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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 451 records · Page 25

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NASA NTRS2017

Thermal Protection for Mars Sample Return Earth Entry Vehicle: A Grand Challenge for Design Methodology and Reliability Verification

Mars Sample Return is our Grand Challenge for the coming decade. TPS (Thermal Protection System) nominal performance is not the key challenge. The main difficulty for designers is the need to verify unprecedented reliability for the entry system: current guidelines for prevention of backward contamination require that the probability of spores larger than 1 micron diameter escaping into the Earth environment be lower than 1 million for the entire system, and the allocation to TPS would be more stringent than that. For reference, the reliability allocation for Orion TPS is closer to 11000, and the demonstrated reliability for previous human Earth return systems was closer to 1100. Improving reliability by more than 3 orders of magnitude is a grand challenge indeed. The TPS community must embrace the possibility of new architectures that are focused on reliability above thermal performance and mass efficiency. MSR (Mars Sample Return) EEV (Earth Entry Vehicle) will be hit with MMOD (Micrometeoroid and Orbital Debris) prior to reentry. A chute-less aero-shell design which allows for self-righting shape was baselined in prior MSR studies, with the assumption that a passive system will maximize EEV robustness. Hence the aero-shell along with the TPS has to take ground impact and not break apart. System verification will require testing to establish ablative performance and thermal failure but also testing of damage from MMOD, and structural performance at ground impact. Mission requirements will demand analysis, testing and verification that are focused on establishing reliability of the design. In this proposed talk, we will focus on the grand challenge of MSR EEV TPS and the need for innovative approaches to address challenges in modeling, testing, manufacturing and verification.

Design and Verification for Reliability↗

NASA NTRS2003

A New Objective Technique for Verifying Mesoscale Numerical Weather Prediction Models

This report presents a new objective technique to verify predictions of the sea-breeze phenomenon over east-central Florida by the Regional Atmospheric Modeling System (RAMS) mesoscale numerical weather prediction (NWP) model. The Contour Error Map (CEM) technique identifies sea-breeze transition times in objectively-analyzed grids of observed and forecast wind, verifies the forecast sea-breeze transition times against the observed times, and computes the mean post-sea breeze wind direction and speed to compare the observed and forecast winds behind the sea-breeze front. The CEM technique is superior to traditional objective verification techniques and previously-used subjective verification methodologies because: It is automated, requiring little manual intervention, It accounts for both spatial and temporal scales and variations, It accurately identifies and verifies the sea-breeze transition times, and It provides verification contour maps and simple statistical parameters for easy interpretation. The CEM uses a parallel lowpass boxcar filter and a high-order bandpass filter to identify the sea-breeze transition times in the observed and model grid points. Once the transition times are identified, CEM fits a Gaussian histogram function to the actual histogram of transition time differences between the model and observations. The fitted parameters of the Gaussian function subsequently explain the timing bias and variance of the timing differences across the valid comparison domain. Once the transition times are all identified at each grid point, the CEM computes the mean wind direction and speed during the remainder of the day for all times and grid points after the sea-breeze transition time. The CEM technique performed quite well when compared to independent meteorological assessments of the sea-breeze transition times and results from a previously published subjective evaluation. The algorithm correctly identified a forecast or observed sea-breeze occurrence or absence 93% of the time during the two- month evaluation period from July and August 2000. Nearly all failures in CEM were the result of complex precipitation features (observed or forecast) that contaminated the wind field, resulting in a false identification of a sea-breeze transition. A qualitative comparison between the CEM timing errors and the subjectively determined observed and forecast transition times indicate that the algorithm performed very well overall. Most discrepancies between the CEM results and the subjective analysis were again caused by observed or forecast areas of precipitation that led to complex wind patterns. The CEM also failed on a day when the observed sea- breeze transition affected only a very small portion of the verification domain. Based on the results of CEM, the RAMS tended to predict the onset and movement of the sea-breeze transition too early and/or quickly. The domain-wide timing biases provided by CEM indicated an early bias on 30 out of 37 days when both an observed and forecast sea breeze occurred over the same portions of the analysis domain. These results are consistent with previous subjective verifications of the RAMS sea breeze predictions. A comparison of the mean post-sea breeze winds indicate that RAMS has a positive wind-speed bias for .all days, which is also consistent with the early bias in the sea-breeze transition time since the higher wind speeds resulted in a faster inland penetration of the sea breeze compared to reality.

Case, Jonathan L.↗

NASA NTRS2013

Final Report - Regulatory Considerations for Adaptive Systems

This report documents the findings of a preliminary research study into new approaches to the software design assurance of adaptive systems. We suggest a methodology to overcome the software validation and verification difficulties posed by the underlying assumption of non-adaptive software in the requirementsbased- testing verification methods in RTCA/DO-178B and C. An analysis of the relevant RTCA/DO-178B and C objectives is presented showing the reasons for the difficulties that arise in showing satisfaction of the objectives and suggested additional means by which they could be satisfied. We suggest that the software design assurance problem for adaptive systems is principally one of developing correct and complete high level requirements and system level constraints that define the necessary system functional and safety properties to assure the safe use of adaptive systems. We show how analytical techniques such as model based design, mathematical modeling and formal or formal-like methods can be used to both validate the high level functional and safety requirements, establish necessary constraints and provide the verification evidence for the satisfaction of requirements and constraints that supplements conventional testing. Finally the report identifies the follow-on research topics needed to implement this methodology.

Wilkinson, Chris↗

DOE OSTI2025

An approach for spent nuclear fuel containment integrity verification using gas tagging

Verification of containment integrity is required for spent nuclear fuel (SNF) managed by the commercial nuclear industry and U.S. Department of Energy (DOE), especially after extended storage. Certain SNF storage systems, such as the DOE road-ready dry storage system, hold several packaged containments within a welded over-canister. These packaged containments are called Department of Energy Standard Canisters (DOESCs). DOESC leakage identification is challenging because their containment boundary cannot be accessed for testing and their contents (i.e., SNF and fill gas) are often similar. There are concerns that this could result in costly characterization and repackaging operations of DOE road-ready dry storage systems if compromised DOESCs are suspected. Here, to address these concerns, this paper presents an approach for applying a gas tagging process using xenon to uniquely identify compromised inaccessible containments following extended storage. The containments considered for this application are seven DOESCs, each packaged within a single over-canister. Two different SNF loading configurations from the Advanced Test Reactor and Fort Saint Vrain nuclear power plant are considered. These configurations are used to represent research reactor aluminum-clad spent nuclear fuel (ASNF) and TRi-structural ISOtropic (TRISO) SNF types. Results for this application show that for ASNF and TRISO type fuels for which the selected fuels are representative, the volume of taggant required at loading is determined primarily by the lower detection limit and leak rate of taggant from a compromised DOESC, rather than the amount of fission-generated xenon in the loaded fuel. While the application presented is suited for larger leaks, smaller leaks could be detected by modifying certain design parameters. This gas tagging approach can also be applied to other DOE containments and advanced reactor SNF storage systems.

07 - ISOTOPES AND RADIATION SOURCES↗

DOE OSTI2024

SAM: A Modern System Code for Advanced Non-LWR Safety Analysis

The System Analysis Module (SAM), developed at Argonne National Laboratory and by collaborators at other organizations, is for advanced non–light water reactor safety analysis. SAM aims to provide fast-running, modest-fidelity, whole-plant transient analysis capabilities that are essential for fast-turnaround design scoping and engineering analyses of advanced reactor concepts. To facilitate code development, SAM utilizes the MOOSE object-oriented application framework, its underlying finite element library, and linear and nonlinear solvers to leverage modern advanced software environments and numerical methods. SAM aims to solve tightly coupled physical phenomena, including fission reaction, heat transfer, fluid dynamics, and thermal-mechanical responses in advanced reactor structures, systems, and components with high accuracy and efficiency. Finally, this paper gives an overview of the SAM code development, including goals and functional requirements, physical models, current capabilities, verification and validation, software quality assurance, and examples of simulations for advanced nuclear reactor applications.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2025

DMTN-222: Calibration Generation, Verification, Acceptance, and Certification

This technote defines the best practices to be used for calibration generation, the verification that that calibration meets requirements, and when deciding if the calibration should be accepted for use in processing at both the summit and USDF. Other aspects of calibration product management, including the contents of the appropriate "defaults" collection, are also discussed.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2025

DMTN-101: Verifying LSST Calibration Data Products

A description of plans for verifying LSST's Calibration Data Products. This document covers our approach to verification element LVV-57, addressing requirement DMS-REQ-0130.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1976

Computer program for design and performance analysis of navigation-aid power systems

The paper examines the requirements, design rationale, operation, and verification of a computer program designated as design synthesis/performance analysis (DSPA) computer program, which is capable of performing all the calculations necessary to understand the overall characteristics of solar array/battery power systems for navigation-aid applications. Despite the uncertainties in the erratic solar array degradation data and the potential impact on actual battery behavior, verification of the DSPA is considered successful. The program is shown to have the capability of simulating the performance of solar array/battery navigation-aid power systems. It can also be used to synthesize power system designs and provide essential design and cost data.

Weiner, H.↗

NASA NTRS1977

Space transportation system payload safety policy

A brief description of the Space Transportation System (STS) is given, and the evolution of a payload safety policy for it is described. The policy adopted in June, 1976, minimizes STS involvement in the payload design process while maintaining the assurance of a safe operation. The payload developer is responsible for assurance of safety and verification of compliance with the requirements. The STS will exercise reviews to ensure that interaction between payloads does not create hazards.

Scheller, J. A.↗

NASA NTRS1979

Determining potential 30/20 GHZ domestic satellite system concepts and establishment of a suitable experimental configuration

NASA is conducting a series of millimeter wave satellite communication systems and market studies to: (1) determine potential domestic 30/20 GHz satellite concepts and market potential, and (2) establish the requirements for a suitable technology verification payload which, although intended to be modest in capacity, would sufficiently demonstrate key technologies and experimentally address key operational issues. Preliminary results and critical issues of the current contracted effort are described. Also included is a description of a NASA-developed multibeam satellite payload configuration which may be representative of concepts utilized in a technology flight verification program.

Stevens, G. H.↗

NASA NTRS1981

System analysis approach to deriving design criteria (loads) for Space Shuttle and its payloads. Volume 1: General statement of approach

Space shuttle, the most complex transportation system designed to date, illustrates the requirement for an analysis approach that considers all major disciplines simultaneously. Its unique cross coupling and high sensitivity to aerodynamic uncertainties and high performance requirements dictated a less conservative approach than those taken in programs. Analyses performed for the space shuttle and certain payloads, Space Telescope and Spacelab, are used a examples. These illustrate the requirements for system analysis approaches and criteria, including dynamic modeling requirements, test requirements control requirements and the resulting design verification approaches. A survey of the problem, potential approaches available as solutions, implications for future systems, and projected technology development areas are addressed.

Ryan, R. S.↗

NASA NTRS1981

System analysis approach to deriving design criteria (Loads) for Space Shuttle and its payloads. Volume 2: Typical examples

The achievement of an optimized design from the system standpoint under the low cost, high risk constraints of the present day environment was analyzed. Space Shuttle illustrates the requirement for an analysis approach that considers all major disciplines (coupling between structures control, propulsion, thermal, aeroelastic, and performance), simultaneously. The Space Shuttle and certain payloads, Space Telescope and Spacelab, are examined. The requirements for system analysis approaches and criteria, including dynamic modeling requirements, test requirements, control requirements, and the resulting design verification approaches are illustrated. A survey of the problem, potential approaches available as solutions, implications for future systems, and projected technology development areas are addressed.

Ryan, R. S.↗

NASA NTRS1985

Overview od STS ground operations/orbiter turnaround STS-1 through STS-7

A review of STS-1 processing is presented as a reference for Shuttle processing time and the magnitude of the associated modifications, discrepancies, technical requirements, and ground systems activities. STS-1 processing provided the basis from which a plan to perform operational turnaround was established. Turnaround processing for Launch and Landing are treated separately to depict more clearly the progress made to reduce turnaround time and manhours expended. Turnaround time was reduced from 187 days for STS-2 to 60 days for STS-7 and landing turnaround was reduced from 14 days to 5 days. Modifications were reduced from 114 to 51. Requirements changes for launch readiness verification were reduced from 536 to 107. Special tests or inspections were reduced from 292 to 52. Anomalies resolved concurrent with processing were reduced from 13,000 to 4,000. Integration in the Vehicle Assembly Building (VAB) is about 10 percent of the flow, and Launch Pad operations comprise 40 percent of the turnaround. The work force has matured and has demonstrated the capability to perform planned and contingency operations. The turnaround program is fast approaching the goal of becoming operational.

Schwartz, R.↗

NASA NTRS1983

Gas side heat transfer

Improvements in methods for predicting heat transfer rates on the hot gas side of turbine airfoils are necessary for improved turbine durability and performance. The development and verification of improved analytical models requires a systematic, closely coupled experimental and analytical program.

Hylton, L. D.↗

NASA NTRS1986

Software engineering environment tool set integration

Space Transportation System Division (STSD) Engineering has a program to promote excellence within the engineering function. This program resulted in a capital funded facility based on a VAX cluster called the Rockwell Operational Engineering System (ROSES). The second phase of a three phase plan to establish an integrated software engineering environment for ROSES is examined. It discusses briefly phase one which establishes the basic capability for a modern software development environment to include a tool set, training and standards. Phase two is a tool set integration. The tool set is primarily off-the-shelf tools acquired through vendors or government agencies (public domain). These tools were placed into categories of software development. These categories are: requirements, design, and construction support; verification and validation support; and software management support. The integration of the tool set is being performed through concept prototyping and development of tools specifically designed to support the life cycle and provide transition from one phase to the next.

Selfridge, William P.↗

NASA NTRS1990

Multipurpose hardened spacecraft insulation

A Multipurpose Hardened Spacecraft Multilayer Insulation (MLI) system was developed and implemented to meet diverse survivability and performance requirements. Within the definition and confines of a MLI assembly (blanket), the design: (1) provides environmental protection from natural and induced nuclear, thermal, and electromagnetic radiation; (2) provides adequate electrostatic discharge protection for a geosynchronous satellite; (3) provides adequate shielding to meet radiated emission needs; and (4) will survive ascent differential pressure loads between enclosed volume and space. The MLI design is described which meets these requirements and design evolution and verification is discussed. The application is for MLI blankets which closeout the area between the laser crosslink subsystem (LCS) equipment and the DSP spacecraft cabin. Ancillary needs were implemented to ease installation at launch facility and to survive ascent acoustic and vibration loads. Directional venting accommodations were also incorporated to avoid contamination of LCS telescope, spacecraft sensors, and second surface mirrors (SSMs).

Steimer, Carlos H.↗

NASA NTRS1991

The development of the EOS data and information system

The architecture of the Earth Observing System (EOS), a major component of NASA's contribution to the U.S. Global Change Research Program, is described with emphasis on its development strategy. It is noted that the EOS is comprised of a scientific research program, a space measurement system, and an EOS Data and Information System (EOSDIS). Details are presented concerning the EOS program and its candidate instruments. Major components of EOS include Version 0 (V0) built on existing Distributed Active Archive Centers (DAACs), the EOSDIS core system (ECS), DAAC-unique functions, science computing facilities (SCF), and independent verification validation of the ECS. Requirements for EODIS are also reviewed noting that, among other requirements, it must keep up with an orbital average data rate of more than 30 Mbps as well as store, distribute, and manage information about tens of Petabytes of data during and after the 15-year mission.

Taylor, Thomas D.↗

NASA NTRS1992

Space Station Freedom ground systems program - A survey

The key facilities identified to support Space Station Freedom Program (SSFP) integrated operations and their SSFP roles are described in detail. The ground infrastructure, which must be able to support both assembly and long-term operations, will consist of ground facilities, support systems, and the associated planning and management procedures. During 1992 the SSFP is conducting a major program review of the ground infrastructure including the definition of all facility and support system functional capabilities, interfaces, and data-flow requirements. Operations functionality and interface verification tests are being identified, and operations readiness dates are being set.

Accola, A.↗