Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “operator”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,279 records · Page 71
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Mission operations for Astronomy Spacelab Payloads

An overview is provided of mission operations for Astronomy Spacelab Payloads. Missions considered are related to solar physics, high energy astrophysics, and stellar ultraviolet/optical astronomy. Operational aspects are examined. Mission operations include the flight activities and associated ground support work for implementing the mission. The prelaunch activity will begin about a year before launch with the assignment of a mission operations manager.

Osler, S. J.↗
NASA NTRS1977

The operational processing of wind estimates from cloud motions: Past, present and future

Current NESS winds operations provide approximately 1800 high quality wind estimates per day to about twenty domestic and foreign users. This marked improvement in NESS winds operations was the result of computer techniques development which began in 1969 to streamline and improve operational procedures. In addition, the launch of the SMS-1 satellite in 1974, the first in the second generation of geostationary spacecraft, provided an improved source of visible and infrared scanner data for the extraction of wind estimates. Currently, operational winds processing at NESS is accomplished by the automated and manual analyses of infrared data from two geostationary spacecraft. This system uses data from SMS-2 and GOES-1 to produce wind estimates valid for 00Z, 12Z and 18Z synoptic times.

Novak, C.↗
NASA NTRS1977

ERDA/NASA 100 kilowatt mod-o wind turbine operations and performance

The ERDA/NASA 100 kW Mod-0 wind turbine is operating at the NASA Plum Brook Station near Sandusky, Ohio. The operation of the wind turbine has been fully demonstrated and includes start-up, synchronization to the utility network, blade pitch control for control of power and speed, and shut-down. Also, fully automatic operation has been demonstrated by use of a remote control panel, 50 miles from the site, similar to what a utility dispatcher might use. The operation systems and experience with the wind turbine loads, electrical power and aerodynamic performance obtained from testing are described.

Thomas, R. L.↗
NASA NTRS1978

On Nth roots of positive operators

A bounded operator A on a Hilbert space H was positive. These operators were symmetric, and as such constitute a natural generalization of nonnegative real diagonal matrices. The following result is thus both well known and not surprising: A positive operator has a unique positive square root (under operator composition).

Brown, D. R.↗
NASA NTRS1978

Economic evaluation of DSS 13 unattended operations demonstration

The goals and data collection requirements to be used for the economic and performance evaluation indexes and life cycle cost parameters for the upcoming operations demonstration of an automated Deep Space Station (DSS) run unattended and controlled remotely from JPL are presented. These evaluation indexes compare the remote operation of telemetry at DSS 13 with the cost and performance of a comparable manned operation at DSS 11. A description is presented of the data that needs to be collected, how the data will be analyzed, and what can and cannot be learned from this operations demonstration.

Remer, D. S.↗
NASA NTRS1978

Operations of the ATS-6 ion engine and plasma bridge neutralizer at geosynchronous altitude

The ion engine on ATS-6 has been operated in daylight and eclipse. The effect on particle fluxes to the spacecraft was monitored. This data provides information on the potential of the spacecraft with respect to the ambient plasma and the local electric fields caused by the charge distribution on the spacecraft. Operation of the ion engine and/or the neutralizer clamps the spacecraft within a few volts of the ambient plasma potential. Operation of only the neutralizer tends to reduce the differential charge on the satellite, whereas operation of the ion engine reduces it below the sensitivity limit of the detectors.

Olsen, R. C.↗
NASA NTRS1978

Satellite Power Systems (SPS) concept definition study. Volume 5: Transportation and operations analysis

The development of transportation systems to support the operations required for the orbital assembly of a 5-gigawatt satellite is discussed as well as the construction of a ground receiving antenna (rectenna). Topics covered include heavy lift launch vehicle configurations for Earth-to LEO transport; the use of chemical, nuclear, and electric orbit transfer vehicles for LEO to GEO operations; personnel transport systems; ground operations; end-to-end analysis of the construction, operation, and maintenance of the satellite and rectenna; propellant production and storage; and payload packaging.

Hanley, G.↗
NASA NTRS1978

Combined monitoring, decision and control model for the human operator in a command and control desk

A report is given on the ongoing efforts to mode the human operator in the context of the task during the enroute/return phases in the ground based control of multiple flights of remotely piloted vehicles (RPV). The approach employed here uses models that have their analytical bases in control theory and in statistical estimation and decision theory. In particular, it draws heavily on the modes and the concepts of the optimal control model (OCM) of the human operator. The OCM is being extended into a combined monitoring, decision, and control model (DEMON) of the human operator by infusing decision theoretic notions that make it suitable for application to problems in which human control actions are infrequent and in which monitoring and decision-making are the operator's main activities. Some results obtained with a specialized version of DEMON for the RPV control problem are included.

Muralidharan, R.↗
NASA NTRS1978

Human operator identification model and related computer programs

Four computer programs which provide computational assistance in the analysis of man/machine systems are reported. The programs are: (1) Modified Transfer Function Program (TF); (2) Time Varying Response Program (TVSR); (3) Optimal Simulation Program (TVOPT); and (4) Linear Identification Program (SCIDNT). The TV program converts the time domain state variable system representative to frequency domain transfer function system representation. The TVSR program computes time histories of the input/output responses of the human operator model. The TVOPT program is an optimal simulation program and is similar to TVSR in that it produces time histories of system states associated with an operator in the loop system. The differences between the two programs are presented. The SCIDNT program is an open loop identification code which operates on the simulated data from TVOPT (or TVSR) or real operator data from motion simulators.

Kessler, K. M.↗
NASA NTRS1979

Pilot interministerial operation for remote sensing

Advantages and disadvantages of traditional methods of obtaining required information for land and resources management and the possibilities of remote sensing are discussed. The services available, organization and objectives of the pilot operation are presented. Emphasis is placed on multidisciplinary dialog among designers, builders, operators, interpreters and users in all phases. The principles, operation and practical applications of remote sensing systems and processing systems under the pilot operation are presented.

Delamare, J. M.↗
NASA NTRS1979

General aviation IFR operational problems

Operational problems of general aviation IFR operators (particularly single pilot operators) were studied. Several statistical bases were assembled and utilized to identify the more serious problems and to demonstrate their magnitude. These bases include official activity projections, historical accident data and delay data, among others. The GA operating environment and cockpit environment were analyzed in detail. Solutions proposed for each of the problem areas identified are based on direct consideration of currently planned enhancements to the ATC system, and on a realistic assessment of the present and future limitations of general aviation avionics. A coordinated set of research program is suggested which would provide the developments necessary to implement the proposed solutions.

Bolz, E. H.↗
NASA NTRS1979

Optical devices for proximity operations study and test report

Operational and physical requirements were investigated for a low-light-level viewing device to be used as a window-mounted optical sight for crew use in the pointing, navigating, stationkeeping, and docking of space vehicles to support space station operations and the assembly of large structures in space. A suitable prototype, obtained from a commercial vendor, was subjected to limited tests to determine the potential effectiveness of a proximity optical device in spacecraft operations. The constructional features of the device are discussed as well as concepts for its use. Tests results show that a proximity optical device is capable of performing low-light-level viewing services and will enhance manned spacecraft operations.

Smith, R. A.↗
NASA NTRS1979

Satellite communications for disaster relief operations

The use of existing and planned communication satellite systems to provide assistance in the implementation of disaster relief operations on a global basis was discussed along with satellite communications system implications and their potential impact on field operations in disaster situations. Consideration are given to the utilization of both INTELSAT and MARISAT systems operating at frequencies ranging from 1.5 to 4 GHz and to the size and type of ground terminals necessary for satellite access. Estimates of communication requirements for a global system are given. Some discussion of cost estimates for satellite services to support operations are included. Studies of communication satellites for both pre and post disaster applications conducted for NOAA are included as well as recent experiments conducted in conjunction with the Office of Foreign Disaster Assistance of the Agency for International Development.

Sivo, J. N.↗
NASA NTRS1977

A life cycle cost economics model for automation projects with uniformly varying operating costs

The described mathematical model calculates life-cycle costs for projects with operating costs increasing or decreasing linearly with time. The cost factors involved in the life-cycle cost are considered, and the errors resulting from the assumption of constant rather than uniformly varying operating costs are examined. Parameters in the study range from 2 to 30 years, for project life; 0 to 15% per year, for interest rate; and 5 to 90% of the initial operating cost, for the operating cost gradient. A numerical example is presented.

Remer, D. S.↗
NASA NTRS1980

Improved PFB operations: 400-hour turbine test results

A pressurized fluidized bed (PFB) coal-burning reactor was used to provide hot effluent gases for operation of a small gas turbine. Preliminary tests determined the optimum operating conditions that would result in minimum bed particle carryover in the combustion gases. Solids were removed from the gases before they could be transported into the test turbine by use of a modified two stage cyclone separator. Design changes and refined operation procedures resulted in a significant decrease in particle carryover, from 2800 to 93 ppm (1.5 to 0.05 grains/std cu ft), with minimal drop in gas temperature and pressure. The achievement of stable burn conditions and low solids loadings made possible a 400 hr test of small superalloy rotor, 15 cm (6 in.) in diameter, operating in the effluent. Blades removed and examined metallographically after 200 hr exhibited accelerated oxidation over most of the blade surface, with subsurface alumina penetration to 20 micron m. After 400 hours, average erosion loss was about 25 micron m (1 mil). Sulfide particles, indicating hot corrosion, were present in depletion zones, and their presence corresponded in general to the areas of adherent solids deposit. Sulfidation appears to be a materials problem equal in importance to erosion.

Rollbuhler, R. J.↗
NASA NTRS1979

The University of Colorado OSO-8 spectrometer experiment. IV - Mission operations

The remote operation of two high-resolution ultraviolet spectrometers on the OSO-8 satellite is discussed. Mission operations enabled scientific observers to plan observations based on current solar data, interact with the observing program using real- or near real-time data and commands, evaluate quick-look instrument data, and analyze the observations for publication. During routine operations, experiments were planned a day prior to their execution, and the data from these experiments received a day later. When a shorter turnaround was required, a real-time mode was available. Here, the real-time data and command links into the remote control center were used to evaluate experiment operation and make satellite pointing or instrument configuration changes with a 1-90 minute turnaround.

Hansen, E. R.↗
NASA NTRS1980

A long-life bipropellant system demonstration: Viking Orbiter Propulsion System - 4 years in space and operating

On April 23, 1980, Viking Orbiter One (VO-1), operating in the blowdown mode, completed a ten second Mars orbit trim maneuver to position the spacecraft for its final science sequence in May-June 1980. This brought the number of propulsive maneuvers for VO-1 to 23. Total accumulated operating time for the rocket engine was 2896 seconds, representing a total impulse of 3.93 x 10 to the 6th N-sec. The estimated propellant remaining was sufficient to operate the rocket engine for an additional 30 seconds. VO-1 has completed more than 1700 days in space, 1400 days in orbit around Mars and more than two years of attitude control system operation with helium gas transferred from the propulsion system pressurant tank. The mass of helium remaining is expected to be sufficient for attitude control through June 1980. This paper presents the flight history of the Viking 75 Orbiter Propulsion Systems and summarizes the design and test philosophy which have contributed to their success.

Schmit, D. D.↗
NASA NTRS1980

Redundant operation of counter modules

A technique for the redundant operation of counter modules is described. Redundant operation is maintained by detecting the zero state of each counter and clearing the other to that state, thus periodically resynchronizing the counters, and obtaining an output from both counters through AC coupled diode-OR gates. Redundant operation of counter flip flops is maintained in a similar manner, and synchronous operation of redundant squarewave clock generators of the feedback type is effected by connecting together the feedback inputs of the squarewave generators through a coupling resistor, and obtaining an output from both generators through AC coupled diode-OR gates.

Nagano, S.↗