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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 901 records · Page 50
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Atmospheric Probe Model: Construction and Wind Tunnel Tests

The material contained in this document represents a summary of the results of a low speed wind tunnel test program to determine the performance of an atmospheric probe at low speed. The probe configuration tested consists of a 2/3 scale model constructed from a combination of hard maple wood and aluminum stock. The model design includes approximately 130 surface static pressure taps. Additional hardware incorporated in the baseline model provides a mechanism for simulating external and internal trailing edge split flaps for probe flow control. Test matrix parameters include probe side slip angle, external/internal split flap deflection angle, and trip strip applications. Test output database includes surface pressure distributions on both inner and outer annular wings and probe center line velocity distributions from forward probe to aft probe locations.

Vogel, Jerald M.↗
NASA NTRS1998

A Fresh Look at Coupled-Oscillator Spatial Power Combining

Quasi-optical oscillators were proposed a little more than ten years ago as a means of developing the power levels needed for applications at millimeter frequencies using large numbers of individual semiconductor devices each of which produces only a modest amount of power [J.W. Mink, IEEE Trans. MTT., vol. 34, p. 273, 19861. An operating system was demonstrated soon after [Z.B. Popovic et. al, Int. J. Infrared and Millimeter Waves, v. 9, p. 647, 1988] in the form of a so-called grid oscillator. This device constituted a rectangular array of oscillating devices that are mutually coupled so that they oscillator coherently. The interconnecting lines in one direction serve as radiators so that the oscillators radiate directly, and the radiated fields add. Subsequently, coupled oscillators using resonant transmission line lengths was demonstrated by Mortazawi and Itoh [IEEE Trans. MTT., vol. 38, p. 86,1990). In recent work, coupled-oscillator power combiners have received less attention, with amplifier/combiners receiving more attention. Specific weaknesses of spatial-combining oscillators have motivated this transition. Namely, the oscillators employ low-Q resonators (resulting in low signal quality) and no clear means of modulation has been identified until recently. In this presentation, we review coupled-oscillator combiners in broad terms, indicating the features that make particular systems viable. We indicate how these features can be reconciled to functional requirements for system applications. Comparisons are drawn between two approaches to obtain mutual coupling: One employs low-Q oscillator circuits at each site, with concomitantly high propensity for the oscillators to couple. The other approach employs moderate-Q oscillators at each site with the concomitant requirement to tune the oscillators so that they share a range of frequencies over which they can couple and lock. In either case, precise frequency control and modulation can be achieved through locking to an external frequency source that ensures high quality signals. A recent development in coupled-oscillator arrays provides a means for beam-steering the radiation field of coupled oscillators through de-tuning of the edge elements in the array. This detuning introduces a progressive phase shift across the oscillator array. This 0 suggests architectures that can replace the functionality of a phased array without the cost 0 incurred by phase shifters. A comprehensive theory of the phase interactions among devices in such arrays is under development [e.g., Pogorzelski, York, and Maccarini, 1998 AP-S International Symposium, Atlanta, GA. June, 19981.

Pearson, L.W.↗
NASA NTRS2005

RP-1 and JP-8 Thermal Stability Experiments

This work experimentally investigates the effect of fuel composition changes on jet and rocket fuel thermal stability. A High Reynolds Number Thermal Stability test device evaluated JP-8 and RP-1 fuels. The experiment consisted of an electrically heated, stainless steel capillary tube with a controlled fuel outlet temperature. An optical pyrometer monitored the increasing external temperature profiles of the capillary tube as deposits build inside during each test. Multiple runs of each fuel composition provided results on measurement repeatability. Testing a t two different facilities provided data on measurement reproducibility. The technique is able to distinguish between thermally stable and unstable compositions of JP-8 and intermediate blends made by combining each composition. The technique is also able to distinguish among standard RP-1 rocket fuels and those having reduced sulfur levels. Carbon burn off analysis of residue in the capillary tubes on the RP-1 fuels correlates with the external temperature results.

Brown, Sarah P.↗
NASA NTRS2006

Importance Of Quality Control in Reducing System Risk, a Lesson Learned From The Shuttle and a Recommendation for Future Launch Vehicles

This paper presents lessons learned from the Space Shuttle return to flight experience and the importance of these lessons learned in the development of new the NASA Crew Launch Vehicle (CLV). Specifically, the paper discusses the relationship between process control and system risk, and the importance of process control in improving space vehicle flight safety. It uses the External Tank (ET) Thermal Protection System (TPS) experience and lessons learned from the redesign and process enhancement activities performed in preparation for Return to Flight after the Columbia accident. The paper also, discusses in some details, the Probabilistic engineering physics based risk assessment performed by the Shuttle program to evaluate the impact of TPS failure on system risk and the application of the methodology to the CLV.

Safie, Fayssal M.↗
NASA NTRS2002

Automated testing of the Deep Space Network's Uplink Subsystem

This paper describes some of the lessons we learned in implementing two different Tcl-basedtest frameworks used to automate testing of the Deep Space Network's new Uplink Subsystem, and discusses the advantages and disadvantages of each. The first framework was external to the Uplink Subsystem's software and provided complete control of the environment; the second was integrated with the software and provided less control, but motivated more and better testing. Some implementation details of the second frameworkare discussed as well.

DSN automated testing Tcl/Tk↗
NASA NTRS2010

Phytometric intelligence sensors

Methods and apparatus for determining when plants require watering, and methods of attending to the watering of plants including signaling the grower that the plants are in need of hydration are provided. The novel methods include real-time measurement of plant metabolics and phytometric physiology changes of intrinsic physical or behavioral traits within the plant such as determining physiological flux measurement of enzyme flux due to environmental changes such as the wind and drought stress, soil and plant mineral deficiencies, or the interaction with a bio-control for organic disease control including, cell movement, signal transduction, internal chemical processes and external environmental processes including when plants require watering, and methods of attending to the watering of plants including signaling the grower that the plants are in need of hydration.

Seelig, Hans-Dieter↗
NASA NTRSDate not supplied

Development of a Portable Stand-Alone 20 K Brayton Cycle Helium Refrigeration System

From 2012 to 2015, NASA funded development of the Ground Operations Demonstration Unit for Liquid Hydrogen (GODU-LH2) at Kennedy Space Center that scaled up and matured Integrated Refrigeration and Storage (IRAS) technology. IRAS involves the integration of an external helium refrigeration system with a cryogenic storage tank via an internal heat exchanger and allows advanced operations such as zero boiloff and densification of the liquid. The refrigeration system employed for GODU-LH2 was a Linde LR1620 piston-Brayton cycle machine with an RSX helium compressor. The GODU-LH2 system was installed in two separate shipping containers—one housing the cold-box, compressor, and gas management hardware, and the other the water chiller unit—with 480 VAC and 120 VAC electrical power fed from external hardware at the test site, and data capture and controls achieved using four different, independent software packages. From 2017 to 2019, in support of a densified hydrogen loading test program, the entire system was repackaged into a single, 40’ (12 m) shipping container, including the refrigeration system, water chiller, and electrical power distribution hardware, and controls were consolidated into a single Allen Bradley PanelView. Details regarding the design, build-out, and testing of the system will be presented and discussed.

W F Reaves↗
NASA NTRS2024

MAGIK Animation of Robotic Operations for Flight SpaceX-30 to ISS

The MAGIK Robotic analysis team provides kinematic feasibility assessments for the ISS and has produced an animation to evaluate Extravehicular Robotics (EVR) activities for the SpaceX (SpX)-30 flight. Shown EVR activities are preliminary and final operations will be developed by Flight Operations Directorate (FOD) Robotics (ROBO). The animation also displays the current ISS configuration at the time of the flight. Flight SpX-30 includes a SpaceX Cargo Dragon vehicle docked to Node 2 Zenith (N2Z) International Docking Adapter (IDA) and consists of the delivery of the Pump Module (PM) Integrated Assembly (IA). Robotic operations shown include the Special Purpose Dexterous Manipulator (SPDM) based on the Space Station Remote Manipulator System (SSRMS) for Trunk extraction of the PM IA, maneuvering to the External Stowage Platform 3 (ESP-3), temporary removal of the Control Moment Gyro (CMG) from ESP-3 Site 4, install of the PM IA at ESP-3 Site 3 and re-install of the CMG to ESP-3 Site4. There is no disposal payload for this flight.

ISS↗
DOE OSTI2020

The organic redox transistor for neuromorphic computing

Inspired by the in-memory computing architectures of biological systems, neuromorphic computing using crossbar arrays of artificial synapses based on non-volatile memory (NVM) devices with variable conductances has emerged as a new paradigm to enable massively parallel and ultra-low power computing hardware for data centric applications. Although inference has been demonstrated successfully using crossbars based on a variety of NMV technologies, efficient learning and scaling to large arrays (>10 6 elements) remains a challenge due to the synaptic elements' non-ideal electrical characteristics which degrades ANN accuracy. A further challenge is that in the conductive state memristors draw large currents >μA resulting in significant voltage drops in the interconnect wires and increased probability of failure in scaled arrays. We suggest the organic polymer redox transistor (RT) is an alternate approach that could solve many of these challenges, enabling both inference and parallel outer product updates, as recently demonstrated by Fuller et al. An RT consists of redox-active channel and gate electrodes in contact with a liquid or solid electrolyte. lon insertion through the electrolyte controls the channel electronic conductivity, while electron transfer through an external circuit maintains overall charge neutrality. Unlike a rechargeable battery, in the RT the voltage built-up across the electrolyte is kept to a minimum (typically <100 mV) by using the same material for the gate and channel. Elimination of the voltage offset simplifies integration of the RT into programmable arrays by enabling the use of various selectors. RTs based on inorganic and organic materials have been recently demonstrated with conductance tuning occurring at potentials of just a few mV and hundreds to thousands of linearly and symmetrically programmable conductance states, enabling near ideal accuracy in neural network simulations. Introduced in the 1980's, redox transistors with metallic gate electrodes and organic channel materials, also known as organic electrochemical transistors (OECTs), have been explored for a variety of applications such as chem- and bio-sensing, neural interfaces, and low cost printed circuits. A typical channel material for OECTs is the conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS). PEDOT is a p-type semiconducting polymer with mobile positively charged polarons that hop chain-to-chain.

Talin, Albert Alec↗
DOE OSTI2024

Solid state protective smart plug device

A wireless-controlled smart plug device and methods of use and operation, using a solid state switch to provide electrical power from an outlet to a load, and provide protection against overload, short circuit, ground, arc, or voltage surge faults. The switch includes a bidirectional semiconductor switch with two back-to-back connected transistors, such as silicon power MOSFETs, silicon insulated-gate bipolar transistors (IGBTs), silicon carbide (SiC) transistors, or gallium nitride (GaN) transistors, each configured to control the current flow from the electrical receptacle to the external electrical load.

Shen, Zheng↗
DOE OSTI2025

Optimal Control Strategy With Efficiency and Reliability Improvement for Offshore DC Microgrids

Offshore microgrids, due to their remote location and lack of external energy support, face significant challenges in wide-range load operation and maintenance. Consequently, efficiency and reliability are critical concerns for converters in offshore dc microgrids. This article presents an optimal control strategy aimed at enhancing both efficiency and reliability. A normalized nonlinear relationship between power loss and thermal stress of a paralleled converter is first established. Based on this, a dual-objective optimization function with an active weight function as well as a system overall performance index is established. The active weight function dynamically adjusts the control priority based on converter efficiency and switching device thermal stress. Then, the optimal power-sharing strategy is derived by the Lagrange multiplier method with the proposed optimal function. Additionally, to accommodate a wide load range, an optimal selection strategy for operating converter combinations is proposed, requiring only low-bandwidth communication. Experiment verification is given to validate the effectiveness of the proposed control strategy. The experiment results demonstrate that the proposed control strategy can improve the overall performance of offshore microgrids by optimizing efficiency and reliability.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2022

System and method for measuring sun-induced chlorophyll fluorescence

A chlorophyll fluorescence measuring system having at least one spectrometer coupled to a data logger. The data logger provides direct control of the spectrometer and includes on-board memory for storage of target and reference spectrum data obtained by the spectrometer. The data logger may be coupled to an external computer that receives and analyzes target and reference spectrum data to determine SIF using a spectral fitting algorithm. The system may include a spectrometer aiming system coupled to and controlled by the data logger. The system may also include one or more environmental sensors configured to measure environment variables. The environmental sensors may be coupled to the data logger for control and data storage. The environmental data may be communicated to the external computer for use in the spectral fitting algorithm. The data logger may be connected to a network for remote monitoring and control.

Gu, Lianhong↗
NASA NTRS1996

Active Interior Noise Control Studies

Analytical and experimental investigations into the control of noise in the interior of a three-dimensional enclosure with a flexible boundary are presented. The rigid boundaries are constructed from acrylic material, and in the different cases considered the flexible boundary is constructed from either aluminum or composite material. Noise generated by an external speaker is transmitted into the enclosure through the flexible boundary and active control is realized by using Lead Zirconate Titanate (PZT) piezoelectric actuators bonded to the flexible boundary. Condenser microphones are used for noise measurements inside and outside the enclosure. Minimization schemes for global and local noise control in the presence of a harmonic disturbance are developed and discussed. In the experiments, analog feedforward control is implemented by using the harmonic disturbance as a reference signal.

Park, J.↗
NASA NTRS1992

An advanced intelligent control system framework

A reusable rocket-engine intelligent control system (RREICS) framework was developed to a define a control framework for rocket-engine systems that reduces the required engine maintenance, extends the useful operating life, and maximizes the probability of mission success. The RREICS framework defines a controller that handles a rocket engine cluster as a single system rather than as a collection of individual engines. This enables the controller to alter individual engine operations in response to engine performance or integrity degradations while maintaining the propulsion subsystem external parameters at the levels required for mission success. A simplified model of a three engine cluster and the associated propulsion subsystem controller is also described.

Nemeth, ED↗
NASA NTRSDate not supplied

Gateway Implementation of Cybersecurity Requirements

Cyber threats are a constant present-day reality for any type of business -- Space exploration is not excluded from these threats either. The Gateway Program is one of NASA’s latest initiatives that extend space exploration beyond low earth orbit. Gateway allows for NASA to prove technologies and mature systems necessary to live and work on another celestial body before embarking on multi-year missions to Mars. The Gateway is a small, human-tended space station in orbit around the Moon. With the increased autonomy, distance and criticality of systems, cybersecurity is one of the critical subsystems that touches and integrates with most if not all subsystems of the Gateway. Building a gateway to the lunar orbit is no simple task. In this presentation, we outline an approach that the Gateway team adopted in creating a cyber safe and robust vehicle to support operations and assure protection of the critical functions. Gateway Program is required to implement National Institute of Standards and Technology (NIST) guidelines to adhere to the Federal Information Security Modernization Act (FISMA). NIST provides a framework for managing and controlling cybersecurity risks by defining cybersecurity controls and methodologies for implementation. The NIST framework is based upon the system, data within the system, integrations with external systems, and risk assessments to determine impacts for each of those systems. The goals and objectives are to identify appropriate security controls that fulfill and map to the NIST 800-53 framework. The implementation process involves developing an organizational understanding to manage cybersecurity risk to systems, people, assets, data, and capabilities. NIST Security controls are interpreted and defined within the Gateway vehicle requirements subsystems specifications. This paper details the approach, implementation, and challenges faced during the development and design phases to address cyber threats during the Gateway vehicle operations.

Svetlana Hanson↗
NASA NTRSDate not supplied

Gateway Implementation of Cybersecurity Requirements

Cybersecurity threats are a constant present-day reality for any type of business -- Space exploration is not excluded from these threats either. The Gateway Program is one of NASA’s latest initiatives that extend space exploration beyond low earth orbit. Gateway allows for NASA to prove technologies and mature systems necessary to live and work on another celestial body before embarking on multi-year missions to Mars. The Gateway is a small, human-tended space station in orbit around the Moon. With the increased autonomy, distance and criticality of systems, cybersecurity is a critical discipline that touches and integrates with most if not all subsystems of the Gateway. Building a gateway to the lunar orbit is no simple task. In this presentation, we outline an approach that the Gateway team adopted in creating a cyber safe and robust vehicle to support operations and assure protection of the critical functions. Gateway Program is required to implement National Institute of Standards and Technology (NIST) guidelines to adhere to the Federal Information Security Modernization Act (FISMA). NIST provides a framework for managing and controlling cybersecurity risks by defining cybersecurity controls and methodologies for implementation. The NIST framework is based upon the system, data within the system, integrations with external systems, and risk assessments to determine impacts for each of those systems. The goals and objectives are to identify appropriate security controls that fulfil and map to the NIST 800-53 framework. The implementation process involves developing an organizational understanding to manage cybersecurity risk to systems, people, assets, data, and capabilities. NIST Security controls are interpreted and defined within the Gateway vehicle requirements subsystems specifications. This paper details the approach, implementation, and challenges faced during the development and design phases to address cyber threats during the Gateway vehicle operations.

Cybersecurity↗
NASA NTRS2016

Robust Thermal Control of Propulsion Lines for Space Missions

In spacecraft that have propulsion lines that are located externally with open bus architecture, the lines are typically insulated by Multi Layer Insulation (MLI) blankets to protect them thermally from the cold space environment. In addition to heat loss through the insulation, mechanical supports used to attach the lines to the spacecraft structure also create heat leaks from the lines. These lines typically have very low thermal conduction in the axial direction, so the heat balance in the lines tends to be very local without much heat spreading. The typical allowable temperature range for hydrazine-based lines is +15/+50°C. This tight temperature range has to be maintained for every location on these lines. For typical spacecraft, these lines can be several meters long. Temperature control is typically achieved by closed loop monitoring of temperatures along the lines and the corresponding powering of the heaters in a bang-bang approach to maintain the temperatures within the dead band of the control loop. The temperatures of propulsion lines are a function of several parameters with heat loss characteristics of the MLI being the key one. Unfortunately, this same key characteristic (MLI effective emittance) has a large variation along its length due to its dependence on workmanship, which in turn leads to large uncertainties in the propulsion lines’ local temperatures. Because of the poor conduction along the axial direction, heat balance along the length varies dramatically from one location to the next, even few inches apart, depending on the combination of the controlling parameters. This paper describes various robust design and implementation approaches that have been investigated to greatly reduce the randomness associated with predicting the temperature of these propulsion lines.

Bhandari, Pradeep↗
NASA NTRS1988

The effects of RCS jet firing on the isolated Orbiter and mated coast phases of the glide return to launch site maneuver at Mach number 6 (IA302B)

An updated Space Shuttle aerodynamic data base was obtained in Tunnel B for two phases of the Glide Return to Launch Site (GRTLS) abort maneuver. One-and-a-quarter percent scale models of the Space Shuttle Orbiter and External Tank were used to measure the effects of various combinations of Reaction Control System (RCS) jet thrusters at Mach number 6. The angle-of-attack range for the isolated orbiter was -10 to 15 deg at sideslip angles from -5 to 10 deg during Phase 1 of testing. The angle-of-attack range for the mated orbiter and external tank was -5 to 15 deg with sideslip angles of -2 to 5 deg during Phase 2. The test was conducted at a unit Reynolds number of 0.75 million per foot.

Garrett, L. V.↗