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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 721 records · Page 40

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NASA NTRS1973

Apollo/Saturn 5 Postflight Trajectory - SA-513 Skylab 1 Mission. Tracking and Flight Reconstruction

The postflight trajectory for the Apollo/Saturn V SA-513 Skylab I flight is presented. An analysis is included of the orbital and powered flight trajectories of the launch vehicle, the orbital trajectory of the spent S-II stage, and the free flight impact trajectory of the expended S-IC stage. Launch vehicle trajectory dependent parameters are provided in earth-fixed launch site, launch vehicle navigation, and geographic polar coordinate systems. The time history of the trajectory parameters for the launch vehicle is presented from guidance reference release to the transfer to ATM control. Tables of significant launch vehicle parameters at engine cutoff, stage separation, and workshop orbit insertion are included. Figures of such parameters as altitude, surface and cross range, and the magnitude of total velocity and acceleration as a function of range time for the powered flight trajectory are given.

Source record↗

NASA NTRS1973

Apollo/Saturn 5 postflight trajectory: AS-512

The postflight trajectory is presented for the Apollo/Saturn V AS-512 flight. An analysis is included of the orbital and powered flight trajectories of the launch vehicle and the free flight trajectories of the expended S-IC and S-II stages. Trajectory dependent parameters are provided in earth-fixed launch site, launch vehicle navigation, and geographic polar coordinate systems. The time history of the trajectory parameters for the launch vehicle is presented from guidance reference release to Command Service Module (CSM) separation. Tables of significant parameters at engine cutoff, stage separation, parking orbit insertion, and translunar injection are included. Figures of such parameters as altitude, surface and cross range, and the magnitude of total velocity and acceleration as a function of range time for the powered flight trajectories are presented.

Pinson, G. T.↗

NASA NTRS1974

A multichannel EEG telemetry system utilizing a PCM subcarrier

A multichannel personal-type telemetry system is described that utilizes PCM encoding for the most effective range with minimum RF bandwidth and noise interference. Recent IC developments (COS MOS) make it possible to implement a sophisticated encoding system (PCM) within the low power and size constraints necessary for a personal biotelemetry system. This system includes low-level high-impedance preamplifiers to make the system suitable for EEG recording.

Fryer, T. B.↗

NASA NTRS1976

Rapid and precise measurement of flatband voltage

The paper outlines the design, principles of operation, and calibration of a five-IC network intended to give a rapid, precise, and automatic determination of the flatband voltage of MOS capacitors. The basic principle of measurement is to compare the analog output voltage of a capacitance meter - which is directly proportional to the capacitance being measured - with a preset or dialed-in voltage proportional to the calculated flatband capacitance by means of a comparator circuit. The bias to the MOS capacitor supplied through the capacitance meter is provided by a ramp voltage going from a negative toward a positive voltage level and vice versa. The network employs two monostable multivibrators for reading and recording the flatband voltage and for resetting the initial conditions and restarting the ramp. The flatband voltage can be held and read on a digital voltmeter.

Li, S. P.↗

NASA NTRS1976

CCD correlation techniques

Two CCD techniques were discussed for performing an N-point sampled data correlation between an input signal and an electronically programmable reference function. The design and experimental performance of an implementation of the direct time correlator utilizing two analog CCDs and MOS multipliers on a single IC were evaluated. The performance of a CCD implementation of the chirp z transform was described, and the design of a new CCD integrated circuit for performing correlation by multiplication in the frequency domain was presented. This chip provides a discrete Fourier transform (DFT) or inverse DFT, multipliers, and complete support circuitry for the CCD CZT. The two correlation techniques are compared.

Hewes, C. R.↗

NASA NTRS1975

Migratory gold resistive shorts - Chemical aspects of a failure mechanism

Integrated-circuit devices using the Ti/W/Au metal system are subject to failure mechanisms based on electrolytic corrosion. The migratory gold resistive short (MGRS) failure mode is one example of this mechanism and results in the formation of filamentary or dendritic deposits of gold between adjacent stripes on the IC chip. This reaction requires the presence of a sufficient amount of water, a bias voltage between adjacent stripes, and the activation of the cathodic (-) stripe. Gold ions are transported from anode to cathode through a film of moisture adsorbed on the surface of the chip; halide ions are probably involved in the transfer. Their presence is verified experimentally by X-ray photoelectron spectroscopy. Some of the chemical and electrostatic factors involved in the MGRS mechanism are discussed in this paper, including the questions of a threshold level of moisture and contamination.

Grunthaner, F. J.↗

NASA NTRS1977

Low-cost high-performance VLF receiver front-end

A VLF receiver front end has been designed using standard linear IC's. The basic methods have been evaluated extensively on the omega 10.2-kHz channel but are readily adaptable to any other VLF frequency in the 10.2-20 kHz region. Applications for the modules exist in position location, time-frequency measurements, and signal propagation. The set provides control gates, zero-crossing signals, and analog outputs to interface with any type of digital logic, microprocessor, or analog signal processor.

Burhans, R. W.↗

NASA NTRS1978

An inductively powered telemetry system for temperature, EKG, and activity monitoring

An implant telemetry system for the simultaneous monitoring of temperature, activity, and EKG from small animals, such as rats, was designed with the feature that instead of a battery the system is energized by an inductive field. A 250 kHz resonant coil surrounds the cage (30 x 30 x 20 cm) and provides the approximately 100 microns of power required to operate the implant transmitter while allowing the animal unrestrained movement in the cage. The implant can also be battery operated if desired. RF transmission is in the 8-10 MHz band, which allows the use of a simple, essentially single IC chip, receiver.

Fryer, T. B.↗

NASA NTRS1978

Far-infrared observations of H II regions in M33

Three H II regions in M33, namely, IC 133, NGC 595, and NGC 604, have been observed at far-infrared wavelengths. Only NGC 604, the strongest radio source of the three, was detected. The far-infrared radiation appears to be thermal emission from dust. The amount of dust known to be present in NGC 604 from comparison of optical and radio data is sufficient to account for the observed far-infrared emission. The total power radiated in the far-infrared is comparable to the total luminosity of the exciting stars of the H II region.

Gatley, I.↗

NASA NTRS1978

Tungsten in iron meteorites

Tungsten concentrations have been determined by instrumental neutron activation in 104 iron meteorites, and range from 0.07 to 5 microg/g. In individual groups, concentrations vary by factors of between 1.5 and 8, but there are negative W-Ni correlations in 8 groups: IAB, IC, IIAB, IID, IIE, IIIAB, IIICD, and IIIF. The lowest W concentrations are found in groups IAB and IIICD, which also have the smallest slopes on a W-Ni plot. Eighteen anomalous irons have W concentrations between 5 microg/g (Butler) and 0.11 microg/g (Rafrueti). The distribution of W in irons shows similarities to that of other refractory sideophilic elements (except Mo), but is closest to the distribution of Ru and Pt. Assuming that chemical trends in group IIIAB were produced by fractional crystallization, a value of 1.6 can be deduced for the distribution coefficient of W between solid and liquid metal, as compared with 0.89 for Mo. Experimental evidence in support of these values is tenuous.

Scott, E. R. D.↗

NASA NTRS1980

Bidirectional Manchester repeater

Bidirectional Manchester repeater is inserted at periodic intervals along single bidirectional twisted pair transmission line to detect, amplify, and transmit bidirectional Manchester 11 code signals. Requiring only 18 TTL 7400 series IC's, some line receivers and drivers, and handful of passive components, circuit is simple and relatively inexpensive to build.

Ferguson, J.↗

NASA NTRS1980

All-digital QPSK modulator

Circuit consisting to only four components (2 IC chips and 2 time delay devices) modulates RF signal with 2 asynchronous digital data signals. Digital modulator is virtually free of amplitude modulation, is not subject to temperature effects from other components, dissipates less power, and is far simpler than its analog predecessors.

Burgess, R. W.↗

NASA NTRS1979

Linear Approximation SAR Azimuth Processing Study

A segmented linear approximation of the quadratic phase function that is used to focus the synthetic antenna of a SAR was studied. Ideal focusing, using a quadratic varying phase focusing function during the time radar target histories are gathered, requires a large number of complex multiplications. These can be largely eliminated by using linear approximation techniques. The result is a reduced processor size and chip count relative to ideally focussed processing and a correspondingly increased feasibility for spaceworthy implementation. A preliminary design and sizing for a spaceworthy linear approximation SAR azimuth processor meeting requirements similar to those of the SEASAT-A SAR was developed. The study resulted in a design with approximately 1500 IC's, 1.2 cubic feet of volume, and 350 watts of power for a single look, 4000 range cell azimuth processor with 25 meters resolution.

Lindquist, R. B.↗

NASA NTRS1979

Electrical Characterization of the RCA CDP1822SD Random Access Memory, Volume 1, Appendix a

Electrical characteristization tests were performed on 35 RCA CDP1822SD, 256-by-4-bit, CMOS, random access memories. The tests included three functional tests, AC and DC parametric tests, a series of schmoo plots, rise/fall time screening, and a data retention test. All tests were performed on an automated IC test system with temperatures controlled by a thermal airstream unit. All the functional tests, the data retention test, and the AC and DC parametric tests were performed at ambient temperatures of 25 C, -20 C, -55 C, 85 C, and 125 C. The schmoo plots were performed at ambient temperatures of 25 C, -55 C, and 125 C. The data retention test was performed at 25 C. Five devices failed one or more functional tests and four of these devices failed to meet the expected limits of a number of AC parametric tests. Some of the schmoo plots indicated a small degree of interaction between parameters.

Klute, A.↗

NASA NTRS1979

A photometric determination of twists in three early-type galaxies

Detailed photometric data have been obtained for three early-type galaxies by using the Cerro Tololo 1.5-m telescope and an SEC television camera. The aim of this photometry is to gain further accurate information on the occurrence of twists in such galaxies; i.e., on any variations with radius of the position angle of the major axes of the isophotes. The results of the photometry are: (1) the finding of no detectable twist within the bulge of the S0 galaxy NGC 5102; (2) confirmation of a substantial twist (about 10 deg) in the inner portion of the E3 galaxy IC 1459; and (3) determination of a moderate twist (about 5 deg) within the E4 galaxy NGC 4697, possibly too small to have been previously detected. If such moderate twists should turn out to be common in elliptical galaxies, the suspicion of triaxiality for most such galaxies would be enhanced.

Williams, T. B.↗

NASA NTRS1977

The use of hybrid integrated circuit techniques in biotelemetry applications

A review is presented of some features of hybrid integrated circuits that make their use advantageous in miniature biotelemetry applications. The various techniques for fabricating resistors, capacitors and interconnections by both thin film and thick film technology are discussed. The use of chip capacitors, resistors, and especially standard IC chips on substrates with fired-on interconnection patterns is emphasized. The review is designed primarily to acquaint biotelemetry users and designers with an overview of this fabrication technique so that they can better communicate their needs with an understanding of its limitations and advantages to facilities specializing in hybrid construction.

Fryer, T. B.↗

NASA NTRS1978

Implementation of real-time digital signal processing systems

Special purpose hardware implementation of DFT Computers and digital filters is considered in the light of newly introduced algorithms and IC devices. Recent work by Winograd on high-speed convolution techniques for computing short length DFT's, has motivated the development of more efficient algorithms, compared to the FFT, for evaluating the transform of longer sequences. Among these, prime factor algorithms appear suitable for special purpose hardware implementations. Architectural considerations in designing DFT computers based on these algorithms are discussed. With the availability of monolithic multiplier-accumulators, a direct implementation of IIR and FIR filters, using random access memories in place of shift registers, appears attractive. The memory addressing scheme involved in such implementations is discussed. A simple counter set-up to address the data memory in the realization of FIR filters is also described. The combination of a set of simple filters (weighting network) and a DFT computer is shown to realize a bank of uniform bandpass filters. The usefulness of this concept in arriving at a modular design for a million channel spectrum analyzer, based on microprocessors, is discussed.

Narasimha, M.↗

NASA NTRS1979

Radiation hardened PMOS process with ion implanted threshold adjust

By including specific process modifications the effect of ion implantation on radiation hardness can be minimized and radiation hard ion implanted MOS circuits can be fabricated. The experimental procedure followed was to examine key processing steps (with respect to radiation hardness) on ion-implanted individual PMOS transistors. The individual transistors were evaluated by continuously monitoring the threshold voltage as the transistors were being irradiated. By comparing runs it was possible to deduce what is considered a radiation hard ion implanted process. Tests with a complex LSI PMOS IC processor chip containing over 2000 transistors and resistors were also conducted

Jhabvala, M.↗