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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 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Thermal Vacuum/Balance Test Results of Swift BAT with Loop Heat Pipe Thermal System

The Swift Burst Alert Telescope (BAT) Detector Array is thermally well coupled to eight constant conductance heat pipes (CCHPs) embedded in the Detector Array Plate PAP), and two loop heat pipes (LHPs) transport heat from the CCHPs to a radiator. The CCHPs have ammonia as the working fluid and the LHPs have propylene as the working fluid. Precision heater controllers, which have adjustable set points in flight, are used to control the LHP compensation chamber and Detector Array xA1 ASIC temperatures. The radiator has AZ-Tek's AZW-LA-II low solar absorptance white paint as the thermal coating, and is located on the anti-sun side of the spacecraft. A thermal balance (T/B) test on the BAT was successfully completed. It validated that the thermal design satisfies the temperature requirements of the BAT in the flight thermal environments. Instrument level and observatory level thermal vacuum (TN) cycling tests of the BAT Detector Array by using the LHP thermal system were successfully completed. This paper presents the results of the T/B test and T N cycling tests.

Choi, Michael K.↗
DOE OSTI2020

Discovery of Marburg virus neutralizing antibodies from virus-naïve human antibody repertoires using large-scale structural predictions

Marburg virus (MARV) disease is lethal, with fatality rates up to 90%. Neutralizing antibodies (Abs) are promising drug candidates to prevent or treat the disease. Current efforts are focused in part on vaccine development to induce such MARV-neutralizing Abs. We analyzed the antibody repertoire from healthy unexposed and previously MARV-infected individuals to assess if naïve repertoires contain suitable precursor antibodies that could become neutralizing with a limited set of somatic mutations. Here, we computationally searched the human Ab variable gene repertoire for predicted structural homologs of the neutralizing Ab MR78 that is specific to the receptor binding site (RBS) of MARV glycoprotein (GP). Eight Ab heavy-chain complementarity determining region 3 (HCDR3) loops from MARV-naïve individuals and one from a previously MARV-infected individual were selected for testing as HCDR3 loop chimeras on the MR78 Ab framework. Three of these chimerized antibodies bound to MARV GP. We then tested a full-length native Ab heavy chain encoding the same 17-residue-long HCDR3 loop that bound to the MARV GP the best among the chimeric Abs tested. Despite only 57% amino acid sequence identity, the Ab from a MARV-naïve donor recognized MARV GP and possessed neutralizing activity against the virus. Crystallization of both chimeric and full-length native heavy chain-containing Abs provided structural insights into the mechanism of binding for these types of Abs. Our work suggests that the MARV GP RBS is a promising candidate for epitope-focused vaccine design to induce neutralizing Abs against MARV.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Dynamic Decarbonization through Autonomous Physics-Centric Deep Learning and Optimization of Building Operations (Abstract only)

This project directly addresses the primary goal of Area of Interest 2 in the CRADA call: to advance optimization-based integrated energy management systems in commercial and residential buildings. Pacific Northwest National Laboratory (PNNL) and its industry partner PassiveLogic aim to accomplish this by reaching three key objectives. First, to ensure a broad impact in the building controls industry, PNNL will extend its open-source library for predictive control synthesis by augmenting its capabilities with data-driven self-learning of building models and auto-calibration of predictive controllers. The effort will focus on building use cases selected in collaboration with PassiveLogic. The team will specifically address the development of methods for data-driven adaptation of building models, investigation of model architectures that best address specific building types, and automated synthesis of differentiable predictive controllers that optimize diverse objectives. Second, PNNL will collaborate with PassiveLogic to integrate the aforementioned methods with PasiveLogic’s advanced controls platform. The collaborative integration effort will inform the developments under the first objective by providing specific data on the attainable performance of model learning on resource-constrained edge computing platforms. This software integration effort will increase the technical maturity of the developed libraries by exploring the use of software integration tools and methods. Third, PNNL and PassiveLogic will work to improve the technology readiness of the developed predictive controllers by testing their performance in relevant test environments, such as high-fidelity simulation, hardware in the loop, and actual test buildings.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1996

Advanced liquid Oxygen (LO2) propellant conditioning concept testing

Extensive testing was performed on the promising L02 propellant conditioning concept of passive recirculation (no-bleed). Data from the project is being used to further anchor models in L02 conditioning behavior and broaden the data base of no-bleed and low-bleed conditioning. Data base expansion includes results from testing the limits of no-bleed and low-bleed conditioning with various configuration changes to the test facility and designed test article. Configuration changes include low velocity effects in the recirculation loop above the test article, test article internal constriction impacts, test article out-of-plane effects, impact from an actual Titan L02 pump attachment, feed duct slope effects, and up-leg booster effects. LN2 was used as the test fluid. The testing was conducted between July 1994 and January 1995 at the west test area of Marshall Space Flight Center. Data have shown that in most cases passive recirculation was demonstrated when the aforementioned limits were applied.

Hasting, J. H.↗
NASA NTRS2011

Geoscience Laser Altimetry System (GLAS) Loop Heat Pipe Anomaly and On Orbit Testing

The Geoscience Laser Altimetry System (GLAS) is the sole instrument on the ICESat Satellite. On day 230 of 2003, the GLAS Component Loop Heat Pipe (CLHP) entered a slow circulation mode that resulted in the main electronics box reaching its hot safing temperature, after which the entire instrument was turned off. The CLHP had a propylene working fluid and was actively temperature controlled via a heater on the compensation chamber. The slow circulation mode happened right after a planned propulsive yaw maneuver with the spacecraft. It took several days to recover the CLHP and ensure that it was still operational. The recovery occurred after the entire instrument was cooled to survival temperatures and the CLHP compensation chamber cycled on a survival heater. There are several theories as to why this slow circulation mode exhibited itself, including: accumulation of Non-Condensible Gas (NCG), the secondary wick being under designed or improperly implemented, or an expanded (post-launch) leak across the primary wick. Each of these is discussed in turn, and the secondary wick performance is identified as the most likely source of the anomalous behavior. After the anomaly, the CLHP was controlled to colder temperatures to improve its performance (as the surface tension increases with lower temperature, as does the volume of liquid in the compensation chamber) and only precursor pulses occurred later in the mission. After GLAS s last laser failed, in late 2009, a decision was made to conduct engineering tests of both LHPs to try and duplicate this flight anomaly. The engineering tests consisted of control setpoint changes, sink changes, and one similar propulsive Yaw maneuver. The only test that showed any similar anomaly precursors on the CLHP was the propulsive maneuver followed by a setpoint increase. The ICESat Satellite was placed in a decaying orbit and ended its mission on August 30, 2010 in Barents Sea.

Baker, Charles↗
NASA NTRS2011

Human-in-the-Loop Integrated Life Support Systems Ground Testing

Human exploration missions beyond low earth orbit will be long duration with abort scenarios of days to months. This necessitates provisioning the crew with all the things they will need to sustain themselves while carrying out mission objectives. Systems engineering and integration is critical to the point where extensive integrated testing of life support systems on the ground is required to identify and mitigate risks. Ground test facilities (human-rated altitude chamber) at the Johnson Space Center are being readied to integrate all the systems for a mission along with a human test crew. The relevant environment will include deep space habitat human accommodations, sealed atmosphere of 8 psi total pressure and 32% oxygen concentration, life support systems (food, air, water), communications, crew accommodations, medical, EVA, tools, etc. Testing periods will approximate those of the expected missions (such as a near Earth asteroid, Earth-Moon L2 or L1, the moon). This type of integrated testing is needed for research and technology development as well as later during the mission design, development, test, and evaluation (DDT&E) phases of an approved program. Testing will evolve to be carried out at the mission level fly the mission on the ground . Mission testing will also serve to inform the public and provide the opportunity for active participation by international partners.

Henninger, Donald L.↗
NASA NTRS2012

Human in the Loop Integrated Life Support Systems Ground Testing

Human exploration missions beyond low earth orbit will be long duration with abort scenarios of days to months. This necessitates provisioning the crew with all the things they will need to sustain themselves while carrying out mission objectives. Systems engineering and integration is critical to the point where extensive integrated testing of life support systems on the ground is required to identify and mitigate risks. Ground test facilities (human-rated altitude chambers) at the Johnson Space Center are being readied to integrate all the systems for a mission along with a human test crew. The relevant environment will include deep space habitat human accommodations, sealed atmosphere capable of 14.7 to 8 psi total pressure and 21 to 32% oxygen concentration, life support systems (food, air, and water), communications, crew accommodations, medical, EVA, tools, etc. Testing periods will approximate those of the expected missions (such as a near Earth asteroid, Earth-Moon L2 or L1, the moon, Mars). This type of integrated testing is needed for research and technology development as well as later during the mission design, development, test, and evaluation (DDT&E) phases of an approved program. Testing will evolve to be carried out at the mission level fly the mission on the ground . Mission testing will also serve to inform the public and provide the opportunity for active participation by international, industrial and academic partners.

Henninger, Donald L.↗
NASA NTRS1980

Measurements of control stability characteristics of a wind-tunnel model using a transfer function method

Recent state-of-the-art techniques in rotor systems include the use of active feedback to augment the dynamic control characteristics of an aircraft system. A recent test of a stoppable rotor with blade circulation blowing was conducted in the Ames Research Center's 40by 80-ft wind tunnel. A major part of the test schedule was dedicated to the acquisition of data to determine the stability of a closed-loop hub-moment feedback control system. Therefore, the open-loop control response was measured at several flight conditions to ascertain the stability of the system prior to the final closed-loop feedback control test. Measurements were made during both the stopped and rotating rotor modes, and open-loop Bode plots were obtained for the control loops associated with the moments about the longitudinal and lateral axis.

Chopra, I.↗
DOE OSTI2021

Cyber-Attack Detection for Photovoltaic Farms Based on Power-Electronics-Enabled Harmonic State Space Modeling

Here in this paper, a physics-data-based detection method is proposed to detect a variety of cyber-attacks in Photovoltaic (PV) farms using the power electronics-enabled harmonic state space (HSS) models, which, to our knowledge, is original. At the device level, HSS-based detection is developed to monitor harmonic vectors of individual PV converter with minimum sensor measurements, thus improving accuracy and robustness compared to Kalman Filter-based detection. At the system level that involves multiple PV converters, a clustering approach is developed to investigate attack propagation and accurately locate attack sources within a PV farm. The proposed approach is one of the first attempts to address PV security through interaction between the device and system, maximizing the accuracy and robustness at different levels. To verify the feasibility, a comprehensive attacks model is built, including single attack, coordinated attacks, and replay attacks. Besides, the impacts of irradiance changes are taken into consideration in the test scenarios. With the real-time data acquisition and hardware-in-the-loop testbed, comprehensive test results are provided to verify the feasibility of the proposed detection methodology.

42 ENGINEERING↗
DOE OSTI2023

Multifunctional Fiber-Reinforced Polymer Composites for Damage Detection and Memory

Self-structural health monitoring (SHM) functionalities for fiber-reinforced polymer composites have become highly sought after to ensure the structural safety of newly advancing components in the automotive, civil, mechanical, and aerospace industries. This paper introduces a self-damage detection and memory (SDDM) hybrid composite material, where the structural carbon fiber tow is transformed into a piezoresistive sensor network, and the structural glass fiber operates as electrical insulation. In this study, SDDM specimens were fabricated, and tensile and impact tests were performed. The tensile tests of SDDM specimens find two distinct loading peaks: first where the carbon fiber fails, and second where the glass fiber fails. A linear correlation was observed between the carbon fiber resistance and composite strain up to a threshold, beyond which a sharp nonlinear increase in resistance occurred. The resistance then approached infinity, coinciding with the first loading peak and failure of the carbon fiber elements. This demonstrates the potential for a damage early warning threshold. Additionally, the effect of stitching the sensor tow in a zig-zag pattern over a large area was investigated using tailored fiber placement (TFP) of 1-loop, 3-loop, and 5-loop specimens. Tensile testing found that increasing the number of loops improved the sensor’s accuracy for strain sensing. Furthermore, impact tests were conducted, and as the impact energy progressively increased, the sensor resistance permanently increased. This illustrates a capability for self-memory of microdamage throughout the life cycle of the structure, potentially useful for predicting the remaining life of the composite.

Demo, Luke B. (ORCID:0000000208806522)↗
NASA NTRS2015

Experimentally Determined Heat Transfer Coefficients for Spacesuit Liquid Cooled Garments

A Human-In-The-Loop (HITL) Portable Life Support System 2.0 (PLSS 2.0) test has been conducted at NASA Johnson Space Center in the PLSS Development Laboratory from October 27, 2014 to December 19, 2014. These closed-loop tests of the PLSS 2.0 system integrated with human subjects in the Mark III Suit at 3.7 psi to 4.3 psi above ambient pressure performing treadmill exercise at various metabolic rates from standing rest to 3000 BTU/hr (880 W). The bulk of the PLSS 2.0 was at ambient pressure but effluent water vapor from the Spacesuit Water Membrane Evaporator (SWME) and the Auxiliary Membrane Evaporator (Mini-ME), and effluent carbon dioxide from the Rapid Cycle Amine (RCA) were ported to vacuum to test performance of these components in flight-like conditions. One of the objectives of this test was to determine the heat transfer coefficient (UA) of the Liquid Cooling Garment (LCG). The UA, an important factor for modeling the heat rejection of an LCG, was determined in a variety of conditions by varying inlet water temperature, flowrate, and metabolic rate. Three LCG configurations were tested: the Extravehicular Mobility Unit (EMU) LCG, the Oceaneering Space Systems (OSS) LCG, and the OSS auxiliary LCG. Other factors influencing accurate UA determination, such as overall heat balance, LCG fit, and the skin temperature measurement, will also be discussed.

Bue, Grant↗
NASA NTRS2015

Experimentally Determined Overall Heat Transfer Coefficients for Spacesuit Liquid Cooled Garments

A Human-In-The-Loop (HITL) Portable Life Support System 2.0 (PLSS 2.0) test has been conducted at NASA Johnson Space Center in the PLSS Development Laboratory from October 27, 2014 to December 19, 2014. These closed-loop tests of the PLSS 2.0 system integrated with human subjects in the Mark III Suit at 3.7 psi to 4.3 psi above ambient pressure performing treadmill exercise at various metabolic rates from standing rest to 3000 BTU/hr (880 W). The bulk of the PLSS 2.0 was at ambient pressure but effluent water vapor from the Spacesuit Water Membrane Evaporator (SWME) and the Auxiliary Membrane Evaporator (Mini-ME), and effluent carbon dioxide from the Rapid Cycle Amine (RCA) were ported to vacuum to test performance of these components in flight-like conditions. One of the objectives of this test was to determine the overall heat transfer coefficient (UA) of the Liquid Cooling Garment (LCG). The UA, an important factor for modeling the heat rejection of an LCG, was determined in a variety of conditions by varying inlet water temperature, flow rate, and metabolic rate. Three LCG configurations were tested: the Extravehicular Mobility Unit (EMU) LCG, the Oceaneering Space Systems (OSS) LCG, and the OSS auxiliary LCG. Other factors influencing accurate UA determination, such as overall heat balance, LCG fit, and the skin temperature measurement, will also be discussed.

Bue, Grant↗