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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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1,530 records · Page 66

High-Performance Reactionless Scan Mechanism

A high-performance reactionless scan mirror mechanism was developed for space applications to provide thermal images of the Earth. The design incorporates a unique mechanical means of providing reactionless operation that also minimizes weight, mechanical resonance operation to minimize power, combined use of a single optical encoder to sense coarse and fine angular position, and a new kinematic mount of the mirror. A flex pivot hardware failure and current project status are discussed.

Ellen I Williams

General Purpose Data-Driven System Monitoring for Space Operations

Modern space propulsion and exploration system designs are becoming increasingly sophisticated and complex. Determining the health state of these systems using traditional methods is becoming more difficult as the number of sensors and component interactions grows. Data-driven monitoring techniques have been developed to address these issues by analyzing system operations data to automatically characterize normal system behavior. The Inductive Monitoring System (IMS) is a data-driven system health monitoring software tool that has been successfully applied to several aerospace applications. IMS uses a data mining technique called clustering to analyze archived system data and characterize normal interactions between parameters. This characterization, or model, of nominal operation is stored in a knowledge base that can be used for real-time system monitoring or for analysis of archived events. Ongoing and developing IMS space operations applications include International Space Station flight control, satellite vehicle system health management, launch vehicle ground operations, and fleet supportability. As a common thread of discussion this paper will employ the evolution of the IMS data-driven technique as related to several Integrated Systems Health Management (ISHM) elements. Thematically, the projects listed will be used as case studies. The maturation of IMS via projects where it has been deployed, or is currently being integrated to aid in fault detection will be described. The paper will also explain how IMS can be used to complement a suite of other ISHM tools, providing initial fault detection support for diagnosis and recovery.

Satellites

Performance of the Lester battery charger in electric vehicles

Tests are performed on an improved battery charger. The primary purpose of the testing is to develop test methodologies for battery charger evaluation. Tests are developed to characterize the charger in terms of its charge algorithm and to assess the effects of battery initial state of charge and temperature on charger and battery efficiency. Tests show this charger to be a considerable improvement in the state of the art for electric vehicle chargers.

Vivian, H. C.

The JPL Telerobot Operator Control Station: Operational Experiences

The Operator Control Station of the JPL/NASA Telerobot Demonstration System provides an efficient man-machine interface for the performance of telerobot tasks. Its hardware and software have been designed with high flexibility. It provides a feedback-rich interactive environment in which the Operator performs teleoperation tasks, robotic tasks, and telerobotic tasks with ease. The to-date operational experiences of this system, particularly related to the Object Designate Process and the Voice Input/Output Process are discussed.

Edwin P Kan

Prevention of Coupled Structure-Propulsion Instability (POGO) On The Space Shuttle

Many liquid-propellant rocket vehicles have experienced longitudinal vibration, nicknamed pogo after the jumping stick, due to an instability arising from interaction of the vehicle structure with the propulsion system. These vibrations can produce an intolerable environment for astronauts and equipment, can overload vehicle structure, and can lead to loss of propulsion performance. A NASA monograph concerned with the prevention of pogo is well on its way toward publication and should serve as a useful guide to design for the Space Shuttle. The paper will briefly describe the nature of the pogo phenomenon, present a summary of past instabilities, relate the possible deleterious effects of pogo, and discuss the contents of the design criteria monograph. Finally, research tasks are recommended for support of pogo development activities on the Space Shuttle.

S. Rubin

Battery Cell-to-Pack Scaling Laws for Electric Aircraft

Battery pack gravimetric energy density is one of the most important, yet often miss-estimated design parameters for sizing all-electric aircraft. Proper accounting for thermal, structural, and operational safety margins are frequently lost when extrapolating performance from the cell level to the aircraft level. This paper summarizes the relevant engineering and certification details needed to better account for the penalties associated when assembling battery packs. The relationship between the cell and pack energy density is not linear, as is often assumed. Furthermore, the relationship varies depending on pack requirements, cell chemistry, and architecture. Parametric, high-fidelity models are used to determine optimal battery pack sizes over a range of conditions to better quantify technology scaling effects.

Battery Electric Aircraft

Review of European Microgravity Measurements

AA In a French/Russion cooperation, CNES developed a microgravity detection system for analyzing the Mir space station micro-g-environment for the first time. European efforts to characterize the microgravity (1/9) environment within a space laboratory began in the late seventies with the design of the First Spacelab Mission SL-1. Its Material Science Double Rack was the first payload element to carry its own tri-axial acceleration package. Even though incapable for any frequency analysis, the data provided a wealth of novel information for optimal experiment and hardware design and operations for missions to come. Theoretical investigations under ESA contract demonstrated the significance of the detailed knowledge of micro-g data for a thorough experiment analysis. They especially revealed the high sensitivity of numerous phenomena to low frequency acceleration. Accordingly, the payloads of the Spacelab missions D-1 and D-2 were furnished with state-of-the-art detection systems to ensure frequency analysis between 0.1 and 100 Hz. The Microgravity Measurement Assembly (MMA) of D-2 was a centralized system comprising fixed installed as well as mobile tri-axial packages showing real-time data processing and transmission to ground. ESA's free flyer EURECA carried a system for continuous measurement over the entire mission. All EURECA subsystems and experimental facilities had to meet tough requirements defining the upper acceleration limits. In a French/Russion cooperation, CNES developed a mi crogravity detection system for analyzing the Mir space station micro-g-environment for the first time. An approach to get access to low frequency acceleration between 0 and 0.02 Hz will be realized by QSAM (Quasi-steady Acceleration Measurement) on IML-2, complementary to the NASA system Spacelab Acceleration Measurement System SAMS. A second flight of QSAM is planned for the Russian free flyer FOTON.

H Hamacher

Sterilizable battery

Development program for separator and modified polyethylene separator material for silver-zinc battery, and program for development of sealed heat sterilizable batteries

MATERIAL TESTING

Workshop on Advances in NASA-Relevant, Minimally Invasive Instrumentation

The purpose of this meeting is to highlight those advances in instrumentation and methodology that can be applied to the medical problems that will be encountered as the duration of manned space missions is extended. Information on work that is presently being done by NASA as well as other approaches in which NASA is not participating will be exchanged. The NASA-sponsored efforts that will be discussed are part of the overall Space Medicine Program that has been undertaken by NASA to address the medical problems of manned spaceflight. These problems include those that have been observed in the past as well as those which are anticipated as missions become longer, traverse different orbits, or are in any way different. This conference is arranged in order to address the types of instrumentation that might be used in several major medical problem areas. Instrumentation that will help in the cardiovascular, musculoskeletal, and psychological areas, among others will be presented. Interest lies in identifying instrumentation which will help in learning more about ourselves through experiments performed directly on humans. Great emphasis is placed on non-invasive approaches, although every substantial program basic to animal research will be needed in the foreseeable future. Space Medicine is a rather small affair in what is primarily an engineering organization. Space Medicine is conducted throughout NASA by a very small skeleton staff at the headquarters office in Washington and by our various field centers. These centers include the Johnson Space Center in Houston, Texas, the Ames Research Center in Moffett Field, California, the Jet Propulsion Laboratory in Pasadena, California, the Kennedy Space Center in Florida, and the Langley Research Center in Hampton, Virginia. Throughout these various centers, work is conducted in-house by NASA's own staff scientists, physicians, and engineers. In addition, various universities, industries, and other government laboratories perform research that cannot be effectively carried out in-house. At the moment, approximately 50% of the work is performed in-house and 50% is extramural. The area of bioinstrumentation pervades every one of our problem areas. In each, equipment or procedures are being developed that will allow more clinical work to be done in a ground-based or spacecraft setting. Although work of this kind goes on throughout the NASA organization and through its grants and contracts in the community at large, the major thrust of it is concentrated at the Jet Propulsion Laboratory which plays a lead role in this type of research and acts as the lead center in bioinstrumentation for NASA. It is recognized that there is much additional research being pursued in this area which would be potentially valuable to NASA and could, with some stimulation from, be made more applicable to NASA's needs. It is hoped, therefore, that the proceedings of this conference will be used as the basis for developing research strategies to be used as a road map to point the way in which NASA's own sponsored program should proceed over the course of the next three years. Additionally, it is hoped that the conference will highlight additional areas in which NASA should be involved either in-house or through the sponsorship of non-NASA scientists. NASA would also like to get an idea of which areas should be emphasized or perhaps de-emphasized among those that it is currently pursuing. In considering these questions, the discussion should concern itself not so much with whether a particular procedure or piece of equipment would work in a spacecraft, but rather, with whether the procedures that are advocated are at the state-of-the-art or beyond the state-of-the-art and whether they hold promise of giving additional insight into the problems to be confronted as humans venture into space for longer and longer periods of time.

Source record

Control of Thermo-Acoustics Instabilities: The Multi-Scale Extended Kalman Approach

"Multi-Scale Extended Kalman" (MSEK) is a novel model-based control approach recently found to be effective for suppressing combustion instabilities in gas turbines. A control law formulated in this approach for fuel modulation demonstrated steady suppression of a high-frequency combustion instability (less than 500Hz) in a liquid-fuel combustion test rig under engine-realistic conditions. To make-up for severe transport-delays on control effect, the MSEK controller combines a wavelet -like Multi-Scale analysis and an Extended Kalman Observer to predict the thermo-acoustic states of combustion pressure perturbations. The commanded fuel modulation is composed of a damper action based on the predicted states, and a tones suppression action based on the Multi-Scale estimation of thermal excitations and other transient disturbances. The controller performs automatic adjustments of the gain and phase of these actions to minimize the Time-Scale Averaged Variances of the pressures inside the combustion zone and upstream of the injector. The successful demonstration of Active Combustion Control with this MSEK controller completed an important NASA milestone for the current research in advanced combustion technologies.

Dzu K Le

GPS on-orbit battery performance

Three batteries designed for the GPS system were evaluated. The batteries were wired together, and during the eclipse period were discharged through parallel diodes into a boost converter which then boosted the battery voltage up to the totally regulated bus voltage. Each battery, with a system life of approximately five years, had its own charger. During testing the battery was maintained or used on trickle charge. Data are presented for the battery capacity during the reconditioning. Raw data for each eclipse period and calculations for the average discharge voltage for each battery are given. Thermal cycling for one of the batteries and reconditioning cycles and regimes for all of the batteries are discussed. A reconditioning discharge curve is also given. The problem of temperature cycling in one of the batteries was resolved by redesigning the battery radiator system.

Kasten, J. L.

Bipolar nickel-hydrogen battery design

The initial design for the NASA-Lewis advanced nickel-hydrogen battery is discussed. Fabrication of two 10-cell boilerplate battery stacks will soon begin. The test batteries will undergo characterization testing and low Earth orbit life cycling. The design effectively deals with waste heat generated in the cell stack. Stack temperatures and temperature gradients are maintained to acceptable limits by utilizing the bipolar conduction plate as a heat path to the active cooling fluid panel external to the edge of the cell stack. The thermal design and mechanical design of the battery stack together maintain a materials balance within the cell. An electrolyte seal on each cell frame prohibits electrolyte bridging. An oxygen recombination site and electrolyte reservoir/separator design does not allow oxygen to leave the cell in which it was generated.

Koehler, C. W.

Battery Cell-to-Pack Scaling Trends for Electric Aircraft

Battery pack gravimetric energy density is one of the most important, yet often miss- estimated design parameters for sizing all-electric aircraft. Proper accounting for thermal, structural, and operational safety margins are frequently lost when extrapolating performance from the cell level to the aircraft level. This paper summarizes the relevant engineering and certification details needed to better account for the penalties associated when assembling battery packs. The relationship between the cell and pack energy density is not linear, as is often assumed. Furthermore, the relationship varies depending on pack requirements, cell chemistry, and architecture. Parametric, high-fidelity models are used to determine optimal battery pack sizes over a range of conditions to better quantify technology scaling effects.

Battery Electric Aircraft

NASA aerospace battery system program initiation

Preflight and flight battery system problems in flight programs at NASA created high-level concern and interest in the current battery technology status. As a result, NASA conducted an in-house review of problems experienced both internally and by other government users. The derived issues which encompassed the programmatic scope from cell manufacturing to in-flight operations of the system are discussed. From the identified deficiencies, a modestly scaled battery program was established to alleviate or minimize the risks of future occurrences.

Schulze, Norman R.

Lyotropic Liquid Crystalline Phase Behavior of Boron Nitride Nanotube Aqueous Dispersions

Boron nitride nanotubes (BNNTs) are gaining significant interest due to their outstanding mechanical and thermal properties, as well as their potential to serve as a model nanorod system. Processing BNNT liquid crystalline (LC) dispersions enables precise control over BNNT orientation in macroscopic assemblies, while their low absorption in the visible spectrum facilitates studying LCs at exceptionally high concentrations. Here, we investigate the behavior of BNNTs in aqueous solutions stabilized by the surfactant sodium deoxycholate (SDC), examining the effect of BNNT purity and BNNT−SDC concentrations on lyotropic LC formation. We disperse up to 15wt% BNNT in SDC solutions and use polarized light microscopy to detail the transition from an isotropic state to a biphasic regime, where isotropic and nematic domains coexist due to phase separation, to a single fully nematic phase. Cryogenic electron microscopy provides direct evidence of BNNT alignment within nematic domains. Our results show that enhanced depletion-induced attractions, driven by increased surfactant concentration, lower the threshold concentration of BNNT required to form nematic domains. In contrast, low surfactant concentrations relative to BNNT result in insufficiently coated nanotube surfaces, leading to poor dispersions and BNNT aggregation. Additionally, we fabricate well-aligned BNNT films from aqueous LC dispersions. Our findings advance the understanding of BNNT LCs, offering insight into controlling their orientation and highlighting their potential for high-performance materials.

Joe Khoury

Update of the IUE battery in-flight performance

The in-flight performance data of two 17-cell, 6-ampere-hour nickel cadmium spacecraft batteries are presented covering 22 months of operation. Fluctuations in the battery voltage and the battery temperature are presented for spacecraft movement throughout a beta range of 0 to 130 deg. The battery discharge voltages during the peak eclipse seasons, daily seasons, and daily eclipse periods are noted. Finally, the spacecraft data are compared to data from a 6-ampere-hour test pack and test flight data.

Tiller, S. E.