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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS2003

Space Weather Effects on Spacecraft Systems

Space-based systems are developing into critical infrastructure required to support the quality of life on Earth. Hence, spacecraft reliability is a serious issue that is complicated by exposure to the space environment. Complex mission designs along with rapidly evolving technologies have outpaced efforts to accommodate detrimental space environment impacts on systems. Hazardous space environments, the effects on systems, and the accommodation of the effects are described with a focus on the need to predict space environments.

Barth, Janet L.↗
NASA NTRS2006

Dielectronic Recombination In Active Galactic Nuclei

XMM-Newton and Chandra observations of active galactic nuclei (AGN) show rich spectra of X-ray absorption lines. These observations have detected a broad unresolved transition array (UTA) between approx. 15-17 A. This is attributed to inner-shell photoexcitation of M-shell iron ions. Modeling these UTA features is currently limited by uncertainties in the low-temperature dielectronic recombination (DR) data for M-shell iron. In order to resolve this issue, and to provide reliable iron M-shell DR data for plasma modeling, we are carrying out a series of laboratory measurements using the heavy-ion Test Storage Ring (TSR) at the Max-Plank-Institute for Nuclear Physics in Heidelberg, Germany. Currently, laboratory measurements of low temperature DR can only be performed at storage rings. We use the DR data obtained at TSR, to calculate rate coefficients for plasma modeling and to benchmark theoretical DR calculations. Here we report our recent experimental results for DR of Fe XIV forming Fe XIII.

Lukic, D. V.↗
NASA NTRS2007

Promoting Robust Design of Diode Lasers for Space: A National Initiative

The Diode-laser Array Working Group (DAWG) is a national-level consumer/provider forum for discussion of engineering and manufacturing issues which influence the reliability and survivability of high-power broad-area laser diode devices in space, with an emphasis on laser diode arrays (LDAs) for optical pumping of solid-state laser media. The goals of the group are to formulate and validate standardized test and qualification protocols, operational control recommendations, and consensus manufacturing and certification standards. The group is using reliability and lifetime data collected by laser diode manufacturers and the user community to develop a set of standardized guidelines for specifying and qualifying laser diodes for long-duration operation in space, the ultimate goal being to promote an informed U.S. Government investment and procurement strategy for assuring the availability and durability of space-qualified LDAs. The group is also working to establish effective implementation of statistical design techniques at the supplier design, development, and manufacturing levels to help reduce product performance variability and improve product reliability for diodes employed in space applications

Tratt, David M.↗
NASA NTRS2016

Body of Knowledge for Silicon Carbide Power Electronics

Wide band gap semiconductors, such as silicon carbide (SiC), have emerged as very promising materials for future electronic components due to the tremendous advantages they offer in terms of power capability, extreme temperature tolerance, and high frequency operation. This report documents some issues pertaining to SiC technology and its application in the area of power electronics, in particular those geared for space missions. It also serves as a body of knowledge (BOK) in reference to the development and status of this technology obtained via literature and industry survey as well as providing a listing of the major manufacturers and their capabilities. Finally, issues relevant to the reliability of SiC-based electronic parts are addressed and limitations affecting the full utilization of this technology are identified.

Silicon Carbide Power Electronics↗
NASA NTRS2019

Body of Knowledge (BOK): Gallium Nitride (GaN) Power Electronics for Space Applications

Gallium nitride (GaN), a wide bandgap (WBG) semiconductor, has emerged as a very promising material for electronic components due to the tremendous advantages it offers compared to silicon (Si), such as power capability, extreme temperature tolerance, and high frequency operation. This presentation summarizes a body of knowledge (BOK) document in reference to the development and current status of GaN technology obtained via literature and industry surveys. It provides a listing of the major manufacturers and their capabilities, as well as government, industry, and academic parties interested in the technology. The presentation also discusses GaN's applications in the area of power electronics, in particular those geared for space missions. Finally, issues relevant to the reliability of GaN-based electronic parts are addressed and limitations affecting the full utilization of this technology are identified.

Boomer, Kristen↗
NASA NTRS2020

Body of Knowledge for Gallium Nitride Power Electronics

Gallium nitride (GaN), a wide bandgap (WBG) semiconductor, has emerged as a very promising material for electronic components due to the tremendous advantages it offers compared to silicon (Si), such as power capability, extreme temperature tolerance, and high frequency operation. This report serves as a body of knowledge (BOK) in reference to the development and current status of GaN technology obtained via literature and industry surveys. It provides a listing of the major manufacturers and their capabilities, as well as government, industry, and academic parties interested in the technology. The document also discusses GaN’s applications in the area of power electronics, in particular those geared for space missions. Finally, issues relevant to the reliability of GaN-based electronic parts are addressed and limitations affecting the full utilization of this technology are identified. This BOK focuses mainly on power applications for GaN, but will also briefly mention radio frequency (RF) applications for completeness.

Gallium Nitride Power Electronics↗
NASA NTRS1991

Active and passive vibration suppression for space structures

The relative benefits of passive and active vibration suppression for large space structures (LSS) are discussed. The intent is to sketch the true ranges of applicability of these approaches using previously published technical results. It was found that the distinction between active and passive vibration suppression approaches is not as sharp as might be thought at first. The relative simplicity, reliability, and cost effectiveness touted for passive measures are vitiated by 'hidden costs' bound up with detailed engineering implementation issues and inherent performance limitations. At the same time, reliability and robustness issues are often cited against active control. It is argued that a continuum of vibration suppression measures offering mutually supporting capabilities is needed. The challenge is to properly orchestrate a spectrum of methods to reap the synergistic benefits of combined advanced materials, passive damping, and active control.

Hyland, David C.↗
NASA NTRS2003

An Advanced Hierarchical Hybrid Environment for Reliability and Performance Modeling

The key issue we intended to address in our proposed research project was the ability to model and study logical and probabilistic aspects of large computer systems. In particular, we wanted to focus mostly on automatic solution algorithms based on a state-space exploration as their first step, in addition to the more traditional discrete-event simulation approaches commonly employed in industry. One explicitly-stated goal was to extend by several orders of magnitude the size of models that can be solved exactly, using a combination of techniques: 1) Efficient exploration and storage of the state space using new data structures that require an amount of memory sublinear in the number states; and 2) Exploitation of the existing symmetries in the matrices describing the system behavior using Kronecker operators. Not only we have been successful in achieving the above goals, but we exceeded them in many respects.

Ciardo, Gianfranco↗
NASA NTRS2000

Chip Scale Package Issues

Availability of board solder joint reliability information is critical to the wider implementation of Chip Scale Packages (CSPs).

solder↗
NASA NTRS2017

X-Ray Computed Tomography: The First Step in Mars Sample Return Processing

The Mars 2020 rover mission will collect and cache samples from the martian surface for possible retrieval and subsequent return to Earth. If the samples are returned, that mission would likely present an opportunity to analyze returned Mars samples within a geologic context on Mars. In addition, it may provide definitive information about the existence of past or present life on Mars. Mars sample return presents unique challenges for the collection, containment, transport, curation and processing of samples [1] Foremost in the processing of returned samples are the closely paired considerations of life detection and Planetary Protection. In order to achieve Mars Sample Return (MSR) science goals, reliable analyses will depend on overcoming some challenging signal/noise-related issues where sparse martian organic compounds must be reliably analyzed against the contamination background. While reliable analyses will depend on initial clean acquisition and robust documentation of all aspects of developing and managing the cache [2], there needs to be a reliable sample handling and analysis procedure that accounts for a variety of materials which may or may not contain evidence of past or present martian life. A recent report [3] suggests that a defined set of measurements should be made to effectively inform both science and Planetary Protection, when applied in the context of the two competing null hypotheses: 1) that there is no detectable life in the samples; or 2) that there is martian life in the samples. The defined measurements would include a phased approach that would be accepted by the community to preserve the bulk of the material, but provide unambiguous science data that can be used and interpreted by various disciplines. Fore-most is the concern that the initial steps would ensure the pristine nature of the samples. Preliminary, non-invasive techniques such as computed X-ray tomography (XCT) have been suggested as the first method to interrogate and characterize the cached samples without altering the materials [1,2]. A recent report [4] indicates that XCT may minimally alter samples for some techniques, and work is needed to quantify these effects, maximizing science return from XCT initial analysis while minimizing effects.

Welzenbach, L. C.↗
NASA NTRS1991

Expert system verification and validation study. Delivery 3A and 3B: Trip summaries

Key results are documented from attending the 4th workshop on verification, validation, and testing. The most interesting part of the workshop was when representatives from the U.S., Japan, and Europe presented surveys of VV&T within their respective regions. Another interesting part focused on current efforts to define industry standards for artificial intelligence and how that might affect approaches to VV&T of expert systems. The next part of the workshop focused on VV&T methods of applying mathematical techniques to verification of rule bases and techniques for capturing information relating to the process of developing software. The final part focused on software tools. A summary is also presented of the EPRI conference on 'Methodologies, Tools, and Standards for Cost Effective Reliable Software Verification and Validation. The conference was divided into discussion sessions on the following issues: development process, automated tools, software reliability, methods, standards, and cost/benefit considerations.

French, Scott↗
NASA NTRS2005

Serial Back-Plane Technologies in Advanced Avionics Architectures

Current back plane technologies such as VME, and current personal computer back planes such as PCI, are shared bus systems that can exhibit nondeterministic latencies. This means a card can take control of the bus and use resources indefinitely affecting the ability of other cards in the back plane to acquire the bus. This provides a real hit on the reliability of the system. Additionally, these parallel busses only have bandwidths in the 100s of megahertz range and EMI and noise effects get worse the higher the bandwidth goes. To provide scalable, fault-tolerant, advanced computing systems, more applicable to today s connected computing environment and to better meet the needs of future requirements for advanced space instruments and vehicles, serial back-plane technologies should be implemented in advanced avionics architectures. Serial backplane technologies eliminate the problem of one card getting the bus and never relinquishing it, or one minor problem on the backplane bringing the whole system down. Being serial instead of parallel improves the reliability by reducing many of the signal integrity issues associated with parallel back planes and thus significantly improves reliability. The increased speeds associated with a serial backplane are an added bonus.

Varnavas, Kosta↗
NASA NTRS2001

Residue detection for real-time removal of paint from metallic surfaces

Paint stripping from large steel ships and other metallic surfaces is a major issue in the maintenance and refurbishing of structures, and environmental concerns are greatly limiting the possible options. As a result, waterjet with water recycling has become the leading form of paint stripping and robotic manipulators with scanning bridges were constructed by various manufacturers to address this need. The application of such scanning bridges is slow and their access is constrained by the complex shape of the ship hull and various features on the surface. To overcome these limitations, a robotic system that is called Ultrastrip (UltraStrip Systems, Inc., Stuart, FL) is developed. This system uses magnetic wheels to attach the stripper to the structure and travel on it while performing paint stripping. To assure efficient paint stripping feedback data is required to control the travel speed by monitoring the paint thickness before and during the stripping process. Efforts at JPL are currently underway to develop the required feedback capability to assure effective paint stripping. Various possible sensors were considered and issues that can affect the sensitivity, reliability and applicability of the sensors are being investigated with emphasis on measuring the initial conditions of the paint. Issues that affect the sensory data in dynamic conditions are addressed while providing real-time real feedback for the control of the paint stripper speed of travel.

NDT↗
NASA NTRSDate not supplied

How Can We Efficiently Build A Spacecraft That Has Longevity? Experiences From the GSFC Perspective to Inform Lunar Exploration and Science Orbiter’s Architecture

Recent successes in NASA planetary science missions has shown that long-lived missions can yield significant science return. These missions, despite their longevity, were not planned to operate beyond their deign life. For example, the Lunar Reconnaissance Orbiter has a design life of 2-3 years, and yet we are entering its 14th year on orbit. Spacecraft longevity in practice has been related to: 1) mission class; 2) did we test it long enough and resolve all the anomalies to be beyond the early failure curve; 3) consumables budgets, and 4) how components are de-signed and tested. Mission class has been perceived as one of the primary ways to drive longevity. But higher mission class is a significant cost and mission driver. Parts selection only from the limited military standard parts and extensive parts qualification adds to development time and cost. Largely redundant (often erroneously interpreted as fully redundant) adds to launch mass and increases testing complexity (which may reduce the amount of testing in the nominal con-figuration). Lower Risk Posture (reflected in a higher mission class) drives significant additional processes and quality assurance analyses. Higher mission class also drives significantly greater sparing and life testing costs. This discussion focuses on whether this is indeed the best way to achieve longevity efficiently or whether there are more efficient ways to achieve longevity. Empirical evidence shows that lower mission classes that implement effective risk reduction and selective redundancy generally results in long life at a lower Spacecraft bus cost. By evaluating redundancy careful-ly, spacecraft cost can be lowered which can enable a more capable payload. Risk of the mission is highly dependent on the complexity of the mission and is only loosely dependent on Class of Mission. High complexity missions can have many single point failures and require the development of new technology, while lower class mission can have lower risk by baselining or incorporating: (selective) redundancy, fault-tolerant design, design for minimum risk, ability to reset, and/or design for graceful degradation. The team met with Goddard Space Flight Center Space Systems Mission Operations leaders to discuss which avionics have proven in flight to be the most reliable and which have had lifetime issues. The paper proposes a list of components to focus on for redundancy for a long-lived lunar mission. Reliability numbers are presented for both single string and dual string missions. The history of life-time performance versus planned mission life according to mission class is presented. A mission with well thought out selective redundancy and effective on the ground test program, can be expected to last well beyond its mission lifetime and provided enhanced return for the community. This approach minimizes project expenditures that do not retire significant risk and allows the project to focus risk mitigation efforts on those risks that will have a significant likelihood of threatening mission success. This is aided by keeping the amount of technology maturation and mission complexity low, while focusing effort on ensuring all component stress-ing parameters well within the bounds of their capabilities.

Lessons Learned↗
DOE OSTI2025

High-Temperature Aquifer Thermal Energy Storage (HT-ATES) Projects in Germany and the Netherlands—Review and Lessons Learned

Aquifer thermal energy storage (ATES) is a concept that can help to address heating and cooling needs through the use of the subsurface as a seasonal thermal energy storage (STES) system. Over 2800 ATES systems have been deployed with storage temperatures typically below 25 °C and only a few with higher temperatures (>40 °C), which would increase the energy density and utility of the stored thermal fluids. Until now, only a few high-temperature aquifer thermal energy storage (HT-ATES) projects have been initiated and are still in operation. These HT-ATES projects have encountered a range of technical and non-technical challenges. This study reviews ten such projects: four in Germany and six in the Netherlands. The non-technical issues include public acceptance, a lack of regulatory framework for these systems, managing overlapping uses of the subsurface, managing changes with the providers and off-takers of thermal energy, and obtaining financing to implement these projects. Common technical issues include geological factors such as incomplete characterization of the subsurface and reservoir heterogeneity; geochemical issues such as mineral scaling, corrosion, and biofouling; lower than expected thermal recovery; and issues with system design and reliability. This review highlights benefits and challenges faced by HT-ATES projects with the goal to use the lessons learned to improve the siting, design, development, and operation of such systems. Recommendations include improved initial subsurface site characterization, use of coupled process models to optimize system design and predict system performance, cascaded uses of stored thermal energy to better utilize the stored heat, monitoring networks to provide feedback on system performance, and expanded system scale to allow for continued operation even when maintenance of some system components is required. Techno-economic modeling and risk analysis could be used to optimize such HT-ATES project design and identify key factors that will affect sustained economic viability. In addition, design flexibility is important for these systems to allow for changing conditions regarding the supply and demand of thermal energy. Adopting these findings should improve the performance and reduce the risks for future HT-ATES projects worldwide.

15 - GEOTHERMAL ENERGY↗
DOE OSTI2024

A Real-Time Testbed for Smart Inverter Cyber Security Studies

Distributed energy resources (DER) have become a popular solution to modern-day issues surrounding the efficiency and reliability of power generation, as well as climate change concerns. Energy centers are shifting towards incorporating smart inverters with embedded functionalities such as high voltage ride through (HVRT), low voltage ride through (LVRT), active and reactive power compensation. However, the integration of smart inverters leave DER systems highly vulnerable to cybersecurity threats. The distributed network protocol 3 (DNP3) is a common method of communication between grid-tied hardware. Despite its popularity, the level of security leaves all hardware connected to the grid at risk of severe cyber-attacks. Thus, it is important to study any potential cybersecurity threats towards grid-tied smart inverters to mitigate cybersecurity vulnerabilities and refine existing cyber-security protections. This report describes the proposed testbed design to study cybersecurity threats to smart inverters. The testbed utilizes a real-time simulation case in RSCAD that includes a grid-tied wind turbine (WT) topology featuring two back-to-back two-level voltage source converters (BTB,2L-VSCs) and a permanent magnet synchronous machine (PMSM). The simulated case runs within the NovaCor real time digital simulator (RTDS). This report focuses on the design and implementation of a single module of the GTNETx2 card as a distributed network protocol and the configuration of an IEEE 1518 DNP database file that includes input and output variables mapped to different connection points in the grid that transmit and receive discrete, analog, and binary signals on command. This allows realistic emulation of the communication between the smart inverter and the grid for cybersecurity studies.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1989

Space Station Technology Summary

The completion of the Space Station Propulsion Advanced Technology Programs established an in-depth data base for the baseline gaseous oxygen/gaseous hydrogen thruster, the waste gas resistojet, and the associated system operations. These efforts included testing of a full end-to-end system at National Aeronautics and Space Administration (NASA)-Marshall Space Flight Center (MSFC) in which oxygen and hydrogen were generated from water by electrolysis at 6.89 MPa (1,000 psia), stored and fired through the prototype thruster. Recent end-to-end system tests which generate the oxygen/hydrogen propellants by electrolysis of water at 20.67 MPa (3,000 psia) were completed on the Integrated Propulsion Test Article (IPTA) at NASA-Johnson Space Center (JSC). Resistojet testing has included 10,000 hours of life testing, plume characterization, and electromagnetic interference (EMI) testing. Extensive 25-lbf thruster testing was performed defining operating performance characteristics across the required mixture ratio and thrust level ranges. Life testing has accumulated 27 hours of operation on the prototype thruster. A total of seven injectors and five thrust chambers were fabricated to the same basic design. Five injectors and three thrust chambers designed to incorporate improved life, performance, and producibility characteristics are ready for testing. Five resistojets were fabricated and tested, with modifications made to improve producibility. The lessons learned in the area of producibility for both the O2/H2 thrusters and for the resistojet have resolved critical fabrication issues. The test results indicate that all major technology issues for long life and reliability for space station application were resolved.

Iacabucci, R.↗