For the upcoming formation flying technology demonstration mission NetSat a relative orbit propagator as well as a relative orbit controller were developed. The formation will consist of four equal nano-satellites with an electric propulsion system for orbit correction manoeuvres. This demands the use of continuous low-thrust models for relative orbit control, which is a novel field. A software framework was developed which allows orbit simulations of the whole fleet in a fully non-linear environment. The final on-board relative propagator is based on the Gim-Alfriend STM and incorporates eccentricity and the non-spherical shape of the Earth. The controller uses control Lyapunov function-based design and model predictive control, depending on the task. The guidance and control system is able to safely govern the relative motion for one-, two and three-dimensional formation configurations with inter-satellite distances as low as 50m. Based on these results, a complete mission plan is proposed.

Approved for public release, distribution is unlimited / This thesis explores using a direct pseudospectral method for the solution of optimal control problems with mixed dynamics. An easy to use MATLAB optimization package known as DIDO is used to obtain the solutions. The modeling of both low thrust interplanetary trajectories as well as aerocapture trajectories is detailed and the solutions for low thrust minimum time and minimum fuel trajectories are explored with particular emphasis on verification of the optimality of the obtained solution. Optimal aerocpature trajectories are solved for rotating atmospheres over a range of arrival Vinfinities. Solutions are obtained using various performance indexes including minimum fuel, minimum heat load, and minimum total aerocapture mass. Finally, the problem formulation and solutions for the mixed dynamic problem of low thrust trajectories with a terminal aerocapture maneuver is addressed yielding new trajectories maximizing the total scientific mass at arrival. / Lieutenant, United States Navy

Near Burlington, Vermont, the Champlain Thrust fault placed massive Cambrian dolostones over calcareous shales of Ordovician age during the Ordovician Taconic Orogeny. Although the Champlain Thrust has been studied previously throughout the Champlain Valley, the architecture and structural evolution of its fault zone have never been systematically defined. To document these fault zone characteristics, a detailed structural analysis of multiple outcrops was completed along a 51 km transect between South Hero and Ferrisburgh, Vermont. The Champlain Thrust fault zone is predominately within the footwall and preserves at least four distinct events that are heterogeneous is both style and slip direction. The oldest stage of structures—stage 1—are bedding parallel thrust faults that record a slip direction of top-to-the-W and generated localized fault propagation folds of bedding and discontinuous cleavages. This stage defines the protolith zone and has a maximum upper boundary of 205 meters below the Champlain Thrust fault surface. Stage 2 structures define the damage zone and form two sets of subsidiary faults form thrust duplexes that truncate older recumbent folds of bedding planes and early bedding-parallel thrusts. Slickenlines along stage 2 faults record a change in slip direction from top-to-the-W to top-to-the-NW. The damage zone is ~197 meters thick with its upper boundary marking the lower boundary of the fault core. The core, which is ~8 meters thick, is marked by the appearance of mylonite, phyllitic shales, fault gouge, fault breccia, and cataclastic lined faults. In addition, stage 3 sheath folds of bedding and cleavage are preserved as well as tight folds of stage 2 faults. Stage 3 faults include thrusts that record slip as top-to-the-NW and -SW and coeval normal faults that record slip as top-to-the-N and -S. The Champlain Thrust surface is the youngest event as it cuts all previous structures, and records fault reactivation with any top-to-the-W slip direction and a later top-to-the-S slip. Axes of mullions on this surface trend to the SE and do not parallel slickenlines. The Champlain Thrust fault zone evolved asymmetrically across its principal slip surface through the process of strain localization and fault reactivation. Strain localization is characterized by the changes in relative age, motion direction along faults, and style of structures preserved within the fault zone. Reactivation of the Champlain Thrust surface and the corresponding change in slip direction was due to the influence of pre-existing structures at depth. This study defines the architecture of the Champlain Thrust fault zone and documents the importance of comparing the structural architecture of the fault zone core, damage zone, and protolith to determine the comprehensive fault zone evolution.

Analysis of quartz c-axis fabrics and microstructures from ductily deformed rocks allows for the examination of the kinematics associated with crustal deformation. This thesis expands on the current knowledge of the kinematic evolution of the Himalayas and Scottish Caledonides, by examining samples from the Main Central Thrust (MCT) (Himalayas) and the Sgurr Beag Thrust (SBT) (Scottish Caledonides).  Metamorphic temperatures (Tm) associated above the MCT are inverted; chapter one attempts to test if deformation temperatures (Td) correlate to Tm, indicating that ductile shearing occurred during peak Tm. In the Scottish Caledonides, Td and Tm increase from foreland to hinterland, potentially indicating a right way up thermal structure;  chapter two presents Td and Tm associated with the region around the SBT. Above the MCT, quartz c-axis fabrics yield Td ranging between 500-650 "C, corresponding to the temperatures of dynamic recrystallization for subgrain rotation (SGR) and grain boundary migration (GBM). Up to 1000m above the MCT, Td and Tm are within error of each other, suggesting that shearing occurred during peak Tm; while further away from the MCT  Tm is significantly hotter than Td, suggesting that shearing continued past Tm. Deformation associated with the upper part of the Moine thrust sheet and the SBT yields quartz c-axis fabrics with Td ranging between 395-583 "C, corresponding to the regional dynamic recrystallization. Tm calculations original to this study yield pressure-temperature constraints of 4.8-5.8 kbar and 586-625 "C. Tm is within error of Td, suggesting that deformation and metamorphism were synchronous. / Master of Science

The VEM Drive (Variable-Electro-Magnetic Drive) is an invention by Space Warp Dynamics LLC that claims to distort space-time and thus creating an attractive force upon a target using frequencies in the VHF band. The experimental setup was replicated and tested at the Institute of Aerospacee Engineering at TU Dresden. We conclude that no anomalous force was present within our tested power levels and balance resolution some 6 orders of magnitude below the reported claim. The interaction of the high frequency with the power supply that was controlling a voice-coil actuator for teh balance was found to be responsible for a faciity side-effect that can mimic such an effect. This is important to consider foro future measurements.

Dynamically recrystallized quartz microstructures preserved in contact aureoles allow for stress and strain rate estimates associated with penetrative deformation of rocks surrounding pluton margins. Microstructural analysis of the Harkless quartzites surrounding the western margin of Papoose Flat pluton indicates that recrystallization occurred by grain boundary migration with mean recrystallized grain size ranging from 86-225 µm. The application of three calibrated piezometers results in differential stress estimates between ~11 and ~29 MPa. Published wet-quartzite dislocation creep flow laws combined with deformation temperature, water fugacity, and differential stress estimates infer strain rates that range from 1.2 x 10⁻¹⁴ s⁻¹ to 2.3 x 10⁻¹² s⁻¹. In order to analyze 3D subsurface fault geometry along map-pattern curves (salients and recesses), a structure contour map of the Moine thrust, extending from the North Coast southwards to the Dundonnel area, was constructed from 1:50,000 scale British Geological Survey (BGS) maps by correlating between elevation control points constrained by the intersection of the fault trace with topographic contours. The structure contour map indicates significant lateral variation in fault geometry along the Moine thrust, with recesses associated with antiformal corrugations in the subsurface and salients characterized by planar geometries or broad synformal corrugations. Additionally, structure contour maps constructed on the Glencoul thrust, as depicted by original BGS maps confirms that the thrust segments to the NE and SW of Loch Glencoul are part of the same structure, rather than different structures separated by a lateral ramp as shown on more recent BGS maps. / Master of Science

Dynamically recrystallized quartz microstructure and grainsize evolution along mid-crustal shear zones allows for the estimation of tectonic driving stresses and strain rates acting in the mid-crust. Quartz-rich tectonites from three exhumed mid-crustal shear zones, the Main Central Thrust (MCT; Sutlej valley, NW India), South Tibetan Detachment System (STDS; Rongbuk valley, S Tibet), and Moine thrust (NW Scotland), were analyzed. Deformation temperatures estimated from quartz microstructural and petrofabric thermometers indicate steep apparent thermal gradients (80–420 °C/km) across 0.5–2.3 km thick sample transects across each shear zone. Quartz recrystallization microstructures evolve from transitional bulging/sub-grain rotation to dominant grain boundary migration at ~ 200 m structural distance as traced away from each shear zone. Optically measured quartz grainsizes increase from ~ 30 μm nearest the shear zones to 120+ μm at the largest structural distances. First-order Zener space analysis across the Moine nappe suggests strong phyllosilicate control on recrystallized quartz grainsize. Recrystallized quartz grainsize piezometry indicates that differential stress levels sharply decrease away from the shear zones from ~ 35 MPa to 10 MPa at ~ 200 m structural distance. Strain rates estimated with quartz dislocation creep flow laws are tectonically reasonable, between 10⁻¹² – 10⁻¹⁴ s⁻¹. Traced towards each shear zone strain rate estimates first decrease one order of magnitude before rapidly increasing one to two orders of magnitude at structural distances of ~ 200 m. This kinked strain rate profile is likely due to the steep apparent thermal gradients and relatively constant differential stress levels at large structural distances. / Master of Science

No description available.

Fracture distribution in a fold and thrust belt is commonly thought to vary depending on structural position, strain, lithology and mechanical stratigraphy. The distribution, geometry, orientation, intensity, connectivity and fill of fractures in a reservoir are all important influences on fractured reservoir quality. The presence of fractures is particularly beneficial in reservoirs that contain little matrix porosity or permeability, for example tight sandstones. In these examples fractures provide essential secondary porosity and permeability that enhance reservoir production. To predict how reservoir quality may fluctuate spatially, it is important to understand how fracture attributes may vary, and what controls them. This research aims to investigate the influence of structural position on fracture attribute variations. Detailed fracture data collection is undertaken on folded sandstone outcrops. 2D forward modelling and 3D model restorations are used to predict strain distribution in the fold-and-thrust belt. Relationships between fracture attributes and predicted strain are determined. Discrete Fracture Network (DFN) modelling is then undertaken to predict fracture attribute variations. DFN modelling results are compared with field fracture data to determine how well fractured reservoir quality can be predicted. Field data suggests strain is a major controlling factor on fracture formation. Fractures become more organised and predictable as strain increases. For example in high strain forelimb regions, fracture intensity and connectivity are high, and fracture orientations are consistent. In lower strain regions, fracture attributes are much more variable and unpredictable. Fracture variations often do not correspond to strain fluctuations, and correlations can be seen between fracture intensity and lithology. Reservoir quality is likely to be much more variable in low strain regions than high strain regions. DFN modelling is also challenging because fracture attribute variations in low strain regions do not correspond to strain, and therefore cannot be predicted.

The thin-skinned structures of the late Paleozoic Ouachita thrust belt intersect the basement structures of the Southern Oklahoma aulacogen beneath the Mesozoic strata of the Gulf Coastal Plain in southeastern Oklahoma. The Ouachita thrust belt forms a large northwest-directed salient which extends primarily in the subsurface from central Mississippi northwestward to Arkansas and eastern Oklahoma, and from there, southwestward toward central Texas. Kinematics are complicated in the center of the Ouachita salient, where the average southwesterly strike of thrust faults is nearly perpendicular to average trend of compressional basement structures in the Southern Oklahoma aulacogen (Arbuckle uplift) and Muenster arch. Furthermore, the frontal fault of the Ouachita thrust belt curves sharply eastward around the southeastern end of the Arbuckle uplift, and bends sharply to the west between the Arbuckle uplift and the Muenster arch farther south in Texas. Nine new interpreted structural cross sections show the structural complexity of the area where the Ouachita thrust belt intersects the Arbuckle uplift and Muenster arch. Detailed study of the structural geology of the Ouachita Mountains and Arkoma basin indicates that along-strike changes in structural style evidently are related to along-strike changes in mechanical stratigraphy (relative thicknesses of weak units, in contrast to stiff units). The middle part of the Stanley Group (Formation) evidently serves as a wavelength transition and/or volume compensation zone. Along-strike change in stratigraphic level of detachments and abrupt eastward thickening of the Atoka Formation along the Ouachita thrust front strongly affected the structural style of the Ouachita thrust belt. Regional stratigraphy, palinspastic restorations of the footwall cutoff of the Ti Valley fault, and an abrupt change in character of seismic reflectors indicate an abrupt facies transition in the Middle Ordovician-Mississippian succession along the southeastern flank of the Arbuckle uplift and southwestward toward the deep southeastern part of the Ardmore basin. Out-of-syncline structures in the Bryan smallscale salient, distinct sub-thrust angular unconformities imaged on seismic profiles, and sediment dispersal patterns in the early Atokan-Desmoinesian strata of the northern Fort Worth basin (south of the Muenster arch) all indicate that the Tishomingo-Belton and Muenster structures were pre-thrust structural highs.