A 25,000 cycle life battery
Regression analysis of cycle life data for long life 20 ampere hour sealed nickel cadmium battery
Carr, E.↗
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Life cycle cost modeling of conceptual space vehicles
This paper documents progress to date by the University of Dayton on the development of a life cycle cost model for use during the conceptual design of new launch vehicles and spacecraft. This research is being conducted under NASA Research Grant NAG-1-1327. This research effort changes the focus from that of the first two years in which a reliability and maintainability model was developed to the initial development of a life cycle cost model. Cost categories are initially patterned after NASA's three axis work breakdown structure consisting of a configuration axis (vehicle), a function axis, and a cost axis. The focus will be on operations and maintenance costs and other recurring costs. Secondary tasks performed concurrent with the development of the life cycle costing model include continual support and upgrade of the R&M model. The primary result of the completed research will be a methodology and a computer implementation of the methodology to provide for timely cost analysis in support of the conceptual design activities. The major objectives of this research are: to obtain and to develop improved methods for estimating manpower, spares, software and hardware costs, facilities costs, and other cost categories as identified by NASA personnel; to construct a life cycle cost model of a space transportation system for budget exercises and performance-cost trade-off analysis during the conceptual and development stages; to continue to support modifications and enhancements to the R&M model; and to continue to assist in the development of a simulation model to provide an integrated view of the operations and support of the proposed system.
Ebeling, Charles↗
Software security checklist for the software life cycle
A formal approach to security in the software life cycle is essential to protect corporate resources. However, little thought has been given to this aspect of software development. Due to its criticality, security should be integrated as a formal approach in the software life cycle.
software security checklist security tools securit↗
Full Life-Cycle Defect Management Assessment: Initial Inspection Data Collection Results and Research Questions for Further Study
It is often the case in software projects that when schedule and budget resources are limited, the Verification and Validation (V&V) activities suffer. Fewer V&V activities can be afforded and moreover, short-term challenges can result in V&V activities being scaled back or dropped altogether. As a result, too often the default solution is to save activities for improving software quality until too late in the life-cycle, relying on late-term code inspections followed by thorough testing activities to reduce defect counts to acceptable levels. As many project managers realize, however, this is a resource-intensive way of achieving the required quality for software. The Full Life-cycle Defect Management Assessment Initiative, funded by NASA s Office of Safety and Mission Assurance under the Software Assurance Research Program, aims to address these problems by: Improving the effectiveness of early life-cycle V&V activities to make their benefits more attractive to team leads. Specifically, we focus on software inspection, a proven method that can be applied to any software work product, long before executable code has been developed; Better communicating this effectiveness to software development teams, along with suggestions for parameters to improve in the future to increase effectiveness; Analyzing the impact of early life-cycle V&V on the effectiveness and cost required for late life-cycle V&V activities, such as testing, in order to make the tradeoffs more apparent. This white paper reports on an initial milestone in this work, the development of a preliminary model of inspection effectiveness across multiple NASA Centers. This model contributes toward reaching our project goals by: Allowing an examination of inspection parameters, across different types of projects and different work products, for an analysis of factors that impact defect detection effectiveness. Allowing a comparison of this NASA-specific model to existing recommendations in the literature regarding how to plan effective inspections. Forming a baseline model which can be extended to incorporate factors describing: the numbers and types of defects that are missed by inspections; how such defects flow downstream through software development phases; how effectively they can be caught by testing activities in the late stages of development. The model has been implemented in a prototype web-enabled decision-support tool which allows developers to enter their inspection data and receive feedback based on a comparison against the model. The tool also allows users to access reusable materials (such as checklists) from projects included in the baseline. Both the tool itself and the model underlying it will continue to be extended throughout the remainder of this initiative. As results of analyzing inspection effectiveness for defect containment are determined, they can be shared via the tool and also via updates to existing training courses on metrics and software inspections. Moreover, the tool will help satisfy key CMMI requirements for the NASA Centers, as it will enable NASA to take a global view across peer review results for various types of projects to identify systemic problems. This analysis can result in continuous improvements to the approach to verification.
Shull, Forrest↗
Charting the Course: Life Cycle Management of Mars Mission Digital Information
This viewgraph presentation reviews the life cycle management of MER Project information. This process was an essential key to the successful launch of the MER Project rovers. Incorporating digital information archive requirements early in the project life cycle resulted in: Design of an information system that included archive metadata, Reduced the risk of information loss through in-process appraisal, Easier transfer of project information to institutional online archive and Project appreciation for preserving information for reuse by future projects
information life cycles↗
Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells. An update
An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.
Smithrick, John J.↗
Effect of KOH concentration on LEO cycle life of IPV nickel-hydrogen flight cells - An update
An update of validation test results confirming the breakthrough in LEO cycle life of nickel-hydrogen cells containing 26 percent potassium hydroxide (KOH) electrolyte is presented. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen cells is reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 LEO cycles compared to 3500 cycles for cells containing 31 percent KOH.
Smithrick, John J.↗
Evaluation of the developing DSN life-cycle cost standard practice
The DSN is developing a life-cycle cost standard practice by comparison to those of industry and the Department of Defense. Results show that the DSN uses the accepted concept of life-cycle costing, tailoring the concept to DSN specific needs, but does not push the concept past the point of prevailing theory.
Mckenzie, M.↗
Expected cycle life vs. depth of discharge relationships of well-behaved single cells and cell strings
The present investigation is concerned with the factors which might influence the cycle life vs. depth of discharge relationship, taking into account the rate of loss of cell capacity, the amount of excess capacity built into the cells, and the penalty in capacity loss resulting from the use of deep depths of discharge. 'First principles' are used to develop a cell life model for somewhat arbitrary conditions. This model is then used to estimate the cycle life vs. depth of discharge relationships for 'well behaved' cells. The stochastic variations associated with groupings of single cells are then introduced to the battery pack cycle life model. The term 'well behaved' cell is used to describe a single cell which does not suffer any abrupt failure mode during the course of its operation. It gradually loses capacity for any number of the usual reasons at a rate which is the product of the fractional depth of discharge and a factor which is characteristic of the cell under consideration.
Thaller, L. H.↗
Transpiration during life cycle in controlled wheat growth
A previously-developed model of wheat growth, designed for convenient incorporation into system-level models of advanced space life support systems is described. The model is applied to data from an experiment that grew wheat under controlled conditions and measured fresh biomass and cumulated transpiration as a function of time. The adequacy of modeling the transpiration as proportional to the inedible biomass, and an age factor which varies during the life cycle, are examined. Results indicate that during the main phase of vegetative growth in the first half of the life cycle, the rate of transpiration per unit mass of inedible biomass is more than double the rate during the phase of grain development and maturation during latter half of the life cycle.
Volk, Tyler↗
New Approaches in Reusable Booster System Life Cycle Cost Modeling
This paper presents the results of a 2012 life cycle cost (LCC) study of hybrid Reusable Booster Systems (RBS) conducted by NASA Kennedy Space Center (KSC) and the Air Force Research Laboratory (AFRL). The work included the creation of a new cost estimating model and an LCC analysis, building on past work where applicable, but emphasizing the integration of new approaches in life cycle cost estimation. Specifically, the inclusion of industry processes/practices and indirect costs were a new and significant part of the analysis. The focus of LCC estimation has traditionally been from the perspective of technology, design characteristics, and related factors such as reliability. Technology has informed the cost related support to decision makers interested in risk and budget insight. This traditional emphasis on technology occurs even though it is well established that complex aerospace systems costs are mostly about indirect costs, with likely only partial influence in these indirect costs being due to the more visible technology products. Organizational considerations, processes/practices, and indirect costs are traditionally derived ("wrapped") only by relationship to tangible product characteristics. This traditional approach works well as long as it is understood that no significant changes, and by relation no significant improvements, are being pursued in the area of either the government acquisition or industry?s indirect costs. In this sense then, most launch systems cost models ignore most costs. The alternative was implemented in this LCC study, whereby the approach considered technology and process/practices in balance, with as much detail for one as the other. This RBS LCC study has avoided point-designs, for now, instead emphasizing exploring the trade-space of potential technology advances joined with potential process/practice advances. Given the range of decisions, and all their combinations, it was necessary to create a model of the original model and use genetic algorithms to explore results. A strong business case occurs when viable paths are identified for an affordable up-front investment, and these paths can credibly achieve affordable, responsive operations, characterized by smaller direct touch labor efforts at the wing level from flight to flight. The results supporting this approach, its potential, and its conclusions are presented here.
Zapata, Edgar↗
New Approaches in Reuseable Booster System Life Cycle Cost Modeling
This paper presents the results of a 2012 life cycle cost (LCC) study of hybrid Reusable Booster Systems (RBS) conducted by NASA Kennedy Space Center (KSC) and the Air Force Research Laboratory (AFRL). The work included the creation of a new cost estimating model and an LCC analysis, building on past work where applicable, but emphasizing the integration of new approaches in life cycle cost estimation. Specifically, the inclusion of industry processes/practices and indirect costs were a new and significant part of the analysis. The focus of LCC estimation has traditionally been from the perspective of technology, design characteristics, and related factors such as reliability. Technology has informed the cost related support to decision makers interested in risk and budget insight. This traditional emphasis on technology occurs even though it is well established that complex aerospace systems costs are mostly about indirect costs, with likely only partial influence in these indirect costs being due to the more visible technology products. Organizational considerations, processes/practices, and indirect costs are traditionally derived ("wrapped") only by relationship to tangible product characteristics. This traditional approach works well as long as it is understood that no significant changes, and by relation no significant improvements, are being pursued in the area of either the government acquisition or industry?s indirect costs. In this sense then, most launch systems cost models ignore most costs. The alternative was implemented in this LCC study, whereby the approach considered technology and process/practices in balance, with as much detail for one as the other. This RBS LCC study has avoided point-designs, for now, instead emphasizing exploring the trade-space of potential technology advances joined with potential process/practice advances. Given the range of decisions, and all their combinations, it was necessary to create a model of the original model and use genetic algorithms to explore results. A strong business case occurs when viable paths are identified for an affordable up-front investment, and these paths can credibly achieve affordable, responsive operations, characterized by smaller direct touch labor efforts at the wing level from flight to flight. The results supporting this approach, its potential, and its conclusions are presented here.
Zapata, Edgar↗
Major weapon system environmental life-cycle cost estimating for Conservation, Cleanup, Compliance and Pollution Prevention (C3P2)
The Titan 4 Space Launch Vehicle Program is one of many major weapon system programs that have modified acquisition plans and operational procedures to meet new, stringent environmental rules and regulations. The Environmental Protection Agency (EPA) and the Department of Defense (DOD) mandate to reduce the use of ozone depleting chemicals (ODC's) is just one of the regulatory changes that has affected the program. In the last few years, public environmental awareness, coupled with stricter environmental regulations, has created the need for DOD to produce environmental life-cycle cost estimates (ELCCE) for every major weapon system acquisition program. The environmental impact of the weapon system must be assessed and budgeted, considering all costs, from cradle to grave. The Office of the Secretary of Defense (OSD) has proposed that organizations consider Conservation, Cleanup, Compliance and Pollution Prevention (C(sup 3)P(sup 2)) issues associated with each acquisition program to assess life-cycle impacts and costs. The Air Force selected the Titan 4 system as the pilot program for estimating life-cycle environmental costs. The estimating task required participants to develop an ELCCE methodology, collect data to test the methodology and produce a credible cost estimate within the DOD C(sup 3)P(sup 2) definition. The estimating methodology included using the Program Office weapon system description and work breakdown structure together with operational site and manufacturing plant visits to identify environmental cost drivers. The results of the Titan IV ELCCE process are discussed and expanded to demonstrate how they can be applied to satisfy any life-cycle environmental cost estimating requirement.
Hammond, Wesley↗
The TMIS life-cycle process document, revision A
The Technical and Management Information System (TMIS) Life-Cycle Process Document describes the processes that shall be followed in the definition, design, development, test, deployment, and operation of all TMIS products and data base applications. This document is a roll out of TMIS Standards Document (SSP 30546). The purpose of this document is to define the life cycle methodology that the developers of all products and data base applications and any subsequent modifications shall follow. Included in this methodology are descriptions of the tasks, deliverables, reviews, and approvals that are required before a product or data base application is accepted in the TMIS environment.
Source record↗
KOH concentration effect on the cycle life of nickel-hydrogen cells. Part 4: Results of failure analyses
KOH concentration effects on cycle life of a Ni/H2 cell have been studied by carrying out a cycle life test of ten Ni/H2 boiler plate cells which contain electrolytes of various KOH concentrations. Failure analyses of these cells were carried out after completion of the life test which accumulated up to 40,000 cycles at an 80 percent depth of discharge over a period of 3.7 years. These failure analyses included studies on changes of electrical characteristics of test cells and component analyses after disassembly of the cell. The component analyses included visual inspections, dimensional changes, capacity measurements of nickel electrodes, scanning electron microscopy, BET surface area measurements, and chemical analyses. Results have indicated that failure mode and change in the nickel electrode varied as the concentration was varied, especially, when the concentration was changed from 31 percent or higher to 26 percent or lower.
Lim, H. S.↗
The role of interest and inflation rates in life-cycle cost analysis
The effect of projected interest and inflation rates on life cycle cost calculations is discussed and a method is proposed for making such calculations which replaces these rates by a single parameter. Besides simplifying the analysis, the method clarifies the roles of these rates. An analysis of historical interest and inflation rates from 1950 to 1976 shows that the proposed method can be expected to yield very good projections of life cycle cost even if the rates themselves fluctuate considerably.
Eisenberger, I.↗
KOH concentration effect on the cycle life of nickel-hydrogen cells. IV - Results of failure analysis
Potassium hydroxide concentration effects on the cycle life of a Ni/H2 cell have been studied by carrying out a cycle life test on ten Ni/H2 boiler plate cells which contain electrolytes of various KOH concentrations. Failure analyses of these cells were carried out after completion of the life test, which accumulated up to 40,000 cycles at an 80-percent depth of discharge over a period of 3.7 years. These failure analyses included studies on changes of electrical characteristics of test cells, and component analyses after disassembly of the cell. The component analyses included visual inspections, dimensional changes, capacity measurements of nickel electrodes, scanning electron microscopy, surface area measurements, and chemical analyses. Results have indicated that failure mode and change in the nickel electrode varied as the concentration was varied, especially when the concentration was changed from 31 percent or higher to 26 percent or lower.
Lim, H. S.↗
Evaluation of Cycle Life and Characterization of YTP 45 Ah Li-Ion Battery for EMU
Li-ion batteries, with longer cycle life and higher energy density features, are now more and more attractive and applied in multiple fields. The YTP 45 Ah Li-ion battery has been evaluated here and may be employed in EMU in the future. Evaluations were on: (1) Cycle life tests - 500 cycles total (completed 40 cycles in simulated shuttle use mode and 460 cycles in an accelerated use mode, and recorded differential voltage of individual cell in battery); (2) Characterization test - discharge capacity measurement in environment temperature of -10, 25, 50 C before and after 500 cycles; and (3) Thermal testing - charge and discharge at 50 C and -10 C before and after 500 cycles. The battery showed less than a 9% drop of initial discharge capacity and energy within 500 cycles with 475 cycles 59% DOD plus 25 cycles 100% DOD. The EOD voltage ranged from 16.0 to 18.0 V, which fits the requirement for operating the EMU.
Deng, Yi↗