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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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Omni Technologies, Inc. worked with Stennis Space Center to develop the FOTR-125, a redundant fiber-optic transceiver for remote transmission of high-speed digital data. The 125-megabit-per-second transceiver can collect data for up to 25 kilometers, much longer than standard coaxial cable, which is limited to 50 meters. The Research Triangle Institute assisted in determining the commercial marketplace for the technology.
A differential pulse code modulation (DPCM) encoding and decoding method is described along with an apparatus which is capable of transmission with minimum bandwidth. The apparatus is not affected by data transition density, requires no direct current (DC) response of the transmission link, and suffers from minimal ambiguity in resolution of the digital data.
The paper describes the system configuration and data manipulation capabilities of a solar image display system which allows interactive analysis of visual images and on-line manipulation of digital data. Image processing features include smoothing or filtering of images stored in the display, contrast enhancement, and blinking or flickering images. A computer with a core memory of 28,672 words provides the capacity to perform complex calculations based on stored images, including computing histograms, selecting subsets of images for further analysis, combining portions of images to produce images with physical meaning, and constructing mathematical models of features in an image. Some of the processing modes are illustrated by some image sequences from solar observations.
The Image Processing Facility at Goddard Space Flight Center has the requirement to move volumes of digital data (100 billion data bits per day) that exceed the capacity of conventional computer tape. This paper presents the requirements for a high-density digital tape recorder compatible with conventional computer systems. The steps leading to the formulation of these requirements are described. The use and interaction of the recorder with the various elements in the facility are treated. The formulation of the requirements resulted in the selection of a tape transport modified for digital serial-in, serial-out operation. This selection followed a competitive procurement action.
This paper summarizes three remote sensing experiments in which changes in remotely measured reflected radiance patterns of vegetation correlated with changes in geology. In two cases using airborne spectroradiometer data, changes in the physical properties of a uniform species correlated with zones of porphyry copper mineralization. In another case using Landsat digital data, changes were detected in the distribution and density of a number of species and combined with soil brightness data to produce a composite index useful for distinguishing lithologies.
Summarized here are key advances in experimental techniques and theoretical applications which point the way to a broad understanding and control of turbomachinery noise. On the experimental side, the development of effective inflow control techniques makes it possible to conduct, in ground based facilities, definitive experiments in internally controlled blade row interactions. Results can now be valid indicators of flight behavior and can provide a firm base for comparison with analytical results. Inflow control coupled with detailed diagnostic tools such as blade pressure measurements can be used to uncover the more subtle mechanisms such as rotor strut interaction, which can set tone levels for some engine configurations. Initial mappings of rotor wake-vortex flow fields have provided a data base for a first generation semiempirical flow disturbance model. Laser velocimetry offers a nonintrusive method for validating and improving the model. Digital data systems and signal processing algorithms are bringing mode measurement closer to a working tool that can be frequently applied to a real machine such as a turbofan engine. On the analytical side, models of most of the links in the chain from turbomachine blade source to far field observation point have been formulated. Three dimensional lifting surface theory for blade rows, including source noncompactness and cascade effects, blade row transmission models incorporating mode and frequency scattering, and modal radiation calculations, including hybrid numerical-analytical approaches, are tools which await further application.
In support of investigations of mishaps like the crash of the space shuttle Columbia, a process based on digital reconstruction from recovered components has been developed. The process is expected to reduce the need for physical reconstruction from recovered parts, reduce the time and cost of determining the cause of a mishap, and provide information useful in redesigning to prevent future mishaps. The process involves utilization of pre-existing techniques, hardware, and software to capture sizes and shapes of recovered parts in sets of digital data. The data are manipulated to enable rendering of captured geometric information by use of computer-aided design (CAD) and viewing software. The digitization of a part and study of its spatial relationship with other parts is taken to one of three levels of successively greater detail, depending on its importance to the investigation. The process includes a trajectory-analysis subprocess in which information from the digital reconstruction is combined with locations of recovered parts to reduce the area that must be searched to find other specified parts that have not yet been recovered. The digital product of the process is compatible with preexisting CAD and solid-model-rendering software.
President Obama's Big Data Research and Development Initiative seeks to improve our ability to acquire knowledge and discover insights into large and complex collections of digital data. The Big Earth Data Initiative (BEDI) Invests in standardizing and optimizing the collection, management and delivery of U.S. Government's civil Earth observation data.
Humans will soon be returning to the surface of the Moon with NASA’s Artemis program. The Artemis program is an international collaboration that will consist of a complex series of space systems and missions to explore the lunar surface and pave the way for the future exploration of Mars. NASA and its partners rely heavily on simulation for lighting and navigation studies as well as training astronauts, flight controllers, and mission support staff. The NASA Exploration Systems Simulations (NExSyS) team in the Simulation and Graphics Branch (ER7) in the Engineering Directorate at NASA’s Johnson Space Center has built up many simulation products to support this effort, one of which is the Digital Lunar Exploration Sites (DLES). DLES is a collection of products used to simulate and render the lunar surface in a digital environment. We discussed and presented an overview of the DLES products at the 2022 IEEE Aerospace Conference in Big Sky, MT with a paper titled "Digital Lunar Exploration Sites". This “DLES Terrain Crafting” paper will expand on the information previously provided in “DLES” paper and dive deeper into the details of the terrain crafting process and the toolsets used to support this task. The best digital data currently available of the lunar surface is provided by the Lunar Reconnaissance Orbiter (LRO). Its Lunar Orbiter Laser Altimeter (LOLA) achieves an impressive resolution of 5m per pixel at the Lunar South Pole (LSP) and can generate datasets covering a large continuous region near the LSP. There are a few additional methods, such as Shape from Shading which can infer higher resolution data (up to 1m per pixel) from the LRO Narrow Angle Camera (NAC) images. However, surface-based simulations require higher-resolution data, and this paper will discuss the process of enhancing the terrain to meet that need. The process begins with capturing statistical data of craters in the regions of interest using images provided by the LRO NAC. This data is then used to scatter artificial features which are not captured in the truth data, resulting in an enhanced DEM with a much higher resolution of 20cm per pixel. Many tools were built up to assist in the creation of these artificial Digital Elevation Models (DEM), which this paper will discuss in detail. DEMs themselves are a very powerful representation of a planetary surface, and many operations and tools can utilize the data they contain. This paper includes a description of the rendering of the lunar surface in a graphics engine, generation of contact patches to simulate tire to ground interaction, and ray tracing utilities to model Line of Sight (LOS) interactions with the terrain. This paper will also explore some new tool sets currently under development which aim to utilize Machine Learning (ML) to assist in the identification of craters from LRO NAC imagery. While this is not a novel idea, the NExSyS team is developing a unique approach which may result in more robust identification of crater characteristics.
An objective method of assessing information workload based on physiological measurements was developed. Information workload, or reserve capacity, was measured using a visual discrimination secondary task and subjective rating of task difficulty. The primary task was two axis (pitch and roll) tracking, and the independent variables in this study were aircraft pitch dynamics and wind gust disturbances. The study was structured to provide: (1) a sensitive, nonloading measure of reserve capacity, and (2) an unencumbering reliable measurement of the psychophysiological state. From these, a measured workload index (MWI) and physiological workload index (PWI) were extracted. An important measure of the success of this study was the degree to which the MWI and PWI agreed across the 243 randomly-presented, four-minute trials (9 subjects X 9 tasks X 3 replications). The electrophysiological data collected included vectorcardiogaram, respiration, electromyogram, skin impedance, and electroencephalogram. Special computer programs were created for the analysis of each physiological variable. The digital data base then consisted of 82 physiological features for each of the 243 trials. A prediction of workload based on physiological observations was formulated as a simultaneous least-squares prediction problem. A best subset of 10 features was chosen to predict the three measures of reserve capacity. The cannonical correlation coefficient was .754 with a chi squared value of 91.3 which allows rejection of the null hypothesis with p of .995.
Systems encoding and decoding method allows data to be transmitted with less bandwidth than required for conventional system codes, and is not affected by data-transition density. In addition it requires no direct-current response of transition link and there is little ambiguity in resolution of digital data.
The need for high data rates from a variety of experiments on Spacelab/Shuttle produced the requirement for the Spacelab High Rate Multiplexer/Demultiplexer system. This system acquires serial digital data at asynchronous bit rates from up to sixteen experiments, two data buses, three voice links, two tape recorders, and a universal time channel. Experiment data rates may vary from 200 bps to 16 Mbps while recorded data rates range from 250 Kbps to 32 Mbps. The High Rate Multiplexer (HRM) accepts these data inputs and forms a serial PCM output at flexible rates up to 48 Mbps. This PCM output is transmitted to ground by a Ku-Band RF link via the Tracking and Data Relay Satellite System (TDRSS) or recorded on board for delayed transmission. A complementary ground based High Rate Demultiplexer (HRDM) accepts and demultiplexes the composite PCM data at ground processing locations.
Meteorological data and LANDSAT spectral data from growing regions in the U.S. Great Plains, the U.S.S.R., and Canada were used to assess growing conditions and to document where anomalies such as drought, floods, and freezes were impacting the crop yield and appearance of spring and winter wheat. In the United States, the weekly rainfall and temperature data were used to estimate soil moisture, which was then related to crop needs by a crop moisture index. The transformation of LANDSAT digital data into a green index number provided a procedure whereby data from a LACIE segment could be classified as drought affected or not. The growing seasons encountered in each LACIE country during the three phases are described.
A "quick look" investigation of the initial LANDSAT-4, thematic mapper (TM) scene received from Goddard Space Flight Center was performed to gain early insight into the characteristics of TM data. The initial scene, containing only the first four bands of the seven bands recorded by the TM, was acquired over the Detroit, Michigan, area on July 20, 1982. It yielded abundant information for scientific investigation. A wide variety of studies were conducted to assess all aspects of TM data. They ranged from manual analyses of image products to detect obvious optical, electronic, or mechanical defects to detailed machine analyses of the digital data content for evaluation of spectral separability of vegetative/nonvegetative classes. These studies were applied to several segments extracted from the full scene. No attempt was made to perform end-to-end statistical evaluations. However, the output of these studies do identify a degree of positive performance from the TM and its potential for advancing state-of-the-art crop inventory and condition assessment technology.
End user concerns about the content and accessibility of libraries of remote sensing data in general are addressed. Recommendations pertaining to the United States' satellite remote sensing programs urge: (1) the continuation of the NASA/EROS Data Center program to convert pre-1979 scenes to computer readable tapes and create a historical archive of this valuable data; (2) improving the EROS archive by adding geologically interesting scenes, data from other agencies (including previously classified data), and by adopting a policy to retire data from the archive; (3) establishing a computer data base inquiry system that includes remote sensing data from all publically available sources; (4) capability for prepurchase review and evaluation; (5) a flexible price structure; and (6) adoption of standard digital data products format. Information about LANDSAT 4, the status of worldwide LANDSAT receiving stations, future non-U.S. remote sensing satellites, a list of sources for LANDSAT data, and the results of a survey of GEOSAT members' remote sensing data processing systems are also considered.
This grant covers the initial data reduction and analysis of the magnetic field measurements of the Polar spacecraft. At this writing data for the first three years of the mission have been processed and deposited in the key parameter database. These data are also available in a variety of time resolutions and coordinate systems via a webserver at UCLA that provides both plots and digital data. The flight software has twice been reprogrammed: once to remove a glitch in the data where there were rare collisions between commands in the central processing unit and once to provide burst mode data at 100 samples per second on a regular basis. The instrument continues to function as described in the instrument paper (1.1 in the bibliography attached below). The early observations were compared with observations on the same field lines at lower altitude. The polar magnetic measurements also proved to be most useful for testing the accuracy of MHD models. WE also made important contributions to study of waves and turbulence.
The visible and reflected infrared channels of the NOAA-7 Advanced Very High Resolution Radiometer (AVHRR) are used for environmental monitoring, including agricultural crop assessment. An index consisting of a combination of digital data from these channels is used to screen the AVHRR data for cloud. The effects on spectral signature of sub-pixel sized cloud, which does not fill the entire IFOV of the instrument, are considered. It is shown that, for two different targets, for clear and turbid atmospheric conditions and for various scan angles, cloud which would not be detected during the screening process will cause substantial effects (up to a five-fold decrease) in the data.
In the near future, conventional radio communications, currently the primary medium for the transfer of information between aircraft and ground stations, will be replaced by digital data link. This paper briefly describes this technology and summarizes what are believed to be the principal human factor issues associated with data link implementation in the airspace system. Integration of data link communications with existing systems on the flight deck and in the Air Traffic Control system is discussed with regard for both near term implementation and longer term operational issues.