Lunar and planetary surface analysis using neutron activation.
Neutron activation analysis of Si, Fe, Al, Mg and O content of lunar and planetary surfaces
ELEMENT ABUNDANCE↗
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Active control of sound transmission/radiation from elastic plates by vibration inputs. I - Analysis
Active control of sound radiation from vibrating plates by oscillating forces applied directly to the structure is analytically studied. The model consists of a plane acoustic wave incident on a clamped elastic circular thin plate. Control is achieved by point forces, and quadratic optimization is used to calculate the optimal control gains necessary to minimize a cost function proportional to the radiated acoustic power (the transmitted field). The results show that global attenuation of broadband radiated sound levels for low to mid-range frequencies can be achieved with one or two control forces, irrespective of whether the system is on or off resonance. The efficiency of the control strategy is demonstrated to be related to the nature of the coupling between the plate modes of response and the radiated field.
Fuller, C. R.↗
Activation volume analysis for Cr and Cr-35 Re
Activation volume analysis for Cr and Cr-35Re
STRESS ANALYSIS↗
Topological analysis of active networks
Computer programs for application to topological analysis of active networks
COMPUTER PROGRAM↗
Interactive analysis program activity
The development of an analysis software system capable of performing interdisciplinary preliminary design analyses of large space structure configurations is discussed. Disciplines such as thermal, structures, and controls are to be integrated into a highly user oriented analysis capability. The key feature of the integrated analysis capability, a rapid and efficient system that will minimize solution turnaround time, is discussed.
Young, J. P.↗
JPSS-1 ATMS Post-launch Active Geolocation Analysis
A NOAA-20 (N20) ATMS active geolocation test was performed around Jan. 2018 with 24 pre-selected coastline crossing scenes. After comprehensive analysis of ATMS stare data and the corresponding VIIRS data, the ATMS pitch, roll and yaw pointing angle errors are found from the nadir perpendicular, the nadir oblique shallow angle, and the off-nadir perpendicular coastline crossing data, respectively. In this study, we first determine the ATMS radiometric coastline crossing time by using the ATMS radiometric count data. Since the coastline can be located anywhere within one ATMS FOV from the passive (regular scanning) geolocation data, depending on the scan starting time, it is not a valid assumption for the inflection point being the same as the coastline location. Consequently, using the passive geolocation data to validate the sensor’s on-orbit pointing angle performance is limited. After finding the ATMS radiometric coastline crossing time from the ATMS data, we compare it with the VIIRS effective time stamp (see main text). Specifically the VIIRS M3, M4 & M5 (true color) & M15 and M16 bands (thermal) data have a much smaller footprint size. Using the differences of the ATMS and VIIRS (effective) coastlines crossing times, the N20 ATMS pitch, roll and yaw pointing angle errors are found to be -0.09o, -0.24o and 0.28o, respectively. To determine ATMS geolocation properly, these on-orbit pointing errors need to be corrected, adding to the ATMS SDR Processing Coefficient Table, and passed on to the operational geolocation processing code.
Active Geolocation↗
Measurement of Mn-53 in deep-sea iron and stony spherules
Cosmic-ray-produced Mn-53 (half-life, 3.7 x 10 to the 6th yr) is measured in individual and groups of deep-sea iron and stony spherules by highly sensitive neutron activation analysis. The activities found are less than 20 dpm Mn-53/kg Fe (10 to the -5th-10 to the -6th dpm Mn-53/sample) in iron spherules, with the exception of one iron spherule, whose activity is 241 + or - 73 dpm Mn-53/kg Fe. It is believed that these low activities may indicate evaporative loss of Mn-53 caused by heating in the earth's atmosphere. On the other hand, all the stony spherules are found to contain 200-260 dpm Mn-53/kg Fe, which is similar to chondritic values. It is pointed out that these spherules may be ablation debris from large objects.
Nishiizumi, K.↗
Igneous inclusions from ordinary chondrites: High temperature cumulates and a shock melt
We report microprobe, instrumental neutron activation analysis, and radiochemical neutron activation analysis data for three large igneous inclusions in the Yamato (Y-)75097, Y-793241, and Y-794046 ordinary chondrites. The inclusions in the first two chondrites are troctolitic cumulates that have undergone appreciable reactions with their hosts either during emplacement and/or cooling. Olivine-spinel Fe-Mg exchange pairs in these two inclusions record equilibration temperatures of about 710 C, and these temperatures are similar to those exhibited by mineral pairs in the Y-75097 and Y-793241 hosts. The inclusion in Y-794046 is texturally unique, consisting of fine-grained, randomly distributed olivines, coarse (approximately 2 mm) fascicular pyroxene laths, and angular pockets of maskelynite/plagioclase feldspar. The phase compositions are readily interpreted as having resulted from extremely rapid, essentially isochemical cooling to temperatures less than 1000 C of a melt with an initial temperature greater than 1670 C. We suggest that this igneous inclusion formed in-situ by shock.
Sack, Richard O.↗
Overview of MSFC's Applied Fluid Dynamics Analysis Group Activities
TD64, the Applied Fluid Dynamics Analysis Group, is one of several groups with high-fidelity fluids design and analysis expertise in the Space Transportation Directorate at Marshall Space Flight Center (MSFC). TD64 assists personnel working on other programs. The group participates in projects in the following areas: turbomachinery activities, nozzle activities, combustion devices, and the Columbia accident investigation.
Garcia, Roberto↗
Customer Avionics Interface Development and Analysis Development Activity Tracking System
The Customer Avionics Interface Development and Analysis (CAIDA) Development Activity (DA)Tracking System is a Microsoft Access Database that tracks, organizes, and analyzes data about DAs from the work management tool. The CAIDA DA Tracking System takes data imported from the work management system. Once in the system, the data is filtered to generate each DA’s Asset. From there, many different queries are run on the data and their results are imported into forms to create graphs to get and display a wide range of metrics. These graphs are automatically updated with each new data import and over time. They can be easily exported for use in presentations, documents, etc. Additionally, the system is highly customizable and can be added upon to include more data members, generate new graphs, and much more.
Tara Conti↗
SPS flexible system control assessment analysis
Active control of the Satellite Power System (SPS0, a large mechanically flexible aerospace structure is addressed. The control algorithm is the principle component in the feedback link from sensors to actuators. An analysis of the interaction of the SPS structure and its active control system is presented.
Balas, M. J.↗
Large space antenna communications systems: Integrated Langley Research Center/Jet Propulsion Laboratory development activities. 2: Langley Research Center activities
The electromagnetic analysis activities at the Langley Research Center are resulting in efficient and accurate analytical methods for predicting both far- and near-field radiation characteristics of large offset multiple-beam multiple-aperture mesh reflector antennas. The utilization of aperture integration augmented with Geometrical Theory of Diffraction in analyzing the large reflector antenna system is emphasized.
Cambell, T. G.↗
Overview af MSFC's Applied Fluid Dynamics Analysis Group Activities
This paper presents viewgraphs on NASA Marshall Space Flight Center's Applied Fluid Dynamics Analysis Group Activities. The topics include: 1) Status of programs at MSFC; 2) Fluid Mechanics at MSFC; 3) Relevant Fluid Dynamics Activities at MSFC; and 4) Shuttle Return to Flight.
Garcia, Roberto↗
Multidisciplinary analysis of actively controlled large flexible spacecraft
The control of Flexible Structures (COFS) program has supported the development of an analysis capability at the Langley Research Center called the Integrated Multidisciplinary Analysis Tool (IMAT) which provides an efficient data storage and transfer capability among commercial computer codes to aid in the dynamic analysis of actively controlled structures. IMAT is a system of computer programs which transfers Computer-Aided-Design (CAD) configurations, structural finite element models, material property and stress information, structural and rigid-body dynamic model information, and linear system matrices for control law formulation among various commercial applications programs through a common database. Although general in its formulation, IMAT was developed specifically to aid in the evaluation of the structures. A description of the IMAT system and results of an application of the system are given.
Cooper, Paul A.↗
Galaxy interactions and strength of nuclear activity
Analysis of data in the literature for differential velocities and projected separations of nearby Seyfert galaxies with possible companions shows a clear difference in projected separations between type 1's and type 2's. This kinematic difference between the two activity classes reinforces other independent evidence that their different nuclear characteristics are related to a non-nuclear physical distinction between the two classes. The differential velocities and projected separations of the galaxy pairs in this sample yield mean galaxy masses, sizes, and mass to light ratios which are consistent with those found by the statistical methods of Karachentsev. Although the galaxy sample discussed here is too small and too poorly defined to provide robust support for these conclusions, the results strongly suggest that nuclear activity in Seyfert galaxies is associated with gravitational perturbations from companion galaxies, and that there are physical distinctions between the host companions of Seyfert 1 and Seyfert 2 nuclei which may depend both on the environment and the structure of the host galaxy itself.
Simkin, S. M.↗
Dynamics-A explorer RIMS data analysis
Activities of the RIMS instrument during the extended mission are planned. The modes of operation for RIMS to achieve the science requirements utilizing the new and exciting information on the composition and dynamics of the low energy (0-50eV) ions in the Earth's ionosphere and magnetosphere are determined. The specific science problems and the required RIMS operational modes needed to acquire the desired data are identified. The analysis was performed on the RIMS data to achieve the science results and this new information was used in determining RIMS operations during the latter part of the mission. Necessary sensitivity tests of RIMS operating modes and instrument performance was suggested. The inflight results was compared with theoretical models.
Banks, P. M.↗
Results of special mechanical analyses of Luna 16 material
The studies carried out on the Luna 16 regolith have confirmed the data that were already published internationally. By means of activation analysis under irradiation in the reactor, activation analysis with a 14 MeV U-generator, and mass spectroscopy on samples of 10 or 20 mg, six main and 63 trace elements were quantitatively determined and compared with known data.
Stiller, H.↗
Advanced Transportation System Studies Technical Area 2 (TA-2) Heavy Lift Launch Vehicle Development Contract: Technical Results - Volume 2
The purpose of the Advanced Transportation System Studies (ATSS) Technical Area 2 (TA-2) Heavy Lift Launch Vehicle Development contract was to provide advanced launch vehicle concept definition and analysis to assist NASA in the identification of future launch vehicle requirements. Contracted analysis activities included vehicle sizing and performance analysis, subsystem concept definition, propulsion subsystem definition (foreign and domestic), ground operations and facilities analysis, and life cycle cost estimation. This document is Volume 2 of the final report for the contract. It provides documentation of selected technical results from various TA-2 analysis activities, including a detailed narrative description of the SSTO concept assessment results, a user's guide for the associated SSTO sizing tools, an SSTO turnaround assessment report, an executive summary of the ground operations assessments performed during the first year of the contract, a configuration-independent vehicle health management system requirements report, a copy of all major TA-2 contract presentations, a copy of the FLO launch vehicle final report, and references to Pratt & Whitney's TA-2 sponsored final reports regarding the identification of Russian main propulsion technologies.
Source record↗