Recursos de colección

DSpace at MIT (104.280 recursos)

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Aeronautics and Astronautics - Master's degree

Mostrando recursos 1 - 20 de 2.180

  1. An investigation of the flutter of low density wings

    Pratt, Rose Marie
    by Rose Marie Pratt.

  2. Pointing acquisition and tracking design and analysis for CubeSat Laser communication

    Long, Michael J. (Michael Joseph)
    This thesis proposes a low size, weight, and power (SWaP) laser communication pointing, acquisition, and tracking (PAT) design for CubeSats in low earth orbit (LEO). As data production on-orbit continues to grow due to sensor miniaturization and the increased prevalence of satellites in LEO, current RF communication systems struggle to meet the data routing demands on resource constrained platforms. Laser communication provides an attractive alternative with reduced regulatory constraints and efficient use of available SWaP, but introduces the new challenge of stringent pointing requirements. The approach in this thesis is to survey historic capable laser communication space systems and identify...

  3. On the convergence of higher-order finite element methods to weak solutions

    Couchman, Benjamin Luke Streatfield
    The ability to handle discontinuities appropriately is essential when solving nonlinear hyperbolic partial differential equations (PDEs). Discrete solutions to the PDE must converge to weak solutions in order for the discontinuity propagation speed to be correct. As shown by the Lax-Wendroff theorem, one method to guarantee that convergence, if it occurs, will be to a weak solution is to use a discretely conservative scheme. However, discrete conservation is not a strict requirement for convergence to a weak solution. This suggests a hierarchy of discretizations, where discretely conservative schemes are a subset of the larger class of methods that converge to...

  4. Online risk-aware conditional planning with qualitative autonomous driving applications

    Deyo, Matthew Quinn
    Driving is often stressful and dangerous due to uncertainty in the actions of nearby vehicles. Having the ability to model driving maneuvers qualitatively and guarantee safety bounds in uncertain traffic scenarios are two steps towards building trust in vehicle autonomy. In this thesis, we present an approach to the problem of Qualitative Autonomous Driving (QAD) using risk-bounded conditional planning. First, we present Incremental Risk-aware AO* (iRAO*), an online conditional planning algorithm that builds off of RAO* for use in larger dynamic systems like driving. An illustrative example is included to better explain the behavior and performance of the algorithm. Second,...

  5. Learning Gaussisan noise models from high-dimensional sensor data with deep neural networks

    Liu, Katherine Y
    While measurement covariances are often taken to be constant in many robotic state estimation systems, many sensors exhibit different interactions with their environment. Accurate covariance estimation allows graph-based estimation techniques to better optimize state estimates by reasoning about the utility of different methods relative to each other. This thesis describes a method of learning compact feature representations for real-time covariance estimation. A direct log-likelihood optimization technique is used to train a deep convolutional neural network to predict the covariance matrix of a Gaussian measurement model, given representative data. This method is algorithm-agnostic, and therefore does not require the handcoding of...

  6. Mitigation of sickle cell crises using chaos-based analysis

    Atsaves, Louis
    Sickle-cell diseased persons suffer finite pain episodes (luring their lifetime, which are termed sickle cell crises. Using a sickle cell blood flow model, we mathematically demonstrate that the onset of a sickle cell crisis is chaotic. We further show that sickle cell crises may be mitigated by manipulating certain physiological parameters, namely the partial pressure of oxygen at 50% hemoglobin ([mathematical formula]%) and the kinetic dissociation rate of hemoglobin (kub) These physiological parameters control the chaotic nature of sickle cell crises and have the ability to transfer a person from a crisis state to a non-crisis state. We determine that...

  7. Conceptual engineering design and optimization methodologies using geometric programming

    Öztürk, Berk
    Geometric programs (GPs) and other forms of convex optimization have recently experienced a resurgence due to the advent of polynomial-time solution algorithms and improvements in computing. Observing the need for fast and stable methods for multidisciplinary design optimization (MDO), previous work has shown that geometric programming can be a powerful framework for MDO by leveraging the mathematical guarantees and speed of convex optimization. However, there are barriers to the implementation of optimization in design. In this work, we formalize how the formulation of non-linear design problems as GPs facilitates design process. Using the principles of pressure and boundedness, we demonstrate...

  8. Fundamental design principles of an attack simulator for airborne fire control systems

    Duncan, Robert C. (Robert Clifton)
    by Robert C. Duncan.

  9. Distance measurement by inertial means

    Chilton, Robert G; Seville, Alfred R
    by Robert G. Chilton and Alfred R. Seville.

  10. Investigation of aircraft lateral motion performance function by pulse technique

    Bain, John B; Michaelis, Frederick H; Wootton, James C
    by John B. Bain, Frederick H. Michaelis, James C. Wootton.

  11. Subsystem development and flight testing of an electroaerodynamic UAV

    Hennick, Cooper Curtis
    Electroaerodynamic (EAD) propulsion is a form of in-atmosphere electric thrust generation with no direct emissions, no moving parts, and is nearly silent. Previous work has quantified the thrust-to-power and thrust density of EAD propulsion. An unmanned aerial vehicle (UAV) was designed with the optimization tool GPkit and with the flight mission goal of steady-level flight. This thesis describes the design and testing of several subsystems of the UAV, including the power system, the communication system, the aircraft tail, and the aircraft launching system. The power system is tested to deliver up to a maximum of 600 W at 40 kV....

  12. The Design, development, and analysis of a wearable, multi-modal information presentation device to aid astronauts in obstacle avoidance during surface exploration

    Gibson, Alison Eve
    The future of human space exploration will involve extra-vehicular activities (EVA) on foreign planetary surfaces (i.e. Mars), an activity that will have significantly different characteristics than exploration scenarios on Earth. These activities become challenging due to restricted vision and limitations placed on sensory feedback from altered gravity and the space suit. The use of a bulky, pressurized EVA suit perceptually disconnects human explorers from the hostile environment, increasing navigation workload and risk of collision associated with traversing through unfamiliar terrain. Due to the hazardous nature of this work, there is a critical need to design interfaces for optimizing task performance...

  13. Sparsity and computation reduction for high-rate visual-inertial odometry

    Frey, Kristoffer M. (Kristoffer Martin)
    The navigation problem for mobile robots operating in unknown environments can be posed as a subset of Simultaneous Localization and Mapping (SLAM). For computationally-constrained systems, maintaining and promoting system sparsity is key to achieving the high-rate solutions required for agile trajectory tracking. This thesis focuses on the computation involved in the elimination step of optimization, showing it to be a function of the corresponding graph structure. This observation directly motivates the search for measurement selection techniques to promote sparse structure and reduce computation. While many sophisticated selection techniques exist in the literature, relatively little attention has been paid to the...

  14. Risk-bounded autonomous information gathering for localization of phenomena in hazardous environments

    Ayton, Benjamin James
    Exploration of new environments is often conducted in search of some phenomenon of interest. Examples include the search for extreme forms of life in the deep ocean or under the ice on Europa, or localizing resource deposits on the ocean floor. Exploration of all these environments is dangerous because of uncertainty in the environment and poorly characterized disturbances that can damage the exploration vehicle. Autonomous vehicles allows exploration in those environments where it is too dangerous or expensive to send a human-operated craft. Autonomous exploration has been well-studied from the perspective of information maximization, but information gathering has not been...

  15. Design and analysis of penetrator probes for planetary science applications

    Lowey, Charlotte (Charlotte Emily)
    Penetrator probes emplace by impact into a solid medium, carrying scientific instrumentation to fulfil specified post-impact mission objectives. They have been used successfully for multiple terrestrial applications, but only flown once unsuccessfully as a planetary exploration vehicle, with many proposed penetrator missions over several decades being cancelled at various stages of development. We examine past applications of penetrator probes alongside current Antarctic research instrumentation, setting out the context for design and analysis work carried out on the Geodetic Seismic Ice Penetrator (GSIP). GSIP is a separable two-body penetrator designed for air-deployment from LC-130 aircraft into snow pack on the Ross...

  16. A doublet panel method for generalized supersonic lifting surfaces

    Hoskin, Dominique (Dominique Sampson)
    An improved doublet panel method for calculating the aerodynamic properties of lifting surfaces in supersonic flows is derived and implemented. The lifting surfaces are discretized into an arbitrary number of doublet panels with unknown singularity strength, whose perturbation velocity potentials satisfy the supersonic Prandtl-Glauert equation. To prevent field singularities in the potential and velocity, the doublet strength of each panel is piecewise linear and continuous in the streamwise direction. In addition, the panels can be swept at different angles at their leading and trailing edges, allowing for generalized lifting surfaces to be analyzed. The component of the perturbation velocity that...

  17. Modeling the effects of aircraft flight track variability on community noise exposure

    Brooks, Callen T. (Callen Theodore)
    The implementation of Performance Based Navigation (PBN) routes across the National Airspace System (NAS) has caused a significant concentration of flight tracks. This flight track concentration also creates a concentration of noise impacts on the communities surrounding airports, which has led to an increase in noise complaints at many airports that have implemented these routes. In order to understand these changes in noise, and to design procedures that could help mitigate any negative effects, it is important to have modeling tools capable of capturing the noise impacts of flight track variability. This thesis develops a model for this purpose. First,...

  18. Development, modeling and testing of a slow-burning solid rocket propulsion system

    Vernacchia, Matthew T
    Small, unmanned aerial vehicles (UAVs) are expanding the capabilities of aircraft systems. However, a gap exists in the size and capability of aircraft: no aircraft smaller than 10 kilograms are capable of flight faster than 100 meters per second. A small, fast aircraft requires a propulsion system which is both miniature and high-power, requirements which current UAV propulsion technologies do not meet. To meet this need, a slow-burning solid rocket motor has been developed. Such motors require slow-burning solid propellants with tailorable burn rate. This thesis reports experimental results and combustion theory for a slow-burning solid propellant. It also describes...

  19. Developing a component reuse strategy for space launch vehicles

    Good, Marissa Ann
    Launch vehicle hardware is traditionally very expensive to design, develop, produce and certify, because it must operate in extreme environments with high reliability. The result is that most hardware for NASA-funded launch vehicles is custom built to execute a specific mission on a single platform. In contrast to other industries (e.g. automotive), very few components are used across product platforms, a strategy known as reuse that has the potential to decrease the cost, schedule and risk of new product introduction. Budget constraints on NASA's next launch vehicle, the Space Launch System (SLS), brought about a desire to realize some of...

  20. Experiments and numerical analysis on air bearing slumping of segmented thin-shell mirrors for X-ray telescopes

    Zuo, Heng (Heng Elizabeth)
    Slumping (or thermal shaping) of thin glass sheets onto high precision mandrels was used by NASA Goddard Space Flight Center to fabricate the NuSTAR telescope with success. But this process requires long thermal cycles and produces mid-range spatial frequency errors due to the anti-stick mandrel coatings. Over the last few years, MIT Space Nanotechnology Lab has developed a non-contact slumping process differentiating from the preceding contact slumping, which utilizes a pair of porous air bearing mandrels through which compressed nitrogen is forced, with a thin piece of glass sheet floating between two thin layers of nitrogen during the thermal cycle....

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