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At least 37 records · Page 2

A versatile nondestructive evaluation imaging workstation

Ultrasonic C-scan and eddy current imaging systems are of the pointwise type evaluation systems that rely on a mechanical scanner to physically maneuver a probe relative to the specimen point by point in order to acquire data and generate images. Since the ultrasonic C-scan and eddy current imaging systems are based on the same mechanical scanning mechanisms, the two systems can be combined using the same PC platform with a common mechanical manipulation subsystem and integrated data acquisition software. Based on this concept, we have developed an IBM PC-based combined ultrasonic C-scan and eddy current imaging system. The system is modularized and provides capacity for future hardware and software expansions. Advantages associated with the combined system are: (1) eliminated duplication of the computer and mechanical hardware, (2) unified data acquisition, processing and storage software, (3) reduced setup time for repetitious ultrasonic and eddy current scans, and (4) improved system efficiency. The concept can be adapted to many engineering systems by integrating related PC-based instruments into one multipurpose workstation such as dispensing, machining, packaging, sorting, and other industrial applications.

Chern, E. James↗

Telemetry packetization for improved mission operations

The requirements for mission-operations data management will accelerate sharply when the Space Transportation System (i.e., Space Shuttle) becomes the primary vehicle for research from space. These demands can be satisfied most effectively by providing a higher-level source encoding function within the spaceborne vehicle. An Instrument Telemetry Packet (ITP) concept is described which represents an alternative to the conventional multiplexed telemetry frame approach for acquiring spaceborne instrument data. By providing excellent data-integrity protection at the source and a variable instrument bandwidth capability, this ITP concept represents a significant improvement over present data acquisition procedures. Realignments in the ground telemetry processing functions are described which are intended to take advantage of the ITP concept and to make the data management system more responsive to the scientific investigators.

Greene, E. P.↗

Airborne Imaging Spectrometer - An advanced concept instrument

The Airborne Imaging Spectrometer (AIS) is a multispectral infrared imaging instrument utilizing a 32- x 32-element mercury-cadmium-telluride detector array to achieve high spatial resolution. A novel optical design provides high spectral resolution, and, in conjunction with the 32-element spatial resolution, makes optimal use of the capabilities of the area array. The experiment requirements and the details of instrument design, implementation, and calibration are presented. The superior resolution, accuracy, and data acquisition rate of this sensor/instrument concept for reconnaissance and geophysical survey is detailed and plans for upgrading/improving the instrument and future applications of this design concept are discussed.

Labaw, C.↗

Some comments on particle image displacement velocimetry

Laser speckle velocimetry (LSV) or particle image displacement velocimetry, is introduced. This technique provides the simultaneous visualization of the two-dimensional streamline pattern in unsteady flows as well as the quantification of the velocity field over an entire plane. The advantage of this technique is that the velocity field can be measured over an entire plane of the flow field simultaneously, with accuracy and spatial resolution. From this the instantaneous vorticity field can be easily obtained. This constitutes a great asset for the study of a variety of flows that evolve stochastically in both space and time. The basic concept of LSV; methods of data acquisition and reduction, examples of its use, and parameters that affect its utilization are described.

Lourenco, L. M.↗

Characterization of slow and fast phase nystagmus

A current literature review of the analog and digital process of vestibular and optical kinetic nystagmus reveals little agreement in the methods used by various labs. The strategies for detection of saccade (fast phase velocity component of nystagmus) vary between labs, and most of the process have not been evaluated and validated with a standard database. A survey was made of major vestibular labs in the U.S. that perform computer analyses of vestibular and optokinetic reflexes to stimuli, and a baseline was established from which to standardize data acquisition and analysis programs. The concept of an Error Index was employed as the criterium for evaluating the performance of the vestibular analysis software programs. The performance criterium is based on the detection of saccades and is the average of the percentages of missed detections and false detections. Evaluation of the programs produced results for lateral gaze with saccadic amplitude of one, two, three, five, and ten degrees with various signal-to-noise ratios. In addition, results were obtained for sinusoidal pursuit of 0.05, 0.10, and 0.50 Hz with saccades from one to ten degrees at various signal-to-noise ratios. Selection of the best program was made from the performance in the lateral gaze with three degrees of saccadic amplitude and in the 0.10 Hz sinusoid with three degrees of saccadic amplitude.

Lessard, Charles S.↗

Information management system breadboard data acquisition and control system.

Description of a breadboard configuration of an advanced information management system based on requirements for high data rates and local and centralized computation for subsystems and experiments to be housed on a space station. The system is to contain a 10-megabit-per-second digital data bus, remote terminals with preprocessor capabilities, and a central multiprocessor. A concept definition is presented for the data acquisition and control system breadboard, and a detailed account is given of the operation of the bus control unit, the bus itself, and the remote acquisition and control unit. The data bus control unit is capable of operating under control of both its own test panel and the test processor. In either mode it is capable of both single- and multiple-message operation in that it can accept a block of data requests or update commands for transmission to the remote acquisition and control unit, which in turn is capable of three levels of data-handling complexity.

Mallary, W. E.↗

Advances in Engine Test Capabilities at the NASA Glenn Research Center's Propulsion Systems Laboratory

The Propulsion Systems Laboratory at the National Aeronautics and Space Administration (NASA) Glenn Research Center is one of the premier U.S. facilities for research on advanced aeropropulsion systems. The facility can simulate a wide range of altitude and Mach number conditions while supplying the aeropropulsion system with all the support services necessary to operate at those conditions. Test data are recorded on a combination of steady-state and highspeed data-acquisition systems. Recently a number of upgrades were made to the facility to meet demanding new requirements for the latest aeropropulsion concepts and to improve operational efficiency. Improvements were made to data-acquisition systems, facility and engine-control systems, test-condition simulation systems, video capture and display capabilities, and personnel training procedures. This paper discusses the facility s capabilities, recent upgrades, and planned future improvements.

Pachlhofer, Peter M.↗

Structural qualification of large spacecraft

Over the past twenty-five (25) years of the space program, the major challenge in the structural qualification of the primary structure has shifted from conducting a test that simulated the environment to accurately predicting the structural member loads in flight. Once the flight loads are avaliable, a number of different test methods are used to qualify the structure by subjecting it to the proper loads. The qualification challenge for future large spacecraft will be to adequately predict its dynamic characteristic in space to assure that it can be controlled to meet the mission objectives. A new test concept that may allow acquisition of modal data by ground tests for verification of mathematical models of large flexible space structures which can't be ground tested by conventional methods is discussed.

Wada, Ben K.↗

Optimal spectral windows for microwave diversity imaging

Tomographic microwave diversity imaging is analyzed using linear system theory concepts, and optimal spectral windows for data acquisition are obtained either by considering window position in the spectral domain or by using simulated annealing to find an optimal phase weighting of the object frequency response samples collected over the specified spectral window. This study provides a means of microwave image formation that is applicable under general assumptions. Results of numerical simulations and representative images reconstructed from realistic experimental microwave scattering data are given, demonstrating that the proposed approach is superior to previous image reconstruction methods.

Farhat, Nabil H.↗

MODIS information, data and control system (MIDACS) operations concepts

The MODIS Information, Data, and Control System (MIDACS) Operations Concepts Document provides a basis for the mutual understanding between the users and the designers of the MIDACS, including the requirements, operating environment, external interfaces, and development plan. In defining the concepts and scope of the system, how the MIDACS will operate as an element of the Earth Observing System (EOS) within the EosDIS environment is described. This version follows an earlier release of a preliminary draft version. The individual operations concepts for planning and scheduling, control and monitoring, data acquisition and processing, calibration and validation, data archive and distribution, and user access do not yet fully represent the requirements of the data system needed to achieve the scientific objectives of the MODIS instruments and science teams. The teams are not yet formed; however, it is possible to develop the operations concepts based on the present concept of EosDIS, the level 1 and level 2 Functional Requirements Documents, and through interviews and meetings with key members of the scientific community. The operations concepts were exercised through the application of representative scenarios.

Han, D.↗

The Data Acquisition and Control Systems of the Jet Noise Laboratory at the NASA Langley Research Center

The features of the data acquisition and control systems of the NASA Langley Research Center's Jet Noise Laboratory are presented. The Jet Noise Laboratory is a facility that simulates realistic mixed flow turbofan jet engine nozzle exhaust systems in simulated flight. The system is capable of acquiring data for a complete take-off assessment of noise and nozzle performance. This paper describes the development of an integrated system to control and measure the behavior of model jet nozzles featuring dual independent high pressure combusting air streams with wind tunnel flow. The acquisition and control system is capable of simultaneous measurement of forces, moments, static and dynamic model pressures and temperatures, and jet noise. The design concepts for the coordination of the control computers and multiple data acquisition computers and instruments are discussed. The control system design and implementation are explained, describing the features, equipment, and the experiences of using a primarily Personal Computer based system. Areas for future development are examined.

Jansen, B. J., Jr.↗

Influence Network: Network visualization of influence between stories for Earth Science data and information exploration

Using storytelling to present data has been demonstrated as an effective way to help data users gain deeper insight of information. For this purpose, the “Data in Action” story concept has been adopted by NASA Commercial Smallsat Data Acquisition (CSDA) Program to encourage creating and sharing data information in story form. To aid researchers in exploring similar stories and data in their fields of interest, we created an “Influence Network” within the “Data in Action” framework. The Influence Network is a data visualization system component which gathers information of story relationships using a concept called “influence,” which we define based on the number of visits and keyword similarity between stories. The visualization then provides insights into the influence flows between different stories within the system. The visualization of this “Influence Network” focuses on one story at a time, introducing a time series of neighbor stories that have the most influence to the currently focused story. By focusing on views over time and visualizing influence flows between stories, we aim to assist authors in understanding how their readers perceive their stories as well as advancing their methods for delivering more meaningful stories to expand and lower the barrier to use of CSDA datasets.

Dan Pham↗

Attempt of automated space network operations at ETS-VI experimental data relay system

National Space Development Agency of Japan (NASDA) is to perform experimental operations to acquire necessary technology for the future inter-satellite communications configured with a data relay satellite. This paper intends to overview functions of the experimental ground system which NASDA has developed for the Engineering Test Satellite VI (ETS-VI) Data Relay and Tracking Experiment, and to introduce Space Network System Operations Procedure (SNSOP) method with an example of Ka-band Single Access (KSA) acquisition sequence. To reduce operational load, SNSOP is developed with the concept of automated control and monitor of both ground terminal and data relay satellite. To perform acquisition and tracking operations fluently, the information exchange with user spacecraft controllers is automated by SNSOP functions.

Ishihara, Kiyoomi↗

Integration of NASA Research into Undergraduate Education in Math, Science, Engineering and Technology at North Carolina A&T State University

The NASA PAIR program incorporated the NASA-Sponsored research into the undergraduate environment at North Carolina Agricultural and Technical State University. This program is designed to significantly improve undergraduate education in the areas of mathematics, science, engineering, and technology (MSET) by directly benefiting from the experiences of NASA field centers, affiliated industrial partners and academic institutions. The three basic goals of the program were enhancing core courses in MSET curriculum, upgrading core-engineering laboratories to compliment upgraded MSET curriculum, and conduct research training for undergraduates in MSET disciplines through a sophomore shadow program and through Research Experience for Undergraduates (REU) programs. Since the inception of the program nine courses have been modified to include NASA related topics and research. These courses have impacted over 900 students in the first three years of the program. The Electrical Engineering circuit's lab is completely re-equipped to include Computer controlled and data acquisition equipment. The Physics lab is upgraded to implement better sensory data acquisition to enhance students understanding of course concepts. In addition a new instrumentation laboratory in the department of Mechanical Engineering is developed. Research training for A&T students was conducted through four different programs: Apprentice program, Developers program, Sophomore Shadow program and Independent Research program. These programs provided opportunities for an average of forty students per semester.

Monroe, Joseph↗

Development Status of the CECE Cryogenic Deep Throttling Demonstrator Engine

As one of the first technology development programs awarded by NASA under the U.S. Space Exploration Policy (USSEP), the Pratt & Whitney Rocketdyne (PWR) Deep Throttling, Common Extensible Cryogenic Engine (CECE) program was selected by NASA in November 2004 to begin technology development and demonstration toward a deep throttling, cryogenic engine supporting ongoing trade studies for NASA's Lunar Lander descent stage. The CECE program leverages the maturity and previous investment of a flight-proven hydrogen/oxygen expander cycle engine, the PWR RLI0, to develop and demonstrate an unprecedented combination of reliability, safety, durability, throttlability, and restart capabilities in a high-energy, cryogenic engine. The testbed selected for the deep throttling demonstration phases of this program was a minimally modified RL10 engine, allowing for maximum current production engine commonality and extensibility with minimum program cost. Two series of demonstrator engine tests, the first in April-May 2006 and the second in March-April 2007, have demonstrated in excess of 10:1 throttling of the hydrogen/oxygen expander cycle engine. Both test series have explored a combustion instability ("chug") environment at low throttled power levels. These tests have provided an early demonstration of an enabling cryogenic propulsion concept with invaluable system-level technology data acquisition toward design and development risk mitigation for future CECE Demonstrator engine tests.

Source record↗

CECE: A Deep Throttling Demonstrator Cryogenic Engine for NASA's Lunar Lander

As one of the first technology development programs awarded under NASA's Vision for Space Exploration, the Pratt & Whitney Rocketdyne (PWR) Deep Throttling, Common Extensible Cryogenic Engine (CECE) program was selected by NASA in November 2004 to begin technology development and demonstration toward a deep throttling, cryogenic Lunar Lander engine for use across multiple human and robotic lunar exploration mission segments with extensibility to Mars. The CECE program leverages the maturity and previous investment of a flight-proven hydrogen/oxygen expander cycle engine, the RL10, to develop and demonstrate an unprecedented combination of reliability, safety, durability, throttlability, and restart capabilities in a high-energy, cryogenic engine. NASA Marshall Space Flight Center and NASA Glenn Research Center personnel were integral design and analysis team members throughout the requirements assessment, propellant studies and the deep throttling demonstrator elements of the program. The testbed selected for the initial deep throttling demonstration phase of this program was a minimally modified RL10 engine, allowing for maximum current production engine commonality and extensibility with minimum program cost. In just nine months from technical program start, CECE Demonstrator No. 1 engine testing in April/May 2006 at PWR's E06 test stand successfully demonstrated in excess of 10:1 throttling of the hydrogen/oxygen expander cycle engine. This test provided an early demonstration of a viable, enabling cryogenic propulsion concept with invaluable system-level technology data acquisition toward design and development risk mitigation for both the subsequent CECE Demonstrator No. 2 program and to the future Lunar Lander Design, Development, Test and Evaluation effort.

Giuliano, Victor J.↗

CECE: Expanding the Envelope of Deep Throttling Technology in Liquid Oxygen/Liquid Hydrogen Rocket Engines for NASA Exploration Missions

As one of the first technology development programs awarded by NASA under the Vision for Space Exploration, the Pratt & Whitney Rocketdyne (PWR) Deep Throttling, Common Extensible Cryogenic Engine (CECE) program was selected by NASA in November 2004 to begin technology development and demonstration toward a deep throttling, cryogenic engine supporting ongoing trade studies for NASA s Lunar Lander descent stage. The CECE program leverages the maturity and previous investment of a flight-proven hydrogen/oxygen expander cycle engine, the PWR RL10, to develop and demonstrate an unprecedented combination of reliability, safety, durability, throttlability, and restart capabilities in high-energy, cryogenic, in-space propulsion. The testbed selected for the deep throttling demonstration phases of this program was a minimally modified RL10 engine, allowing for maximum current production engine commonality and extensibility with minimum program cost. Four series of demonstrator engine tests have been successfully completed between April 2006 and April 2010, accumulating 7,436 seconds of hot fire time over 47 separate tests. While the first two test series explored low power combustion (chug) and system instabilities, the third test series investigated and was ultimately successful in demonstrating several mitigating technologies for these instabilities and achieved a stable throttling ratio of 13:1. The fourth test series significantly expanded the engine s operability envelope by successfully demonstrating a closed-loop control system and extensive transient modeling to enable lower power engine starting, faster throttle ramp rates, and mission-specific ignition testing. The final hot fire test demonstrated a chug-free, minimum power level of 5.9%, corresponding to an overall 17.6:1 throttling ratio achieved. In total, these tests have provided an early technology demonstration of an enabling cryogenic propulsion concept with invaluable system-level technology data acquisition toward design and development risk mitigation for future lander descent main engines.

Giuliano, Victor J.↗

Planning for large construction projects in space

The paper discusses briefly some broad plans for developing the technology needed for large construction projects in space ranging from orbiting solar power stations to large communications antennas. Space construction classes include assembly of modules, deployment of compacted structures, assembly of passive preformed pieces, and fabrication of structures from sheet stock. Technological areas related to structural concepts include (1) analyses for prediction of structural behavior, structural/control interaction, electromagnetic and control performance, and integrated design development; (2) electronics for signal conditioning and data acquisition, power distribution, and signal channel interference and multipaction; (3) concepts for shape control, attitude/pointing control, and orbital transfer and station keeping; and (4) materials and techniques for 30-year dimensional stable composites, thermal control, thin-lightweight structural alloys, and material joining in space. The concept of a power module for the construction operations is discussed along with a concept for a habitability module.

Disher, J. H.↗