Nuclear rocket know-how.
Nuclear rockets operating efficiency and flexibility, reliability, safety, hot high stress structures, nozzle cooling, etc
Gabriel, D.↗
SEARCH · Engineering Papers
Results for “Operational Reliability”
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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Precision calibration and reference voltage source for data acquisition systems
Hybrid integrated circuit operational amplifiers, which have inherent characteristics of low quiescent power dissipation and extended operational lifetime with high reliability, are source for digital systems. Amplifiers are coupled to Zener reference diode in current control and buffer configuration.
Source record↗
A traverse gravimeter for the lunar surface
A semi-automatic, self-levelling lunar gravimeter was designed for the purpose of measuring gravity at predetermined stops along the route of a lunar rover vehicle to obtain a gravity profile. The traverse gravimeter is completely self-contained and is powered by an internal battery. The gravity sensor is a vibrating string accelerometer (VSA) which is enclosed in a precision oven. Gravity data are obtained by initiating a measurement. After the gravimeter has levelled, the VSA difference frequency is counted down and a gate is generated to enable a crystal-controlled clock to a BCD counter. The BCD counter stores the data which are a measurement of gravity. These data, displayed upon command by the astronaut, are transmitted by voice back to earth. It is expected that the accuracy of the gravimeter will be better than one milligal. Low power, light weight, reliability, and simplicity of operation are major considerations in the design of the gravimeter.
Mamon, G.↗
A simple, accurate depth check guage
Easily made, pen-light battery operated production check gauge has probe-activated switch with fail-safe features to insure proper operation. Parts can be reliably and quickly checked. Gauge is equipped with tolerance band adjustment and can use interchangeable probes for different applications. Accompanying tester permits frequent check of calibration.
Rauch, E. P.↗
Single-channel digital command-detection system
System, fabricated of highly-reliable digital logic elements, operates on binary pulse-code-modulated signals and derives internal synchronization from data signal. All-digital implementation of detector develops synchronization from data signal by computer cross-correlation of command modulation signal with its expected forms in sequence and adjusts detector phases in accordance with correlation peaks.
Carl, C. C.↗
Monitoring physical and chemical parameters of Delaware Bay waters with an ERTS-1 data collection platform
The author has identified the following significant results. Evaluation of the probe performances during the initial phase indicates that the dissolved oxygen sensor available as part of the package is not sufficiently reliable for long term operation. The turbidity probe requires frequent visits to the site to maintain it in proper operating condition. The cost of these visits would have to be weighed against the information obtained. The conductivity/salinity, temperature, pH, and depth indicators have worked extremely well over the course of the study. Monthly cleanings would maintain all these probes in top operating condition. Currently the accuracy of each measurement returned via satellite is being compared to the accuracy of the probe reading and water samples analyzed in the laboratory.
Klemas, V.↗
Discussion and theoretical summarization of the experimental data
A summary of research on psychological factors that cause substantial changes in the reliability indicators of an operators work is followed by a conclusion that strong moral-volitional qualities are the basic factors that make the human behavior under conditions of stress effective; emotional subcortical subdominants affect a person's conscious organization and self control in a man machine environment.
Mileryan, Y. A.↗
Development of beam lead RF integrated circuits
This paper describes the design and development of a set of multifunction VHF/UHF integrated circuits aimed at providing a major improvement in spacecraft radio reliability through low stress operation and the processing of these circuits in beam-lead form. The methods evolved for the high frequency characterization of the devices are discussed together with the design of suitable test fixtures. Typical test results and the distribution of test parameters are presented. A unique carrier for beam-lead devices is described, and the need for such a device is discussed. The application of the carrier to device screening, burn-in and drift measurements is discussed together with the incentives for providing these capabilities. An overview of the integration of the devices into the spacecraft radio is given and candidate assembly processes are discussed. The technology impact of this approach upon future spacecraft radio systems is qualitatively examined.
Kline, A. J.↗
Design study of a 15 kW free-piston Stirling engine-linear alternator for dispersed solar electric power systems
A conceptual design of a free piston solar Stirling engine-linear alternator which can be designed and developed to meet the requirements of a near-term solar test bed engine with minimum risks was developed. The conceptual design was calculated to have an overall system efficiency of 38% and provide 15kW electric output. The free piston engine design incorporates features such as gas bearings, close clearance seals, and gas springs. This design is hermetically sealed to provide long life, reliability, and maintenance free operation. An implementation assessment study performed indicates that the free piston solar Stirling engine-linear alternator can be manufactured at a reasonable price cost (direct labor plus material) of $2,500 per engine in production quantities of 25,000 units per year. Opportunity for significant reduction of cost was also identified.
Dochat, G. R.↗
An 8 x 10 to the 5th bit bubble memory cell for spacecraft applications
A multiple chip magnetic bubble memory cell design developed for NASA embodies the low power, low weight, environmental tolerance and reliability necessary for successful operation in spacecraft launch and mission environments. Packaging of multiple chips in a common magnetic bias, drive coil assembly reduces weight and volume overhead per chip and also reduces the number of coil drive components required. This 8 x 10 to the 5th bit cell is conduction cooled and provides a metal and ceramic sealed hermetic chip environment.
Becker, F. J.↗
Aircraft maintenance. Citations from the International Aerospace Abstracts data base
These citations from the international literature concern various aspects of aircraft maintenance. Both military and civil aviation experience are included. Articles cited concern airline operations, engine and avionics reliability, the use of automatic test equipment, maintenance scheduling, and reliability engineering. This updated bibliography contains 347 citations, 85 of which are new additions to the previous edition.
Zollars, G. F.↗
Department of Defense meteorological and environmental inputs to aviation systems
Recommendations based on need, cost, and achievement of flight safety are offered, and the re-evaluation of weather parameters needed for safe landing operations that lead to reliable and consistent automated observation capabilities are considered.
Paul D. Try↗
Outline of the Mu radar
A middle and upper atmospheric radar system is described. The antenna array consists of 25 groups each of which consists of 19 crossed-Yagis with three elements; each antenna has semiconductor transmitter and receiver, called a module, and each group of 19 antennas works as an independent small radar steering its radar beam under the control of a microcomputer. Thus, the total system consists of 25 small radars of this kind, enabling one to do various sophisticated operations with the system. The system is controlled by two other computers, one for radar controlling (HP9835A) and the other for data taking and on-line analysis (VAX11/750). The computer-controlled system is simple in operation for users and reliable in observation. Very quick beam steering (as quick as in a msec) is also possible because of electronic phase-changing of each module output under control of the microcomputer which is further controlled by the radar controller.
Kato, S.↗
Positional repeatability measurements of stepper motors at cryogenic temperatures
For cryogenically-cooled infrared instruments and telescopes employed in space, reliable and predictable motor operations at 4 K in vacuum are in most cases necessary. For the Shuttle Infrared Telescope Facility (SIRTF), stepper motors may be employed in a number of applications. A test facility was designed and built for measuring stepper motor positional repeatability, in vacuum, over a temperature range from ambient to liquid helium temperature. Tests regarding positional repeatability were conducted at different motor speeds, directions of motor rotation, step sizes, and power conditions. In addition, tests were performed with respect to the ability of the motor to remain in a position with no power applied to the motor.
Pompea, S. M.↗
High frequency plasma generator for ion thrusters
The results of a program to experimentally develop two new types of plasma generators for 30 cm electrostatic argon ion thrusters are presented. The two plasma generating methods selected for this study were by radio frequency induction (RFI), operating at an input power frequency of 1 MHz, and by electron cyclotron heating (ECH) at an operating frequency of 5.0 GHz. Both of these generators utilize multiline cusp permanent magnet configurations for plasma confinement and beam profile optimization. The program goals were to develop a plasma generator possessing the characteristics of high electrical efficiency (low eV/ion) and simplicity of operation while maintaining the reliability and durability of the conventional hollow cathode plasma sources. The RFI plasma generator has achieved minimum discharge losses of 120 eV/ion while the ECH generator has obtained 145 eV/ion, assuming a 90% ion optical transparency of the electrostatic acceleration system. Details of experimental tests with a variety of magnet configurations are presented.
Goede, H.↗
Development of an unsteady aerodynamics model to improve correlation of computed blade stresses with test data
A reliable rotor aeroelastic analysis operational that correctly predicts the vibration levels for a helicopter is utilized to test various unsteady aerodynamics models with the objective of improving the correlation between test and theory. This analysis called Rotor Aeroelastic Vibration (RAVIB) computer program is based on a frequency domain forced response analysis which utilizes the transfer matrix techniques to model helicopter/rotor dynamic systems of varying degrees of complexity. The results for the AH-1G helicopter rotor were compared with the flight test data during high speed operation and they indicated a reasonably good correlation for the beamwise and chordwise blade bending moments, but for torsional moments the correlation was poor. As a result, a new aerodynamics model based on unstalled synthesized data derived from the large amplitude oscillating airfoil experiments was developed and tested.
Gangwani, S. T.↗
Plasma contactor performance characterization
The plasma contactor performance is outlined. Some performance objectives are given including expellant compatibility, high electron production capability, high ion production capability, high reliability for starting and operation, passive emission control, switchover capability between ion/electron emission, low ion and electron energies, low system mass, and low expellant consumption rate. The basic elements of the hollow cathode are shown along with key features of the plasma source.
Wilbur, P.↗
Unattended deep space station tracking station development: Monitor and control technology
The major developments leading to successful demonstration of fully unattended operation of a Deep Space Network (DSN) station (DSS 13) are reviewed. Unattended operation was demonstrated by reliably tracking, commanding, and delivering telemetry from the Pioneer 8 spacecraft. Transfer of automated monitor and control technology to DSN implementation is summarized, along with related accomplishments.
Foster, C.↗