Ever since the revolutionary CubeSat form factor took hold in the Aerospace industry, there has been a desire to send them further and further into space. This thesis introduces an optimization approach to deployment that explores new possibilities of interplanetary CubeSats. In this approach there are three categories of objective functions that are defined by the type of trajectory of a “primary” spacecraft, which carries the CubeSat deployer. These categories are flyby, orbiter, and lander. For each category the objective function starts with four design variables. These are the ΔV of the deployer broken up into three component directions and the true anomaly at the time of deployment. The method then calculates the mission specific objective to be minimized and uses Matlab®’s built in gradient-based optimizer, fmincon. The results show that in the flyby category, the CubeSat has a significantly different turning angle than the primary. The CubeSat can even flyby on the opposite side of the planet. In the orbiter case it is shown that the method works by testing it with two objective functions, the difference in inclination and the difference in eccentricity between the primary and the CubeSat. It is shown that the inclination can be changed by 0.1314° and the eccentricity can be changed by 0.0033. These values, although low in magnitude, are an order of magnitude greater than non-optimal deployment scenarios. Still, another optimization method is introduced to find out how much extra ΔV the CubeSat would need to reach a desired change. This shows that with just an extra 75 m/s of ΔV, the CubeSat can change its orbit by 5°. This could come from either a propulsion system or a modified deployer. The final category, lander, used the flight path angle when entering the atmosphere as an objective. The method shows that flight path angle can be changed by 2.6°. Overall, these examples have proven that the method can find optimal solutions to CubeSat deployment scenarios at other planets.

Throughout the history of interplanetary space travel, the Newtonian dynamics of the two-body problem have been used to design orbital trajectories to traverse the solar system. That is, that a spacecraft orbits only one large celestial body at a time. These dynamics have produced impressive interplanetary trajectories utilizing numerous gravity assists, such as those of Voyager, Cassini, Rosetta and countless others. But these missions required large amounts of delta-v for their maneuvers and therefore large amounts of fuel mass. As we desire to travel farther and more extensively in space, these two-body dynamics lead to impossibly high delta-v values, and missions become infeasible due to the massive amounts of fuel that they would need to carry. In the last few decades a new dynamical system has been researched in order to find new ways of designing mission trajectories: the N-body problem. This utilizes the gravitational acceleration from multiple celestial bodies on a spacecraft, and can lead to unconventional, but very useful trajectories. The goal of this thesis is to use the dynamics of the Circular Restricted Three-Body Problem (CRTBP) to design interplanetary transfer trajectories. This method of modelling orbital dynamics takes into account the gravitational acceleration of two celestial bodies acting on a spacecraft, rather than just one. The invariant manifolds of halo orbits about Sun-planet Lagrange points are used to aid in the transfer from one planet to another, and can lead into orbital insertion about the destination planet or flyby trajectories to get to another planet. This work uses this method of dynamics to test transfers from Earth to both Jupiter and Saturn, and compares delta-v and time of flight values to traditional transfer methods. Using the CRTBP can lead to reduced delta-v amounts for completing the same missions as two-body dynamics would. The aim of this work is to research if using manifolds for interplanetary transfers could be superior for some high delta-v missions, as it could drastically reduce the required delta-v for maneuvers. With this method it could be possible to visit more distant destinations, or carry more mass of scientific payloads, due to the reduced fuel requirements. Results of this research showed that using manifolds to aid in interplanetary transfers can reduce the delta-v of both departure from Earth and arrival at a destination planet. For transfers to Jupiter the delta-v for the interplanetary transfer was reduced by 4.12 km/s compared to starting and ending in orbits about the planets. For a transfer to Saturn the delta-v required for the interplanetary transfer was reduced by 6.77 km/s. These delta-v savings are significant and show that utilizing manifolds can lead to lower energy interplanetary transfer trajectories, and have the potential to be useful for high delta-v missions.

L'acquisition de connaissances sur l'espace fascine les humains depuis l'antiquité. Depuis quelques décennies, il y a augmentation significative des programmes spatiaux concernant Mars, des missions d'exploration lunaire et des projets d'exploration spatiale de plus en plus complexes, impliquant plusieurs nœuds de communication: satellites, robots (Rovers, Landers) ou "aerorobots" (ie capteurs atmosphériques). Dans ce cadre, des efforts ont été faits par les organismes de normalisation pour l'espace comme le Comité consultatif pour les systèmes de données spatiales (CCSDS) et le Delay Tolérant Networking groupe de travail au sein del’ Internet Research Task Force (IRTF) pour élaborer une architecture de protocoles efficace pour des missions spatiales. Dans cette thèse, nous avons analysé quelques unes de ces propositions : (les piles de protocole CCSDS, et DTN) pour leurs performances sur la surface de Mars (une sous-section de Interplanetary Network) et obtenu les paramètres qui affectent les performances du système, comme la mémoire tampon, les limitations de puissance. Également exploré divers problèmes de réseau de routage, Transport & couches de l'application de la pile de protocole, qui doit être abordée. Pour qui s'étendent, dans cette thèse nous avons proposé un nouvel algorithme de routage prenant en compte les ressources disponibles, qui prend en considération les limitations des ressources du réseau pour le routage et transmet les décisions permettant une politique efficace de gestion des tampons. Comme il existe différentes piles de protocoles d'interopérabilité proposées par l’agence spatiale, dans nos travaux, nous avons développé un framework de QoS qui est joint à chaque application, et peut sélectionner la pile de protocoles sous-jacents adéquate, selon les exigences de qualité de service des applications, qui sont les mieux adaptés pour améliorer les performances globales de ce réseau. Comme l'analyse révèle que les performances du protocole de remise de fichiers CCSDS lequel est le plus couramment utilisé le protocole d'application dans la mission spatiale. Pour améliorer les performances du protocole, nous avons proposé un algorithme dynamique du timer qui fixe la valeur du time-out en fonction de l’état du réseau pour tous les timers du protocole, afin de réduire les retransmissions inutiles de données d'UFC, accroissant ainsi les performances de débit. / Acquiring knowledge about space has fascinated humans since the antiquity. Since a few decades, there is a significant increase in space mission programs like Mars and Lunar Exploration Missions, and Spatial exploration projects become more and more complex, involving several different communicating nodes: satellites, robots (Rovers, Landers) or "aerorobots" (i.e. atmospheric sensors). To this extend, efforts have been made by the space standardization bodies such as the Consultative Committee for Space Data Systems (CCSDS) and the Delay Tolerant Networking working group within the Internet Research Task Force (IRTF) to develop effective protocol architecture for space missions. In this dissertation, we have analyzed various newly proposed protocol stack (CCSDS, DTN) for their performance over Interplanetary Network and derived the parameters which affect the performance of the system, like buffer storage, power limitation, also explored various networking issues in routing, transport & application layers of the protocol stack, which is to be addressed. To that extend, in this thesis we have proposed a Resource Aware routing protocol, which uses knowledge about the connectivity, resource consumption of the nodes and buffer management policy to make an effective routing decision to route all kind of traffic in interplanetary network, where communicating entities are of different natures. Since there are various interoperable protocols proposed by space agencies, we then developed a QoS framework, which help the interplanetary applications to choose optimum underlying protocols (Transport), suitably measured in term of ability to achieve the application QoS requirements with the environmental, constrains. As the analysis shows that the performance CCSDS File delivery protocol which is most commonly used application protocol in space mission, depends on the preset timeout value of its timer due to varying propagation delay. To improve the performance of the protocol, in out thesis we have developed a dynamic timer algorithm which sets the timeout values according to network condition for all the timers in the protocol, in a way that reduces unnecessary retransmission of data PDUs, thereby increasing the throughput performance.

Critical aspects of spacecraft missions, such as component organization, control algorithms, and trajectories, can be optimized using a variety of algorithms or solvers. Each solver has intrinsic strengths and weaknesses when applied to a given optimization problem. One way to mitigate limitations is to combine different solvers in an island model that allows these algorithms to share solutions. The program Spacecraft Trajectory Optimization Suite (STOpS) is an island model suite of heterogeneous and homogeneous Evolutionary Algorithms (EA) that analyze interplanetary trajectories for multiple gravity assist (MGA) missions. One limitation of STOpS and other spacecraft trajectory optimization programs (GMAT and Pygmo/Pagmo) is that they require a defined encounter body sequence to produce a constant length set of design variables. Early phase trajectory design would benefit from the ability to consider problems with an undefined encounter sequence as it would provide a set of diverse trajectories -- some of which might not have been considered during mission planning. The Hybrid Optimal Control Problem (HOCP) and the concept of hidden genes are explored with the most common EA, the Genetic Algorithm (GA), to compare how the methods perform with a Variable Size Design Space (VSDS). Test problems are altered so that the input to the cost function (the object being optimized) contains a set of continuous variables whose length depends on a corresponding set of discrete variables (e.g. the number of planet encounters determines the number of transfer time variables). Initial testing with a scalable problem (Branin's function) indicates that even though the HOCP consistently converges on an optimal solution, the expensive run time (due to algorithm collaboration) would only escalate in an island model system. The hidden gene mechanism only changes how the GA decodes variables, thus it does not impact run time and operates effectively in the island model. A Hidden Gene Genetic Algorithm ( HGGA) is tested with a simplified Mariner 10 (EVM) problem to determine the best parameter settings to use in an island model with the GTOP Cassini 1 (EVVEJS) problem. For an island model with all GAs there is improved performance when the different base algorithm settings are used. Similar to previous work, the model benefits from migration of solutions and using multiple algorithms or islands. For spacecraft trajectory optimization programs that have an unconstrained fly-by sequence, the design variable limits have the largest impact on the results. When the number of potential fly-by sequences is too large it prevents the solver from converging on an optimal solution. This work demonstrates HGGA is effective in the STOpS environment as well as with GTOP problems. Thus the hidden gene mechanism can be extended to other EAs with members containing design variables that function similarly. It is shown that the tuning of the HGGA is dependent on the specific constraints of the spacecraft trajectory problem at hand, thus there is no need to further explore the general capabilities of the algorithm.

In interplanetary trajectory applications, it is common to design arrival trajectories based on B-plane target values. This targeting scheme, B-plane targeting, allows for specific target orbits to be obtained during mission design. A primary objective of this work was to implement B-plane targeting into the Spacecraft Trajectory Optimization Suite (STOpS). This work was based on the previous versions of STOpS done by Fitzgerald and Sheehan, however STOpS was redeveloped from MATLAB to python. This updated version of STOpS implements 3-dimensional computation, departure and arrival orbital phase modeling with patched conics, B-plane targeting, and a trajectory correction maneuver. The optimization process is done with three evolutionary algorithms implemented in an island model paradigm. The algorithms and the island model were successfully verified with known optimization functions before being used in the orbital optimization cases. While the algorithms and island model are not new to this work, they were altered in this redevelopment of STOpS to closer relate to literature. This enhanced literature relation allows for easier comprehension of the both the formulation of the schemes and the code itself. With a validated optimization scheme, STOpS is able to compute near-optimal trajectories for numerous historical missions. New mission types were also easily implemented and modeled with STOpS. A trajectory correction maneuver was shown to further optimize the trajectories end conditions, when convergence was reached. The result is a versatile optimization scheme that is highly customization to the invested user, while remaining simple for novice users.

The effects of interplanetary shock impact angles have the potential to have far reaching consequences. By their nature, interplanetary shocks are a direct consequence of a variety of solar events including both Coronal Mass Ejections (CMEs) and Co-rotating Interaction Regions (CIRs). They have the ability to move the magnetopause, the boundary between the Earth's magnetosphere and the surrounding plasma, leading to ionospheric current systems and an enhanced ring current. Their association with a time-varying EMF also makes them potentially dangerous at a human level. This EMF can couple to electrical currents in technological infrastructure that can overload transformers, communication cables, and power grids. As IP shocks have the potential to have a large impact on our society, research to further our understanding of these events is prudent. We know that shocks can couple to currents and ULF waves in the magnetosphere-ionosphere system. Much of the current research into their behaviors has been focused on models and simulations and has indicated that the shock impact angle should affect the properties of the waves. To investigate the potential influence of the impact angle, data from a series of Antarctic magnetometers was collected and compared to a database of known interplanetary shocks to determine when the response to different shocks was detected at the magnetometer. For this investigation, we were concerned with determining what impact if any, the impact angle of the IP shock had on the generation of Pc5 waves. To that end, the power spectra both before and after the shock was calculated. This information was then combined with the shock impact angle to determine what effects if any, the shock impact angle had on Pc5 wave occurrence rates. From our research, it was determined that the impact angle of the interplanetary shock had a significant impact on the occurrence rate and properties of Pc5 waves observed by high-latitude ground magnetometers. / Master of Science / Interplanetary shocks, drive interactions between the solar wind and the Earth’s atmosphere, and they have the potential to have far reaching consequences. Caused by a variety of solar events including both Coronal Mass Ejections (CMEs) and Co-rotating Interaction Regions (CIRs), they have the ability to physically move the locations of regional boundaries of the ionized part of Earth’s atmosphere, leading to a variety of electromagnetic effects. They also pose a danger at the human level by generating electrical currents in technological infrastructure that can overload transformers, communication cables, and power grids. As they pose a danger to our society, understanding them is prudent. A large portion of the current research into their behaviors has been focused on models and simulations and has shown that the shock impact angle should affect the properties of the waves. For this investigation, data from a series of Antarctic sensors was collected and compared to a database of known interplanetary shocks to determine when different shocks were detected. Specifically, for our investigation, we were concerned with determining what impact if any, the impact angle of the IP shock had on the generation of Pc5 waves, a specific type of ULF wave. This was accomplished by calculating the power level at different frequencies both before and after the shock. This information was then combined with the shock impact angle to determine what effects if any, the shock impact angle had on Pc5 wave occurrence rates. From our research we found that the impact angle of the interplanetary shock had a significant impact on the generation of Pc5 waves.

This thesis studies the characteristics of data hosted on the interplanetary name system, which is a part of the interplanetary file system. From these records, information such as file names, locations, and sizes, was investigated. Data was collected on the number of peers hosting the records, thereby determining the decentralization of the record on the network. Data on how often content on the network changes, were collected and investigated. In addition to evaluating records, a search engine was prototyped to show how to integrate the data into a system. A large part of the network was crawled and the rate of change was found to be high. Most of the peers were found to host HTML files. Most content identifiers found were hosted by more than one peer. This means that a search engine needs to be able to support text file formats and revisit peers regularly to be up-to-date with the records.

Published online: 26 April 2013

The data harvest from the Voyagers' (V1 and V2) Ultraviolet Spectrometers (UVS) covers encounters with the outer planets, measurements of the heliosphere sky-background, and stellar spectrophotometry. Because their period of operation overlaps with many ultraviolet missions, the calibration of V1. and V2 UVS with other spectrometers is invaluable. Here we revisit the UVS calibration to assess the intriguing sensitivity enhancements of 243% (V1) and 156% (V2) proposed recently. Using the Ly alpha airglow from Saturn, observed in situ by both Voyagers, and remotely by International Ultraviolet Explorer (IUE), we match the Voyager values to IUE, taking into account the shape of the Saturn Ly alpha line observed with the Goddard High Resolution Spectrograph on board the Hubble Space Telescope. For all known ranges of the interplanetary hydrogen density, we show that the V1 and V2 UVS sensitivities cannot be enhanced by the amounts thus far proposed. The same diagnostic holds for distinct channels covering the diffuse He I 58.4 nm emission. Our prescription is to keep the original calibration of the Voyager UVS with a maximum uncertainty of 30%, making both instruments some of the most stable EUV/FUV spectrographs in the history of space exploration. In that frame, we reassess the excess Ly alpha emission detected by Voyager UVS deep in the heliosphere, to show its consistency with a heliospheric but not galactic origin. Our finding confirms results obtained nearly two decades ago-namely, the UVS discovery of the distortion of the heliosphere and the corresponding obliquity of the local interstellar magnetic field (similar to 40 degrees from upwind) in the solar system neighborhood-without requiring any revision of the Voyager UVS calibration.

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