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At least 91 records · Page 5

Lunar Regenerative Fuel Cell (RFC) Reliability Testing for Assured Mission Success

NASA's Constellation program has selected the closed cycle hydrogen oxygen Polymer Electrolyte Membrane (PEM) Regenerative Fuel Cell (RFC) as its baseline solar energy storage system for the lunar outpost and manned rover vehicles. Since the outpost and manned rovers are "human-rated," these energy storage systems will have to be of proven reliability exceeding 99 percent over the length of the mission. Because of the low (TRL=5) development state of the closed cycle hydrogen oxygen PEM RFC at present, and because there is no equivalent technology base in the commercial sector from which to draw or infer reliability information from, NASA will have to spend significant resources developing this technology from TRL 5 to TRL 9, and will have to embark upon an ambitious reliability development program to make this technology ready for a manned mission. Because NASA would be the first user of this new technology, NASA will likely have to bear all the costs associated with its development.When well-known reliability estimation techniques are applied to the hydrogen oxygen RFC to determine the amount of testing that will be required to assure RFC unit reliability over life of the mission, the analysis indicates the reliability testing phase by itself will take at least 2 yr, and could take up to 6 yr depending on the number of QA units that are built and tested and the individual unit reliability that is desired. The cost and schedule impacts of reliability development need to be considered in NASA's Exploration Technology Development Program (ETDP) plans, since life cycle testing to build meaningful reliability data is the only way to assure "return to the moon, this time to stay, then on to Mars" mission success.

Bents, David J.↗

Lunar RFC Reliability Testing for Assured Mission Success

NASA's Constellation program has selected the closed cycle hydrogen oxygen Polymer Electrolyte Membrane (PEM) regenerative Fuel Cell (RFC) as its baseline solar energy storage system for the lunar outpost and manned rover vehicles. Since the outpost and manned rovers are "human-rated", these energy storage systems will have to be of proven reliability exceeding 99 percent over the length of the mission. Because of the low (TRL=5) development state of the closed cycle hydrogen oxygen PEM RFC at present, and because there is no equivalent technology base in the commercial sector from which to draw or infer reliability information from, NASA will have to spend significant resources developing this technology from TRL 5 to TRL 9, and will have to embark upon an ambitious reliability development program to make this technology ready for a manned mission. Because NASA would be the first user of this new technology, NASA will likely have to bear all the costs associated with its development. When well-known reliability estimation techniques are applied to the hydrogen oxygen RFC to determine the amount of testing that will be required to assure RFC unit reliability over life of the mission, the analysis indicates the reliability testing phase by itself will take at least 2 yr, and could take up to 6 yr depending on the number of QA units that are built and tested and the individual unit reliability that is desired. The cost and schedule impacts of reliability development need to be considered in NASA's Exploration Technology Development Program (ETDP) plans, since life cycle testing to build meaningful reliability data is the only way to assure "return to the moon, this time to stay, then on to Mars" mission success.

Bents, David J.↗

Reliability analysis in the Office of Safety, Environmental, and Mission Assurance (OSEMA)

The technical personnel in the SEMA office are working to provide the highest degree of value-added activities to their support of the NASA Langley Research Center mission. Management perceives that reliability analysis tools and an understanding of a comprehensive systems approach to reliability will be a foundation of this change process. Since the office is involved in a broad range of activities supporting space mission projects and operating activities (such as wind tunnels and facilities), it was not clear what reliability tools the office should be familiar with and how these tools could serve as a flexible knowledge base for organizational growth. Interviews and discussions with the office personnel (both technicians and engineers) revealed that job responsibilities ranged from incoming inspection to component or system analysis to safety and risk. It was apparent that a broad base in applied probability and reliability along with tools for practical application was required by the office. A series of ten class sessions with a duration of two hours each was organized and scheduled. Hand-out materials were developed and practical examples based on the type of work performed by the office personnel were included. Topics covered were: Reliability Systems - a broad system oriented approach to reliability; Probability Distributions - discrete and continuous distributions; Sampling and Confidence Intervals - random sampling and sampling plans; Data Analysis and Estimation - Model selection and parameter estimates; and Reliability Tools - block diagrams, fault trees, event trees, FMEA. In the future, this information will be used to review and assess existing equipment and processes from a reliability system perspective. An analysis of incoming materials sampling plans was also completed. This study looked at the issues associated with Mil Std 105 and changes for a zero defect acceptance sampling plan.

Kauffmann, Paul J.↗

NASA's Office Safety Mission Assurance Efforts to Improve Non-destructive Evaluation Methods for Additive Manufacturing and In-Space Inspection

National Aeronautics and Space Administration (NASA) continues to push the boundary of manned flight. Current mission profiles include flights to the Moon and Mars. Many of these missions require advance manufacturing and planned off planet resource utilization. As NASA continues to develop highly advance materials and manufacturing techniques to meet these mission profiles, inspection of these increasingly complex parts has had to evolve as well. Additive manufacturing is coming to the forefront as a primary manufacturing technique but offers unique challenges when inspection and certification are required. NASA has been working diligently to be a leader in developing and utilizing inspection techniques capable of inspecting these highly advanced parts. Additionally additive manufacturing techniques can also be used to build parts in space and provides a vehicle for in-situ resource utilization for off world missions. As NASA and its commercial crew partners move forward, inspection techniques will need to continue to advance to ensure safe manned space flight. In this talk NASA will highlight many of the advanced nondestructive evaluation efforts going on across the agency, as well as providing highlights for points of infusion for helping NASA meet its future mission goals.

NDE↗

Gateway Program Safety and Mission Assurance IAASS Conference Keynote Presentation

This next wave of lunar exploration will be fundamentally different than the past. The goal today is long term human presence in Earth orbit, exploration around the Moon, exploration anywhere on the Moon, and challenging exploration missions beyond the Moon. Sustainability is the key to enabling human expansion across the solar system and bringing back to Earth new knowledge and opportunities, and requires the early engagement of scientific, international, and U.S. commercial interests, innovations, and new approaches. The Gateway’s agile acquisition strategy will shape the entire system life cycle, from design and analysis through production, verification, launch, logistics and operations. This strategy will encourage new ways of doing business to accommodate new techniques, technologies and approaches; improving affordability and maximizing Gateway utility. The full range of acquisition authorities and contracting mechanisms available to NASA will be considered and appropriately tailored in response to the unique demands of each procurement activity. Gateway will provide scientific and research benefits, in addition to providing a sustainable staging location for crewed lunar surface landings and technology demonstrations that help NASA develop the knowledge and technology needed for Mars missions. These payloads are expected to provide operational and scientific benefit for the duration of their stay on Gateway, as the hardware will provide data during the transit to the Gateway and while in lunar orbit as changes in solar activity occur over time. Gateway is designed to support a variety of utilization activities during both crewed and uncrewed periods and is planned for continuous operations throughout its lifetime. These operations include demonstrating key exploration capabilities in a relevant deep space environment, conducting science beyond the influence of Earth, and providing opportunities for Gateway partners and customers for deep space exploration. Located in cislunar orbit, the Gateway capabilities can be further leveraged to enhance lunar and Mars exploration. With the Gateway and other elements of the Artemis Program, NASA is encouraging new ways of doing business to accommodate new techniques, technologies and approaches, consider affordability, and encourage innovation from U.S. industry.

Terri Castillo↗

Gateway Program Safety And Mission Assurance Integration - The Future Of Safe Deep Space Human Exploration

This next wave of lunar exploration will be fundamentally different than the past. The goal today is long term human presence in Earth orbit, exploration around the Moon, exploration anywhere on the Moon, and challenging exploration missions beyond the Moon. Sustainability is the key to enabling human expansion across the solar system and bringing back to Earth new knowledge and opportunities, and requires the early engagement of scientific, international, and U.S. commercial interests, innovations, and new approaches. The Gateway’s agile acquisition strategy will shape the entire system life cycle, from design and analysis through production, verification, launch, logistics and operations. This strategy will encourage new ways of doing business to accommodate new techniques, technologies and approaches; improving affordability and maximizing Gateway utility. The full range of acquisition authorities and contracting mechanisms available to NASA will be considered and appropriately tailored in response to the unique demands of each procurement activity. Gateway will provide scientific and research benefits, in addition to providing a sustainable staging location for crewed lunar surface landings and technology demonstrations that help NASA develop the knowledge and technology needed for Mars missions. These payloads are expected to provide operational and scientific benefit for the duration of their stay on Gateway, as the hardware will provide data during the transit to the Gateway and while in lunar orbit as changes in solar activity occur over time. Gateway is designed to support a variety of utilization activities during both crewed and uncrewed periods and is planned for continuous operations throughout its lifetime. These operations include demonstrating key exploration capabilities in a relevant deep space environment, conducting science beyond the influence of Earth, and providing opportunities for Gateway partners and customers for deep space exploration. Located in cislunar orbit, the Gateway capabilities can be further leveraged to enhance lunar and Mars exploration. With the Gateway and other elements of the Artemis Program, NASA is encouraging new ways of doing business to accommodate new techniques, technologies and approaches, consider affordability, and encourage innovation from U.S. industry.

Helen Vaccaro↗

Smart Composite Overwrapped Pressure Vessel - Integrated Structural Health Monitoring System to Meet Space Exploration and International Space Station Mission Assurance Needs

Currently there are no integrated NDE methods for baselining and monitoring defect levels in fleet for Composite Overwrapped Pressure Vessels (COPVs) or related fracture critical composites, or for performing life-cycle maintenance inspections either in a traditional remove-and-inspect mode or in a more modern in situ inspection structural health monitoring (SHM) mode. Implicit in SHM and autonomous inspection is the existence of quantitative accept-reject criteria. To be effective, these criteria must correlate with levels of damage known to cause composite failure. Furthermore, implicit in SHM is the existence of effective remote sensing hardware and automated techniques and algorithms for interpretation of SHM data. SHM of facture critical composite structures, especially high pressure COPVs, is critical to the success of nearly every future NASA space exploration program as well as life extension of the International Space Station. It has been clearly stated that future NASA missions may not be successful without SHM [1]. Otherwise, crews will be busy addressing subsystem health issues and not focusing on the real NASA mission

Saulsberry, Regor↗

The Multi-scenario Extreme Weather Simulator: Energy Resilience for Mission Assurance

The Multi-scenario extreme weather simulator (MEWS) is a stochastic weather generation tool. The MEWS algorithm uses 50 or more years of National Oceanic and Atmospheric Association (NOAA) daily summaries [1] for maximum and minimum temperature and NOAA climate norms [2] to calculate historical heat wave and cold snap statistics. The algorithm takes these statistics and shifts them according to multiplication factors provided in the Intergovernmental Panel on Climate Change (IPCC) physical basis technical summary [3] for heat waves.

54 ENVIRONMENTAL SCIENCES↗

SiC vs. Si for High Radiation Environments: NASA Electronic Parts and Packaging (NEPP) Program Office of Safety and Mission Assurance

Commercial silicon carbide and silicon Schottky barrier power diodes have been subjected to 203 MeV proton irradiation and the effects of the resultant displacement damage on the I-V characteristics have been observed. Changes in forward bias I-V characteristics are reported for fluences up to 4 x 10(exp 14) p/cm2. For devices of both material types, the series resistance is observed to increase as the fluence increases. The changes in series resistance result from changes in the free carrier concentration due to carrier removal by the defects produced. A simple model is presented that allows calculation of the series resistance of the device and then relates the carrier removal rate to the changes in series resistance. Using this model to calculate the carrier removal rate in both materials reveals that the carrier removal rate in silicon is less than that in silicon carbide, indicating that silicon is the more radiation tolerant material.

Schottky barrier power diodes↗

Ares First Stage "Systemology" - Combining Advanced Systems Engineering and Planning Tools to Assure Mission Success

Ares is an integral part of NASA s Constellation architecture that will provide crew and cargo access to the International Space Station as well as low earth orbit support for lunar missions. Ares replaces the Space Shuttle in the post 2010 time frame. Ares I is an in-line, two-stage rocket topped by the Orion Crew Exploration Vehicle, its service module, and a launch abort system. The Ares I first stage is a single, five-segment reusable solid rocket booster derived from the Space Shuttle Program's reusable solid rocket motor. The Ares second or upper stage is propelled by a J-2X main engine fueled with liquid oxygen and liquid hydrogen. This paper describes the advanced systems engineering and planning tools being utilized for the design, test, and qualification of the Ares I first stage element. Included are descriptions of the current first stage design, the milestone schedule requirements, and the marriage of systems engineering, detailed planning efforts, and roadmapping employed to achieve these goals.

Seiler, James↗

JSC Safety and Mission Assurance Data Analysis Overview

These slides describe the data analysis methods that are used to determine inputs for probabilistic risk models supporting the Space Shuttle Program. Other applications can follow a similar path probably using different data sources. Statistical approaches are different and not addressed here. Topics included here: 1) Prior Distribution; 2) Likelihood Data; 3) Bayesian Updating; and 4) Uncertainty and Error. Note: This is a high-level discussion and is not intended to be a tutorial.

Roelant, Henk↗

Safety and Mission Assurance for In-House Design Lessons Learned from Ares I Upper Stage

This viewgraph presentation identifies lessons learned in the course of the Ares I Upper Stage design and in-house development effort. The contents include: 1) Constellation Organization; 2) Upper Stage Organization; 3) Presentation Structure; 4) Lesson-Importance of Systems Engineering/Integration; 5) Lesson-Importance of Early S&MA Involvement; 6) Lesson-Importance of Appropriate Staffing Levels; 7) Lesson-Importance S&MA Team Deployment; 8) Lesson-Understanding of S&MA In-Line Engineering versus Assurance; 9) Lesson-Importance of Close Coordination between Supportability and Reliability/Maintainability; 10) Lesson-Importance of Engineering Data Systems; 11) Lesson-Importance of Early Development of Supporting Databases; 12) Lesson-Importance of Coordination with Safety Assessment/Review Panels; 13) Lesson-Implementation of Software Reliability; 14) Lesson-Implementation of S&MA Technical Authority/Chief S&MA Officer; 15) Lesson-Importance of S&MA Evaluation of Project Risks; 16) Lesson-Implementation of Critical Items List and Government Mandatory Inspections; 17) Lesson-Implementation of Critical Items List Mandatory Inspections; 18) Lesson-Implementation of Test Article Safety Analysis; and 19) Lesson-Importance of Procurement Quality.

Anderson, Joel M.↗

Investigation of the Semicoa SCF9550 and the International Rectifier IRHM57260SE for Single-Event Gate Rapture and Single-Event Burnout : NASA Electronic Parts and Packaging (NEPP) Program Office of Safety and Mission Assurance

Single-event-effect test results for hi-rel total-dose-hardened power MOSFETs are presented in this report. TheSCF9550 from Semicoa and the IRHM57260SE from International Rectifier were tested to NASA test condition/standards and requirements.The IRHM57260SE performed much better when compared to previous testing. These initial results confirm that parts from the Temecula line are marginally comparable to the El Segundo line. The SCF9550 from Semicoa was also tested and represents the initial parts offering from this vendor. Both parts experienced single-event gate rupture (SEGR) and single-event burnout (SEB). All of the SEGR was from gate to drain.

Single Event Gate Rupture↗

Independent Verification and Validation (IV and V) - Adding Mission Assurance to NASA Flight Software

The NASA Independent Verification and Validation (IV&V) Facility objective is to identify potential defects in flight software using independent analysis techniques. This paper describes the tailored IV&V techniques that have been developed in support of critical interactions on the Mars Science Laboratory (MSL) project, scheduled to launch in November, 2011. The IV&V techniques for interface analysis use independently developed sequence diagrams of critical scenarios. The results from these analyses have had a positive impact on the requirements flow down, consistency amongst MSL requirements and identification of missing requirements. The results of these analyses and the positive impact to the MSL project are provided.

performance evaluation↗