal uranian system get stable. Another important scenario for the formation of satellites is the moon scenario. The study of the origin of the Moon is made through a revised bibliographical revision of the theories of origin of the Moon and with this we try to analyze which forming the most probable collision within the theory of Great Impact that favors a formation of our satellite, taking into account its physical, chemical and petrological characteristics. The most likely scenario was that collisions with comparable masses are used to originate the Moon. The study of coorbital stability of the small satellites of the Pluto-Charon binary system is important since it is also a case of a peculiar satellite formation scenario in Our Solar System. The study of stability has led us to evidence that the system is not coorbitary in its small moons, a fact proven so far by the New Horizons mission

The Thesis objective is the design and implementation of the universal control system for a flying robot, quadrotor concept. The first part deals with ways of solving program for microcontrollers. The special attention is given to the FreeRTOS real-time operating system, which is designed for microcontrollers. The second part of the Thesis is focused on the description of the chosen microcontroller LM3S8962 and the hardware solution. One chapter is devoted to the integration of the robot to the Cassandra-WPF robotic control system. The third part deals with the identification of the new robot construction and the mathematical model creation. Using the model controllers for stabilization pitch and roll are designed and their functionality is verified on a physical model. The last part of the Thesis is focused on the FreeRTOS implementation and the control application creation.

No description available.

The ice giants, Uranus and Neptune, are the two outermost planets in our solar system. With only one satellite flyby each in the late 1980’s, the ice giants are arguably the least understood of the planets orbiting the Sun. A better understanding of these planets’ atmospheres will not only help satisfy the natural scientific curiosity we have about these distant spheres of gas, but also might provide insight into the dynamics and meteorology of our own planet’s atmosphere. Two new ground-based, near-infrared datasets of the ice giants are studied. Both datasets provide data in a portion of the electromagnetic spectrum that provides good constraint on the size of small scattering particles in the atmospheres’ clouds and haze layers. The broad extent of both telescopes’ spectral coverage allows characterisation of these small particles for a wide range of wavelengths. Both datasets also provide coverage of the 825 nm collision-induced hydrogen-absorption feature, allowing us to disentangle the latitudinal variation of CH4 abundance from the height and vertical extent of clouds in the upper troposphere. A two-cloud model is successfully fitted to IRTF SpeX Uranus data, parameterising both clouds with base altitude, fractional scale height, and total opacity. An optically thick, vertically thin cloud with a base pressure of 1.6 bar, tallest in the midlatitudes, shows strong preference for scattering particles of 1.35 μm radii. Above this cloud lies an optically thin, vertically extended haze extending upward from 1.0 bar and consistent with particles of 0.10 μm radii. An equatorial enrichment of methane abundance and a lower cloud of constant vertical thickness was shown to exist using two independent methods of analysis. Data from Palomar SWIFT of three different latitude regions.

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The giant planets exhibit banded zonal jet streams that have maintained theirstructures over decades. There are long-standing questions: how deep the windstructures extend? What mechanisms generate and maintain the observed winds?Why are the wind structures so stable? To answer these questions, we performedthree-dimensional numerical simulations of the atmospheric flow using the primitiveequations.First, we use a simple Newtonian cooling scheme as a crude approach to gener-ate atmospheric latitudinal temperature differences that could be caused by latentheating or radiation. Our Jupiter-like simulations show that shallow thermal forcingconfined to pressures near the cloud tops can produce deep zonal winds from thetropopause all the way down to the bottom of the simulated atmosphere (a fewhundred bars). These deep winds can attain speeds comparable to the zonal jetspeeds within the shallow, forced layer; they are pumped by Coriolis accelerationacting on a deep meridional circulation driven by the shallow-layer eddies.Next, we explicitly include the transport of water vapor and allow condensationand latent heating to occur whenever the water vapor is supersaturated. Our simu-lations show that large-scale moist convection associated with condensation of watervapor can produce multiple zonal jets similar to those on the gas giants (Jupiterand Saturn) and ice giants (Uranus and Neptune). For plausible water abundances(3-5 times solar on Jupiter/Saturn and 30 times solar on Uranus/Neptune), oursimulations produce about 20 zonal jets for Jupiter and Saturn and 3 zonal jetson Uranus and Neptune. Moreover, these Jupiter/Saturn cases produce equatorialsuperrotation whereas the Uranus/Neptune cases produce equatorial subrotation,consistent with the observed equatorial jet direction on these planets. Sensitiv-ity tests show that the water abundance is the controlling factor; modest waterabundances favor equatorial superrotation, whereas large water abundances favorequatorial subrotation. This provides a possible mechanism for the existence ofequatorial superrotation on Jupiter and Saturn and the lack of superrotation onUranus and Neptune.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23007号 / 理博第4684号 / 新制||理||1672(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 嶺重 慎, 准教授 前田 啓一, 教授 太田 耕司 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

<p>Ballistic and chemical trajectory options to Uranus are investigated for launch dates spanning 50 years. Trajectory solutions are found using STOUR, a patched conic propagator with an analytical ephemeris model. STOUR is heritage software developed by JPL and Purdue, written in FORTRAN. A total of 89 distinct gravity-assist paths to Uranus are considered, most of which will allow for a deep space maneuver (DSM) at some point along the path. For each launch year, the most desirable trajectory is identified and cataloged based on time of flight (up to 15 years), total $\Delta$V cost (DSM and capture maneuver), arrival $V_\infty$, and delivered payload. The Falcon Heavy (Recoverable), Vulcan VC6, Falcon Heavy (Expendable) and SLS Block 1B are considered to provide a range of low- to high-performance launch vehicle capabilities. A rough approximation of Starship's performance capabilities is also computed and applied to select years of launch dates. A flagship mission that delivers both a probe and an orbiter at Uranus is considered, which is approximated as a trajectory capable of delivering 2000 kg. Jupiter is unavailable as a gravity-assist body until the end of the 2020s but alternative gravity-assist paths exist, providing feasible trajectories even in years when Jupiter is not available. A rare Saturn-Uranus alignment in the late 2020's is identified which provides some such trajectory opportunities. A probe-and-orbiter mission to Uranus is feasible for a Vulcan VC6 with approximately 13 year flight times and for a Recoverable Falcon Heavy with approximately 14.5 year flight times. An Expendable Falcon Heavy reduces the time of flight to around 12.5 years and opens up `0E0U' as a gravity-assist path, while the SLS Block 1B typically offers trajectories with 10 to 11 year flight times and opens up more direct `JU' and `U' solutions. With the SLS, flight times as low as 7.5 years are possible.</p> <p>  </p> <p>A new, rapid grid search tool called GREMLINS is also outlined. This new software is capable of solving the same problems as STOUR, but improves on it in three crucial ways: an improved user-experience, more maneuver capabilities, and a more easily maintained and modified code base. GREMLINS takes a different approach to the broad search problem, forgoing $C_3$ matching in favor of using maneuvers to patch together tables of pre-computed Lambert arcs. This approach allows for vectorized computations across data frames of Lambert solutions, which can be computed much more efficiently than the for-loop style approach of past tools. Through the use of SQL tables and a two-step trajectory solving approach, this tool is able to run very quickly while still being able to handle any amount of data required for a broad search. Every line of code in GREMLINS is written in Python in an effort to make it more approachable and easier to develop for a wide community of users, as GREMLINS will be the only only grid search tool available as free and open source software. Multiple example missions and trajectory searches are explored to verify the output from GREMLINS and to compare its performance against STOUR. Despite using a slower coding language, GREMLINS is capable of performing the same trajectory searches in approximately 1/5 the runtime of STOUR, a FORTRAN-coded tool, thanks to its vectorized computations.</p>