The thermochemical net reaction CaCO3 + SO2 yields CaSO4 + CO is predicted to be an important sink for incorporation of SO2 into the Venus crust. The reaction rate law was established to understand the dependence of rate on experimental variables such as temperature and partial pressure of SO2, CO2, and O2. The experimental approach was a variant of the thermogravimetric method often employed to study the kinetics of thermochemical gas-solid reactions. Clear calcite crystals were heated at...
Topics: NASA Technical Reports Server (NTRS), CALCITE, CHEMICAL REACTIONS, PLANETARY CRUSTS, RATES (PER...
To identify the fastest algorithm currently available for the numerical integration of chemical kinetic rate equations, several algorithms were examined. Findings to date are summarized. The algorithms examined include two general-purpose codes EPISODE and LSODE and three special-purpose (for chemical kinetic calculations) codes CHEMEQ, CRK1D, and GCKP84. In addition, an explicit Runge-Kutta-Merson differential equation solver (IMSL Routine DASCRU) is used to illustrate the problems associated...
Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTATIONAL FLUID DYNAMICS, NUMERICAL...
Installed fibers such as those at the Kennedy Space Center (KSC) are optimized for use at 1310 nm because they have zero dispersion at that wavelength. An installed fiber system designed to operate at 1310 nm will operate at a much lower data rate when operated at 1550 nm because the dispersion is not zero at 1550 nm. Using dispersion measurements of both installed and dispersion compensating fibers, we compensated a 21.04 km length of installed fiber with 4.25 km of dispersion compensating...
Topics: NASA Technical Reports Server (NTRS), FIBER OPTICS, INSERTION LOSS, TRANSMISSION RATE...
A simulation of the TCP/IP protocol running on a CSMA/CD data link layer was described. The simulation was implemented using the simula language, and object oriented discrete event language. It allows the user to set the number of stations at run time, as well as some station parameters. Those parameters are the interrupt time and the dma transfer rate for each station. In addition, the user may configure the network at run time with stations of differing characteristics. Two types are...
Topics: NASA Technical Reports Server (NTRS), COMPUTERIZED SIMULATION, DATA LINKS, LOCAL AREA NETWORKS,...
An overview is given of a data base management system that can catalog and archive data at rates up to 50M bits/sec. Emphasis is on the laser disk system that is used for the archive. All key components in the system (3 Vax 11/780s, a SEL 32/2750, a high speed communication interface, and the optical disk) are interfaced to a 100M bits/sec 16-port fiber optic bus to achieve the high data rates. The basic data unit is an autonomous data packet. Each packet contains a primary and secondary header...
Topics: NASA Technical Reports Server (NTRS), DATA BASE MANAGEMENT SYSTEMS, DATA BASES, DATA STORAGE, FIBER...
This interim report describes the progress in the construction of a 220 Mbps Q=4 PPM optical communication system that uses a semiconductor laser as the optical transmitter and an avalanche photodiode (APD) as the photodetector. The transmitter electronics have been completed and contain both GaAs and ECL III IC's. The circuit was able to operate at a source binary data rate from 75 Mbps to 290 Mbps with pulse rise and fall times of 400 ps. The pulse shapes of the laser diode and the response...
Topics: NASA Technical Reports Server (NTRS), OPTICAL COMMUNICATION, PHOTODIODES, PHOTOMETERS, PULSED...
Friction and wear experiments conducted on polyimide films bonded to 440C stainless steel disks indicated that a wear transition (from high wear to low wear) accompanied the friction transition (from high friction to low friction). The transition was found to be atmosphere dependent as well as temperature dependent. Wear rate calculations indicated that at temperatures above the transition, wear could be up to 600 times less than at temperatures below the transition. Transfer to metallic riders...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC EFFECTS, LUBRICANTS, POLYIMIDES, POLYMERIC FILMS,...
A preliminary study was conducted to determine the dielectric properties of glass fabric reinforced composites as influenced by the reactions occurring during the preparation of crosslinked polyimides by the PMR process. The variables studied included: formulated molecular weight, staging temperature and time; rate of temperature increase to cure temperature; and cure temperature and time. The changes of capacitance and, particularly, of dissipation factor were found to be strongly dependent on...
Topics: NASA Technical Reports Server (NTRS), DIELECTRIC PROPERTIES, GLASS FIBER REINFORCED PLASTICS,...
A simple physical model is presented to describe some aspects of the sputtering of compound targets. In particular, expressions are developed for the partial sputtering yields for binary systems in terms of the elemental sputtering rates, the stoichiometric concentrations and surface binding energy. The partial yields depend non-linearly on the bulk target concentrations. Comparison of the theoretical predictions with the data on sputtering of PtSi, NiSi and Cu3Au indicates that the general...
Topics: NASA Technical Reports Server (NTRS), BINARY SYSTEMS (MATERIALS), SPUTTERING, BINDING ENERGY, GOLD,...
An array of small optical receivers is proposed as an alternative to a single large optical receiver for high-data-rate communications in NASA s Deep Space Network (DSN). Because the telescope for a single receiver capable of satisfying DSN requirements must be greater than 10 m in diameter, the design, building, and testing of the telescope would be very difficult and expensive. The proposed array would utilize commercially available telescopes of 1-m or smaller diameter and, therefore, could...
Topics: NASA Technical Reports Server (NTRS), OPTICAL COMMUNICATION, DEEP SPACE NETWORK, RECEIVERS, RATES...
This four part report evaluated the performance of high data rate transmission links using the ACTS satellite, and to provide a preparatory test framework for two of the space science applications that have been approved for tests and demonstrations as part of the overall ACTS program. The test plan will provide guidance and information necessary to find the optimal values of the transmission parameters and then apply these parameters to specific applications. The first part will focus on the...
Topics: NASA Technical Reports Server (NTRS), DATA TRANSFER (COMPUTERS), CLIMATE MODELS, TECHNOLOGY...
This article compares the downlink performance in a gross average sense between space and ground network support of low-Earth orbiters. The purpose is to assess what the demand for DSN support of future small, low-cost missions might be, if data storage for spacecraft becomes reliable enough and small enough to support the storage requirements needed to enable support only a fraction of the time. It is shown that the link advantage of the DSN over space reception in an average sense is enormous...
Topics: NASA Technical Reports Server (NTRS), DATA LINKS, DEEP SPACE NETWORK, DOWNLINKING, EARTH ORBITAL...
The activity of the Lyrid meteor stream is in most years fairly low with a visual rate at maximum (21-22 April) of 5-10 meteors per hour. Short bursts of very high Lyrid activity, with visual hourly rates of 100 or more, have sometimes been reported. These observations generally refer to faint visual meteors. The reported bursts of high activity have occurred in a very narrow interval of solar longitudes (deg 31.24 to 31.38 equinox 1950.0), while the recurrent or 'normal' maximum for bright...
Topics: NASA Technical Reports Server (NTRS), METEOROID SHOWERS, METEOROIDS, RATES (PER TIME), SOLAR...
The Cosmic Background Explorer (COBE) spacecraft will exhibit complex attitude motion consisting of a spin rate of approximately -0.8 revolution per minute (rpm) about the x-axis and simultaneous precession of the spin axis at a rate of one revolution per orbit (rpo) about the nearly perpendicular spacecraft-to-Sun vector. The effect of the combined spinning and precession is to make accurate attitude propagation difficult and the 1-degree (3 sigma) solution accuracy goal problematic. To...
Topics: NASA Technical Reports Server (NTRS), ATTITUDE (INCLINATION), COSMIC BACKGROUND EXPLORER SATELLITE,...
A large survey of galaxies in the CO (J=1-0) line is presented. Among different types of active galaxies, within the sample, the detection rate is found to be: Starbursts (15 percent), Liners (60 percent), Seyferts (30 percent). A look at the subsample that is located within 40 Mpc (Ho = 75 km s(-1) Mpc(-1) regarding local density of galaxies reveals no substantial difference between detections and non-detections.
Topics: NASA Technical Reports Server (NTRS), ACTIVE GALAXIES, BLACK HOLES (ASTRONOMY), CARBON MONOXIDE,...
A multiplexer/demultiplexer system has been developed to enable the transmission, over a single channel, of four data streams generated by a variety of sources at different (including variable) bit rates. In the original intended application, replicas of this multiplexer/demultiplexer system would be incorporated into the spacecraft-to-ground communication systems of the space shuttles. The multiplexer of each system would be installed in the spacecraft, where it would acquire and process data...
Topics: NASA Technical Reports Server (NTRS), MULTIPLEXING, BANDWIDTH, CHANNELS (DATA TRANSMISSION), DATA...
Imaging of falling objects is described. Multiple images of a falling object can be captured substantially simultaneously using multiple cameras located at multiple angles around the falling object. An epipolar geometry of the captured images can be determined. The images can be rectified to parallelize epipolar lines of the epipolar geometry. Correspondence points between the images can be identified. At least a portion of the falling object can be digitally reconstructed using the identified...
Topics: NASA Technical Reports Server (NTRS), IMAGING TECHNIQUES, HYDROMETEORS, WEATHER FORECASTING, RATES...
Work in identifying, developing, and analyzing techniques for measuring bulk recombination rates, and surface recombination velocities and rates in all regions of high-efficiency silicon solar cells is presented. The accuracy of the previously developed DC measurement system was improved by adding blocked interference filters. The system was further automated by writing software that completely samples the unkown solar cell regions with data of numerous recombination velocity and lifetime...
Topics: NASA Technical Reports Server (NTRS), MINORITY CARRIERS, RATES (PER TIME), RECOMBINATION REACTIONS,...
The Lewis Research Center is developing a series of microgravity combustion experiments for the Space Shuttle. The Solid Surface Combustion Experiment (SSCE) is the first to be completed. SSCE will study flame spreading over thermally thin fuels (ashless filter paper) under microgravity conditions. The flight hardware consists of a combustion chamber containing the sample and a computer which takes the data and controls the experiment. Experimental data will include gas-phase and solid-phase...
Topics: NASA Technical Reports Server (NTRS), COMBUSTION, FLAME PROPAGATION, MICROGRAVITY, SOLID SURFACES,...
The development of new space communications technologies by NASA has included both commercial applications and space science requirements. NASA's Systems Integration, Test and Evaluation (SITE) Space Communication System Simulator is a hardware based laboratory simulator for evaluating space communications technologies at the component, subsystem, system, and network level, geared toward high frequency, high data rate systems. The SITE facility is well-suited for evaluation of the new...
Topics: NASA Technical Reports Server (NTRS), COMMUNICATION NETWORKS, HIGH FREQUENCIES, SPACE...
Traditionally, satellites have performed the function of a simple repeater. Newer data distribution satellite architectures, however, require demodulation of many frequency division multiplexed uplink channels by a single demultiplexer/demodulator unit, baseband processing and routing of individual voice/data circuits, and remodulation into time division multiplexed (TDM) downlink carriers. The TRW MCDD (Multichannel Demultiplexer/Multirate Demodulator) operates on a 37.4 MHz composite input...
Topics: NASA Technical Reports Server (NTRS), DEMODULATION, DEMODULATORS, DOWNLINKING, FAST FOURIER...
One of the factors that influences the fidelity of an aircraft digital simulation is the sampling rate. As the sampling rate is increased, the calculated response of the discrete representation tends to coincide with the response of the corresponding continuous system. Because of computer limitations, however, the sampling rate cannot be increased indefinitely. Moreover, real-time simulation requirements demand that a finite sampling rate be adopted. In view of these restrictions, a study was...
Topics: NASA Technical Reports Server (NTRS), ACCURACY, DAMPING, DYNAMIC RESPONSE, EQUATIONS OF MOTION,...
The 1.24 second binary pulsar Her X-1, first observed in X-rays in 1971 by UHURU has now been seen as a sporadic gamma ray source from 1 TeV up to at least 500 TeV. In addition, reprocessed optical and infrared pulses are seen from the companion star HZ Herculis. Thus measurements of the Her X-1/HZ Herculis system span 15 decades in energy, rivaling both the Crab pulsar and Cygnus X-3 in this respect for a discrete galactic source.
Topics: NASA Technical Reports Server (NTRS), BINARY STARS, COSMIC RAY SHOWERS, GAMMA RAY BURSTS, INFRARED...
A 24 detector extensive air shower array is being operated at Ootacamund (2300 m altitude, 11.4 deg N latitude) in southern India for a study of arrival directions of showers of energies greater than 5 x 10 to the 13th power eV. Various configurations of the array of detectors have been used to estimate the accuracy in determination of arrival angle of showers with such an array. These studies show that it is possible to achieve an angular resolution of better than 2 deg with the Ooty array for...
Topics: NASA Technical Reports Server (NTRS), ANGULAR RESOLUTION, ARRAYS, CERENKOV RADIATION, COSMIC RAY...
Detection of air showers with primary energies above 10 to the 19th power eV with sufficient statistics is extremely important in an astrophysical aspect related to the Greisen cut off and the origin of such high energy cosmic rays. Recently, a method is proposed to observe such giant air showers by measuring the arrival time distributions of air-shower particles at large core distances with a mini array. Experiments to measure the arrival time distributions of muons were started in 1981 and...
Topics: NASA Technical Reports Server (NTRS), CORES, COSMIC RAY SHOWERS, ELECTRONS, MUONS, PARTICLE...
Laboratory experiments were done to determine the natural frequencies of the electromagnetic resonances of conducting bodies with attached wires. The bodies include two cylinders and an approximate scale model of the NASA F-106B aircraft. All are three feet in length. Time-domain waveforms of B-dot and D-dot were obtained from a sampling oscilloscope, and Prony analysis was used to extract the natural frequencies. This work is an extension of previous work, but smaller, more resistive wires...
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT HAZARDS, AIRCRAFT MODELS, CYLINDRICAL BODIES,...
The objective is to understand how surfaces outgas and how outgassed substances subsequently condense on other surfaces. Preliminary tests produced calculated mass losses that were found to be in reasonable agreement with mass losses determined by weighing the sample before and after testing on analytical balances. However, using test materials with various molecular properties showed characteristic variations in the ratios of calculated total mass loss to experimental loss. These variations...
Topics: NASA Technical Reports Server (NTRS), CONDENSING, CONTAMINATION, MOLECULES, OUTGASSING, SOLID...
Specimens of a cryogenic insulation, proposed for use on the space shuttle external tank, were tested in an arc tunnel over a range of heating rates, pressures, and enthalpies corresponding to the shuttle ascent environment. A regression analysis was used to correlate the test data. Correlation equations involving surface recession rate as a function of heating rate, pressure, and enthalpy were developed. These equations can be used to make total surface recession predictions for shuttle ascent...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC HEATING, CRYOGENIC EQUIPMENT, SURFACE REACTIONS,...
The High Data Rate Instrument Study was a joint effort between the Jet Propulsion Laboratory (JPL) and the Goddard Space Flight Center (GSFC). The objectives were to assess the characteristics of future high data rate Earth observing science instruments and then to assess the feasibility of developing data processing systems and communications systems required to meet those data rates. Instruments and technology were assessed for technology readiness dates of 2000, 2003, and 2006. The highest...
Topics: NASA Technical Reports Server (NTRS), RESEARCH, COMMUNICATION EQUIPMENT, DATA TRANSMISSION, ONBOARD...
The Real Time Vibration Monitoring System (RTVMS) is a 32-channel high speed vibration data acquisition and processing system developed at Marshall Space Flight Center (MSFC). It Delivers sample rates as high as 51,200 samples/second per channel and performs Fast Fourier Transform (FFT) processing via on-board digital signal processing (DSP) chips in a real-time format. Advanced engine health assessment is achieved by utilizing the vibration spectra to provide accurate sensor validation and...
Topics: NASA Technical Reports Server (NTRS), REAL TIME OPERATION, SPACE SHUTTLE MAIN ENGINE, ROCKET...
The photon-starved channel for optical communications from deep space requires the development of detector technology that can achieve photon-counting sensitivities with high bandwidth. In this article, a near-infrared enhanced photomultiplier tube (PMT) with a quantum e.ciency of 0.08 at a 1.06- m wavelength is characterized in the laboratory. A Polya distribution model is used to compute the probability distribution function of the emitted secondary photoelectrons from the PMT. The model is...
Topics: NASA Technical Reports Server (NTRS), OPTICAL COMMUNICATION, PULSE POSITION MODULATION,...
Compact, highly customizable digital receivers are being developed for the system described in 'Radar Interferometer for Topographic Mapping of Glaciers and Ice Sheets' (NPO-43962), NASA Tech Briefs, Vol. 31, No. 7 (August 2007), page 72. The receivers are required to operate in unison, sampling radar returns received by the antenna elements in a digital beam-forming (DBF) mode. The design of these receivers could also be adapted to commercial radar systems. At the time of reporting the...
Topics: NASA Technical Reports Server (NTRS), DIGITAL RADAR SYSTEMS, RADAR RECEIVERS, FIELD-PROGRAMMABLE...
An alternative to an optimal method of automated classification of signals modulated with M-ary phase-shift-keying (M-ary PSK or MPSK) has been derived. The alternative method is approximate, but it offers nearly optimal performance and entails much less complexity, which translates to much less computation time. Modulation classification is becoming increasingly important in radio-communication systems that utilize multiple data modulation schemes and include software-defined or...
Topics: NASA Technical Reports Server (NTRS), CARRIER FREQUENCIES, CLASSIFICATIONS, ERROR CORRECTING CODES,...
This study is concerned with the characteristics of storms exhibiting an abrupt temporal increase in the total lightning flash rate (i.e., lightning jump, LJ). An automated storm tracking method is used to identify storm "clusters" and total lightning activity from three different lightning detection systems over Oklahoma, northern Alabama and Washington, D.C. On average and for different employed thresholds, the clusters that encompass at least one LJ (LJ1) last longer, relate to...
Topics: NASA Technical Reports Server (NTRS), LIGHTNING, FLASH, RATES (PER TIME), LIGHT (VISIBLE...
A digital backend based on the ROACH board has been developed jointly by the National Radio Astronomy Observatory and MIT Haystack Observatory. The RDBE will have both Polyphase Filterbank and Digital Downconverter personalities. The initial configuration outputs sixteen 32-MHz channels, comprised of half the channels from the PFB processing of the two IF inputs, for use in the VLBI2010 geodetic system and in the VLBA sensitivity upgrade project. The output rate is 2x109 bits/second (1x10(exp...
Topics: NASA Technical Reports Server (NTRS), RADIO ASTRONOMY, DOWN-CONVERTERS, FIELD-PROGRAMMABLE GATE...
Visual meteor observations are carried out on a regular basis by many experienced observers worldwide, thus supplying information about activity of meteor showers. The limits of the method are determined by the accuracy of the detection of the meteor trail. This study shows that visual meteor observations provide reliable data for an observable hourly rate of greater than or equal to 3.
Topics: NASA Technical Reports Server (NTRS), METEOROID SHOWERS, SPACE OBSERVATIONS (FROM EARTH), VISUAL...
The Microelectronic Systems Branch (MSB) at Goddard Space Flight Center (GSFC) has developed a Spacecraft Data Simulator (SDS) to support the development, test, and verification of prototype and production Level Zero Processing (LZP) systems. Based on a disk array system, the SDS is capable of generating large test data sets up to 5 Gigabytes and outputting serial test data at rates up to 80 Mbps. The SDS supports data formats including NASA Communication (Nascom) blocks, Consultative Committee...
Topics: NASA Technical Reports Server (NTRS), DATA SYSTEMS, MICROELECTRONICS, NASCOM NETWORK, PACKETS...
Current operational capabilities of tape recording for Very Long Baseline Interferometry (VLBI) at the Haystack Observatory allow 0.7 terabytes (12 hours at 128 Mb/s) of data to be stored in a 128 cu. inch volume. On-going efforts are aimed at full time 1 Gb/s operation with two 36-channel headstacks. Applications for linear digital tape recording, with suitable development of thin-film head arrays, suggest a volume density exceeding 1 TB/cu. inch to be achievable in the future.
Topics: NASA Technical Reports Server (NTRS), DATA RECORDING, DATA STORAGE, DIGITAL SYSTEMS, RATES (PER...
The specific thermal capacity and heat dissipation rate for lithium ion cells containing LiNiO2 and mixed oxide (75%LiCoO2+ 25%LiNiO2) as cathode materials are compared. The experimental measurements were made using a radiative calorimeter consisting of a copper chamber maintained at -168 C by circulating liquid nitrogen and enclosed in a vacuum bell jar. The specific thermal capacity was determined based on warm-up and cool-down transients. The heat dissipation rate was calculated from the...
Topics: NASA Technical Reports Server (NTRS), LITHIUM, METAL IONS, THERMAL ANALYSIS, ELECTRIC BATTERIES,...
One of the goals of this program was to develop the experimental and analytical/computational tools required to predict the flow of non-Newtonian fluids through the various system components of a propulsion system: pipes, valves, pumps etc. To achieve this goal we selected to augment the capabilities of NASA's Generalized Fluid System Simulation Program (GFSSP) software. GFSSP is a general-purpose computer program designed to calculate steady state and transient pressure and flow distributions...
Topics: NASA Technical Reports Server (NTRS), FLOW DISTRIBUTION, COMPUTERIZED SIMULATION, RHEOLOGY,...
George Meade defeated Robert E. Lee, one of the greatest military leaders of all time. How did he do it? By using the skills he had learned as a project manager and outperforming Lee in all aspects of project management. Most project managers are familiar with the Project Management Institute's "Guide to the Project Management Body of Knowledge" (PMBOK), which identifies the skills and knowledge crucial to successful project management. Project managers need to make sure that all the...
Topics: NASA Technical Reports Server (NTRS), PROJECT MANAGEMENT, SCHEDULES, RISK, WARFARE, RATES (PER...
This slide presentation reviews the exploration of NASA using a Ka-band system for spacecraft communications in Near-Earth orbits. The reasons for changing to Ka-band are the higher data rates, and the current (X-band spectrum) is becoming crowded. This will require some modification to the current ground station antennas systems. The results of a Request for Information (RFI) are discussed, and the recommended solution is reviewed.
Topics: NASA Technical Reports Server (NTRS), EXTREMELY HIGH FREQUENCIES, SATELLITE COMMUNICATION, EARTH...
A three-channel data acquisition system was developed for the NASA Multi-Frequency Radar (MFR) system. The system is based on a commercial-off-the-shelf (COTS) industrial PC (personal computer) and two dual-channel 14-bit digital receiver cards. The decimated complex envelope representations of the three radar signals are passed to the host PC via the PCI bus, and then processed in parallel by multiple cores of the PC CPU (central processing unit). The innovation is this parallelization of the...
Topics: NASA Technical Reports Server (NTRS), RADAR RANGE, RADAR DATA, DATA ACQUISITION, PARALLEL...
The thermal performance of the solar collector field for the NASA Langley Solar Building Test Facility is given for October 1976 through January 1977. A 1,180 square meter solar collector field with seven collector designs helped to provide hot water for the building heating system and absorption air conditioner. The collectors were arranged in 12 rows with nominally 51 collectors per row. Heat transfer rates for each row were calculated and recorded along with sensor, insolation, and weather...
Topics: NASA Technical Reports Server (NTRS), AIR CONDITIONING, SOLAR COLLECTORS, SOLAR HEATING, BUILDINGS,...
In this innovation, the three-way combiner consists internally of two branch-line hybrids that are connected in series by a short length of waveguide. Each branch-line hybrid is designed to combine input signals that are in phase with an amplitude ratio of two. The combiner is constructed in an E-plane split-block arrangement and is precision machined from blocks of aluminum with standard WR-28 waveguide ports. The port impedances of the combiner are matched to that of a standard WR-28...
Topics: NASA Technical Reports Server (NTRS), SOLID STATE DEVICES, EXTREMELY HIGH FREQUENCIES, BROADBAND,...
With the recent explosion of the Internet and the enormous business opportunities available to communication system providers, great interest has developed in improving the efficiency of data transfer using the Transmission Control Protocol (TCP) of the Internet Protocol (IP) suite. The satellite system providers are interested in solving TCP efficiency problems associated with long delays and error-prone links. Similarly, the terrestrial community is interested in solving TCP problems over...
Topics: NASA Technical Reports Server (NTRS), ASYNCHRONOUS TRANSFER MODE, COMMUNICATION SATELLITES,...
Uplink antenna arrays have the potential to greatly increase the Deep Space Network s high-data-rate uplink capabilities as well as useful range, and to provide additional uplink signal power during critical spacecraft emergencies. While techniques for calibrating an array of receive antennas have been addressed previously, proven concepts for uplink array calibration have yet to be demonstrated. This article describes a method of utilizing the Moon as a natural far-field reflector for...
Topics: NASA Technical Reports Server (NTRS), ANTENNA ARRAYS, PHASED ARRAYS, FAR FIELDS, RADIO FREQUENCIES,...
In a proposed coding-and-modulation scheme, a high-rate binary data stream would be processed as follows: 1. The input bit stream would be demultiplexed into multiple bit streams. 2. The multiple bit streams would be processed simultaneously into a high-rate outer Hamming code that would comprise multiple short constituent Hamming codes a distinct constituent Hamming code for each stream. 3. The streams would be interleaved. The interleaver would have a block structure that would facilitate...
Topics: NASA Technical Reports Server (NTRS), ACCUMULATORS, PARALLEL PROCESSING (COMPUTERS), QUADRATURE...
The effect of pitch rate on abort landing caused by wind shear encounters is discussed. Optimal trajectories, airspeed, and wind shear warning systems are briefly discussed. The bulk of the presentation is in viewgraph form.
Topics: NASA Technical Reports Server (NTRS), AIRCRAFT INSTRUMENTS, AIRCRAFT MANEUVERS, PITCH...
The main objective has been the experimental verification of the corrosive vapor deposition theory in high-temperature, high-velocity environments. Towards this end a Mach 0.3 burner-rig appartus was built to measure deposition rates from salt-seeded (mostly Na salts) combustion gases on the internally cooled cylindrical collector. Deposition experiments are underway.
Topics: NASA Technical Reports Server (NTRS), BURNERS, COMBUSTION PRODUCTS, GAS TURBINE ENGINES, HOT...