Verification of saturn instrument unit electrical support equipment.
Checkout computer for verifying Saturn instrument unit electrical support system
SUPPORT SYSTEM↗
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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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Managed Development Environment Successes for MSFC's VIPA Team
This paper outlines the best practices of the Vehicle Design Team for VIPA. VIPA is the Vehicle Integrated Performance Analysis Team at MSFC. This team was created to reconnect the individual engineering disciplines to be able to perform system level technical assessments in support of program decisions. The functions of the VIPA Vehicle Design (VVD) discipline team are to maintain the controlled reference geometry and provide linked, simplified geometry for each of the other discipline analyses. The core of the VVD work, and the approach for VVD s first task of controlling the reference geometry, involves systems engineering, top-down, layout-based CAD modeling within a Product Data Manager (PDM) development environment. The topdown approach allcws for simple contrnl of very large, integrated assemblies and greatly enhances the ability to generate trade configurations and reuse data. The second W D task, model simplification for analysis, is handled within the managed environment through application of the master model concept. In this approach, there is a single controlling, or master, product definition dataset. Connected to this master model are reference datasets with live geometric and expression links. The referenced models can be for drawings, manufacturing, visualization, embedded analysis, or analysis simplification. A discussion of web based interaction, including visualization, between the design and other disciplines is included. Demonstrated examples are cited, including the Space Launch Initiative development cycle, the Saturn V systems integration and verification cycle, an Orbital Space Plane study, and NASA Exploration Office studies of Shuttle derived and clean sheet launch vehicles. The VIPA Team has brought an immense amount of detailed data to bear on program issues. A central piece of that success has been the Managed Development Environment and the VVD Team approach to modeling.
Finckenor, Jeff↗
Paving the Way for Net Zero Energy Codes through Performance Based Approaches
The prescriptive path is the most widely used approach for commercial code compliance in the United States. However, to achieve near-term net zero energy performance that many stakeholders in the buildings industry desire, it is clear that energy codes will need to transition from prescriptive to performance-based approaches. However, that transition is not without potential pitfalls. Among the concerns expressed by stakeholders are added complexity and cost, lack of confidence in energy modeling results, gamesmanship on the part of applicants, lack or qualified reviewers, challenges in promoting de-carbonization, and the inequity of trading long lived envelope efficiency for short lived measures such as building controls. This paper will discuss multiple approaches being evaluated and implemented by Pacific Northwest National Laboratory to improve the usability of the performance-based approach for both code compliance and beyond code programs to meet aggressive energy savings targets. A 'system performance' approach provides a simpler approach compared to whole building performance, while keeping tradeoffs limited to specific building systems. A simplified whole-building performance-based approach for small commercial buildings can cost effectively achieve deeper savings for buildings that typically follow the prescriptive compliance approach. Improved reporting and verification processes applied to the traditional performance path can provide greater confidence in simulation results and facilitate adoption of performance-based approaches. Prescriptive packages provide prescriptive solutions while targeting specific performance thresholds. This paper discusses the progress being made with each of these approaches and provides examples of their implementation in energy codes and beyond code programs.
Performance Based Codes, Appendix G, PRM, TSPR, Sy↗
Vibration testing of large structures (CLAES Instrument)
The vibration testing performed on the Cryogenic Limb Array Etalon Spectrometer (CLAES) Instrument, installed on the Upper Atmosphere Research Satellite, is discussed. The tests discussed include random vibration, model verification using random vibration, and structural verification using a low frequency sine burst. Particular attention is given to the use of the sine burst test method to verify the structural integrity. Lessons learned from the program are summarized.
Newkirk, Roger↗
Recent advances in the modelling of crack growth under fatigue loading conditions
Fatigue crack growth associated with cyclic (secondary) plastic flow near a crack front is modelled using an incremental formulation. A new description of threshold behaviour under small load cycles is included. Quasi-static crack extension under high load excursions is described using an incremental formulation of the R-(crack growth resistance)- curve concept. The integration of the equations is discussed. For constant amplitude load cycles the results will be compared with existing crack growth laws. It will be shown that the model also properly describes interaction effects of fatigue crack growth and quasi-static crack extension. To evaluate the more general applicability the model is included in the NASGRO computer code for damage tolerance analysis. For this purpose the NASGRO program was provided with the CORPUS and the STRIP-YIELD models for computation of the crack opening load levels. The implementation is discussed and recent results of the verification are presented.
Dekoning, A. U.↗
Mechanical Properties of T650-35/AFR-PE-4 at Elevated Temperatures for Lightweight Aeroshell Designs
Considerable efforts have been underway to develop multidisciplinary technologies for aeroshell structures that will significantly increase the allowable working temperature for the aeroshell components, and enable the system to operate at higher temperatures while sustaining performance and durability. As part of these efforts, high temperature polymer matrix composites and fabrication technologies are being developed for the primary load bearing structure (heat shield) of the spacecraft. New high-temperature resins and composite material manufacturing techniques are available that have the potential to significantly improve current aeroshell design. In order to qualify a polymer matrix composite (PMC) material as a candidate aeroshell structural material, its performance must be evaluated under realistic environments. Thus, verification testing of lightweight PMC's at aeroshell entry temperatures is needed to ensure that they will perform successfully in high-temperature environments. Towards this end, a test program was developed to characterize the mechanical properties of two candidate material systems, T650-35/AFR-PE-4 and T650-35/RP46. The two candidate high-temperature polyimide resins, AFR-PE-4 and RP46, were developed at the Air Force Research Laboratory and NASA Langley Research Center, respectively. This paper presents experimental methods, strength, and stiffness data of the T650-35/AFR-PE-4 material as a function of elevated temperatures. The properties determined during the research test program herein, included tensile strength, tensile stiffness, Poisson s ratio, compressive strength, compressive stiffness, shear modulus, and shear strength. Unidirectional laminates, a cross-ply laminate and two eight-harness satin (8HS)-weave laminates (4-ply and 10-ply) were tested according to ASTM standard methods at room and elevated temperatures (23, 316, and 343 C). All of the relevant test methods and data reduction schemes are outlined along with mechanical data. These data contribute to a database of material properties for high-temperature polyimide composites that will be used to identify the material characteristics of potential candidate materials for aeroshell structure applications.
Whitley, Karen S.↗
James Webb Space Telescope - Applying Lessons Learned to I&T
The James Webb Space Telescope (JWST) is part of a new generation of spacecraft acquiring large data volumes from remote regions in space. To support a mission such as the JWST, it is imperative that lessons learned from the development of previous missions such as the Hubble Space Telescope and the Earth Observing System mission set be applied throughout the development and operational lifecycles. One example of a key lesson that should be applied is that core components, such as the command and telemetry system and the project database, should be developed early, used throughout development and testing, and evolved into the operational system. The purpose of applying lessons learned is to reap benefits in programmatic or technical parameters such as risk reduction, end product quality, cost efficiency, and schedule optimization. In the cited example, the early development and use of the operational command and telemetry system as well as the establishment of the intended operational database will allow these components to be used by the developers of various spacecraft components such that development, testing, and operations will all use the same core components. This will reduce risk through the elimination of transitions between development and operational components and improve end product quality by extending the verification of those components through continual use. This paper will discuss key lessons learned that have been or are being applied to the JWST Ground Segment integration and test program.
Johns, Alan↗
Design and Development of Sequential Rotary Valve
Valves are used to regulate the flow of fluids through systems. This rotary valve's main purpose is to fill, pressurize, empty, and vent three smaller tanks with the supply of one larger tank. Many different designs are being taken into consideration, which are each at different stages of development. The furthest along uses three ball valves on a common shaft to open and close their respective ports as the shaft completes one full rotation or cycle. We were tasked with advancing this design to its first test as a plastic model for flow verification, as well as sizing and ordering the necessary O-rings and fasteners. A motor will also be sized to satisfy the torque requirements, and will then be programmed using a Raspberry Pi to rotate the shaft at the calculated speed and dwelling times needed to fill each tank equally. In addition, we have also been advancing designs that use a camshaft and poppets. These are earlier on in their development, currently being sized to replicate the expected flow patterns of the rotary ball valve. Expected outcomes of this valve include bi-directionality, successful sealing under pressure, and accurate cycling.
D’Orsi, Nicholas↗
A Flight Rule Checker for the LADEE Lunar Spacecraft
As part of the design of a space mission, an important part is the design of so-called flight rules. Flight rules express constraints on various parts and processes of the mission, that if followed, will reduce the risk of failure. One such set of flight rules constrain the format of command sequences regularly (e.g. daily) sent to the spacecraft to con- trol its next near term behavior. We present a high-level view of the automated flight rule checker Frc for checking command sequences sent to NASA’s LADEE Lunar mission spacecraft, used throughout its entire mission. A command sequence is in this case essentially a program (a sequence of commands) with no loops or conditionals, and it can there- fore be verified with a trace analysis tool. Frc is implemented using the TraceContract runtime verification tool, an internal Scala DSL for checking event sequences against “formal specifications”. The paper illustrates this untraditional use of runtime verification in a real con- text, with strong demands on the expressiveness and flexibility of the specification language, illustrating the advantages of an internal DSL.
Kurklu, Elif↗
ePROJECT BUILDER: PROMOTING WIDER ADOPTION OF ENERGY SAVINGS PERFORMANCE CONTRACTS THROUGH STANDARDIZATION AND TRANSPARENCY
The United States Federal Government has been conducting guaranteed savings energy savings performance contracts for over 20 years and now relies on ESPC for the majority of its energy efficiency work. Along with a related financed project type, these deals resulted in $4.2 billion of project investment in the five years ending in 2016, a pace that has even accelerated since. Measurement and verification (M&V) on the projects is the key to assuring savings realization and persistence. Perceived as a weakness or burdensome added cost in the early years of the program, M&V has become a strength. All energy conservation measures (ECMs) have some form of measurement – defined as a measured baseline establishment followed by at least one measurement of the main energy-saving parameter taken in the performance period for each ECM. The government’s in-house energy consulting office, the Federal Energy Management Program (FEMP), now recommends measurement of these “Option A” M&V ECMs throughout the contract term, usually annually. Moreover, a significantly higher percentage of projects are now characterized by more ambitious M&V, including Option B (all parameter measurement) for most generation (including renewable) and some efficiency measures, and more frequent Option C (whole facility utility bill analysis) for “deep retrofit” projects with multiple, interactive ECMs. Coincident with this progress in M&V has been a much greater embracing of ESPC by the federal agencies, resulting in the enormous rate of projects now executed. This paper traces the evolution of M&V in federal ESPC and argues that the heightened credibility of the savings has contributed significantly to the procurement vehicle’s long-term viability. This focus on savings integrity via M&V has been learned over two decades for U.S. federal ESPC, but countries with developing ESPC markets would be wise to emphasize it as their markets emerge, allowing them to avoid some of the “growing pains” experienced in the U.S.
Earni, Shankar↗
M&V in ESPC: The U.S. Federal Experience and Implications for Developing ESPC Markets
The United States Federal Government has been conducting guaranteed savings energy savings performance contracts for over 20 years and now relies on ESPC for the majority of its energy efficiency work. Along with a related financed project type, these deals resulted in $4.2 billion of project investment in the five years ending in 2016, a pace that has even accelerated since. Measurement and verification (M&V) on the projects is the key to assuring savings realization and persistence. Perceived as a weakness or burdensome added cost in the early years of the program, M&V has become a strength. All energy conservation measures (ECMs) have some form of measurement – defined as a measured baseline establishment followed by at least one measurement of the main energy-saving parameter taken in the performance period for each ECM. The government’s in-house energy consulting office, the Federal Energy Management Program (FEMP), now recommends measurement of these “Option A” M&V ECMs throughout the contract term, usually annually. Moreover, a significantly higher percentage of projects are now characterized by more ambitious M&V, including Option B (all parameter measurement) for most generation (including renewable) and some efficiency measures, and more frequent Option C (whole facility utility bill analysis) for “deep retrofit” projects with multiple, interactive ECMs. Coincident with this progress in M&V has been a much greater embracing of ESPC by the federal agencies, resulting in the enormous rate of projects now executed. This paper traces the evolution of M&V in federal ESPC and argues that the heightened credibility of the savings has contributed significantly to the procurement vehicle’s long-term viability. This focus on savings integrity via M&V has been learned over two decades for U.S. federal ESPC, but countries with developing ESPC markets would be wise to emphasize it as their markets emerge, allowing them to avoid some of the “growing pains” experienced in the U.S.
Coleman, Philip↗
M&V in ESPC: The U.S. Federal Experience and Implications for Developing ESPC Markets
The United States Federal Government has been conducting guaranteed savings energy savings performance contracts for over 20 years and now relies on ESPC for the majority of its energy efficiency work. Along with a related financed project type, these deals resulted in $4.2 billion of project investment in the five years ending in 2016, a pace that has even accelerated since.Measurement and verification (M&V) on the projects is the key to assuring savings realization and persistence. Perceived as a weakness or burdensome added cost in the early years of the program, M&V has become a strength. All energy conservation measures (ECMs) have some form of measurement – defined as a measured baseline establishment followed by at least one measurement of the main energy-saving parameter for a given ECM taken in the performance period. The government’s in-house energy consulting office, the Federal Energy Management Program (FEMP), now recommends measurement of these “Option A” M&V ECMs throughout the contract term, usually annually. Moreover, a significantly higher percentage of projects are now characterized by more ambitious M&V, including Option B (all parameter measurement) for most generation (including renewable) and some efficiency measures, and more frequent Option C (whole facility utility bill analysis) for “deep retrofit” projects with multiple, interactive ECMs. Coincident with this progress in M&V has been a much greater embracing of ESPC by the federal agencies, resulting in the enormous rate of projects now executed. This paper traces the evolution of M&V in federal ESPC and argues that the heightened credibility of the estimated (and guaranteed) savings has contributed significantly to the procurement vehicle’s long-term viability. This focus on savings integrity via M&V has been learned over two decades for U.S. federal ESPC, but countries with developing ESPC markets would be wise to emphasize it as their markets emerge, allowing them to avoid some of the “growing pains” experienced in the U.S.
Coleman, Philip↗
Prediction and verification of creep behavior in metallic materials and components for the space shuttle thermal protection system. Volume 2: Phase 2 subsize panel cyclic creep predictions
A method for predicting permanent cyclic creep deflections in stiffened panel structures was developed. The resulting computer program may be applied to either the time-hardening or strain-hardening theories of creep accumulation. Iterative techniques were used to determine structural rotations, creep strains, and stresses as a function of time. Deflections were determined by numerical integration of structural rotations along the panel length. The analytical approach was developed for analyzing thin-gage entry vehicle metallic-thermal-protection system panels subjected to cyclic bending loads at high temperatures, but may be applied to any panel subjected to bending loads. Predicted panel creep deflections were compared with results from cyclic tests of subsize corrugation and rib-stiffened panels. Empirical equations were developed for each material based on correlation with tensile cyclic creep data and both the subsize panels and tensile specimens were fabricated from the same sheet material. For Vol. 1, see N75-21431.
Cramer, B. A.↗
Diode step stress program for JANTX1N1202A
Power/temperature step stress was applied to the switching diode JANTX1N1202A manufactured by General Electric and International Rectifier. A total of 48 samples from each manufacturer was submitted to the process. In addition, two control sample units were maintained for verification of the electrical parametric testing. All test samples were subjected to the electrical tests after completing the prior power/temperature step stress point. Results are given.
Source record↗
An overview of the NSCAT/N-ROSS program
The NASA Scatterometer (NSCAT) to fly on the U.S. Navy Remote Ocean Sensing System (N-ROSS) mission is presented. The overall N-ROSS mission, the NSCAT flight instrument and groundbased data processing/distribution system, and NASA-supported science and verification activities are described. The N-ROSS system is designed to provide measurements of near-surface wind, ocean topography, wave height, sea-surface temperature, and atmospheric water content over the global oceans. The NSCAT is an improved version of the Seasat scatterometer. It will measure near surface vector winds.
Martin, B. D.↗
Results of Small-scale Solid Rocket Combustion Simulator testing at Marshall Space Flight Center
The Small-scale Solid Rocket Combustion Simulator (SSRCS) program was established at the Marshall Space Flight Center (MSFC), and used a government/industry team consisting of Hercules Aerospace Corporation, Aerotherm Corporation, United Technology Chemical Systems Division, Thiokol Corporation and MSFC personnel to study the feasibility of simulating the combustion species, temperatures and flow fields of a conventional solid rocket motor (SRM) with a versatile simulator system. The SSRCS design is based on hybrid rocket motor principles. The simulator uses a solid fuel and a gaseous oxidizer. Verification of the feasibility of a SSRCS system as a test bed was completed using flow field and system analyses, as well as empirical test data. A total of 27 hot firings of a subscale SSRCS motor were conducted at MSFC. Testing of the Small-scale SSRCS program was completed in October 1992. This paper, a compilation of reports from the above team members and additional analysis of the instrumentation results, will discuss the final results of the analyses and test programs.
Goldberg, Benjamin E.↗
FOCAL Campaign I: Advanced Wind Turbine Control Strategies
Campaign I of the Floating Offshore-wind Controls Advanced Laboratory Experimental Program (FOCAL) aims to generate a dataset enabling the validation of aerodynamic performance of a scaled turbine mounted on a rigid tower in a fixed condition. The turbine considered in the FOCAL testing campaigns is the IEA-Wind 15MW Reference Wind Turbine. This scaled model is capable of simulating advanced blade-pitch control strategies in a high-quality wind field. The turbine is fully instrumented to record a variety of parameters in real time such as structural loads and dynamics. The test data considered was generated at the University of Maine's Harold Alfond Wind and Wave (W2) testing facility. The Load Cases (LC) considered in this testing campaign are as follows: LC 1.X - Constant wind and blade-pitch with varying rotor speeds LC 2.X - Constant wind and rotor speed with varying blade-pitch LC 3.X - Varying wind with active closed-loop control Detailed properties on the modeled system are found in the following reference: Lenfest E., Floating Offshore-wind Controls Advanced Laboratory (FOCAL) Experimental Program - Campaign I: 1:70 Model-scale Testing of the IEA-Wind 15MW Reference Turbine. UMaine ASCC Report Number 23-40-1183. Details on the results of the verification and validation are found in the following reference: Mendoza, Nicole et al., "Verification and Validation of Model-Scale Turbine Performance and Control for the IEA Wind 15 MW Reference Wind Turbine," Energies, vol. 15, no. 20, 2022, https://doi.org/10.3390/en15207649.
17 WIND ENERGY↗
Adaptation of a software development methodology to the implementation of a large-scale data acquisition and control system
A progress report is presented on a program to upgrade the existing NASA Deep Space Network in terms of a redesigned computer-controlled data acquisition system for channelling tracking, telemetry, and command data between a California-based control center and three signal processing centers in Australia, California, and Spain. The methodology for the improvements is oriented towards single subsystem development with consideration for a multi-system and multi-subsystem network of operational software. Details of the existing hardware configurations and data transmission links are provided. The program methodology includes data flow design, interface design and coordination, incremental capability availability, increased inter-subsystem developmental synthesis and testing, system and network level synthesis and testing, and system verification and validation. The software has been implemented thus far to a 65 percent completion level, and the methodology being used to effect the changes, which will permit enhanced tracking and communication with spacecraft, has been concluded to feature effective techniques.
Madrid, G. A.↗