Results for “integral experiment” — Page 55

NASA NTRS2016

Experimenting Galileo on Board the International Space Station

The SCaN Testbed is an advanced integrated communications system and laboratory facility installed on the International Space Station (ISS) in 2012. The testbed incorporates a set of new generation of Software Defined Radio (SDR) technologies intended to allow researchers to develop, test, and demonstrate new communications, networking, and navigation capabilities in the actual environment of space. Qascom, in cooperation with ESA and NASA, is designing a Software Defined Radio GalileoGPS Receiver capable to provide accurate positioning and timing to be installed on the ISS SCaN Testbed. The GalileoGPS waveform will be operated in the JPL SDR that is constituted by several hardware components that can be used for experimentations in L-Band and S-Band. The JPL SDR includes an L-Band Dorne Margolin antenna mounted onto a choke ring. The antenna is connected to a radio front end capable to provide one bit samples for the three GNSS frequencies (L1, L2 and L5) at 38 MHz, exploiting the subharmonic sampling. The baseband processing is then performed by an ATMEL AT697 processor (100 MIPS) and two Virtex 2 FPGAs. The JPL SDR supports the STRS (Space Telecommunications Radio System) that provides common waveform software interfaces, methods of instantiation, operation, and testing among different compliant hardware and software products. The standard foresees the development of applications that are modular, portable, reconfigurable, and reusable. The developed waveform uses the STRS infrastructure-provided application program interfaces (APIs) and services to load, verify, execute, change parameters, terminate, or unload an application. The project is divided in three main phases. 1)Design and Development of the GalileoGPS waveform for the SCaN Testbed starting from Qascom existing GNSS SDR receiver. The baseline design is limited to the implementation of the single frequency Galileo and GPS L1E1 receiver even if as part of the activity it will be to assess the feasibility of a dual frequency implementation (L1E1+L5E5a) in the same SDR platform.2)Qualification and test the GalileoGPS waveform using ground systems available at the NASA Glenn Research Center. Experimenters can have access to two SCaN Testbed ground based systems for development and verification: the Experimenter Development System (EDS) that is intended to provide initial opportunity for software testing and basic functional validation and the Ground Integration Unit (GIU) that is a high fidelity version of the SCaN Testbed flight system and is therefore used for more controlled final development testing and verification testing.3)Perform in-orbit validation and experimentation: The experimentation phase will consists on the collection of raw measurements (pseudorange, Carrier phase, CN0) in space, assessment on the quality of the measurements and the receiver performances in terms of signal acquisition, tracking, etc. Finally computation of positioning in space (Position, Velocity and time) and assessment of its performance.(Complete abstract in attached document).

GPS↗

NASA NTRS2016

Experimenting Galileo on Board the International Space Station

The SCaN Testbed is an advanced integrated communications system and laboratory facility installed on the International Space Station (ISS) in 2012. The testbed incorporates a set of new generation of Software Defined Radio (SDR) technologies intended to allow researchers to develop, test, and demonstrate new communications, networking, and navigation capabilities in the actual environment of space. Qascom, in cooperation with ESA and NASA, is designing a Software Defined Radio GalileoGPS Receiver capable to provide accurate positioning and timing to be installed on the ISS SCaN Testbed. The GalileoGPS waveform will be operated in the JPL SDR that is constituted by several hardware components that can be used for experimentations in L-Band and S-Band. The JPL SDR includes an L-Band Dorne Margolin antenna mounted onto a choke ring. The antenna is connected to a radio front end capable to provide one bit samples for the three GNSS frequencies (L1, L2 and L5) at 38 MHz, exploiting the subharmonic sampling. The baseband processing is then performed by an ATMEL AT697 processor (100 MIPS) and two Virtex 2 FPGAs. The JPL SDR supports the STRS (Space Telecommunications Radio System) that provides common waveform software interfaces, methods of instantiation, operation, and testing among different compliant hardware and software products. The standard foresees the development of applications that are modular, portable, reconfigurable, and reusable. The developed waveform uses the STRS infrastructure-provided application program interfaces (APIs) and services to load, verify, execute, change parameters, terminate, or unload an application. The project is divided in three main phases. 1)Design and Development of the GalileoGPS waveform for the SCaN Testbed starting from Qascom existing GNSS SDR receiver. The baseline design is limited to the implementation of the single frequency Galileo and GPS L1E1 receiver even if as part of the activity it will be to assess the feasibility of a dual frequency implementation (L1E1+L5E5a) in the same SDR platform.2)Qualification and test the GalileoGPS waveform using ground systems available at the NASA Glenn Research Center. Experimenters can have access to two SCaN Testbed ground based systems for development and verification: the Experimenter Development System (EDS) that is intended to provide initial opportunity for software testing and basic functional validation and the Ground Integration Unit (GIU) that is a high fidelity version of the SCaN Testbed flight system and is therefore used for more controlled final development testing and verification testing.3)Perform in-orbit validation and experimentation: The experimentation phase will consists on the collection of raw measurements (pseudorange, Carrier phase, CN0) in space, assessment on the quality of the measurements and the receiver performances in terms of signal acquisition, tracking, etc. Finally computation of positioning in space (Position, Velocity and time) and assessment of its performance.(Complete abstract in attached document).

Galileo↗

NASA NTRSDate not supplied

Computational Assessment of the Opening Mode Facesheet-to-Core Fracture Toughness of a Thin-Gage Facesheet Sandwich Structure

The single-cantilevered beam test (SCB) is currently being considered for standardization for measuring the opening mode fracture toughness of sandwich structures subjected to facesheet-to-core separation. At present, the Area method is considered the benchmark method for determining energy required to propagate the crack. This method is problematic since it requires periodic unloading and cannot be evaluated instantaneously. Therefore, a method is needed to accurately and instantaneously calculate opening mode fracture toughness. In previous work, SCB tests with thin-gauge facesheets were performed to compare the J-integral approach to data reduction methods including the Modified Beam Theory (MBT) and the Area method. Large deviations (over 10%) in the calculated fracture toughness were observed between the J-integral and MBT for large displacements. In this study, a simulated SCB experiment using a virtual crackclosure technique was performed to assess the previously observed discrepancies. The predicted load displacement response, the predicted angle at the load application point, and the predicted crack growth results are in good agreement (within 5%) with the corresponding experimental data. Using the predicted load and angles, the predicted J-integral is in good agreement (within 10%) with the experimentally obtained solution. Using the MBT approach, the previously observed deviations in the fracture toughness were determined to be associated with the empirical extrapolation procedure to estimate the crack-root rotation correction from nonlinear compliance curves. The nonlinear compliance is determined to be associated with large displacement effects observed within the predicted and experimental results.

Sandwich Composite↗

NASA NTRS2004

A 100 kW-Class Technology Demonstrator for Space Solar Power

A first step in the development of solar power from space is the flight demonstration of critical technologies. These fundamental technologies include efficient solar power collection and generation, power management and distribution, and thermal management. In addition, the integration and utilization of these technologies into a viable satellite bus could provide an energy-rich platform for a portfolio of payload experiments such as wireless power transmission (WPT). This paper presents the preliminary design of a concept for a 100 kW-class free-flying platform suitable for flight demonstration of technology experiments. Recent space solar power (SSP) studies by NASA have taken a stepping stones approach that lead to the gigawatt systems necessary to cost-effectively deliver power from space. These steps start with a 100 kW-class satellite, leading to a 500 kW and then a 1 MW-class platform. Later steps develop a 100 MW bus that could eventually lead to a 1-2 GW pilot plant for SSP. Our studies have shown that a modular approach is cost effective. Modular designs include individual laser-power-beaming satellites that fly in constellations or that are autonomously assembled into larger structures at geosynchronous orbit (GEO). Microwave power-beamed approaches are also modularized into large numbers of identical units of solar arrays, power converters, or supporting structures for arrays and microwave transmitting antennas. A cost-effective approach to launching these modular units is to use existing Earth-to-orbit (ETO) launch systems, in which the modules are dropped into low Earth orbit (LEO) and then the modules perform their own orbit transfer to GEO using expendable solar arrays to power solar electric thrusters. At GEO, the modules either rendezvous and are assembled robotically into larger platforms, or are deployed into constellations of identical laser power-beaming satellites. Since solar electric propulsion by the modules is cost-effective for both self-transport of the modules from LEO to GEO, and for on-orbit stationkeeping and repositioning capability during the satellite’s lifetime, this technology is also critical in technology development for SSP. The 100 kW-class technology demonstrator will utilize advanced solar power collection and generation technologies, power management and distribution, advanced thermal management, and solar electric propulsion. State-of-the-art solar concentrators, highly efficient multi-junction solar cells, integrated thermal management on the arrays, and innovative deployable structure design and packaging make the 100 kW satellite feasible for launch on one existing launch vehicle. Early SSP studies showed that a major percentage of the on-orbit mass for power-beaming satellites was from massive power converters at the solar arrays, at the bus, at the power transmitter, or at combinations of these locations. Higher voltage mays and power management and distribution (PMAD) systems reduce or eliminate the need for many of these massive power converters, and could enable direct-drive of high-voltage solar electric thrusters. Lightweight, highly efficient thermal management systems are a critical technology that must be developed and flown for SSP feasibility. Large amounts of power on satellites imply that large amounts of waste heat will need to be managed. In addition, several of the more innovative lightweight configurations proposed for SSP satellites take advantage of solar concentrators that are intractable without advanced thermal management technologies for the solar arrays. These thermal management systems include efficient interfaces with the WPT systems or other high-power technology experiments, lightweight deployable radiators that can be easily integrated into satellite buses, and efficient reliable thermal distribution systems that can pipe heat from the technology experiments to the radiators. In addition to demonstrating the integration and use of these mission-critical technologies, the 100 kw-class satellite will provide a large experiment deck for a portfolio of technology experiments. Current plans for this technology demonstrator allow 2000 kg of payload capability and up to 100 kW of power. The technology experiments could include one or more wireless power transmission demonstrations, either to the Earth’s surface or to a suitable space-based receiver. Technology experiments to quantify the on-orbit performance of critical technologies for SSP or space exploration are welcomed. In addition, the technology experiments provide an opportunity for international cooperation, to advance technology readiness levels of SSP technologies that require flight demonstration. This paper will present the preliminary design for a 100 kW solar-powered satellite and a variety of technology experiments that may be suitable for flight demonstration. In addition, a space-to-Earth-surface WPT experiment will be discussed.

Connie Carrington↗

NASA NTRS1995

Using an architectural approach to integrate heterogeneous, distributed software components

Many computer programs cannot be easily integrated because their components are distributed and heterogeneous, i.e., they are implemented in diverse programming languages, use different data representation formats, or their runtime environments are incompatible. In many cases, programs are integrated by modifying their components or interposing mechanisms that handle communication and conversion tasks. For example, remote procedure call (RPC) helps integrate heterogeneous, distributed programs. When configuring such programs, however, mechanisms like RPC must be used explicitly by software developers in order to integrate collections of diverse components. Each collection may require a unique integration solution. This paper describes improvements to the concepts of software packaging and some of our experiences in constructing complex software systems from a wide variety of components in different execution environments. Software packaging is a process that automatically determines how to integrate a diverse collection of computer programs based on the types of components involved and the capabilities of available translators and adapters in an environment. Software packaging provides a context that relates such mechanisms to software integration processes and reduces the cost of configuring applications whose components are distributed or implemented in different programming languages. Our software packaging tool subsumes traditional integration tools like UNIX make by providing a rule-based approach to software integration that is independent of execution environments.

Callahan, John R.↗

NASA NTRS2008

Integration Testing of Space Flight Systems

This paper discusses the benefits of conducting multi-system integration testing of space flight elements in lieu of merely shipping and shooting to the launch site and launching. "Ship and shoot" is a philosophy that proposes to transport flight elements directly from the factory to the launch site and begin the mission without further testing. Integration testing, relevant to validation testing in this context, is a risk mitigation effort that builds upon the individual element and system levels of qualification and acceptance tests, greatly improving the confidence of operations in space. The International Space Station Program (ISSP) experience is the focus of most discussions from a historical perspective, while proposed integration testing of the Constellation Program is also discussed. The latter will include Multi-Element Integration Testing (MElT) and Flight Element Integration Testing (FElT).

Sowards, Stephanie↗

NASA NTRS2016

Simulations & Measurements of Airframe Noise: A BANC Workshops Perspective

Airframe noise corresponds to the acoustic radiation due to turbulent flow in the vicinity of airframe components such as high-lift devices and landing gears. Since 2010, the American Institute of Aeronautics and Astronautics has organized an ongoing series of workshops devoted to Benchmark Problems for Airframe Noise Computations (BANC). The BANC workshops are aimed at enabling a systematic progress in the understanding and high-fidelity predictions of airframe noise via collaborative investigations that integrate computational fluid dynamics, computational aeroacoustics, and in depth measurements targeting a selected set of canonical yet realistic configurations that advance the current state-of-the-art in multiple respects. Unique features of the BANC Workshops include: intrinsically multi-disciplinary focus involving both fluid dynamics and aeroacoustics, holistic rather than predictive emphasis, concurrent, long term evolution of experiments and simulations with a powerful interplay between the two, and strongly integrative nature by virtue of multi-team, multi-facility, multiple-entry measurements. This paper illustrates these features in the context of the BANC problem categories and outlines some of the challenges involved and how they were addressed. A brief summary of the BANC effort, including its technical objectives, strategy, and selective outcomes thus far is also included.

Choudhari, Meelan↗

NASA NTRS1972

The influence of laser ranging on selenodetic control.

In this paper, a mathematical model is presented which can be used to perform an adjustment using laser distances to improve coordinates of points of the earth and on the moon. The observation equations are given and the orientation of the earth and the moon is defined in terms of three Eulerian angles. Parameters related to the orientation of the two bodies are the six initial conditions in each case, for the numerical integration of the three angles and their time derivatives. Numerical experiments were performed for the purpose of investigating the expected accuracies of the various parameters in the adjustment model under differing conditions. The results of the experiments indicate that the statistics for both the coordinates of points on earth and on the moon, and for the orientation parameters of the two bodies, are favorable.

Mueller, I. I.↗

NASA NTRS1972

Precision Pointing Control System (PPCS) system design and analysis

The precision pointing control system (PPCS) is an integrated system for precision attitude determination and orientation of gimbaled experiment platforms. The PPCS concept configures the system to perform orientation of up to six independent gimbaled experiment platforms to design goal accuracy of 0.001 degrees, and to operate in conjunction with a three-axis stabilized earth-oriented spacecraft in orbits ranging from low altitude (200-2500 n.m., sun synchronous) to 24 hour geosynchronous, with a design goal life of 3 to 5 years. The system comprises two complementary functions: (1) attitude determination where the attitude of a defined set of body-fixed reference axes is determined relative to a known set of reference axes fixed in inertial space; and (2) pointing control where gimbal orientation is controlled, open-loop (without use of payload error/feedback) with respect to a defined set of body-fixed reference axes to produce pointing to a desired target.

Frew, A. M.↗

NASA NTRS1975

Joint USAF/NASA hypersonic research aircraft study

A joint USAF/NASA study has developed a conceptual design for a new high-speed research airplane (X-24C) and identified candidate flight research experiments in the Mach 3 to 6 speed range. Four major categories of high priority research experiments are described as well as the X-24C design concept. The vehicle, a rocket-boosted, delta planform aircraft, is air launched from a B-52 and is capable of forty seconds of rocket cruise at Mach 6 with a research scramjet. Research provisions include a dedicated 10-foot long research experiments section, removable fins and strakes, and provisions for testing integrated airbreathing propulsion systems.

F. S. Kirkham↗

NASA NTRS1978

Studies of vorticity imbalance and stability, moisture budget, atmospheric energetics, and gradients of meteorological parameters during AVE 3

Four diagnostic studies of AVE 3. are presented. AVE 3 represents a high wind speed wintertime situation, while most AVE's analyzed previously represented springtime conditions with rather low wind speeds. The general areas of analysis include the examination of budgets of vorticity, moisture, kinetic energy, and potential energy and a synoptic and statistical study of the horizontal gradients of meteorological parameters. Conclusions are integrated with and compared to those obtained in previously analyzed experiments (mostly springtime weather situations) so as to establish a more definitive understanding of the structure and dynamics of the atmosphere under a wide range of synoptic conditions.

Scoggins, J. R.↗

NASA NTRS1981

Toward a space materials systems program

A program implementation model is presented which covers the early stages of space material processing and manufacturing. The model includes descriptions of major program elements, development and experiment requirements in space materials processing and manufacturing, and an integration of the model into NASA's long range plans as well as its evolution from present Materials Processing in Space plans.

Vontiesenhausen, G. F.↗

NASA NTRS1981

Microorganisms and biomolecules in space hard environment

Microorganisms and biomolecules exposed to space vacuum and to different intensities of selected wavelengths of solar ultraviolet radiation is studied. The influence of these factors, applied singly or simultaneously, on the integrity of microbial systems and biomolecules is measured. Specifically, this experiment will study in Bacillus subtilis spores (1) disturbances in subsequent germination, outgrowth, and colony formation; (2) photochemical reactions of the DNA and protein in vivo and in vitro and their role in biological injury; and (3) the efficiency of repair processes in these events.

Horneck, G.↗

NASA NTRS1981

Cosmic ray induced errors in I2L microprocessors and logic devices

Large-scale integrated (LSI) devices fabricated with integrated injection logic (I2L) were studied by both heavy ion experiments and device analysis to determine the upset threshold, the charge collection volumes and ultimately the probability for upset in the galactic cosmic ray spectrum. The devices studied, the SEP9900A, the SBP9989 and the P-Code generator were fabricated by Texas Instruments, Inc.

Price, W. E.↗

NASA NTRS1983

Computer analysis and ground testing of large space systems control strategies

High and low authority control integration; analytical studies, test model, disturbance rejection, LSS control, Toysat experiment, control hardware, slim beam test, plate experiments, and truss experimental results are presented.

Aubrun, J. N.↗

NASA NTRS1984

Prelaunch absolute radiometric calibration of LANDSAT-4 protoflight Thematic Mapper

Results are summarized and analyzed from several prelaunch tests with a 122 cm integrating sphere used as part of the absolute radiometric calibration experiments for the protoflight TM sensor carried on the LANDSAT-4 satellite. The calibration procedure is presented and the radiometric sensitivity of the TM is assessed. The internal calibrator and dynamic range after calibration are considered. Tables show dynamic range after ground processing, spectral radiance to digital number and digital number to spectral radiance values for TM bands 1, 2, 3, 4, 5, 7 and for channel 4 of band 6.

Barker, J. L.↗

NASA NTRS1984

A 406 MHz geostationary satellite SARSAT experiment

A 406 MHz SARSAT experiment using the GOES system to demonstrate the utility of integrating a near-instantaneous distress alerting capability achievable by the geostationary satellites with the location capability of the low altitude, near-polar orbiting satellite system is described. Tests include the evaluation of technical performance of a variety of maritime, aviation, and land-based SARSAT beacons under operational environment conditions as well as a demonstration of system effectiveness in pseudo real distress incident situations. The technical performance tests parallel the CCIR coordinated trials program conducted at L-band frequencies using the INMARSAT satellites. Tests, including schedules, are outlined.

Friedman, M. L.↗

NASA NTRS1985

Nuclear Science Symposium, 31st and Symposium on Nuclear Power Systems, 16th, Orlando, FL, October 31-November 2, 1984, Proceedings

Topics related to physics instrumentation are discussed, taking into account cryostat and electronic development associated with multidetector spectrometer systems, the influence of materials and counting-rate effects on He-3 neutron spectrometry, a data acquisition system for time-resolved muscle experiments, and a sensitive null detector for precise measurements of integral linearity. Other subjects explored are concerned with space instrumentation, computer applications, detectors, instrumentation for high energy physics, instrumentation for nuclear medicine, environmental monitoring and health physics instrumentation, nuclear safeguards and reactor instrumentation, and a 1984 symposium on nuclear power systems. Attention is given to the application of multiprocessors to scientific problems, a large-scale computer facility for computational aerodynamics, a single-board 32-bit computer for the Fastbus, the integration of detector arrays and readout electronics on a single chip, and three-dimensional Monte Carlo simulation of the electron avalanche in a proportional counter.

Biggerstaff, J. A.↗