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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Case for Waste Fraud and Abuse: Stopping the Air Force from Purchasing Spacecraft That Fail Prematurely

Losik, Len 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / Spacecraft and launch vehicle reliability is dominated by premature equipment failures and surprise equipment failures that increase risk and decrease safety, mission assurance and effectiveness. Large, complex aerospace systems such as aircraft, launch vehicle and satellites are first subjected to most exhaustive and comprehensive acceptance testing program used in any industry and yet suffer from the highest premature failure rates. Desired/required spacecraft equipment performance is confirmed during factory testing using telemetry, however equipment mission life requirement is not measured but calculated manually and so the equipment that will fail prematurely are not identified and replaced before use. Spacecraft equipment mission-life is not measured and confirmed before launch as performance is but calculated using stochastic equations from probability reliability analysis engineering standards such as MIL STD 217. The change in the engineering practices used to manufacture and test spacecraft necessary to identify the equipment that will fail prematurely include using a prognostic and health management (PHM) program. A PHM includes using predictive algorithms to convert equipment telemetry into a measurement of equipment remaining usable life. A PHM makes the generation, collection, storage and engineering and scientific analysis of equipment performance data "mission critical" rather than just nice-to-have engineering information.
2

Relying on Telemetry for Mission Critical Decisions: Lessons Learned from NASA's Reusable Launch Vehicle for Use on the Air Force's Next Generation Reusable Launch Vehicle

Losik, Len 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The U.S. Air Force's next generation reusable booster (NGRSB) offers the opportunity for the Space Command to use intelligent equipment for decision making replacing personnel, increasing safety and mission assurance by removing decisions from program management personnel who may not have had any flight-test experience. Adding intelligence to launch vehicle and spacecraft equipment may include requiring the builder to use a prognostic and health management (PHM) program. The PHM was added to NASA's aircraft programs in 2009 and we have requested NASA HQ and NASA Marshal Space Flight Center adopt the NASA PHM in the procurement contracts used on the new Space Launch Systems, NASA's congressionally mandated replacement for the Space Shuttle. Space Vehicle Program managers often make decisions for on-orbit spacecraft without ever having on-orbit space flight experience. Intelligent equipment would have eliminated the catastrophic failures on the NASA Space Shuttle Challenger and Columbia. These accidents occurred due to the lack of space vehicle subsystem engineering personnel analyzing real-time equipment telemetry presented on strip chart and video data prior to lift off during pre-launch checkout for the Space Shuttle Challenger and the lack of space vehicle real-time equipment telemetry for Columbia. The PHM requires all equipment to include analog telemetry for measuring the equipment performance and usable life determination in real-time and a prognostic analysis completed manually will identify the equipment that will fail prematurely for replacement before launch preventing catastrophic equipment failures that may cause loss of life.
3

Stochastic modeling and prognostic analysis of complex systems using condition-based real-time sensor signals

Bian, Linkan 14 March 2013 (has links)
This dissertation presents a stochastic framework for modeling the degradation processes of components in complex engineering systems using sensor based signals. Chapters 1 and 2 discuses the challenges and the existing literature in monitoring and predicting the performance of complex engineering systems. Chapter 3 presents the degradation model with the absorbing failure threshold for a single unit and the RLD estimation using the first-passage-time approach. Subsequently, we develop the estimate of the RLD using the first-passage-time approach for two cases: information prior distributions and non-informative prior distributions. A case study is presented using real-world data from rolling elements bearing applications. Chapter 4 presents a stochastic methodology for modeling degradation signals from components functioning under dynamically evolving environmental conditions. We utilize in-situ sensor signals related to the degradation process, as well as the environmental conditions, to predict and continuously update, in real-time, the distribution of a component’s residual lifetime. Two distinct models are presented. The first considers future environmental profiles that evolve in a deterministic manner while the second assumes the environment evolves as a continuous-time Markov chain. Chapters 5 and 6 generalize the failure-dependent models and develop a general model that examines the interactions among the degradation processes of interconnected components/subsystems. In particular, we model how the degradation level of one component affects the degradation rates of other components in the system. Hereafter, we refer to this type of component-to-component interaction caused by their stochastic dependence as degradation-rate-interaction (DRI). Chapter 5 focuses on the scenario in which these changes occur in a discrete manner, whereas, Chapter 6 focuses on the scenario, in which DRIs occur in a continuous manner. We demonstrate that incorporating the effects of component interactions significantly improves the prediction accuracy of RLDs. Finally, we outline the conclusion remarks and a future work plan in Chapter 7.
4

Using Telemetry to Measure Equipment Mission Life on the NASA Orion Spacecraft for Increasing Astronaut Safety

Losik, Len 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / The surprise failure of two NASA Space Shuttles and the premature failures of satellite subsystem equipment on NASA satellites are motivating NASA to adopt an engineering discipline that uses telemetry specifically developed for preventing surprise equipment failures. The NASA Orion spacecraft is an Apollo module-like capsule planned to replace the NASA Space Shuttle reusable launch vehicle for getting astronauts to space and return to the earth safely as well as a crew escape vehicle stored at the ISS. To do so, NASA is adopting a non-Markov reliability paradigm for measuring equipment life based on the prognostic and health management program on the Air Force F-35 Joint Strike Fighter. The decision is based on the results from the prognostic analysis completed on the Space Shuttle Challenger and Columbia that identified the information that was present but was ignored for a variety of reasons. The goal of a PHM is to produce equipment that will not fail prematurely. It includes using predictive algorithms to measure equipment usable life. Equipment with transient behavior caused from accelerated of parts will fail prematurely with 100% certainty. For many decades, it was believed that test equipment and software used to in testing and noise from communications equipment were the cause of most transient behavior. With the processing speed of today's processors, transient behavior is caused from at least one part suffering from accelerated aging. Transient behavior is illustrated in equipment telemetry in a prognostic analysis. Telemetry is equipment performance information and equipment performance has been used to increase reliability, but performance is unrelated to equipment remaining usable life and so equipment should be failing prematurely. A PHM requires equipment telemetry for analysis and so analog telemetry will be available from all Orion avionics equipment. Replacing equipment with a measured remaining usable life of less than one year will stop the premature and surprise equipment failures from occurring during future manned and unmanned space missions.
5

Stopping Launch Vehicle Failures Using Telemetry to Measure Equipment Usable Life

Losik, Len 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / Launch vehicle equipment reliability is driven by infant mortality failures, which can be eliminated using a prognostic analysis prior, during and/or after the exhaustive and comprehensive dynamic environmental factory acceptance testing. Measuring and confirming equipment performance is completed to increase equipment reliability by identifying equipment that fails during test for repair/replacement. To move to the 100% reliability domain, equipment dynamic environmental factory testing should be followed by a prognostic analysis to measure equipment usable life and identify the equipment that will fail prematurely. During equipment testing, only equipment performance is measured and equipment performance is unrelated to equipment reliability making testing alone inadequate to produce equipment with 100% reliability. A prognostic analysis converts performance measurements into an invasive usable life measurement by sharing test data used to measure equipment performance. Performance data is converted to usable life data provides a time-to-failure (TTF) in minutes/hours/days/months for equipment that will fail within the first year of use, allowing the production of equipment with 100% reliability.
6

Using Telemetry to Measure Equipment Reliability and Upgrading the Satellite and Launch Vehicle Factory ATP

Losik, Len 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / Satellite and launch vehicles continues to suffer from catastrophic infant mortality failures. NASA now requires satellite suppliers to provide on-orbit satellite delivery and a free satellite and launch vehicle in the event of a catastrophic infant mortality failure. A high infant mortality failure rate demonstrates that the factory acceptance test program alone is inadequate for producing 100% reliability space vehicle equipment. This inadequacy is caused from personnel only measuring equipment performance during ATP and performance is unrelated to reliability. Prognostic technology uses pro-active diagnostics, active reasoning and proprietary algorithms that illustrate deterministic data for prognosticians to identify piece-parts, components and assemblies that will fail within the first year of use allowing this equipment to be repaired or replaced while still on the ground. Prognostic technology prevents equipment failures and so is pro-active. Adding prognostic technology will identify all unreliable equipment prior to shipment to the launch pad producing 100% reliable equipment and will eliminate launch failures, launch pad delays, on-orbit infant mortalities, surprise in-orbit failures. Moving to the 100% reliable equipment extends on-orbit equipment usable life.
7

Using Telemetry to Measure Equipment Mission Life on the NASA Orion Spacecraft for Increasing Astronaut Safety

Losik, Len 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The surprise failure of two NASA Space Shuttles and the premature failures of satellite subsystem equipment on NASA satellites are motivating NASA to adopt an engineering discipline specifically developed for preventing surprise equipment failures. The NASA Orion spacecraft is an Apollo module-like capsule planned to replace the NASA Space Shuttle reusable launch vehicle for getting astronauts to space and return to the earth safely as well as a crew escape vehicle stored at the ISS. To do so, NASA is adopting a non-Markov reliability paradigm for measuring equipment life based on the prognostic and health management program on the Air Force F-35 Joint Strike Fighter. The decision is based on the results from the prognostic analysis completed on the Space Shuttle Challenger and Columbia that identified the information that was present but was ignored for a variety of reasons prior to both accidents. The goal of a PHM is to produce equipment that will not fail prematurely and includes using predictive algorithms to measure equipment usable life. Equipment with transient behavior, missed by engineering analysis is caused from accelerated of parts will fail prematurely with 100% certainty. With the processing speed of today's processors, transient behavior is caused from at least one part suffering from accelerated aging. Transient behavior is illustrated in equipment telemetry in a prognostic analysis but not in an engineering analysis. Telemetry is equipment performance information and equipment performance has been used to increase reliability, but performance is unrelated to equipment remaining usable life and so equipment should be failing prematurely. A PHM requires equipment telemetry for analysis and so analog telemetry will be available from all Orion avionics equipment. Replacing equipment with a measured remaining usable life of less than one year will stop the premature and surprise equipment failures from occurring during future manned and unmanned space missions.
8

Stopping Launch Vehicle Failures Using Telemetry to Measure Equipment Usable Life

Losik, Len 10 1900 (has links)
Launch vehicle equipment reliability is driven by infant mortality failures, which can be eliminated using a prognostic analysis prior, during and/or after the exhaustive and comprehensive dynamic environmental factory acceptance testing. Measuring and confirming equipment performance is completed to increase equipment reliability by identifying equipment that fails during test for repair/replacement. To move to the 100% reliability domain, equipment dynamic environmental factory testing should be followed by a prognostic analysis to measure equipment usable life and identify the equipment that will fail prematurely. During equipment testing, only equipment performance is measured and equipment performance is unrelated to equipment reliability making testing alone inadequate to produce equipment with 100% reliability. A prognostic analysis converts performance measurements into an invasive usable life measurement by sharing test data used to measure equipment performance. Performance data is converted to usable life data provides a time-to-failure (TTF) in minutes/hours/days/months for equipment that will fail within the first year of use, allowing the production of equipment with 100% reliability.
9

Structural health monitoring with fiber Bragg grating sensors embedded into metal through ultrasonic additive manufacturing

Chilelli, Sean Kelty 23 December 2019 (has links)
No description available.
10

Results from the Prognostic Analysis Completed on the NASA EUVE Satellite to Measure Equipment Mission Life

Losik, Len 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper addresses the research conducted at U.C. Berkeley Space Sciences Laboratory, Center for Extreme Ultra Violet Astrophysics between 1994 and 1995 on the NASA EUVE ion-orbit satellite. It includes the results from conducting a scientific analysis called a prognostic analysis completed on all satellite subsystem equipment. A prognostic analysis uses equipment analog telemetry to measure equipment remaining usable life. The analysis relates equipment transient behavior, often referred to as "cannot duplicates" in a variety of industries caused from accelerated aging to the equipment end-of-life with certainty. The analysis was confirmed by using proprietary, pattern recognition software by Lockheed Martin personnel Lockheed Martin personnel completed an exploration into the application of statistical pattern recognition methods to identify the behavior caused from accelerated aging that experts in probability reliability analysis claims cannot exist. Both visual and statistical methods were successful in detecting suspect accelerated aging and this behavior was related to equipment end of life with certainty. The long-term objective of this research was to confirm that satellite subsystem equipment failures could be predicted so that satellite subsystem and payload engineering personnel could be allocated for only the time that equipment failures were predicted to occur, lowering the cost of mission operations. This research concluded that satellite subsystem equipment remaining usable life could be measured and equipment failures could be predicted with certainty so that engineering support for mission operations could be greatly reduced.

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