NASA COMMUNICATIONS SATELLITE DEVELOPMENTS
Nasa program survey in the field of communications satellites is presented, discussing syncom, echo, and relay satellite research
RELAY SATELLITE↗
SEARCH · Engineering Papers
Results for “ECHO PROJECT”
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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Communications satellite technology
Communications satellite technology - echo, relay, and syncom projects
ECHO PROJECT↗
Evolution of Web Services in EOSDIS: Search and Order Metadata Registry (ECHO)
During 2005 through 2008, NASA defined and implemented a major evolutionary change in it Earth Observing system Data and Information System (EOSDIS) to modernize its capabilities. This implementation was based on a vision for 2015 developed during 2005. The EOSDIS 2015 Vision emphasizes increased end-to-end data system efficiency and operability; increased data usability; improved support for end users; and decreased operations costs. One key feature of the Evolution plan was achieving higher operational maturity (ingest, reconciliation, search and order, performance, error handling) for the NASA s Earth Observing System Clearinghouse (ECHO). The ECHO system is an operational metadata registry through which the scientific community can easily discover and exchange NASA's Earth science data and services. ECHO contains metadata for 2,726 data collections comprising over 87 million individual data granules and 34 million browse images, consisting of NASA s EOSDIS Data Centers and the United States Geological Survey's Landsat Project holdings. ECHO is a middleware component based on a Service Oriented Architecture (SOA). The system is comprised of a set of infrastructure services that enable the fundamental SOA functions: publish, discover, and access Earth science resources. It also provides additional services such as user management, data access control, and order management. The ECHO system has a data registry and a services registry. The data registry enables organizations to publish EOS and other Earth-science related data holdings to a common metadata model. These holdings are described through metadata in terms of datasets (types of data) and granules (specific data items of those types). ECHO also supports browse images, which provide a visual representation of the data. The published metadata can be mapped to and from existing standards (e.g., FGDC, ISO 19115). With ECHO, users can find the metadata stored in the data registry and then access the data either directly online or through a brokered order to the data archive organization. ECHO stores metadata from a variety of science disciplines and domains, including Climate Variability and Change, Carbon Cycle and Ecosystems, Earth Surface and Interior, Atmospheric Composition, Weather, and Water and Energy Cycle. ECHO also has a services registry for community-developed search services and data services. ECHO provides a platform for the publication, discovery, understanding and access to NASA s Earth Observation resources (data, service and clients). In their native state, these data, service and client resources are not necessarily targeted for use beyond their original mission. However, with the proper interoperability mechanisms, users of these resources can expand their value, by accessing, combining and applying them in unforeseen ways.
Mitchell, Andrew↗
COMMUNICATIONS SATELLITE PROGRAM
Discussion of the nasa passive and active communications satellite programs
COMMUNICATIONS SATELLITE↗
Rocket research and test at the NACA/NASA Wallops Island flight test range 1945-1959
Established by the National Advisory Committee for Aeronautics (NACA) to function under the supervision of the Pilotless Aircraft Research Division (PARD) of the Langley Research Center, the Wallops Island flight test range began operations in 1945. Before the end of the decade, researchers at Wallops Island had developed two techniques for studying transonic problems - the free-falling body technique and the wing-flow technique - accomplishments which won NACA the needed funds to develop a guided missile for the Army Armed Forces. PARD kept abreast of developments in solid rocket motor technology and added new rockets to its inventory as they became available, and by 1955 Wallops Island programs encompassed sounding-rocket and spaceflight research. By 1959, after the Wallops range had become a NASA facility, it had played essential roles in the development of such satellite programs as Echo and Project Mercury.
Shortal, J. A.↗
Conceptual design of a quadrupole kicker and study of beam dynamics for generating echoes in IOTA
In this project we design dipole and quadrupole stripline kickers for echo generation in the IOTA ring. We developed a semi-analytic solver for dipole and quadrupole kickers with curved plates of innitesimal thickness, and independently validated it against a nite element software code (FEMM). The analytic series converges rapidly and is in agreement with FEMM within 5% everywhere except at the tips of the plates. We also consider nite thickness plates of dierent shapes (curved and parallel) and compare the central eld quality and characteristic impedance. We nd that in the dipole case, the parallel plates provide better eld quality than curved plates while in the quadrupole case, the dierence is not signicant. The characteristic impedance of relevant modes are computed. Matching the characteristic impedance to an external load is necessary to prevent unwanted re ection and ringing.
43 PARTICLE ACCELERATORS↗
Investigation of beam echo generation with electrons in the IOTA ring
This project investigates the possibility of echo generation with electrons in the IOTA ring. Through simulations the eects of dierent beam and ring parameters on echo amplitude and full width half max are tested. We nd that transverse coupling and delay time have signicant eects on echo generation and will have to be care- fully controlled in future experiments. Eect of decoherence time, quadrupole kick strength, quantum excitation, synchrotron damping, and momentum spread are also investigated. It is found that it is possible to produce echoes of signicant amplitude and full width half max in the IOTA ring despite the eects of synchrotron damp- ing. Relation and agreement of echoes produced with predictions of nonlinear theory of beam echoes is also investigated. Findings from this study can be used to inform future beam echo experiments at the IOTA ring.
43 PARTICLE ACCELERATORS↗
TH-E-17A-04: Geometric Validation of K-Space Self-Gated 4D-MRI Vs. 4D-CT Using A Respiratory Motion Phantom
Purpose: 4D-CT is often limited by motion artifacts, low temporal resolution, and poor phase-based target definition. We recently developed a novel k-space self-gated 4D-MRI technique with high spatial and temporal resolution. The goal here is to geometrically validate 4D-MRI using a MRI-CT compatible respiratory motion phantom and comparison to 4D-CT. Methods: 4D-MRI was acquired using 3T spoiled gradient echo-based 3D projection sequences. Respiratory phases were resolved using self-gated k-space lines as the motion surrogate. Images were reconstructed into 10 temporal bins with 1.56×1.56×1.56mm3. A MRI-CT compatible phantom was designed with a 23mm diameter ball target filled with highconcentration gadolinium(Gd) gel embedded in a 35×40×63mm3 plastic box stabilized with low-concentration Gd gel. The whole phantom was driven by an air pump. Human respiratory motion was mimicked using the controller from a commercial dynamic phantom (RSD). Four breathing settings (rates/depths: 10s/20mm, 6s/15mm, 4s/10mm, 3s/7mm) were scanned with 4D-MRI and 4D-CT (slice thickness 1.25mm). Motion ground-truth was obtained from input signals and real-time video recordings. Reconstructed images were imported into Eclipse(Varian) for target contouring. Volumes and target positions were compared with ground-truth. Initial human study was investigated on a liver patient. Results: 4D-MRI and 4D-CT scans for the different breathing cycles were reconstructed with 10 phases. Target volume in each phase was measured for both 4D-CT and 4D-MRI. Volume percentage difference for the 6.37ml target ranged from 6.67±5.33 to 11.63±5.57 for 4D-CT and from 1.47±0.52 to 2.12±1.60 for 4D-MRI. The Mann-Whitney U-test shows the 4D-MRI is significantly superior to 4D-CT (p=0.021) for phase-based target definition. Centroid motion error ranges were 1.35–1.25mm (4D-CT), and 0.31–0.12mm (4D-MRI). Conclusion: The k-space self-gated 4D-MRI we recently developed can accurately determine phase-based target volume while avoiding typical motion artifacts found in 4D-CT, and is being further studied for use in GI targeting and motion management. This work supported in part by grant 1R03CA173273-01.
60 APPLIED LIFE SCIENCES↗
Geometric validation of self-gating k-space-sorted 4D-MRI vs 4D-CT using a respiratory motion phantom
Purpose: MRI is increasingly being used for radiotherapy planning, simulation, and in-treatment-room motion monitoring. To provide more detailed temporal and spatial MR data for these tasks, we have recently developed a novel self-gated (SG) MRI technique with advantage of k-space phase sorting, high isotropic spatial resolution, and high temporal resolution. The current work describes the validation of this 4D-MRI technique using a MRI- and CT-compatible respiratory motion phantom and comparison to 4D-CT. Methods: The 4D-MRI sequence is based on a spoiled gradient echo-based 3D projection reconstruction sequence with self-gating for 4D-MRI at 3 T. Respiratory phase is resolved by using SG k-space lines as the motion surrogate. 4D-MRI images are reconstructed into ten temporal bins with spatial resolution 1.56 × 1.56 × 1.56 mm{sup 3}. A MRI-CT compatible phantom was designed to validate the performance of the 4D-MRI sequence and 4D-CT imaging. A spherical target (diameter 23 mm, volume 6.37 ml) filled with high-concentration gadolinium (Gd) gel is embedded into a plastic box (35 × 40 × 63 mm{sup 3}) and stabilized with low-concentration Gd gel. The phantom, driven by an air pump, is able to produce human-type breathing patterns between 4 and 30 respiratory cycles/min. 4D-CT of the phantom has been acquired in cine mode, and reconstructed into ten phases with slice thickness 1.25 mm. The 4D images sets were imported into a treatment planning software for target contouring. The geometrical accuracy of the 4D MRI and CT images has been quantified using target volume, flattening, and eccentricity. The target motion was measured by tracking the centroids of the spheres in each individual phase. Motion ground-truth was obtained from input signals and real-time video recordings. Results: The dynamic phantom has been operated in four respiratory rate (RR) settings, 6, 10, 15, and 20/min, and was scanned with 4D-MRI and 4D-CT. 4D-CT images have target-stretching, partial-missing, and other motion artifacts in various phases, whereas the 4D-MRI images are visually free of those artifacts. Volume percentage difference for the 6.37 ml target ranged from 5.3% ± 4.3% to 10.3% ± 5.9% for 4D-CT, and 1.47 ± 0.52 to 2.12 ± 1.60 for 4D-MRI. With an increase of respiratory rate, the target volumetric and geometric deviations increase for 4D-CT images while remaining stable for the 4D-MRI images. Target motion amplitude errors at different RRs were measured with a range of 0.66–1.25 mm for 4D-CT and 0.2–0.42 mm for 4D-MRI. The results of Mann–Whitney tests indicated that 4D-MRI significantly outperforms 4D-CT in phase-based target volumetric (p = 0.027) and geometric (p < 0.001) measures. Both modalities achieve equivalent accuracy in measuring motion amplitude (p = 0.828). Conclusions: The k-space self-gated 4D-MRI technique provides a robust method for accurately imaging phase-based target motion and geometry. Compared to 4D-CT, the current 4D-MRI technique demonstrates superior spatiotemporal resolution, and robust resistance to motion artifacts caused by fast target motion and irregular breathing patterns. The technique can be used extensively in abdominal targeting, motion gating, and toward implementing MRI-based adaptive radiotherapy.
60 APPLIED LIFE SCIENCES↗
Communications Satellite Program
Communications satellite program - echo, telstar, relay, and syncom projects
ECHO SATELLITE↗
Plasma Density and Radio Echoes in the Magnetosphere
This project provided a opportunity to study a variety of interesting topics related to radio sounding in the magnetosphere. The results of this study are reported in two papers which have been submitted for publication in the Journal of Geophysical Research and Radio Science, and various aspects of this study were also reported at meetings of the American Geophysical Union (AGU) at Baltimore, Maryland and the International Scientific Radio Union (URSI) at Boulder, Colorado. The major results of this study were also summarized during a one-day symposium on this topic sponsored by Marshall Space Flight Center in December 1994. The purpose of the study was to examine the density structure of the plasmasphere and determine the relevant mechanisms for producing radio echoes which can be detected by a radio sounder in the magnetosphere. Under this study we have examined density irregularities, biteouts, and outliers of the plasmasphere, studied focusing, specular reflection, ducting, and scattering by the density structures expected to occur in the magnetosphere, and predicted the echoes which can be detected by a magnetospheric radio sounder.
Calvert, W.↗
Modified Method for Reconstructing the Image from Projections in Magnetic Resonance Tomography
A method for reconstructing the image from projections in magnetic resonance tomography using an excitation pulse with a linear frequency modulation has been considered. The shape of the spin echo envelope coincides with the projection of the spin density onto the direction of the axis along which the magnetic field gradient is applied. The spin echo excitation by a sinc pulse and a pulse with a linear frequency modulation has been simulated. The former pulse excites the required cross section of a 3D object, while the latter pulse has made it possible to form the spin echo envelope, which coincides in shape with the projection of the spin density of nuclei onto the direction of the gradient. The set of the projections onto different directions of the gradient has made it possible to reconstruct the 2D image of a section.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
A modified ATI technique for nowcasting convective rain volumes over areas
This paper explores the applicability of the area-time-integral (ATI) technique for the estimation of the growth portion only of a convective storm (while the rain volume is computed using the entire life history of the event) and for nowcasting the total rain volume of a convective system at the stage of its maximum development. For these purposes, the ATIs were computed from the digital radar data (for 1981-1982) from the North Dakota Cloud Modification Project, using the maximum echo area (ATIA) no less than 25 dBz, the maximum reflectivity, and the maximum echo height as the end of the growth portion of the convective event. Linear regression analysis demonstrated that correlations between total rain volume or the maximum rain volume versus ATIA were the strongest. The uncertainties obtained were comparable to the uncertainties which typically occur in rain volume estimates obtained from radar data employing Z-R conversion followed by space and time integration. This demonstrates that the total rain volume of a storm can be nowcasted at its maximum stage of development.
Makarau, Amos↗
The Echoes of Earth Science
NASA s Earth Observing System Data and Information System (EOSDIS) acquires, archives, and manages data from all of NASA s Earth science satellites, for the benefit of the Space Agency and for the benefit of others, including local governments, first responders, the commercial remote sensing industry, teachers, museums, and the general public. EOSDIS is currently handling an extraordinary amount of NASA scientific data. To give an idea of the volume of information it receives, NASA s Terra Earth-observing satellite, just one of many NASA satellites sending down data, sends it hundreds of gigabytes a day, almost as much data as the Hubble Space Telescope acquires in an entire year, or about equal to the amount of information that could be found in hundreds of pickup trucks filled with books. To make EOSDIS data completely accessible to the Earth science community, NASA teamed up with private industry in 2000 to develop an Earth science "marketplace" registry that lets public users quickly drill down to the exact information they need. It also enables them to publish their research and resources alongside of NASA s research and resources. This registry is known as the Earth Observing System ClearingHOuse, or ECHO. The charter for this project focused on having an infrastructure completely independent from EOSDIS that would allow for more contributors and open up additional data access options. Accordingly, it is only fitting that the term ECHO is more than just an acronym; it represents the functionality of the system in that it can echo out and create interoperability among other systems, all while maturing with time as industry technologies and standards change and improve.
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COMMUNICATIONS SATELLITES NEWS RELEASE
Communication satellites - echo i, echo ii, score, courier, telstar, relay and syncom
TELSTAR SATELLITE↗
Ultrasonic Measurements of Temperature Profile and Heat Fluxes in Coal-Fired Power Plants (Final Report)
Many industrial processes are inaccessible or inhospitable to characterization by traditional temperature measurement methods, such as thermocouples, especially over prolonged exposure to harsh environments. Ultrasound is an established characterization technology with diverse applications ranging from medical imaging to therapies to flaw detection to nondestructive evaluation. Ultrasound may characterize solid materials and components noninvasively as a nondestructive evaluation modality and obtain internal measurements of material properties. For example, the speed of ultrasound propagation changes with Young’s modulus and Poisson’s ratio, which can be found from its measurements. Traditional ultrasonic characterization assumes all material properties remain constant with the position. When this assumption holds, a property of interest may be measured by relating it to the speed of ultrasound propagation (or a speed of sound, SOS) and measuring the SOS by timing the ultrasound propagation through a known distance. However, when a property of interest is spatially distributed, the propagation time depends on the SOS changing with the position along the ultrasound propagation path. The multiple temperature distributions may lead to an identical time of flight (TOF). Temperature is one property that impacts the speed of ultrasound and often cannot be assumed to remain constant with the position. Previously, in the context of temperature, we addressed the challenge of ultrasonic characterization of spatially distributed properties by developing a method for measuring segmental temperature distributions (MSTD). This method divides the ultrasonic propagation into segments bound by echogenic features. These features provide ultrasonic interfaces where some energy is reflected toward the receiving transducer, and the rest continues through the medium. The time-of-flight between the echoes reflected from echogenic features characterizes the spatial distribution in the properties of interest in the corresponding segment of the ultrasonic propagation path. This project demonstrated the application of the MSTD method in industrial conditions of the coal-fired power plant. We implemented the MSTD using metals and alloys waveguides, which may be the existing structure for which the temperature distribution is characterized or purposefully designed waveguides added to the structure by welding or other means specifically to quantify thermal properties using the MSTD method. Previous iterations of the MSTD method used ceramic and cementitious waveguides, which significantly attenuate ultrasound. On the other hand, low attenuation in metallic waveguides creates interactions between echogenic features which compilates the signal analysis in the segmental TOF measurements. We have established the WG design principles that minimize the interferences between trailing and primary echoes and, in some cases, eliminate them. The waveguides in which echoes do not interfere improve the timing accuracy and the robustness of ultrasonic measurements of the spatial distributions in material properties. Our emphasis remained on the estimation of the temperature distributions. We have developed general recommendations for designing ultrasonically segmented waveguides with the reduced influence of trailing echoes. Two of our waveguide designs were tested in the industry. The first waveguide was designed for insertion into a combustion zone of the utility-scale coal-fired power plant boiler. The second design allows the characterization of temperature distribution in the direction normal to the boiler’s water wall, a large heat exchanger converting the chemical energy released during combustion to the steam driving the electrical power generation turbines. These waveguides were designed to operate within a restrictive space of thermally insulated water wall and incorporate densely located echogenic features while combatting the influence of trailing echoes. The project has successfully demonstrated the feasibility of using the developed method for accurate, continuous, and robust temperature measurements in extreme environments of power generation and other industrial processes. It, therefore, has achieved its overarching goal of advancing the technology readiness level of the novel Ultrasound Measurements of Segmental Temperature Distribution (US-MSTD) method for real-time measurements of the temperature distribution and heat fluxes closer to commercial availability, developing a prototype multipoint measurement system, and validating its performance on coal-fired utility boilers. The success of this project was achieved in collaboration with the power generator, Rocky Mountain Power, and set the stage for the transfer of this technology from the laboratory to the industry.
01 COAL, LIGNITE, AND PEAT↗
Data Reproducibility of Spin-Echo Small-Angle Neutron Scattering Instruments
Spin-echo small-angle neutron scattering (SESANS) is a unique method to measure structures of materials in real space with length scales from ∼ 30 μm to ∼20 µm. As shown in Figure 1, the accessible length scale of SESANS is given by its ability to encode the momentum transfer into the Larmor phase, namely Φ = $\vec{𝛿}$ ⋅ $\vec{𝑄}$, where $\vec{𝑄}$ is the momentum transfer and $\vec{𝛿}$ is the encoding vector of the setup and its projection along Q (δQ) is called spin-echo length (SEL). The spin echo length, which is synonymous with the spatial correlation distance probed, is defined as the following 𝛿𝑄 ∝ 𝜆 2 𝐵𝐿cot𝜃 where 𝜆 is neutron wavelength, B is magnetic field, L is length of the parallelogram magnetic field region, and 𝜃 is the angle between the inclined magnetic field boundary and the beam direction, as shown in Figure 1. The result of the SESANS experiment is a Hankel transformation of the SANS scattering function I(Q), which yields the correlation function of the sample in real space.
47 OTHER INSTRUMENTATION↗
Twenty-Five Years of Progress. Part 1: Birth of NASA. Part 2: The Moon-A Goal
Historical footage (1958 - 1983) concerning NASA's Space Program, is reviewed in this two-part video. Host, Lynn Bondurant describes the birth of NASA and its accomplishments through the years. Part one contains: the launch of Russian satellite Sputnik on October 4,1957; the first dog (Soviet) in space; NACA Space Research, Explorer-6; and still photographs of various Space projects. Tiros 1 experimental weather satellite, Microgravity simulators, Echo 1 passive communications satellite, and the first U.S. manned spaceflight Mercury are included in part two. The seven Mercury astronauts are: Captain Donald Slayton, Lt. Commander Alan Shepard, Lt. Commander Walter Schirra, Captain Virgil Grissom, Lt. Col. John Glenn Jr., Captain Leroy Cooper Jr, and Lt. Malcolm Scott Carpenter. Also included are an ongoing interview (throughout the video) with NASA's first Administrator Keith Glennan, the first flight in 1961 with Enos, a chimpanzee, President Kennedy's speech in Washington about the Space Program, Project Gemini - the 2-manned space flights, and the recovery of Virgil Grissom from splash down.
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