Tech Briefs

Model-Based Prognostics for Batteries

Accurate predictions can be made of the remaining useful life for individual discharge cycles, as well as for cycle life. Ames Research Center, Moffett Field, California The innovation provides enhanced health management routines for batteries. A mathematical model has been developed to describe battery behavior during individual discharge cycles, as well as over the cycle life. Different prognostic modes for estimating the state of charge, state of life, end of discharge, and/or end of life of a battery are provided. It employs a mathematical, rigorous reasoning framework for better understanding and representation, manipulation, and management of the various sources of uncertainty inherent in the prognostics of the remaining useful life in a battery. The models used to estimate the remaining useful life of batteries are linked to the internal electrochemical processes of the battery. The effects of load (and, by extension, temperature) have been incorporated into the models. The model is used in conjunction with a particle filtering framework to make state estimations and probabilistic predictions of remaining useful life for individual discharge cycles, as well as for battery life. The model fidelity improves when the influence of factors like temperature, discharge C-rate, end of discharge, state of charge after charging, etc., are explicitly incorporated. Model validation studies were conducted using data from a series of battery cycling experiments at various thermal and electrical loading conditions. In addition, the models and algorithms were integrated on an electric UAV and subsequently flown on numerous test flights.

Posted in: Test & Measurement, Briefs, TSP

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Goddard Mission Services Evolution Center Compliance Test Suite

Goddard Space Flight Center, Greenbelt, Maryland To reduce the cost of building specialized interfaces, missions can adopt Goddard Mission Services Evolution Center (GMSEC) technologies and applications. Assurances need to be made that application implementation should follow the GMSEC messaging standards. The GMSEC Interface Specification Document (ISD) sets forth definitions for all GMSEC message types.

Posted in: Test & Measurement, Software, Briefs, TSP

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Mass Spectrometry of Spacecraft Contamination Using the Direct Analysis in Real-Time Ion Source

NASA’s Jet Propulsion Laboratory, Pasadena, California Mass spectrometry is presented as a powerful tool for the analysis of spacecraft contamination when coupled to the Direct Analysis in Real Time (DART) ionization source. DART technology is based on soft ionization and desorption using metastable helium (MSHe). This provides efficient sample introduction for the rapid analysis of polymers and bio-organic compounds. It is particularly useful to the evaluation of polymers that may outgas in the space environment. In addition, this approach provides sensitive analysis of bio-marker and organic compounds that may interfere with organic and life detection instruments on future spacecraft missions.

Posted in: Physical Sciences, Test & Measurement, Briefs

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Application of a Physics-Based Stabilization Criterion to Flight System Thermal Testing

Goddard Space Flight Center, Greenbelt, Maryland This innovation consists of a procedure and set of equations that allows thermal balance steady-state temperatures to be predicted hours before the balance is reached based on current temperature and rate-of-change measurements. This will allow tests to run faster, since thermal plateau settings may be adjusted prior to reaching an equilibrium state. Additionally, it will allow the test conductors to identify future limit violations hours before they may happen, which would increase flight hardware safety. A similar methodology can be used to predict component temperatures in flight, assuming a relatively constant sink temperature condition, which would be useful for long cool-down missions such as the James Webb Space Telescope (JWST).

Posted in: Test & Measurement, Briefs, TSP

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Battery Fault Detection with Saturating Transformers

This monitoring system for high-power battery health could be useful for electric cars and the aerospace industry. Lyndon B. Johnson Space Center, Houston, Texas A monitoring network has been created that can be added to a battery consisting of many parallel cells. This network allows the health of individual cells, as measured by the current that they produce under load, to be monitored. If one or more cells are producing less current than the others, the network allows the discrepant cell(s) to be sensed and located.

Posted in: Electronics & Computers, Briefs, TSP

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Digitally Controlled, 12-V Precision Current Source for Extreme-Temperature Operation

NASA’s Jet Propulsion Laboratory, Pasadena, California Many control applications require precision, high-voltage-capable stimulus current drivers for sensor excitation. In particular, a requirement for a stimulus driver that can be primarily integrated into a motor feedback signal conditioning ASIC (application specific integrated circuit) for Martian environments is satisfied by this development.

Posted in: Electronics & Computers, Briefs, TSP

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Scandate Cathode for High-Power, Long-Life Electric Space Propulsion

Applications include electron beam-stimulated lasers for high-power video projection systems and new-generation CT-scan x-ray imaging systems. John H. Glenn Research Center, Cleveland, Ohio Scandate cathodes are able to produce about 20 times the emission of conventional all-tungsten cathodes at the same temperature. Conversely, they operate at about 200 °C lower temperature for the same emission. Scandate cathodes have been studied since at least the 1960s. Between then and 2002, numerous approaches were investigated. All cathodes either did not work or degraded within a few thousand hours. The current nanoparticle approach appears to have overcome previous shortcomings.

Posted in: Electronics & Computers, Briefs, TSP

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