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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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102 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Changes in volume, muscle compartment, and compliance of the lower extremities in man following 30 days of exposure to simulated microgravity

To investigate the relationship between leg compliance and a reduction in the size of the leg muscle compartment due to long-duration exposure to microgravity, eight men were exposed for 30 d of continuous 6-deg headdown tilt, and changes in vascular compliance (vol pct/mm Hg x 100) of the calf and serial circumferences of the thigh and the calf were measured before, during, and after the tilt. It was found that the tilt exposure led to calculated leg volume decreases of 9.9 percent in the calf and of 4.5 in the thigh. Leg compliance was found to increase from 3.9 to about 4.9. Calf compliance measured before and after bedrest was found to be inversely related to calf-muscle compartment cross-sectional area (CSA).

Convertino, Victor A.↗
NASA NTRS2003

Kinematics and the implementation of an elephant's trunk manipulator and other continuum style robots

Traditionally, robot manipulators have been a simple arrangement of a small number of serially connected links and actuated joints. Though these manipulators prove to be very effective for many tasks, they are not without their limitations, due mainly to their lack of maneuverability or total degrees of freedom. Continuum style (i.e., continuous "back-bone") robots, on the other hand, exhibit a wide range of maneuverability, and can have a large number of degrees of freedom. The motion of continuum style robots is generated through the bending of the robot over a given section; unlike traditional robots where the motion occurs in discrete locations, i.e., joints. The motion of continuum manipulators is often compared to that of biological manipulators such as trunks and tentacles. These continuum style robots can achieve motions that could only be obtainable by a conventionally designed robot with many more degrees of freedom. In this paper we present a detailed formulation and explanation of a novel kinematic model for continuum style robots. The design, construction, and implementation of our continuum style robot called the elephant trunk manipulator is presented. Experimental results are then provided to verify the legitimacy of our model when applied to our physical manipulator. We also provide a set of obstacle avoidance experiments that help to exhibit the practical implementation of both our manipulator and our kinematic model. c2003 Wiley Periodicals, Inc.

Non-NASA Center↗
NASA NTRS2006

Comparison of Communication Architectures for Spacecraft Modular Avionics Systems

This document is a survey of publicly available information concerning serial communication architectures used, or proposed to be used, in aeronautic and aerospace applications. It focuses on serial communication architectures that are suitable for low-latency or real-time communication between physically distributed nodes in a system. Candidates for the study have either extensive deployment in the field, or appear to be viable for near-term deployment. Eleven different serial communication architectures are considered, and a brief description of each is given with the salient features summarized in a table in appendix A. This survey is a product of the Propulsion High Impact Avionics Technology (PHIAT) Project at NASA Marshall Space Flight Center (MSFC). PHIAT was originally funded under the Next Generation Launch Technology (NGLT) Program to develop avionics technologies for control of next generation reusable rocket engines. After the announcement of the Space Exploration Initiative, the scope of the project was expanded to include vehicle systems control for human and robotics missions. As such, a section is included presenting the rationale used for selection of a time-triggered architecture for implementation of the avionics demonstration hardware developed by the project team

Gwaltney, D. A.↗
NASA NTRS2008

The Repair and Return to Flight of Solid Rocket Booster Forward Skirt Serial Number 20022

On April 5, 1991, a solid rocket booster (SRB) forward skirt serial number (S/N) 20022 sustained buckling damage during water impact after the launch of Space Transportation System Flight 37 (STS-37). As of that date, five forward skirts had been lost during water impact. Repair attempts began with the least damaged skirt available (S/N 20022). Sp ecial hydraulic tooling was used to remove buckled areas of the skirt. Afterwards, its aft clevis pinholes were found to be out of alignment with the redesigned solid rocket motor (RSRM) check gauge, but weld passes were used to correct this condition. Meanwhile, USA Analytics generated mechanical property data for buckled and subsequently debuckled material. Their analysis suggested that structural integrity might be improved by adding stringer reinforcements, stiffeners, to the aft bay section of the skirt. This improvement was recommended as a fleet modification to be implemented on a case-by-case basis.

Malone, T. W.↗
NASA NTRS1991

TOMS FM-2 Calibration Report

The radiance and irradiance sensitivities of the TOMS are tabulated in table 1. The results obtained with FEL standard F-281 are actual while those computed for lamps F-239 and F-207 are for reference purposes as those standards were out of calibration at the time of use. The irradiance results were computed for the serial number 5 carousel surfaces, the flight unit, and the serial number 4 carousel surfaces, the flight backup unit. The data and results are presented tabularly and graphically. The computed instrument sensitivities based on the radiance results are higher than those resulting from the irradiance data (see figure's 9 a,b,&c). No quantitative explanation for this difference has been determined. The radiance data was obtained with the instrument in the NADIR detent while the irradiance data was obtained with the scan mirror rotated 90 degrees from NADIR to view the diffuser. The sensitivity plots show the pronounce effects of the instruments measured spectral bandwidth used in the computations. The radiance data, figures 5 a,b & c, are quite smooth. Sources of error in the calibrations include the normalized radiance, source lamp irradiance , diffuser BRDF, and geometry factors. These are discussed in the errors of calibration section included in this report.

Source record↗
NASA NTRS1993

STS-54 Space Shuttle mission report

The STS-54 Space Shuttle Program Mission Report is a summary of the Orbiter, External Tank (ET), Solid Rocket Booster/Redesigned Solid Rocket Motor (SRB/RSRM), and the Space Shuttle Main Engine (SSME) subsystems performance during this fifty-third flight of the Space Shuttle Program, and the third flight of the Orbiter vehicle Endeavour (OV-105). In addition to the Orbiter, the flight vehicle consisted of an ET, which was designated ET-51; three SSME's, which were serial numbers 2019, 2033, and 2018 in positions 1, 2, and 3, respectively; and two retrievable and reusable SRB's which were designated BI-056. The lightweight RSRM's that were installed in each SRB were designated 360L029A for the left SRB, and 360L029B for the right SRB. The primary objectives of this flight were to perform the operations to deploy the Tracking and Data Relay Satellite-F/Inertial Upper Stage payload and to fulfill the requirements of the Diffuse X-Ray Spectrometer (DXS) payload. The secondary objective was to fly the Chromosome and Plant Cell Division in Space (CHROMEX), Commercial Generic Bioprocessing Apparatus (CGBA), Physiological and Anatomical Rodent Experiment (PARE), and the Solid Surface Combustion Experiment (SSCE). In addition to presenting a summary of subsystem performance, this report also discusses each Orbiter, ET, SSME, SRB, and RSRM in-flight anomaly in the applicable section of the report. The official tracking number for each in-flight anomaly, assigned by the cognizant project, is also shown. All times are given in Greenwich mean time (G.m.t.) and mission elapsed time (MET).

Fricke, Robert W., Jr.↗
DOE OSTI2025

Direct NeTS sampling of nuclear graphite $S(α, β, T)$ in Serpent

For advanced reactor applications, Neural Thermal Scattering (NeTS) modules were developed to predict the thermal scattering law (TSL or $S(α, β, T)$) of a nuclear graphite neutron moderator. NeTS are multi-layer, feedforward artificial neural networks, which act as universal function approximators designed for TSL datasets. In this case, a 4-layer neural network with 164 neurons per layer is trained using FLASSH evaluated data in PyTorch and serialized as a torchscript dictionary to predict $S(α, β, T)$ on-the-fly. Relative, absolute and maximum percent deviations of NeTS from File 7 data generated using the FLASSH code are on the order of 0.01%, 0.1% and 1%, respectively, with low inference latencies of 0.000172 s per $S(α, β, T)$ at a given temperature. Capturing the full dimensionality of possible inelastic neutron-lattice interactions, NeTS functionality is embedded in the Serpent Monte Carlo code, where $S(α, β, T)_{NeTS}$ sampling is conducted on-the-fly and compared to ACE look-up-tables for predicting TREAT criticality. k-eff differences between sampling algorithms of 6 pcm are observed and are within the order of Monte Carlo uncertainty. Compared to discrete and continuous-energy ACE files (30 MB and 131 MB per temperature), the NeTS format is on the order of 200–300 kB for a continuous-temperature, interpolation-free representation of $S(α, β, T)$ and cross sections. NeTS-in-Serpent runtimes comparable with ACE look-up tables are achieved by scaling NeTS for high performance computing architectures with hybrid OpenMP + MPI parallelization. This work validates a novel, self-contained reactor physics framework for predictive cross sections, and demonstrates a general methodology for embedding modern machine learning libraries within existing neutronic analysis frameworks.

Nuclear Criticality Safety Program (NCSP)↗
NASA NTRS1992

STS-46 Space Shuttle mission report

The STS-46 Space Shuttle Program Mission Report contains a summary of the Orbiter, External Tank (ET), Solid Rocket Booster/Redesigned Solid Rocket Motor (SRB/RSRM), and the Space Shuttle main engine (SSME) subsystem performance during the forty-ninth flight of the Space Shuttle Program, and the twelfth flight of the Orbiter vehicle Atlantis (OV-104). In addition to the Atlantis vehicle, the flight vehicle consisted of the following: an ET, designated ET-48 (LWT-41); three SSME's, which were serial numbers 2032, 2033, and 2027 in positions 1, 2, and 3, respectively; and two SRB's which were designated BI-052. The lightweight/redesigned SRM's that were installed in each SRB were designated 360W025A for the left RSRM and 360L025B for the right RSRM. The primary objective of this flight was to successfully deploy the European Retrievable Carrier (EURECA) payload and perform the operations of the Tethered Satellite System-1 (TSS-1) and the Evaluation of Oxygen Interaction with Material 3/Thermal Energy Management Processes 2A-3 (EOIM-3/TEMP 2A-3). The secondary objectives of this flight were to perform the operations of the IMAX Cargo Bay Camera (ICBC), Consortium for Material Development in Space Complex Autonomous Payload-2 and 3 (CONCAP-2 and CONCAP-3), Limited Duration Space Environment Candidate Materials Exposure (LDCE), Pituitary Growth Hormone Cell Function (PHCF), and Ultraviolet Plume Instrumentation (UVPI). In addition to summarizing subsystem performance, this report also discusses each Orbiter, ET, SSME, SRB, and RSRM in-flight anomaly in the applicable section of the report. Also included in the discussion is a reference to the assigned tracking number as published on the Problem Tracking List. All times are given in Greenwich mean time (G.m.t.) as well as mission elapsed time (MET).

Fricke, Robert W.↗
NASA NTRS2004

Advanced Signal Conditioners for Data-Acquisition Systems

Signal conditioners embodying advanced concepts in analog and digital electronic circuitry and software have been developed for use in data-acquisition systems that are required to be compact and lightweight, to utilize electric energy efficiently, and to operate with high reliability, high accuracy, and high power efficiency, without intervention by human technicians. These signal conditioners were originally intended for use aboard spacecraft. There are also numerous potential terrestrial uses - especially in the fields of aeronautics and medicine, wherein it is necessary to monitor critical functions. Going beyond the usual analog and digital signal-processing functions of prior signal conditioners, the new signal conditioner performs the following additional functions: It continuously diagnoses its own electronic circuitry, so that it can detect failures and repair itself (as described below) within seconds. It continuously calibrates itself on the basis of a highly accurate and stable voltage reference, so that it can continue to generate accurate measurement data, even under extreme environmental conditions. It repairs itself in the sense that it contains a micro-controller that reroutes signals among redundant components as needed to maintain the ability to perform accurate and stable measurements. It detects deterioration of components, predicts future failures, and/or detects imminent failures by means of a real-time analysis in which, among other things, data on its present state are continuously compared with locally stored historical data. It minimizes unnecessary consumption of electric energy. The design architecture divides the signal conditioner into three main sections: an analog signal section, a digital module, and a power-management section. The design of the analog signal section does not follow the traditional approach of ensuring reliability through total redundancy of hardware: Instead, following an approach called spare parts tool box, the reliability of each component is assessed in terms of such considerations as risks of damage, mean times between failures, and the effects of certain failures on the performance of the signal conditioner as a whole system. Then, fewer or more spares are assigned for each affected component, pursuant to the results of this analysis, in order to obtain the required degree of reliability of the signal conditioner as a whole system. The digital module comprises one or more processors and field-programmable gate arrays, the number of each depending on the results of the aforementioned analysis. The digital module provides redundant control, monitoring, and processing of several analog signals. It is designed to minimize unnecessary consumption of electric energy, including, when possible, going into a low-power "sleep" mode that is implemented in firmware. The digital module communicates with external equipment via a personal-computer serial port. The digital module monitors the "health" of the rest of the signal conditioner by processing defined measurements and/or trends. It automatically makes adjustments to respond to channel failures, compensate for effects of temperature, and maintain calibration.

Lucena, Angel↗
NASA NTRS1993

TLRS-3 system upgrades

This presentation describes the upgrades to the Transportable Laser Ranging Systems serial number three (TLRS-3), and the impact that these upgrades will have on the TLRS-3 performance in the field. The four major areas of system upgrades are the HP-380 computer, the Optical Attenuation Mechanism (OAM), the upgraded spatial, spectral and temporal filtering for improved daylight ranging capability, and the software upgrade to enable the system to track the Etalon satellites. The TLRS-3 was returned to the Goddard Geophysical and Astronomical Observatory (GGAO) in December 1991 for system upgrades in preparation of the TOPEX/POSEIDON campaign scheduled to begin in the summer of 1992. Many system upgrades were incorporated into the system while interleaving planned facility maintenance making TLRS-3 a more versatile and more dependable laser ranging system. The TLRS-3 was initially baselined with the MOBLAS-7 via simultaneous satellite ranging on the LAGEOS, Ajisai, Starlette, and ERS-I satellites. During the upgrades and following completion of the system upgrades intercomparisons with the MOBLAS-7 were made to verify the integrity and accuracy of the system changes. Several other groups of personnel participated in the TLRS-3 upgrade and they are: the Survey Section, the Precision Measurement Equipment Laboratory, the Architectural and Engineering Services Department, the Precision Timing Section, and the station personnel at TLRS-3 and MOBLAS-7.

Eichinger, Richard↗
NASA NTRS1993

STS-53 Space Shuttle mission report

The STS-53 Space Shuttle Program Mission Report provides a summary of the Orbiter, External Tank (ET), Solid Rocket Booster/Redesigned Solid Rocket Motor (SRB/RSRM), and the Space Shuttle Main Engine (SSME) subsystems performance during the fifty-second flight of the Space Shuttle Program, and the fifteenth flight of the Orbiter vehicle Discovery (OV-103). In addition to the Orbiter, the flight vehicle consisted of an ET, which was designated as ET-49/LWT-42; three SSME's, which were serial numbers 2024, 2012, and 2017 in positions 1, 2, and 3, respectively; and two SRB's, which were designated BI-055. The lightweight RSRM's that were installed in each SRB were designated 360L028A for the left SRB, and 360L028B for the right SRB. The primary objective of this flight was to successfully deploy the Department of Defense 1 (DOD-1) payload. The secondary objectives of this flight were to perform the operations required by the Glow Experiment/Cryogenic Heat Pipe Experiment Payload (GCP); the Hand-Held, Earth-Oriented, Real-Time, Cooperative, User-Friendly, Location-Targeting and Environmental System (HERCULES); the Space Tissue Loss (STL); the Battlefield Laser Acquisition Sensor Test (BLAST); the Radiation Monitoring Equipment-III (RME-III); the Microcapsules in Space-1 (MIS-1); the Visual Function Tester-2 (VFT-2); the Cosmic Radiation Effects and Activation Monitor (CREAM); the Clouds Logic to Optimize Use of Defense Systems-1A (CLOUDS-1A); the Fluids Acquisition and Resupply Experiment (FARE); and the Orbital Debris Radar Calibration Spheres (ODERACS). In addition to presenting a summary of subsystem performance, this report also discusses each Orbiter, ET, SSME, SRB, and RSRM in-flight anomaly in the applicable section of the report. Listed in the discussion of each anomaly is the officially assigned tracking number as published by each Project Office in their respective Problem Tracking List. All times given in this report are in Greenwich mean time (G.m.t.) as well as mission elapsed time (MET).

Fricke, Robert W., Jr.↗
NASA NTRS2002

An Efficient Scheme for Updating Sparse Cholesky Factors

Raghavan had earlier developed the software package DCSPACK which can be used for solving sparse linear systems where the coefficient matrix is symmetric and positive definite (this project was not funded by NASA but by agencies such as NSF). DSCPACK-S is the serial code and DSCPACK-P is a parallel implementation suitable for multiprocessors or networks-of-workstations with message passing using MCI. The main algorithm used is the Cholesky factorization of a sparse symmetric positive positive definite matrix A = LL(T). The code can also compute the factorization A = LDL(T). The complexity of the software arises from several factors relating to the sparsity of the matrix A. A sparse N x N matrix A has typically less that cN nonzeroes where c is a small constant. If the matrix were dense, it would have O(N2) nonzeroes. The most complicated part of such sparse Cholesky factorization relates to fill-in, i.e., zeroes in the original matrix that become nonzeroes in the factor L. An efficient implementation depends to a large extent on complex data structures and on techniques from graph theory to reduce, identify, and manage fill. DSCPACK is based on an efficient multifrontal implementation with fill-managing algorithms and implementation arising from earlier research by Raghavan and others. Sparse Cholesky factorization is typically a four step process: (1) ordering to compute a fill-reducing numbering, (2) symbolic factorization to determine the nonzero structure of L, (3) numeric factorization to compute L, and, (4) triangular solution to solve L(T)x = y and Ly = b. The first two steps are symbolic and are performed using the graph of the matrix. The numeric factorization step is of dominant cost and there are several schemes for improving performance by exploiting the nested and dense structure of groups of columns in the factor. The latter are aimed at better utilization of the cache-memory hierarchy on modem processors to prevent cache-misses and provide execution rates (operations/second) that are close to the peak rates for dense matrix computations. Currently, EPISCOPACY is being used in an application at NASA directed by J. Newman and M. James. We propose the implementation of efficient schemes for updating the LL(T) or LDL(T) factors computed in DSCPACK-S to meet the computational requirements of their project. A brief description is provided in the next section.

Raghavan, Padma↗