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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 1,279 records · Page 71
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

IMF orientation, solar wind velocity, and Pc 3-4 signals - A joint distribution

Separate studies using the same micropulsation data base in the period range 10-150 s have shown earlier that signal levels recorded during September, October, and November 1969 at Calgary correlated positively with both solar-wind alignment of the IMF and solar-wind speed, but each correlation contained enough scatter to allow for the influence of the other factor. In this report, joint correlations of velocity and field direction with parameters representing hourly distributions rather than minima of IMF orientation angle display the relative effect of the two agents on magnetic pulsation signal levels. The joint correlations reduce the overall scatter and show that solar-wind speeds above 200-300 km/s and angles between the IMF and the sun-earth line of less than 50-60 deg are associated with enlarged magnetic pulsation amplitudes. These threshold effects tend to support both the bow-shock origin and the Kelvin-Helmholtz amplification of daytime signal transients in the Pc 3, 4 period ranges.

Greenstadt, E. W.↗
NASA NTRS1979

Crystallography of decahedral and icosahedral particles. II - High symmetry orientations

Based on the exact crystal structure of decahedral and icosahedral particles, high energy electron diffraction patterns and image profiles have been derived for various high symmetry orientations of the particles with respect to the incident beam. These results form a basis for the identification of small metal particle structures with advanced methods of transmission electron microscopy.

Yang, C. Y.↗
NASA NTRS1979

On the effective use of lunar ranging for the determination of the earth's orientation

The history of the lunar laser ranging technique is reviewed, and some of the reasons that have limited the acquisition of basic data are examined. Limitations and advantages of using lunar laser ranging for the determination of earth's orientation are discussed. A set of goals is proposed which addresses the role this type of data will play in conjunction with other available techniques.

Silverberg, E. C.↗
NASA NTRS1979

Evaluation criteria for commercially oriented materials processing in space proposals

An approach and criteria for evaluating NASA funded experiments and demonstrations which have commercial potential were developed. Methods for insuring quick initial screening of commercial proposals are presented. Recommendations are given for modifying the current evaluation approach. New criteria for evaluating commercially orientated materials processing in space (MPS) proposals are introduced. The process for selection of qualified individuals to evaluate the phases of this approach and criteria is considered and guidelines are set for its implementation.

Moore, W. F.↗
NASA NTRS1980

Line-oriented flight training

Some of the concepts related to a line-oriented flight training program are discussed. The need to shift from training in manipulative skills to something closer to management skills is emphasized. The program is evaluated in terms of its realistic approaches which include the simulator's optimized motion and visual capabilities. The value of standard operating procedures as they affect the line pilot in everyday operations are also illustrated.

Beach, B. E.↗
NASA NTRS1980

The dynamics and control of large flexible space structures, 3. Part A: Shape and orientation control of a platform in orbit using point actuators

The dynamics, attitude, and shape control of a large thin flexible square platform in orbit are studied. Attitude and shape control are assumed to result from actuators placed perpendicular to the main surface and one edge and their effect on the rigid body and elastic modes is modelled to first order. The equations of motion are linearized about three different nominal orientations: (1) the platform following the local vertical with its major surface perpendicular to the orbital plane; (2) the platform following the local horizontal with its major surface normal to the local vertical; and (3) the platform following the local vertical with its major surface perpendicular to the orbit normal. The stability of the uncontrolled system is investigated analytically. Once controllability is established for a set of actuator locations, control law development is based on decoupling, pole placement, and linear optimal control theory. Frequencies and elastic modal shape functions are obtained using a finite element computer algorithm, two different approximate analytical methods, and the results of the three methods compared.

Bainum, P. M.↗
NASA NTRS1980

Potentialities of lunar laser range - Differencing for measuring the earth's orientation

An investigation of range differences for their capabilities in determining the orientation of the earth in an earth-moon reference system is presented. Each pair of two coobserving stations forms an observational unit which is preferably located along a meridian or parallel; for a time interval from the instant of the first simultaneous observation of the most eastern line to the last observation of the most western line, a variance analysis shows that the pole position and the earth rotation can be computed independently of errors in the adopted lunar ephemeris. It is concluded that if the stations are within 10 to 15 deg in north-south or east-west direction the standard deviations of the parameters do not increase significantly.

Leick, A.↗
NASA NTRS1982

Orientation Insensitivity for Electrochemical Sensor

Using a wettable polypropylene wick, performance of an electro-chemical hydrazine sensor is made independent of its orientation. Wick keeps all electrodes in constant contact with electrolyte solution so that one or more of the electrodes do not become isolated from the electrolyte if the sensor is tilted or vibrated.

Cromer, R. B.↗
NASA NTRS1982

Orienting and Applying Flux to Solar Cells

Solar cells are oriented and fluxed automatically at first work station along solar-array assembly line. In under 2 seconds rotary drive rotates cell into proper position for applying solder flux to bus pad on collector side. When contact bus pad is in correct position, capstan drive is disengaged, and vacuum holddown beneath cell is turned on. Flux system lowers and applies preset amount of solder flux to bus pad. Two interconnect tabs are soldered to fluxed areas.

Feder, H.↗
NASA NTRS1980

MSFC personnel management tasks: Recruitment and orientation of new employees

In order to encourage highly motivated young students to learn about NASA and consider it for a career, a formal program is to be initiated whereby selected students can work on a voluntary basis at Marshall Space Flight Center (MSFC). The first task was to develop the working plan and procedures for this program, called Student Volunteer Service Program, in the writing of MSFC official guidelines, the Marshall Management Instruction (the MMI) which is a binding document that defines policy and establishes procedures and guidelines. Particular considerations written into the MMI after numerous consultations, interviews, and discussions about a satisfactory policy, include: arrangements to be made between the student, the school authorities, and concerned MSFC employees; management of the work assignments; and procedures for the student's welfare and safety. The second task was the development of a recruitment brochure for the attraction of new employees, especially scientists and engineers. The third task assigned was to develop a plan called Orientation of New Employees.

Brindley, T. A.↗
NASA NTRS1981

The P/POD project: Programmable/Pilot Oriented Display

A pilot orientated display system was developed for general aviation aircraft in order to reduce cockpit workloads. Emphasis was placed on the optimization of flight procedural aspects (i.e., interpretation of Loran data). Low cost hardware/software were utilized in the system to reduce developmental costs. Parallel development and testing were conducted on the ground (simulator) and in the air using the same hardware.

Littlefield, J. A.↗
NASA NTRS1981

Guidelines for Line-Oriented Flight Training, Volume 1

Line-Oriented Flight Training (LOFT) is a developing training technology which synthesizes high-fidelity aircraft simulation and high-fidelity line-operations simulation to provide realistic, dynamic pilot training in a simulated line environment. LOFT is an augmentation of existing pilot training which concentrates upon command, leadership, and resource management skills. This report, based on an NASA/Industry workshop held in January, 1981, is designed to serve as a handbook for LOFT users. In addition to providing background information, guidelines are presented for designing LOFT scenarios, conducting real-time LOFT operations, pilot debriefing, and instructor qualification and training. The final chapter addressed other uses of LOFT and line-operations (or full-mission) simulation.

Lauber, J. K.↗
NASA NTRS1980

On the dynamics of large orbiting flexible beams and platforms oriented along the local horizontal

The dynamics and stability of large orbiting flexible beams and platforms oriented along the local horizontal are treated both analytically and numerically. It is assumed that such structures could be gravitationally stabilized by attaching a rigid lightweight dumbbell at the center of mass by a spring loaded hinge which also could provide viscous damping. For the beam it is seen that the small amplitude inplane pitch motion, dumbbell librational motion, and the anti-symmetric elastic modes are all coupled. The three dimensional equations of motion for a circular flat plate in orbit with a two-degree-of-freedom gimballed dumbbell are also developed and show that only those elastic modes described by a single nodal diameter line are influenced by the dumbbell motion. Stability criteria are developed for both examples and a parametric study of the least damped mode characteristics together with numerically simulated transient responses are carried out.

Bainum, P. M.↗
NASA NTRS1981

The orientation of the solar rotation axis from Doppler velocity observations

Mt. Wilson observations of solar velocity fields have been examined for evidence that the rotation axis of the nonmagnetic gas at the solar surface is oriented differently that the axis found by Carrington (1863) from sunspot observations. No difference is found with accuracy of 0.15 in the angle of inclination of the axis to the ecliptic.

Labonte, B. J.↗
NASA NTRS1981

On the shape and orientation control of an orbiting shallow spherical shell structure

A proposed method for controlling the shape and orientation of very large shallow dish type receiver/reflectors to be used in communication, radiometry and in electronic orbital based mail systems involves connecting a rigid light weight dumbell with heavy tip masses to the shell at its apex by a spring loaded double gimballed joint with dampling. To completely damp the system transient motion in all of the important lower frequency modes, an active control system is required. A mathematical model is extended to include the effects of point actuators located at preselected positions on the shell surface. The formulation of the uncontrolled dynamics assumes an a priori knowledge of the frequencies of all the elastic modes to be incorporated within the system model. As an example, three rigid body modes and six elastic modes are included in the model and six actuators are assumed, none of which lies on a nodal line or circle.

Bainum, P. M.↗
NASA NTRS1981

Guidelines for line-oriented flight training, volume 2

Current approaches to line-oriented flight training used by six American airlines are described. This recurrent training methodology makes use of a full-crew and full-mission simulation to teach and assess resource management skills, but does not necessarily fulfill requirements for the training and manipulation of all skills.

Lauber, J. K.↗
NASA NTRS1981

Issues related to line-oriented flight training

The use of a training simulator along with carefully structured, detailed, line trip scenarios was envisioned by NASA as a means of providing a controllable, repeatable way to observe line crews in a highly realistic simulation of their working environment and obtain better understanding operationally significant human factors problems and issues. Relevant research done by the agency and the results of full-mission simulation scenarios revealed potential implications for flight training. Aspects to be considered in creating training programs closely related to the actual line environment with a total crew application in real world incident experiences include: (1) operational, environmental, equipment, and crew problems in scenario design; (2) real time line oriented flight training operation; (3) performance assessment and debriefing; (4) instructor qualification and training; and (5) other issues such as ub un initial, transition, and upgrade training; procedures developent and evaluation, and equipment evaluation.

Lauber, J. K.↗
NASA NTRS1982

A quantitative applications-oriented evaluation of Thematic Mapper design specifications

Simulated Thematic Mapper data sets were created from aircraft Multispectral Scanner data in order to predict the sensitivity of applications-oriented classification results to variations in selected sensor parameters. It was found that band-to-band misregistration as little as 0.3 pixel can have a pronounced effect on the classification of both field-center pixels and pixels associated with edges and small objects in the scene. It was also determined that a significant improvement in classification accuracy could be achieved if the resolution of the thermal band of the Thematic Mapper were comparable to the resolution of its other spectral bands.

Swain, P. H.↗