Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1991. / Includes bibliographical references (leaves 83-84). / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1993. / Includes bibliographical references (leaf 67). / by William Djaja Tjokroaminata. / M.S.

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 113-116). / This thesis describes (i) guidelines for propulsor sizing, and (ii) strategies for fan turbomachinery conceptual design, for a boundary layer ingesting (BLI) propulsion system for advanced civil transport aircraft. For the former, configuration performance analysis shows BLI yields a reduction in mechanical power required to propel a given aircraft. For the latter, fan turbomachinery design attributes are identified to mitigate the impact of BLI inlet distortion on propulsor performance. The propulsion system requirements are determined using a mechanical energy analysis, in which the performance of the airframe and propulsor are characterized in terms of sources and sinks of power. Using this framework, the propulsor can be sized based on the performance of the isolated airframe. Analysis of the power savings due to BLI (from reduction of viscous dissipation both in the aircraft wake and the propulsor jet) leads to scaling choices for the sizing of propulsor simulators for wind tunnel experiments to assess BLI benefit. Fan stage distortion response is assessed computationally for a range of turbomachinery design parameters and for distortions characteristic of BLI. The numerical results show the importance of three-dimensional flow redistribution upstream of the fan, and indicate that, for the parameters examined, non-axisymmetric fan stators have the largest effect on decreasing blade row velocity distortions and thus mitigating losses due to flow non-uniformity. / by David Kenneth Hall. / Ph. D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1989. / Includes bibliographical references (leaves 259-272). / by Ming-Sang Li. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1997. / Includes bibliographical references (p. 192-195). / by Daniel Kew Skwarek. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1992. / Includes bibliographical references (leaves 219-225). / by Victor D. Lupi. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994. / GRSN 698605 / Includes bibliographical references (p. 231-232). / by Lisa D. Wetherbee. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994. / Includes bibliographical references (p. 147-149). / by John Edward Robinson III. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / Cataloged from student-submitted PDF version of thesis. / Includes bibliographical references (p. 103-105). / Air traffic is expected to continue to grow in the future and improved methods for dealing with the increased demand on the system need to be designed and implemented. One method for reducing surface congestion at airports is surface congestion management (SCM) (also commonly called departure queue management or departure metering). The concept generally involves holding aircraft at the gate or in the ramp area instead of releasing them onto the active movement area during periods of high departure demand. The FAA is planning to implement surface congestion management at airports where the cost/benefit analysis is favorable. Therefore, an estimate of the benefits of implementing surface congestion management in the future is necessary. To overcome the uncertainties and difficulties inherent in forecasting, this thesis adopts a multi-fidelity modeling approach and proposes three methods for estimating the benefits of SCM where the higher fidelity models study a subset of airports to inform and validate the lower fidelity models used on the entire set of airports. In the first model, a detailed analysis of a field trial of SCM at JFK airport is conducted using operational data. The second model estimates the benefits of implementing SCM at 8 major US airports from 2010 to 2030 by simulating congestion and performance levels through taxi time estimation. The last model explores several options for generalizing the results to 35 airports in the US. The results are also validated against historical benefits estimates as well as field trials of SCM where available. The findings show that SCM will result in fuel savings on the order of 1% of the total fuel burn in all stages of flight and between 5% and 45% of taxi-out fuel burn, depending on the airport. / by Alex Nakahara. / S.M.

Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 119-125). / We present and analyze the performance of two algorithms that plan and coordinate activities for a resource-constrained Earth-observing CubeSat constellation. The first algorithm is the Resource-Aware SmallSat Planner (RASP), which performs low-level planning of observation and communication activities for a single satellite while simultaneously keeping the satellite's onboard resources within specified bounds. RASP utilizes a Mixed Integer Linear Program based formulation and Depth First Search for construction of consistent onboard activity timelines. The second algorithm is the Limited Communication Constellation Coordinator (LCCC), which performs high level coordination of observations across the constellation through a distributed, "weak" consensus mechanism. The performance of the algorithms is tested with a 24 hour simulation of an eighteen satellite constellation over multiple orbital geometries and inter-satellite communication contexts. The orbital geometries include a modified Walker Star constellation and an "ad hoc" constellation defined by historical launches of CubeSats. The multiple communication contexts simulate different methods for sharing observation planning information between the satellites, and include sharing through inter-satellite crosslinks, downlink and uplink to ground stations, connection to a commercial communications constellation, and no sharing at all. Five analyses of the algorithms' performance were conducted, including average revisit times achieved, the numbers of communications links executed, how effectively planning information was shared, the resource margins maintained by the satellites, and the average execution time for the planner. Information sharing significantly aided in balancing revisit times across multiple Earth regions and three sensor choices, reducing the disparity in average revisit times between sensors from 514 minutes to 10 minutes for the Walker case and 617 to 11 minutes for he Ad Hoc case. Significantly more crosslink opportunities were available on average for the Walker satellites than for Ad Hoc (89.2 versus 47.7) and more crosslinks were executed for the Walker case (30.3 versus 20.8). Crosslink was found to be less effective than downlink at sharing planning information across the constellation, with a lower average latency (186 minutes versus 434, Walker) and better average initial timeliness (-35 minutes versus -287, Walker). Information sharing through both a commercial constellation and downlink outperformed sharing through just downlink or just crosslink, with an average latency and initial timeliness of 77 and 74 minutes (Walker). Average data storage and energy storage margins were kept high, as desired, for both constellations, at around 85 and 70 %. RASP planning time was found to scale roughly with the square of planning window length, but stays under a minute in all cases tested (achieving a maximum of 37.71 seconds). / by Andrew Kitrell Kennedy. / S.M.