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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2010

Lunar Atmosphere and Dust Environment Explorer Integration and Test

The Lunar Atmosphere and Dust Environment Explorer (LADEE) is a NASA collaborative flight project to explore the lunar exosphere. It is being developed through a unique partnership between NASA's Ames Research Center (ARC) and Goddard Space Flight Center (GSFC). Each center brings its own experience and flight systems heritage to the task of integrating and testing the LADEE subsystems, instruments, and spacecraft. As an "in-house" flight project being implemented at low-cost and moderate risk, LADEE relies on single-string subsystems and protoflight hardware to accomplish its mission. Integration and test (l&T) of the LADEE spacecraft with the instruments will be performed at GSFC, and includes assembly, integration, functional testing, and flight qualification and acceptance testing. Due to the nature of the LADEE mission, l&T requirements include strict contamination control measures and instrument calibration procedures. Environmental testing will include electromagnetic compatibility (EMC), vibro-acoustic testing, and thermal-balance/vacuum. Upon successful completion of spacecraft l&T, LADEE will be launched from NASA's Wallops Flight Facility. Launch of the LADEE spacecraft is currently scheduled for December 2012.

Wright, Michael R.↗
DOE OSTI2025

RELAP5-3D Capabilities for High-Temperature Gas-Cooled Reactor Analysis

RELAP5-3D is the premier systems thermal-hydraulic code in the world. The code has been used significantly for high-temperature gas-cooled reactor (HTGR) analyses over the last 10 years, but there has not been a comprehensive summary of RELAP5-3D capabilities and methods for HTGR modeling. In this paper, we provide a guide for how novice users can build models for prismatic HTGRs. This guide includes best practices for developing heat structures and setting up radiation and conduction heat transfer. We also provide a summary of relevant validation studies. These studies are divided into three categories: separate effects tests, integral effects tests, and nuclear reactor studies. We present a comprehensive review of RELAP5-3D HTGR applications for reactor modeling over the last 10 years. These applications include work for the Modular High-Temperature Gas-Cooled Reactor benchmark, design activities for a prismatic HTGR as part of the U.S. Department of Energy’s Advanced Demonstration and Test Reactor Options Study, and studies performed to design gas-cooled microreactors. Following the comprehensive literature review, we present a gap analysis highlighting capabilities of RELAP5-3D that are available and missing for a complete analysis of HTGR thermal hydraulics. We also discuss the limitations of existing code capabilities and potential improvements that could improve analyses. Current research efforts have yet to fully validate RELAP5-3D for a prismatic HTGR analysis; however, some of this is attributable to confounding factors in the available experimental data as opposed to code capabilities. In conclusion, this paper presents the most comprehensive review to date on RELAP5-3D capabilities, limitations, and applications for HTGR analysis.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

In-Rod Sensor System Overview, Benefits and Recent Irradiation Test Results

Westinghouse is developing an In-Rod Sensor (IRS) System capable of measuring critical fuel rod parameters such as center-line fuel temperature, rod internal pressure and axial fuel pellet stack elongation without having penetrations to the fuel rod. The technology is similar to the Halden Reactor instrumentation, but the IRS system focuses on commercial fuel rod instrumentation. Both systems circumvent fuel rod penetrations, however the IRS system overcomes unique geometric challenges found in commercial fuel rod assemblies. The IRS could also play a key role in accelerated fuel qualification by allowing real-time measurements during separate effects tests, integral fuel testing or during irradiation of lead test rods or lead test assemblies. Combining these measurements with data acquired from targeted separate effects testing and multi-scale modelling could significantly reduce the time required to qualify new fuel and reduce the safety margin uncertainty of operating plants. The IRS is actively in development for Light Water Reactors (LWR) based fuel assemblies but can also be applied to Gen IV reactor designs with minimal modifications.

Carvajal, Jorge↗
NASA NTRS1974

Shuttle active thermal control system development testing. Volume 5: Integrated radiator/expendable cooling system tests

Tests were conducted to gather data on a space shuttle active control system (ATCS) incorporating both radiators and an expendable cooling device to provide vehicle heat removal. Two systems were tested and design information was provided for both nominal and limit conditions. The tests verified the concept that an integrated radiator/expendable cooling system can adequately maintain desired water quantities while responding to variations in heat loads and environments. In addition, the need for duct heating was demonstrated, while exhaust nozzle heating was also shown to be unnecessary.

Scheps, P. B.↗
NASA NTRS1985

Space station data system analysis/architecture study. Task 3: Trade studies, DR-5, volume 2

Results of a Space Station Data System Analysis/Architecture Study for the Goddard Space Flight Center are presented. This study, which emphasized a system engineering design for a complete, end-to-end data system, was divided into six tasks: (1); Functional requirements definition; (2) Options development; (3) Trade studies; (4) System definitions; (5) Program plan; and (6) Study maintenance. The Task inter-relationship and documentation flow are described. Information in volume 2 is devoted to Task 3: trade Studies. Trade Studies have been carried out in the following areas: (1) software development test and integration capability; (2) fault tolerant computing; (3) space qualified computers; (4) distributed data base management system; (5) system integration test and verification; (6) crew workstations; (7) mass storage; (8) command and resource management; and (9) space communications. Results are presented for each task.

Source record↗
NASA NTRS1987

A normal incidence high resolution X-ray telescope for solar coronal observations

The preflight preparation of the multilayer mirror fabrication and testing, integration and testing, and WSMR activities are described. Post-flight analysis shows that all payload systems and subsystems performed well within acceptable limits, with the sole exception of the light-blocking prefilters. Suggested corrective actions were discussed. Refurbishment and reflight are then described.

Golub, Leon↗
NASA NTRS2010

NASA Astronauts on Soyuz: Experience and Lessons for the Future

The U. S., Russia, and, China have each addressed the question of human-rating spacecraft. NASA's operational experience with human-rating primarily resides with Mercury, Gemini, Apollo, Space Shuttle, and International Space Station. NASA s latest developmental experience includes Constellation, X38, X33, and the Orbital Space Plane. If domestic commercial crew vehicles are used to transport astronauts to and from space, Soyuz is another example of methods that could be used to human-rate a spacecraft and to work with commercial spacecraft providers. For Soyuz, NASA's normal assurance practices were adapted. Building on NASA's Soyuz experience, this report contends all past, present, and future vehicles rely on a range of methods and techniques for human-rating assurance, the components of which include: requirements, conceptual development, prototype evaluations, configuration management, formal development reviews (safety, design, operations), component/system ground-testing, integrated flight tests, independent assessments, and launch readiness reviews. When constraints (cost, schedule, international) limit the depth/breadth of one or more preferred assurance means, ways are found to bolster the remaining areas. This report provides information exemplifying the above safety assurance model for consideration with commercial or foreign-government-designed spacecraft. Topics addressed include: U.S./Soviet-Russian government/agency agreements and engineering/safety assessments performed with lessons learned in historic U.S./Russian joint space ventures

Source record↗
NASA NTRS2011

Early Oscillation Detection for DC/DC Converter Fault Diagnosis

The electrical power system of a spacecraft plays a very critical role for space mission success. Such a modern power system may contain numerous hybrid DC/DC converters both inside the power system electronics (PSE) units and onboard most of the flight electronics modules. One of the faulty conditions for DC/DC converter that poses serious threats to mission safety is the random occurrence of oscillation related to inherent instability characteristics of the DC/DC converters and design deficiency of the power systems. To ensure the highest reliability of the power system, oscillations in any form shall be promptly detected during part level testing, system integration tests, flight health monitoring, and on-board fault diagnosis. The popular gain/phase margin analysis method is capable of predicting stability levels of DC/DC converters, but it is limited only to verification of designs and to part-level testing on some of the models. This method has to inject noise signals into the control loop circuitry as required, thus, interrupts the DC/DC converter's normal operation and increases risks of degrading and damaging the flight unit. A novel technique to detect oscillations at early stage for flight hybrid DC/DC converters was developed.

Wang, Bright L.↗
NASA NTRS2019

Adaptations of Guidance, Navigation and Control Verification and Validation Philosophies for Small Spacecraft

Decades of experience developing increasingly capable and more complex space-craft have resulted in a set of accepted practices and philosophies to verify and validate (V&V) guidance, navigation, and control (GN&C) subsystems. Until recently, small, low-cost spacecraft have had very simple or non-existent GN&C subsystems requiring minimal or no subsystem testing. As the next generation of small spacecraft take on more challenging GN&C requirements, the GN&C community is struggling with how to scale the subsystem V&V effort to produce spacecraft approaching the reliability of flagship-class missions while staying within the reduced resources of a small satellite project. For this paper, we will examine five aspects of GN&C V&V (requirements definition, software testing and analysis, hardware component testing, integrated vehicle testing, and in-flight V&V) and compare the V&V campaign of a flagship-class mission (Mars 2020) to that of two recent, successful CubeSat missions: ASTERIA and MarCO. Experiences from the development of these CubeSats yield valuable lessons learned and guidelines for future small spacecraft designers.

Pong, Christopher M.↗
NASA NTRS2019

Adaptations of guidance, navigation, and control verification and validation philosophies for small spacecraft

Decades of experience developing increasingly capable and more complex space-craft have resulted in a set of accepted practices and philosophies to verify and validate (V&V) guidance, navigation, and control (GN&C) subsystems. Until recently, small, low-cost spacecraft have had very simple or non-existent GN&C subsystems requiring minimal or no subsystem testing. As the next generation of small spacecraft take on more challenging GN&C requirements, the GN&C community is struggling with how to scale the subsystem V&V effort to produce spacecraft approaching the reliability of flagship-class missions while staying within the reduced resources of a small satellite project.For this paper, we will examine five aspects of GN&C V&V (requirements definition, software testing and analysis, hardware component testing, integrated vehicle testing, and in-flight V&V) and compare the V&V campaign of a flagship-class mission (Mars 2020) to that of two recent, successful CubeSat missions: ASTERIA and MarCO. Experiences from the development of these CubeSats yield valuable lessons learned and guidelines for future small spacecraft designers.

Chen, George T.↗
NASA NTRS2011

The Integration and Test Program of the James Webb Space Telescope

With the delivery of its flight scientific instruments and the completion of all telescope optics both scheduled to occur later this year, the James Webb Space Telescope (JWST) will enter into a challenging integration and test (I&T) program. Highlights of that program include cryo-vacuum tests of the Integrated Science Instrument Module (ISIM) at Goddard Space Flight Center, ambient integration of the ISIM and the Optical Telescope Element (OTE) at Goddard, and an end-to-end cryo-vacuum test of the OTE + ISIM system at Johnson Space Center. We review the overall flow of the I&T program, highlighting the key activities and the critical verifications to be performed at each step.

Randy, Kimble↗
NASA NTRS2018

NASA's Space Launch System Moves into Testing and Integration

NASA's Space Launch System (SLS) has moved from design and manufacturing into testing and integration for its first flight as early as December 2019. In 2017, the NASA/industry team completed manufacturing of all major structural elements for the launch vehicle for Exploration Mission-I (EM-1 ). That work included shipping the first major flight hardware element to the launch site. The team processed all four RS-25 engines for stage integration, cast all 10 booster flight motor segments, and manufactured all five major sections of the core stage. The program also completed major structural work on the B-2 test stand at Stennis Space Center, which will be used for the core stage "green run" test; delivered the core stage and engine simulators used for training; and much of the transportation equipment for the core stage. Engineers completed structural testing on the upper stage/payload section of the vehicle as well as the engine section test article. In 2018, the program will deliver the Orion Stage Adapter (OSA) to Exploration Ground Systems (EGS) at KSC and send the test articles for the core stage liquid hydrogen tank, liquid oxygen tank, and intertank to NASA's Marshall Space Flight center for structural testing. Additionally, workers will begin the challenging process of integrating the major sections of the 212-foot EM-1 core stage. This work is focused on the initial Block 1 variant of SLS, capable of launching more than 70 metric tons (t) to low Earth orbit (LEO). However, work concurrently is underway on the Block lB variant, which will enable 105 t to LEO and more than 37t to trans-lunar injection (TLI). Block lB will be the workhorse vehicle of NASA's lunar exploration plans. As the needs of the nation's deep space exploration program grow, SLS performance is designed to evolve to a payload mass of 130 t to LEO and up to 45t to TLI. The advantages of this mass - as well as volume- are critical to the entire exploration architecture for deep space exploration. They translate to greater capability, greater infrastructure and operational simplicity, less overall mission risk, and opportunities to accomplish unprecedented exploration and discovery. This paper will discuss SLS progress to date and planned future work.

Honeycutt, John↗
NASA NTRS2017

ExEP Yield Modeling Tool and Validation Test Results

EXOSIMS is an open-source simulation tool for parametric modeling of the detection yield and characterization of exoplanets. EXOSIMS has been adopted by the Exoplanet Exploration Programs Standards De nition and Evaluation Team (ExSDET) as a common mechanism for comparison of exoplanet mission concept studies. To ensure trustworthiness of the tool, we developed a validation test plan that leverages the Python-language unit-test framework, utilizes integration tests for selected module interactions, and performs end-to-end cross- validation with other yield tools. This paper presents the test methods and results, with the physics-based tests such as photometry and integration time calculation treated in detail and the functional tests treated summarily. The test case utilized a 4m unobscured telescope with an idealized coronagraph and an exoplanet population from the IPAC radial velocity (RV) exoplanet catalog. The known RV planets were set at quadrature to allow deterministic validation of the calculation of physical parameters, such as working angle, photon counts and integration time. The observing keepout region was tested by generating plots and movies of the targets and the keepout zone over a year. Although the keepout integration test required the interpretation of a user, the test revealed problems in the L2 halo orbit and the parameterization of keepout applied to some solar system bodies, which the development team was able to address. The validation testing of EXOSIMS was performed iteratively with the developers of EXOSIMS and resulted in a more robust, stable, and trustworthy tool that the exoplanet community can use to simulate exoplanet direct-detection missions from probe class, to WFIRST, up to large mission concepts such as HabEx and LUVOIR.

Nunez, Paul↗
NASA NTRS2020

Hardware Verification and Validation for a Navigation Sensor Software Model in Support of Flight Vehicle Performance Analysis

… or, “It’s in the details, how to make complicated software perform like complicated hardware.” In attempts to minimize development time and quickly build an operational vehicle, NASA’s Space Launch System (SLS) has had to be intentional about integrated testing. Constraints on budget and schedule have required balance between testing needs and the desire for an integrated flight vehicle as soon as possible. To provide key insights early in design and analysis cycles, a large amount of effort has shifted into maturing and validating models at the component level with integrated testing as a means to validate their integration. In terms of SLS Navigation, this, and the model-based design approach have pushed explicit requirements for sensor models to be validated against flight hardware to high precision. This paper covers the approach taken to verify and validate the models for the two key navigation sensors on the SLS vehicle, the Redundant Inertial Navigation Sensor and the Rate Gyro Assembly. These models are used in performance evaluation, fault detection, and operations development extensively. Using a mix of data from hardware vendor documentation and testing reports, limited in-house testing, and integration activities, these models were able to be validated against flight hardware at multiple levels, from the internal software design to statistical behavior at the raw sensor and integrated box levels. The high level of insight into the hardware elements is instrumental to support flight certification activities and building confidence in SLS Navigation capability. Focused testing enabled additional insight and validation that proved invaluable and the resulting insights were used to focus and mature models. Additionally, of having validated performance-based hardware models enables a wide breadth of activities including detailed fault detection studies and integration into future vehicle frameworks, such as an upper stage and provide a valuable asset to continued SLS analysis and design.

Evan J Anzalone↗
NASA NTRS2020

Hardware Verification and Validation for a Navigation Sensor Software Model in Support of Flight Vehicle Performance Analysis

… or, “It’s in the details, how to make complicated software perform like complicated hardware.” In attempts to minimize development time and quickly build an operational vehicle, NASA’s Space Launch System (SLS) has had to be intentional about integrated testing. Constraints on budget and schedule have required balance between testing needs and the desire for an integrated flight vehicle as soon as possible. To provide key insights early in design and analysis cycles, a large amount of effort has shifted into maturing and validating models at the component level with integrated testing as a means to validate their integration. In terms of SLS Navigation, this, and the model-based design approach have pushed explicit requirements for sensor models to be validated against flight hardware to high precision. This paper covers the approach taken to verify and validate the models for the two key navigation sensors on the SLS vehicle, the Redundant Inertial Navigation Sensor and the Rate Gyro Assembly. These models are used in performance evaluation, fault detection, and operations development extensively. Using a mix of data from hardware vendor documentation and testing reports, limited in-house testing, and integration activities, these models were able to be validated against flight hardware at multiple levels, from the internal software design to statistical behavior at the raw sensor and integrated box levels. The high level of insight into the hardware elements is instrumental to support flight certification activities and building confidence in SLS Navigation capability. Focused testing enabled additional insight and validation that proved invaluable and the resulting insights were used to focus and mature models. Additionally, of having validated performance-based hardware models enables a wide breadth of activities including detailed fault detection studies and integration into future vehicle frameworks, such as an upper stage and provide a valuable asset to continued SLS analysis and design.

Thomas Park↗
NASA NTRS1981

A unique integrated flight testing facility for advanced control/display research

NASA is engaged in programs aimed at developing avionic concepts and systems technology for air transportation systems of the 1980's and beyond. A part of these programs is related to the development of advanced concepts and avionics technology for integrated displays and controls. In support of these efforts an interactive Flight Display Research System (FDRS) has been developed as an integral part of integrated flight test facilities which have been used in evaluation studies of integrated display and control concepts in support of a VTOL Approach and Landing Technology (VALT) program and current Terminal Configured Vehicle (TCV) program. A description is provided of several of the advanced integrated display and control concepts that have evolved within the VALT, TCV, and general aviation programs, as well as the integrated flight test facilities.

Batson, V. M.↗
NASA NTRS1996

Mars Pathfinder Flight System Integration and Test

...This paper verviews the system design and the results of the system integration and test activities, including the entry, descent and landing subsystem elements. System test experiences including science instruments, the microrover, Sojourner, and software are discussed.

pathfinder↗