In this work, sensor tasking refers to assigning the times and pointing directions for a sensor to collect observations of cataloged objects, in order to maintain the accuracy of the orbit estimates. Sensor tasking must consider the dynamics of the objects and uncertainty in their positions, the coordinate frame in which the sensor tasking is defined, the timing requirements for observations, the sensor capabilities, the local visibility, and constraints on the information processing and communication. This research focuses on finding efficient ways to solve the sensor tasking optimization problem. First, different coordinate frames are investigated, and it is shown that the observer fixed Local Meridian Equatorial (ground-based) and Satellite Meridian Equatorial (space-based) coordinate frames provide consistent sets of pointing directions and accurate representations of orbit uncertainty for use by the optimizers in solving the sensor tasking problem. Next, two classical optimizers (greedy and Weapon-Target Assignment) which rely on convexity are compared with two Machine Learning optimizers (Ant Colony Optimization and Distributed Q-learning) which attempt to learn about the solution space in order to approximate a global optimal solution. It is shown that the learning optimizers are able to generate better solutions, while the classical optimizers are more efficient to run and require less tuning to implement. Finally, the realistic scenario where the optimization algorithm receives no feedback before it must make the next decision is introduced. The Predicted Measurement Probability (PMP) is developed, and employed in a two sensor optimization framework. The PMP is shown to provide effective feedback to the optimization algorithm regarding the observations of each sensor.<br>

This study investigates how a choreographer, through the abstract language of contemporary dance, generates emotional states/nuances which can be recognised but at the same time allow for ambiguity in the reading of the work. This investigation was addressed through a series of performance projects, culminating in the final dance work Inhabited Space. The setting for the work, triggered by Bachelard's The Poetics of Space, became the imagined spaces of a domestic urban environment, specifically the lounge and bedroom. In order to create a work reflecting emotional states and nuances, a range of choreographic processes were explored to inform the construction of movement vocabulary, framed by performer/space/object relationships. This studio-based study with performative outcomes was supported by a hybrid methodological approach of predominantly practice-led research, incorporating aspects of action research and phenomenology. Findings and understandings emerged from reflective practice in the exegesis but were primarily embedded within the creative work itself.

<div> Space operations from the dawn of the Space Age have resulted in a large, and growing, resident space object population. However, the availability of sensor resources is limited, which presents a challenge to Space Situational Awareness applications. When direct communication with an object is not possible, whether that is due to a lack of access for active satellites or due to the object being characterized as debris, the only independent information source for learning about the resident space object population comes from measurements. Optical measurements are often a cost-effective method for obtaining information about resident space objects.<br></div><div> This work uses observability analysis to investigate the relationship between desired resident space object characteristics and the information resulting from ground-based optical measurements. Observability is a concept developed in modern control theory for evaluating whether the information contained within measurements is sufficient to describe the dynamical progression of a system over time. In this work, observability is applied to Space Situational Awareness applications to determine what object characteristic information can be recovered from ground-based optical measurements and under which conditions these determinations are possible. In addition, the constraints and limitations of applying observability to Space Situational Awareness applications are assessed and quantified.<br></div>

[Legal regulation of space objects] Abstract The space sector has experienced an unprecedented boom in recent years. The number of launched space objects is constantly rising, and new technology allows people to reach outer space much more efficiently than before. At the same time, private companies have taken interest into outer space and are looking for ways to generate profit from the final frontier. But how are issues related to the outer space and cosmic objects addressed legally? Where does outer space begin and what can be defined as a cosmic object? Although the space shuttle took off into an orbit like a rocketship, it returned to the Earth's atmosphere like an airplane. So, will it be space or aerial object? Or maybe both? There are many interesting and complex issues associated with space law and space objects. However, international treaties that form the basis of space law went into force more than 50 years ago. Will those legal institutes that were created in a completely different geopolitical situation be obsolete? Does current space law give us satisfactory answers to questions of jurisdiction or liability for damage caused by space objects? The diploma thesis tries to find answers to these, and other questions related to space law in the context of space objects. At the same time, however,...

With the increase in space traffic, proliferation of inexpensive launch opportunities, and interest from many countries in utilizing the space domain, threats to existing space assets are likely to increase dramatically in the coming years. The development of a system that can identify potential threats and alert space operators is vital to maintaining asset resiliency and security. The focus of this thesis is the design and evaluation of such a system. The design is comprised of the development of a classification hierarchy and the selection of machine learning models that will enable the identification of anomalous object behavior. The hierarchy is based on previous examples applied to object classification while reconsidering the assumption that a satellite may perform only one mission. The selected machine learning models perform both supervised classification of actively maneuvering objects and unsupervised identification of anomalous behavior within large satellite constellations. The evaluation process considers the independent adjustment of model hyperparameters to achieve optimal model settings. The optimal models perform both classification functions and return moderate accuracy. The system is applied to several case studies examining edge cases and what factors constitute a threatening object and what factors do not. Suggestions for improvement of the system in the future are presented. / Master of Science / The increase in space traffic, proliferation of inexpensive launch opportunities, and interest from many countries in utilizing the space domain represent existential threats to existing spacecraft and operations in low-Earth orbit. Threats to the safe operation of spacecraft are likely to increase dramatically in the coming years. The development of a system that can identify potential threats and alert space operators is vital to maintaining asset resiliency and security. The focus of this thesis is the design and evaluation of such a system. This is accomplished by identifying a system architecture through evaluating current assumptions of what missions satellites are capable of performing. Following the system-level design, modules are proposed that utilize machine learning to identify satellite behavior that is abnormal. These modules are tested and tuned with optimal parameters to deliver improved identification performance. The system is applied to several case studies examining edge cases and what factors constitute a threatening object and what factors do not. Suggestions for improvement of the system in the future are presented.

This thesis investigates using adaptive estimation techniques to determine unknown model parameters such as size and surface material reflectivity, while estimating position, velocity, attitude, and attitude rates of a resident space object. This work focuses on the application of these methods to the space situational awareness problem. This thesis proposes a unique method of implementing a top-level gating network in a dual-layer hierarchical mixture of experts. In addition it proposes a decaying learning parameter for use in both the single layer mixture of experts and the dual-layer hierarchical mixture of experts. Both a single layer mixture of experts and dual-layer hierarchical mixture of experts are compared to the multiple model adaptive estimation in estimating resident space object parameters such as size and reflectivity. The hierarchical mixture of experts consists of macromodes. Each macromode can estimate a different parameter in parallel. Each macromode is a single layer mixture of experts with unscented Kalman filters used as the experts. A gating network in each macromode determines a gating weight which is used as a hypothesis tester. Then the output of the macromode gating weights go to a top level gating weight to determine which macromode contains the most probable model. The measurements consist of astrometric and photometric data from non-resolved observations of the target gathered via a telescope with a charge coupled device camera. Each filter receives the same measurement sequence. The apparent magnitude measurement model consists of the Ashikhmin Shirley bidirectional reflectance distribution function. The measurements, process models, and the additional shape, mass, and inertia characteristics allow the algorithm to predict the state and select the most probable fit to the size and reflectance characteristics based on the statistics of the measurement residuals and innovation covariance. A simulation code is developed to test these adaptive estimation techniques. The feasibility of these methods will be demonstrated in this thesis.

Le thème central de la recherche est la place du vide constructif dans la dimension spatiale du décor de cinéma. Il s’agit de mettre en évidence, à travers les racines et le processus de création du décor de cinéma, la notion d’objet espace vide comme source d’informations et comme « troncage narratif » en sus de sa spatialité et de sa dépendance au construit et au visible. En s’appuyant sur la notion de tressage, on observe le jeu du visible et de l’invisible qui devient, pour le décorateur, le jeu du construit, de l’intervalle et du vide. Cette poïétique du décor de cinéma nous fait voyager en aller-retour entre image et espace. L’image de création, l’image iconographique devient matière, ontogénèse à double sens. L’étude des processus de perception des images met en évidence des notions que le créateur d’espace, le décorateur plasticien utilisera dans la modélisation de son espace poétique et la mise en place de sa vraisemblance, émergence de nos jeux d’enfance. Espace de la feinte théâtrale et cinématographique, espace poétique sensible au scopique, véritable installation panoptique du sens dont le processus de perception a été expérimenté par certains artistes du Quattrocento avec la naissance de la perspective puis ensuite par des artistes contemporains. / The central theme of my research is the importance of constructive emptiness in the spatial dimension of the film set. My intent is to highlight, through the roots and processes of the creation of the film set, the notion of empty space object as a source of information and as a “narrative truncation" besides its spatiality and dependence on what is constructed and visible. By relying on the notion of interweaving, one can observe the interactions of what is visible and invisible, which becomes, for the set designer, the interactions of what has been constructed on the set, as well as the intervals and the empty spaces. This poietics of the film set makes us go back and forth between image and space. The creative image, the iconographic image becomes material, a two-way ontogeny. The study of the process of image perception highlights the concepts that the creator of the space, the artistic decorator, will use in the modelling of their poetic space and the establishment of their likelihood, which is the emergence of our childhood games. It is the crafty space of theater and film, the poetic space sensitive to the scopic, a true panoptic installation of meaning whose processes of perception have been experienced by some artists of the Quattrocento with the birth of perspective and now by contemporary artists.

Les transports suborbitaux privés peuvent être définis comme tout vol réalisé au moyen d’un véhicule aérospatial, capable d’atteindre une très haute altitude et d’évoluer dans les couches supérieures de l’atmosphère terrestre, sans pour autant être mis en orbite. Plusieurs entreprises ont pour projet de faire des vols suborbitaux, le mode de transport de personnes à grande vitesse de demain. Dans l’hypothèse d’un tel développement, la réflexion autour de la règlementation de ces activités devient primordiale. Les activités suborbitales ont la particularité de prendre place à la fois dans l’espace aérien et dans l’espace extra-atmosphérique et pour ce faire, empruntent autant les caractéristiques techniques de l’aéronef que de l’engin spatial. Il est donc particulièrement difficile de les qualifier du fait qu’il existe plusieurs corpus législatifs susceptibles de régir ces vols : le droit aérien, le droit spatial ou un nouveau régime qu’il conviendrait alors d’imaginer. Sans prétendre à l’exhaustivité, ce mémoire envisagera les différentes options normatives pouvant permettre de règlementer la responsabilité du transporteur suborbital de personnes lorsqu’il cause un dommage au participant durant le vol. Le cas échéant, nous proposerons les meilleures alternatives pouvant permettre d’assurer le développement pérenne de ce secteur d’activité, tout en garantissant un haut niveau de sécurité juridique pour l’ensemble des parties prenantes, participants comme opérateurs spatiaux. / Private suborbital transportation can be defined as any spaceflight by an aerospace vehicle capable of reaching a very high altitude into the edge of space without reaching orbital velocity. For now, the aim of those activities is to offer customers direct experience with space travel. However, the ultimate goal is to provide high speed flights between various point of the Earth. When this objective will be achieved, the need to promulgate an integrated and uniform legal regime will be of great importance in order to facilitate and secured commercial aerospace activities expansion. Private suborbital activities have the dual specificities of using a vehicle that use either astronautic et aeronautics technology in order to achieve lift and thereby flying in air space, and also traveling through outer space during a small portion of the flight. This hybrid nature raises legal uncertainties about the applicable legal regime that could be one of air law, space law or a new regime that would need to be invented. This essay will focus on the specific issues surrounding liability. In other terms, it will focus on the different options that are available to manage liability issues that will arise between spaceflight participant and spaceflight operators and the way it will impact disputes when an accident occurs. Then, we will make a proposal for solutions that would best preserve the economic needs of this emerging industry, while insuring legal certainties for both spaceflight operators and participants.

<p>Our modern society is more dependent on its assets in space now more than ever. For<br> example, the Global Positioning System (GPS) many rely on for navigation uses data from a<br> 24-satellite constellation. Additionally, our current infrastructure for gas pumps, cell phones,<br> ATMs, traffic lights, weather data, etc. all depend on satellite data from various constel-<br> lations. As a result, it is increasingly necessary to accurately track and predict the space<br> domain. In this thesis, after discussing how space object tracking and object position pre-<br> diction is currently being done, I propose a machine learning-based approach to improving<br> the space object position prediction over the standard SGP4 method, which is limited in<br> prediction accuracy time to about 24 hours. Using this approach, we are able to show that<br> meaningful improvements over the standard SGP4 model can be achieved using a machine<br> learning model built based on a type of recurrent neural network called a long short term<br> memory model (LSTM). I also provide distance predictions for 4 different space objects over<br> time frames of 15 and 30 days. Future work in this area is likely to include extending and<br> validating this approach on additional satellites to construct a more general model, testing a<br> wider range of models to determine limits on accuracy across a broad range of time horizons,<br> and proposing similar methods less dependent on antiquated data formats like the TLE.</p>