Autonomous relative terrain navigation is a problem at the forefront of many space missions involving close proximity operations to any target body. With no definitive answer, there are many techniques to help cope with this issue using both passive and active sensors, but almost all require high fidelity models of the associated dynamics in the environment. Convolutional Neural Networks (CNNs) trained with images rendered from a digital terrain map (DTM) of the body’s surface can provide a way to side-step the issue of unknown or complex dynamics while still providing reliable autonomous navigation. This is achieved by directly mapping an image to a relative position to the target body. The portability of trained CNNs allows “offline” training that can yield a matured network capable of being loaded onto a spacecraft for real-time position acquisition. In this thesis the lunar surface is used as the proving ground for this optical navigation technique, but the methods used are not unique to the Moon, and are applicable in general.

Cenotaph is a work of fifteen minutes duration for solo tape realized on the Synclavier Digital Music System at the Center for Experimental Music and Intermedia. All of the sound materials in the work consist of resynthesized timbres derived from the analysis of digital recordings of seven different human voices, each speaking the last name of one of the Challenger astronauts. The work's harmonic resources are derived in a unique way involving partitioning of the octave by powers of the Golden Section. The work is in a single movement divided into three sections which function as prologue, action, and epilogue, respectively. This formal structure is reinforced by differentiation of harmonicmaterials and texture. Although Cenotaph cannot be performed "live" and exists only as a recording, a graphic score is included to assist analysis and study.

From abstract: Within the next few years a large number of new and vastly more sensitive radio astronomy facilities are scheduled to come online. These new facilities will map large areas of the sky to unprecedented depths and transform radio astronomy into the leading technique for investigating the complex processes which govern the formation and evolution of galaxies. This thesis combines multi-wavelength techniques, highly relevant to future deep radio surveys, to study the evolution and properties of faint radio sources. / TeX / Adobe Acrobat 9.54 Paper Capture Plug-in

Thesis is focused on safety and reliability of space products. It describes assessment methods and applies them on small commercial satellite.

Spacecraft formation flying refers to the coordinated operation of a group of spacecraft with a common objective. While the concept has been in existence for a long time, practical fruition of the ideas was not possible earlier due to technological limitations. The topic has received widespread attention in the last decade, with the development of autonomous control, improved computational facilities and better communication technology. It allows a number of small, lightweight, economical spacecraft to work together to execute the function of a larger, heavier, more complex and expensive spacecraft. The primary advantage of such systems is that they are flexible, modular, and cost-effective.<div><br></div><div>The flexibility of formation flying and other derived concepts comes from the fact that the units are not physically attached, allowing them to change position or orientation when the need arises. To fully realize this possibility, it is important to develop methods for spatial reorganization. This thesis is an attempt to contribute to this development. </div><div><br></div><div>In this thesis, the reconfiguration problem has been formulated as a single system with multiple inputs and multiple outputs, while preserving the individuality of the agents to a certain degree. The agents are able to communicate with their neighbors by sharing information. In this framework, a distributed closed-loop stabilizing controller has been developed, that would drive the spacecraft formation to a target shape. An expression for the controller gain as a function of the graph Laplacian eigenvalues has also been derived. The practical applications of this work have been demonstrated through simulations</div>

Conceptual design optimization (CDO) is a technique proposed for the structured evaluation of different design concepts. Design grammars provide a flexible modular modelling architecture. The model is generated by a compiler based on predefined components and rules. The rules describe the composition of the model; thus, different models can be optimized by the CDO in one run. This allows considering a mission design including the mission analysis and the system design. The combination of a CDO approach with a model based on design grammars is shown for the concept study of a near-Earth asteroid mission. The mission objective is to investigate two asteroids of different kinds. The CDO reveals that a mission concept using two identical spacecrafts flying to one target each is better than a mission concept with one spacecraft flying to two asteroids consecutively.

<div>The methods presented in this thesis follow the three-phase process for System-of-Systems Engineering (SoSE): Definition, Abstraction, and Implementation. It begins with problem definition, then identification of stakeholders and value measures, and then proceeds to value and cost analysis using the Modeling Architectures and Parameterization of Space (MAPS) environment, which was created for this thesis. Each of the methods are applied to the case study of a persistent platform in low-Earth orbit. In the case study, over 18,000 architectures were analyzed to determine the design characteristics that best balanced value and cost. </div><div><br></div><div>Several strategies for demonstrating On-Orbit Servicing, Assembly, and Manufacturing (OSAM) technologies in orbit have been presented to the public over time, but this thesis has defined physical architecture design options and relevant value measures. In addition, the full SoSE process was applied to an OSAM concept for the first time. This work is therefore a significant step towards providing future insight to decision makers. The dialogue on these topics and the SoSE methods should be valuable to a future OSAM market and other new ventures in the space industry. </div>

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With increasing awareness of potential security threats there is a growing interest in communication security for spacecraft control and data. Traditionally commercial and scientific missions have relied on their uniqueness to prevent security breaches. During time the market has changed with open systems for mission control and data distribution, increased connectivity and the use of existing and shared infrastructure. Therefore security layers are being introduced to protect spacecraft communication. In order to mitigate the perceived threats, the Consultative Committee for Space Data Systems (CCSDS) has proposed the addition of communication security in the various layers of the communication model. This thesis describes and discuss their proposal and look into how this application should be implemented into the data link layer of the communication protocol to protect from timing attacks. An implementation of AES-CTR+GMAC is constructed in software to compare different key lengths and another implementation is constructed in synthesized VHDL for use on hardware to investigate the impact on area consumption on the FPGA as well as if it is possible to secure it from cache-timing attacks.

Tradition spacecraft proximity operations require large and expensive on-board sensors and significant ground support. Relative angle measurements can be obtained from small, simple, and inexpensive on-board sensors, but have not traditionally been used for proximity operation because of difficulty generating rang information. In this thesis it is shown that useful relative range data can be generated provided that the spacecraft is experiencing a small continuous thrust such as would be provided by a low-thrust propulsion system.