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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 91 records · Page 5

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NASA NTRS2015

Lightning Protection and Structural Bonding for the B2 Test Stand

With the privatization of the space industry, NASA has entered a new era. To explore deeper parts of the solar system, NASA is developing a new spacecraft, the Space Launch System (SLS), capable of reaching these destinations, such as an asteroid or Mars. However, the test stand that is capable of testing the stage has been unused for many years. In addition to the updating/repair of the stand, more steel is being added to fully support the SLS. With all these modifications, the lightning protection system must be brought up to code to assure the protection of all personnel and assets. Structural bonding is a part of the lightning protection system. The focus of this project was to assure proper structural bonding. To begin, all relevant technical standards and the construction specifications were reviewed. This included both the specifications for the lightning protection and for general construction. The drawings were reviewed as well. From the drawings, bolted structural joints were reviewed to determine whether bonding was necessary. Several bolted joints were determined to need bonding according to the notes in the drawings. This exceeds the industry standards. The bolted joints are an electrically continuous joint. During tests, the stand experiences heavy vibration that may weaken the continuity of the bolted joint. Therefore, the secondary bonding is implemented to ensure that the structural joint has low resistance. If the structural joint has a high resistance because of corrosion, a potential gradient can occur that can cause a side flash. Damage, injury, or death can occur from a side flash so they are to be prevented. A list of the identified structural joints was compiled and sent to the contractor to be bonded. That covers the scope of this project.

Kinard, Brandon↗

NASA NTRS2022

Astronaut Kinematics and Injury Risk for Piloted Lunar Landings and Launches While Standing

During future lunar missions, astronauts may be required to pilot vehicles while standing, and the associated kinematic and injury response is not well understood. In this study we used human body modeling to predict unsuited astronaut kinematics and injury risk for piloted lunar launches and landings in the standing posture. Three pulses (2-5 g; 10–150 ms rise times) were applied in 10 directions (vertical; ± 10-degree offsets) for a total of 30 simulations. Across all simulations, motion envelopes were computed to quantify displacement of the astronaut’s head (max 9.0 cm forward, 7.0 cm backward, 2.1 cm upward, 7.3 cm downward, 2.4 cm lateral) and arms (max 25 cm forward, 35 cm backward, 15 cm upward, 20 cm downward, 20 cm lateral). All head, neck, lumbar, and lower extremity injury metrics were within NASA’s tolerance limits, except tibia compression forces (0–1543 N upper tibia; 0–1482 N lower tibia; tolerance—1350 N) and revised tibia index (0.04–0.58 upper tibia; 0.03–0.48 lower tibia; tolerance—0.43) for the 2.7 g/150 ms pulse. Pulse magnitude and duration contributed over 80% to the injury metric values, whereas loading direction contributed less than 3%. Overall, these simulations suggest piloting a lunar lander vehicle in the standing posture presents a low risk of injury to the astronaut, although risk of tibia injury is potentially outside NASA’s acceptance limits and warrants further investigation.

Mitesh Lalwala↗

NASA NTRS2014

Identification of Noise Sources in a Rocket Engine Test Stand using Microphone Phased Array

A new, phased array of microphones, suitable for the harsh environment of a rocket launch, was built and tested during a static firing of a RS-25 engine. It uses 70 piezo-resistive, dynamic pressure sensors, optimally distributed on a 10.5ft diameter open frame dome structure, and has a 200-ft long cable bundle to carry the signals to a weather-protected cabinet containing the data systems. The test stand was imaged using an infra-red camera and a visible wavelength camera, and the beamformed noise maps were superimposed on the photographs. The first-time data from a full-scale engine test stand showed that the plume deflector at the bottom of the engine to be the primary noise source. The openings of the test stand around the nozzle exit were also found to be noise sources particularly at higher frequencies. The final goal is to use the array during NASA’s Artemis-II launch at Kennedy Space Center.

Identification of Noise Source↗

NASA NTRSDate not supplied

Design Concepts for an Optimized, Modular, and Scalable Liquid Amine Test Stand

The Air Revitalization Labs at NASA Ames Research Center (ARC) is investigating liquid amines to for their performance removing spacecraft carbon dioxide (CO2) for crewed space missions. Development of the current one-crew scale amine test stand stems from several modifications to a test stand initially built at NASA Johnson Space Center (JSC) This sub-scale system has been modified to incorporate a flow spreader for the inlet air stream, an updated contactor design for CO2 capture, a degasser to regenerate the liquid sorbent and recover the captured CO2, and a condenser to reduce water loss. Results from the existing integrated liquid amine test stand have provided valuable insight, but continued performance optimization requires design and build of a new integrated test system. New design concepts will institute a modular configuration to allow for interfacing with novel contactor and degasser architecture, parallel or series flow pathways for the air stream and liquid sorbent, and scaling up to a 4-crew CO2 removal system.

Tiago Faria Costa↗

DOE OSTI2026

On High-Temperature Dynamometer Test Stand Development

RePED is a novel prototype alternator that has been designed and built to operate at 35 kW under 250 degrees C ambient temperature conditions. The operating efficiency will be measured using a 225-kW motor to drive the machine in a back-to-back configuration. The goal is to determine if the RePED alternator can deliver 35 kW at a rotational speed of 1,000 rpm while operating in 250 degrees C ambient temperature and have a minimum efficiency of 60%. Dynamometer testing of a high-temperature alternator for geothermal drilling presents several unique challenges, especially around maintaining and managing the various sources and types of energy passing through the system without impacting data quality. The objectives of this report are to (1) describe the test stand in detail, the relative orientation of each major component, and the data acquisition system and (2) discuss the behavior of the test stand components such that this report can serve as a reference document for future projects.

15 GEOTHERMAL ENERGY↗

NASA NTRSDate not supplied

Pretest Comprehensive Analysis for the Urban Air Mobility Side-by-Side Test Stand

The Urban Air Mobility (UAM) Side-by-Side Test Stand (SBS) is a two-rotor test stand designed and built at NASA Ames Research Center under the Revolutionary Vertical Lift Technology (RVLT) Project. The SBS entered service in the wind tunnel in the latter part of 2021 and allows for the experimental analysis of rotor-rotor interactions for UAM vehicles of the side-by-side variety. The SBS will allow investigation of the effect of numerous variables such as rotor lateral separation, rotor collective pitch, model pitch angle (𝛼), rotor rotation direction, and flight speed. This paper presents performance predictions for the SBS. These predictions, which were generated using CAMRAD II, provided increased assurance of the safe operational limits of the system. Additionally, these results, when compared with future data, will be used for validation of the computational models.

Comprehensive Analysis↗

NASA NTRSDate not supplied

Update to Developing a Multi-bioreactor Test Stand for the Evaluation of Biofilm Mitigation Technologies

Biofilm formation in spacecraft wastewater systems is a complex and impactful problem. Biomass flowing in these wastewater systems can cause clogging, higher differential pressures, and flow restrictions impacting equipment reliability and function. To explore this issue, the Marshall Space Flight Center’s biofilm test stand was created and has been utilized to examine multiple biofilm mitigation techniques over a long duration test time. This paper is an update to a previous paper, ICES-2021-122, and will serve to discuss the modifications and enhancements to the biofilm test stand. While the previous configuration tested heat treatments and coatings, this phase of testing will examine differing materials, competing bacteria provided by an external bioreactor, a prototype phytoremediation unit, and additional testing with a nutrient filter. Configuration changes include the addition of float switches, adjustment of the drain assembly architecture and additional support hardware for the competing bacteria bioreactor and phytoremediation units.

ECLSS↗

NASA NTRS2023

Magnetosonic ULF Waves With Anomalous Plasma–Magnetic Field Correlations: Standing Waves and Inhomogeneous Plasmas

Ultra-low frequency (ULF) wave observations across the heliosphere often rely on the sign of correlations between plasma (density/pressure) and magnetic field perturbations to distinguish between fast and slow magnetosonic modes. However, the assumptions behind this magnetohydrodynamic result are not always valid, particularly within the magnetosphere which is inhomogeneous and supports standing waves along the geomagnetic field. Through theory and a global simulation, we find both effects can result in anomalous plasma–magnetic field correlations. The interference pattern in standing waves can lead both body and surface magnetosonic waves to have different cross-phases than their constituent propagating waves. Furthermore, if the scale of gradients in the background are shorter than the wavelength or the waves are near-incompressible, then advection by the wave of inhomogeneities can overcome the wave's inherent sense of compression. These effects need to be allowed for and taken into account when applying the typical diagnostic to observations.

MHD Waves↗

NASA NTRSDate not supplied

Update to Developing a Multi-bioreactor Test Stand for the Evaluation of Biofilm Mitigation Technologies

ECLSS↗

NASA NTRSDate not supplied

Update to Developing a Multi-bioreactor Test Stand for the Evaluation of Biofilm Mitigation Technologies

ECLSS↗

DOE OSTI2024

A Free-Standing Boron-Doped Diamond Grid Electrode for Fundamental Spectroelectrochemistry

Spectroelectrochemistry (SEC) is a powerful technique that enables a variety of redox properties to be studied, including formal potential (E o ), thermodynamic values (ΔG, ΔH, ΔS), diffusion coefficient (D), electron transfer stoichiometry (n), and others. SEC requires an electrode which light can pass through while maintaining sufficient electrical conductivity. This has been traditionally composed of metal or metal oxide films atop transparent substrates like glass, quartz, or metallic mesh. Robust electrode materials like boron-doped diamond (BDD) could help expand the environments in which SEC can be performed, but most designs are limited to thin films (~100–200 nm) on transparent substrates less resilient than free-standing BDD. Here, this work presents a free-standing BDD grid electrode (G-BDD) for fundamental SEC measurements, using the well-characterized Fe(CN) 6 3–/4– redox couple as proof-of-concept. With a combination of cyclic voltammetry (CV), thin-layer SEC, and chronoabsorptometry, several of the redox properties mentioned above were calculated and compared. For E o' , n, and D, similar results were obtained when comparing the CV [E o' = +0.279 (±0.002) V vs Ag/AgCl; n = 0.97; D = 4.1 × 10 –6 cm 2 ·s –1 ] and SEC [E o' = +0.278 (±0.001) V vs Ag/AgCl; n = 0.91; D = 5.2 × 10 –6 cm 2 ·s –1 ] techniques. Both values align with what has been previously reported. To calculate D from the SEC data, modification of the classical equation used in chronoabsorptometry was required to accommodate the G-BDD electrode geometry. Overall, this work expands on the applicability of SEC techniques and BDD as a versatile electrode material.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2025

Creating free standing covalent organic framework membranes by nanocrystal suturing in sol gel solutions

The sol-gel synthesis represents a versatile platform to fabricate ceramic inorganic membranes. However, it is still a grand challenge to push the boundary of sol-gel chemistry towards high-quality organic membrane construction. Herein, a facile and controlled nanocrystal suturing strategy in sol-gel solutions is developed to afford highly crystalline and free-standing covalent organic framework membranes. The key chemistry design lies in deploying tiny threads (1 mol% dual-NH 2 -tail linear polymer) to efficiently suture the highly charged covalent organic framework nanocrystals stabilized and confined in sol-gel solutions, creating a continuous and intact membrane surface. A subsequent treatment heals the sutured covalent organic framework nanocrystals, yielding a free-standing membrane with high crystallinity and ordered pores. The structure evolution and role of the thread linker are elucidated via operando spectroscopy and microscopy. The as-afforded covalent organic framework membranes demonstrate attractive proton transport performance in high temperature and anhydrous fuel cell applications.

36 MATERIALS SCIENCE↗

DOE OSTI2025

A High-Voltage High-Current Benchtop Test Stand for Solid-State Switch Testing at the SNS

Solid-state switches already replaced thyratrons in the SNS extraction kicker power supplies, offering improved efficiency and reliability. However, recent supply chain disruptions, combined with a self-firing issue, led us to explore alternative solutions. A vendor-developed MOS-Gated Thyristor switch was introduced but ultimately failed during testing. To investigate the failure and assess possible improvements, a benchtop test stand was constructed to evaluate the performance of a single stage board. This test stand features a Pulse Forming Network (PFN) that operates at 6 kV and 6 kA, with a repetition rate exceeding 60 Hz, simulating real operational conditions. By utilizing this setup, we seek to gain a better understanding of the failure mechanisms, refine the switch designs, and ultimately develop a more reliable alternative for the extraction kicker power supplies.

Bullman, Austin [ORNL]↗

DOE OSTI2026

AmeriFlux FLUXNET-1F CA-Ca3 British Columbia - Pole sapling Douglas-fir stand

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Ca3 British Columbia - Pole sapling Douglas-fir stand. This is the FLUXNET version of the carbon flux data for the site CA-Ca3 British Columbia - Pole sapling Douglas-fir stand produced by applying the standard ONEFlux (1F) software. Site Description - Site: 1988 Harvested Douglas Fir (Pole-sapling); Tower Type 10" triangular tower; Latitude/Longitude 49.53462N -124.90044W (GPS survey, 2003. Coordinates updated/corrected May, 2006); Elevation approx. 170 m; Mean Air Temp. (for the growing season) 9.7 C *; Mean Annual Precipitation 1179 mm *; Date Operations Began: September 2001; Frequency of EC Measurements 20 Hz; Frequency of Other Met. Sensors 4 sec, year round; Soil Respiration Measurements Periodically during growing season using portable system in 2002; * 30-yr climate normals from the Comox Airport

Black, T. Andrew [University of British Columbia, ↗

DOE OSTI2024

Test Stand Functional Requirements for Testing MQXFA Magnets and Q1/Q3 Cryostat Assemblies (Rev.3)

This document specifies test stand requirements for testing the High Luminosity LHC (HL-LHC, or HiLumi LHC) MQXFA magnets and LQXFA/B cryostat assemblies. Total of 12 (3 pre-series, 7 series production and 2 re-work) of these cryostat assemblies are expected to be fabricated and delivered to CERN by the U.S. HL-LHC Accelerator Upgrade Project (US HL-LHC AUP) as part of the U.S. contributions to the LHC High Luminosity Upgrade. These cryostat assemblies are the quadrupole magnetic components of the HL-LHC Q1 (LQXFA) and Q3 (LQXFB) inner triplet optical elements in front of the interactions points 1 (ATLAS) and 5 (CMS). One LMQXFA cold mass is installed in each cryostat assembly and each cold mass consists of two MQXFA quadrupole magnets. MQXFA, LMQXFA and LQXFA/B functional requirements are specified in [1,2,3].MQXFA magnets will be tested at BNL Vertical Magnet Test Facility (VMTF) and 12 cryostat assembly tests planned at Fermilab’s Horizontal Magnet Test Facility (HMTF). This document specifies the test stand functional requirements for testing MQXFA magnets and LQXFA/B cryostat assemblies.

43 PARTICLE ACCELERATORS↗

DOE OSTI2025

Comparing computational times for simulations when using PBPK model template and stand-alone implementations of PBPK models

Introduction We previously developed a PBPK model template that consists of a single model “superstructure” with equations and logic found in many physiologically based pharmacokinetic (PBPK) models. Using the template, one can implement PBPK models with different combinations of structures and features. Methods To identify factors that influence computational time required for PBPK model simulations, we conducted timing experiments using various implementations of PBPK models for dichloromethane and chloroform, including template and stand-alone implementations, and simulating four different exposure scenarios. For each experiment, we measured the required computational time and evaluated the impacts of including various model features (e.g., number of output variables calculated) and incorporating various design choices (e.g., different methods for estimating blood concentrations). Results We observed that model implementations that treat body weight and dependent quantities as constant (fixed) parameters can result in a 30% time savings compared with options that treat body weight and dependent quantities as time-varying. We also observed that decreasing the number of state variables by 36% in our PBPK model template led to a decrease of 20–35% in computational time. Other factors, such as the number of output variables, the method for implementing conditional statements, and the method for estimating blood concentrations, did not have large impacts on simulation time. In general, simulations with PBPK model template implementations of models required more time than simulations with stand-alone implementations, but the flexibility and (human) time savings in preparing and reviewing a model implemented using the PBPK model template may justify the increases in computational time requirements. Conclusion Our findings concerning how PBPK model design and implementation decisions impact computational speed can benefit anyone seeking to develop, improve, or apply a PBPK model, with or without the PBPK model template.

Bernstein, Amanda S.↗

NASA NTRS1972

Design and development of a Micropound Extended Range Thrust Stand (MERTS)

The development and operation of a micropound extended range thrust stand are considered. A cesium ion engine was tested in order to determine the measurement accuracy of the apparatus and to verify the calibration techniques used. The ion engine was tracked to within 5 percent. A check of the thrust stand calibration factor against that of the ion engine calibration factor showed a 4.3 percent difference.

Stark, K. W.↗

NASA NTRS1973

Test stand for precise measurement of impulse and thrust vector of small attitude control jets

A test stand which accurately measures the impulse bit and thrust vector of reaction jet thrusters used in the attitude control system of space vehicles has been developed. It can be used to measure, in a vacuum or ambient environment, both impulse and thrust vector of reaction jet thrusters using hydrazine or inert gas propellants. The ballistic pendulum configuration was selected because of its accuracy, simplicity, and versatility. The pendulum is mounted on flexure pivots rotating about a vertical axis at the center of its mass. The test stand has the following measurement capabilities: impulse of 0.00004 to 4.4 N-sec (0.00001 to 1.0 lb-sec) with a pulse duration of 0.5 msec to 1 sec; static thrust of 0.22 to 22 N (0.05 to 5 lb) with a 5 percent resolution; and thrust angle alinement of 0.22 to 22 N (0.05 to 5 lb) thrusters with 0.01 deg accuracy.

Woodruff, J. R.↗