Modular optical test instrument for 1700-11,000 angstrom units.
Optical measuring instrument consisting of eight modular units, specimen chamber and carriage
OPTICAL INSTRUMENT↗
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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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Flight packaged onboard checkout systems development unit. Software documentation, overall specification, level 2 - Test Oriented Onboard Language system /TOOL/
Test Oriented Onboard Language /TOOL/ system for spacecraft checkout
Source record↗
Analysis, design, fabrication and testing of the Mini-Brayton rotating unit (MINI-BRU). Volume 2: Figures and drawings
This volume contains the figures and drawings reference in Volume 1.
Dobler, F. X.↗
DC-to-DC power supply for light aircraft flight testing
The power supply unit was developed to serve as the power source for a loran-C receiver. The power supply can be connected directly to the aircraft's electrical system, and is compatible with either 14 or 28 volt electrical systems. Design specifications are presented for the unit along with a description of the circuit design.
Yost, S. R.↗
Demonstration of a Long Duration Crop in the Advanced Plant Habitat Engineering Demonstration Unit: Key Factors to Consider Prior to Testing and Lessons Learned
Explore the source record for details and available documents.
Lashelle Spencer↗
Exploration Extravehicular Mobility Unit (xEMU) Pressure Garment System (PGS) Cycle Testing Overview and Results
With the development of NASA’s next generation spacesuit, the hardware life expectations for the new spacesuit required evaluation. The xPGS team designed and performed a test series to assess the new hardware against the life requirements. The EMU on the International Space Station (ISS) today tests the life of the suit and new components by performing isometric individual joint cycle motions with the requirements based on previously performed Extra-Vehicular Activities (EVAs). The xPGS includes new designs for suit components to provide increased mobility for performance of lunar operations, thus the requirements for the life cycle of the suit had to be developed and tested with these new operations in mind. Cycle requirements shifted to cycles of functional tasks in lieu of isometric cycles to better understand the life of the suit. Manned cycle testing of the xPGS was conducted by performing repetitions of a series of tasks that reflect predicted Lunar EVA operations. The test series utilized a gravity offload system to simulate Lunar gravity environment. Cycle testing concluded after 30 test days in October of 2022 with lessons learned that will be critical for future spacesuit design. Specific lessons learned with regards to suit performance and test methodology will be provided.
spacesuit↗
Baroreflex modulation of muscle sympathetic nerve activity during cold pressor test in humans
The purpose of this project was to test the hypothesis that baroreceptor modulation of muscle sympathetic nerve activity (MSNA) and heart rate is altered during the cold pressor test. Ten subjects were exposed to a cold pressor test by immersing a hand in ice water for 3 min while arterial blood pressure, heart rate, and MSNA were recorded. During the second and third minute of the cold pressor test, blood pressure was lowered and then raised by intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure was more negative (P < 0.005) during the cold pressor test (-244.9 +/- 26.3 units x beat(-1) x mmHg(-1)) when compared with control conditions (-138.8 +/- 18.6 units x beat(-1) x mmHg(-1)), whereas no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that baroreceptors remain capable of modulating MSNA and heart rate during a cold pressor test; however, the sensitivity of baroreflex modulation of MSNA is elevated without altering the sensitivity of baroreflex control of heart rate.
NASA Discipline Cardiopulmonary↗
Electrostatic Precipitation in Nearly Pure Gaseous Nitrogen
Electrostatic precipitation was performed in a nearly pure gaseous nitrogen system as a possible remedy for black dust contaminant from high pressure 6000 psi lines at the NASA Kennedy Space Center. The results of a prototype electrostatic precipitator that was built and tested using nitrogen gas at standard atmospheric pressures is presented. High voltage pulsed waveforms are generated using a rotating spark gap system at 30 Hz. A unique dust delivery system utilizing the Venturi effect was devised that supplies a given amount of dust per unit time for testing purposes.
Buhler, Charles↗
MEMS Stirling Cooler Development Update
This presentation provides an update on the effort to build and test a prototype unit of the patented MEMS Stirling cooler concept. A micro-scale regenerator has been fabricated by Polar Thermal Technologies and is currently being integrated into a Stirling cycle simulator at Johns Hopkins University Applied Physics Laboratory. A discussion of the analysis, design, assembly, and test plans for the prototype will be presented.
Moran, Matthew E.↗
Test effectiveness study report: An analytical study of system test effectiveness and reliability growth of three commercial spacecraft programs
Failure data from 16 commercial spacecraft were analyzed to evaluate failure trends, reliability growth, and effectiveness of tests. It was shown that the test programs were highly effective in ensuring a high level of in-orbit reliability. There was only a single catastrophic problem in 44 years of in-orbit operation on 12 spacecraft. The results also indicate that in-orbit failure rates are highly correlated with unit and systems test failure rates. The data suggest that test effectiveness estimates can be used to guide the content of a test program to ensure that in-orbit reliability goals are achieved.
Feldstein, J. F.↗
Methodology for Life Testing of Refractory Metal/Sodium Heat Pipes
The focus of this work was to establish an approach to generate carefully controlled data that can conclusively establish heat pipe operating life with material-fluid combinations capable of extended operation. To accomplish this goal acceleration is required to compress 10 years of operational life into 3 years of laboratory testing through a combination of increased temperature and mass fluence. Specific test series have been identi3ed, based on American Society for Testing and Materials (ASTM) specifications, to investigate long term corrosion rates. The refractory metal selected for demonstration purposes is a Molybdenum-44.5%Rhenium alloy formed by powder metallurgy. The heat pipe makes use of an annular crescent wick design formed by hot isostatic pressing of Molybdenum-Rhenium wire mesh. The heat pipes are filled using vacuum distillation and purity sampling is considered. Testing of these units is round-the-clock with 6-month destructive and non-destructive inspection intervals to identify the onset and level of corrosion. Non-contact techniques are employed for providing power to the evaporator (radio frequency induction heating at I to 5 kW per unit) and calorimetry at the condenser (static gas gap coupled water cooled calorimeter). The planned operating temperature range would extend from 1123 to 1323 K. Accomplishments prior to project cancellation included successful demonstration of the heat pipe wick fabrication technique, establishment of all engineering designs, baselined operational test requirements and procurement/assembly of supporting test hardware systems.
Martin, James J.↗
Review of Combustion Stability Characteristics of Swirl Coaxial Element Injectors
Liquid propellant rocket engine injectors using coaxial elements where the center liquid is swirled have become more common in the United States over the past several decades, although primarily for technology or advanced development programs. Currently, only one flight engine operates with this element type in the United States (the RL10 engine), while the element type is very common in Russian (and ex-Soviet) liquid propellant rocket engines. In the United States, the understanding of combustion stability characteristics of swirl coaxial element injectors is still very limited, despite the influx of experimental and theoretical information from Russia. The empirical and theoretical understanding is much less advanced than for the other prevalent liquid propellant rocket injector element types, the shear coaxial and like-on-like paired doublet. This paper compiles, compares and explores the combustion stability characteristics of swirl coaxial element injectors tested in the United States, dating back to J-2 and RL-10 development, and extending to very recent programs at the NASA MSFC using liquid oxygen and liquid methane and kerosene propellants. Included in this study are several other relatively recent design and test programs, including the Space Transportation Main Engine (STME), COBRA, J-2X, and the Common Extensible Cryogenic Engine (CECE). A presentation of the basic data characteristics is included, followed by an evaluation by several analysis techniques, including those included in Rocket Combustor Interactive Design and Analysis Computer Program (ROCCID), and methodologies described by Hewitt and Bazarov.
Hulka, J. R.↗
Performance and Environmental Test Results of the High Voltage Hall Accelerator Engineering Development Unit
NASA Science Mission Directorate's In-Space Propulsion Technology Program is sponsoring the development of a 3.5 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn and Aerojet are developing a high fidelity high voltage Hall accelerator that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the high voltage Hall accelerator engineering development unit have been performed. Performance test results indicated that at 3.9 kW the thruster achieved a total thrust efficiency and specific impulse of 58%, and 2,700 sec, respectively. Thermal characterization tests indicated that the thruster component temperatures were within the prescribed material maximum operating temperature limits during full power thruster operation. Finally, thruster vibration tests indicated that the thruster survived the 3-axes qualification full-level random vibration test series. Pre and post-vibration test performance mappings indicated almost identical thruster performance. Finally, an update on the development progress of a power processing unit and a xenon feed system is provided.
Kamhawi, Hani↗
Design, development and testing of a cryogenic temperature heat pipe for the icicle system
An analytical model was formulated for a cryogenic heat pipe, and thermal and transport analyses were developed to predict the performance characteristics of various heat pipe designs. These analyses permitted optimization of various design parameters. A series of four breadboard heat pipes were fabricated and tested to provide inputs such as internal film coefficients, minimum capillary radii, and wick permeabilities which are required for the analyses. The results of instrumentation, charging, and testing of cryogenic heat pipes were applied to the prototype heat pipes. After a thorough design analysis of three potential heat pipe wicks (slab, artery, and axial groove), the first two were chosen for application to two prototype heat pipes. Detailed designs were made of the two heat pipes and the units were fabricated. Tests were conducted which verified the integrity and safety margin of the design to withstand the internal pressure at ambient temperature and fatigue of thermal cycling. During the acceptance testing in the vacuum chamber, no difficulty was experienced in priming the slab-wick heat pipe and it met the performance design requirements. The artery-wick heat pipe would not prime with nitrogen working fluid for any test conditions.
Trimmer, D. S.↗
Application of pH-dependent environmental protection agency test method 1313 to low-activity nuclear waste glass
Here, in this study, we present results of a room temperature, pH-dependent leach test established by United States Environmental Protection Agency (EPA) Leaching Environmental Assessment Framework (LEAF) (EPA Method 1313 and further abbreviated EPA 1313) to study the alteration behavior of low-activity nuclear waste (LAW) glasses. Implementation of EPA 1313, which is closer to LAW disposal temperatures, could allow for more flexibility in the formulation of Hanford LAW glasses, specifically in terms of increased waste loading. A set of 48 LAW glasses were selected to test with EPA 1313. Briefly, the test method consists of adding glass to a number of solutions at different initial pH values and at a fixed mass-to-solution-volume ratio. The glass is then allowed to corrode for two days and the final solution pH and concentration of different glass elements in solution is measured. The test was modified from the published procedure to constrain particle size to provide more reproducible results, reduce the studied pH range to a more applicable range, and to reduce solution volume to reduce costs associated with material preparation. Compositional modeling was used to predict the measured elemental releases at various pH. The model predictions improved in tests where there was a relatively small difference between initial and final solution pH indicating that pH controls would result in better predictive models.
Accelerated aging↗
Space Shuttle 750 psi Helium Regulator Application on Mars Science Laboratory Propulsion
The Mars Science Laboratory (MSL) is NASA's next major mission to Mars, to be launched in September 2009. It is a nuclear powered rover designed for a long duration mission, with an extensive suite of science instruments. The descent and landing uses a unique 'skycrane' concept, where a rocket-powered descent stage decelerates the vehicle, hovers over the ground, lowers the rover to the ground on a bridle, then flies a safe distance away for disposal. This descent stage uses a regulated hydrazine propulsion system. Performance requirements for the pressure regulator were very demanding, with a wide range of flow rates and tight regulated pressure band. These indicated that a piloted regulator would be needed, which are notoriously complex, and time available for development was short. Coincidentally, it was found that the helium regulator used in the Space Shuttle Orbiter main propulsion system came very close to meeting MSL requirements. However, the type was out of production, and fabricating new units would incur long lead times and technical risk. Therefore, the Space Shuttle program graciously furnished three units for use by MSL. Minor modifications were made, and the units were carefully tuned to MSL requirements. Some of the personnel involved had built and tested the original shuttle units. Delta qualification for MSL application was successfully conducted on one of the units. A pyrovalve slam start and shock test was conducted. Dynamic performance analyses for the new application were conducted, using sophisticated tools developed for Shuttle. Because the MSL regulator is a refurbished Shuttle flight regulator, it will be the only part of MSL which has physically already been in space.
Mizukami, Masashi↗
Development Testing and Subsequent Failure Investigation of a Spring Strut Mechanism
Commodities are transferred between the Multi-Purpose Crew Vehicle (MPCV) crew module (CM) and service module (SM) via an external umbilical that is driven apart with spring-loaded struts after the structural connection is severed. The spring struts must operate correctly for the modules to separate safely. There was no vibration testing of strut development units scoped in the MPCV Program Plan; therefore, any design problems discovered as a result of vibration testing would not have been found until the component qualification. The NASA Engineering and Safety Center (NESC) and Lockheed Martin (LM) performed random vibration testing on a single spring strut development unit to assess its ability to withstand qualification level random vibration environments. Failure of the strut while exposed to random vibration resulted in a follow-on failure investigation, design changes, and additional development tests. This paper focuses on the results of the failure investigations including identified lessons learned and best practices to aid in future design iterations of the spring strut and to help other mechanism developers avoid similar pitfalls.
Dervan, Jared↗
Software Development and Testing Support for the Avionics Systems Telemetry Tool Suite
The Customer Avionics Interface Development and Analysis (CAIDA) team helps to provide modeling and simulation software for the verification of the Launch Control System (LCS). With a new iteration of telemetry tools being developed, extensive work must be done to ensure features are implemented in an efficient manner. The authors worked to develop new functionalities in the telemetry tools, update documentation, and perform various tests on the CAIDA Advanced Telemetry Tool (CATT). This was accomplished with Python through built-in library frameworks. In addition, work needed to be performed to set up a training document for new engineers and interns joining the team in the future. The outcome of this internship was the completion of several new features, unit and functional tests on CATT, thorough documentation, and a developer’s guide to programming under CAIDA.
Negron-Martinez, Antonio Jose↗