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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 1,477 records · Page 82
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Analytical Work in Support of the Design and Operation of Two Dimensional Self Streamlining Test Sections

A method has been developed for accurately computing the imaginary flow fields outside a flexible walled test section, applicable to lifting and non-lifting models. The tolerances in the setting of the flexible walls introduce only small levels of aerodynamic interference at the model. While it is not possible to apply corrections for the interference effects, they may be reduced by improving the setting accuracy of the portions of wall immediately above and below the model. Interference effects of the truncation of the length of the streamlined portion of a test section are brought to an acceptably small level by the use of a suitably long test section with the model placed centrally.

Judd, M.↗
NASA NTRS1976

On the nature of the anti-tail of Comet Kohoutek /1973f/. II - Comparison of the working model with ground-based photographic observations

On the basis of photographic observations made at the Cerro Tololo Inter-American Observatory, the radial and transverse brightness profiles and time variations in the surface brightness of the anti-tail of Comet Kohoutek were examined. In the process of photometric reduction one-dimensional radial tracings passing through the comet's nucleus and covering the entire anti-tail were used in the place of the standard two-dimensional scans. Each radial scan was defined by the position angle, and 'noise' variations were interpolated from the known field brightness outside the anti-tail. An analysis of the results provides quantitative support for a previously proposed model (Sekanina, 1974) suggesting that the dust particles in the anti-tail suffered a significant loss in radius due to evaporation near the perihelion passage. Preliminary calculations indicate that only particles initially larger than 100-150 micrometers in diameter survived. The emission rate of dust may be comparable to those derived for Comets Arend-Roland (1957 III) and Bennett (1970 II).

Sekanina, Z.↗
NASA NTRS1975

Satellite laser ranging work at the Goddard Space Flight Center

The pulsed-laser satellite ranging systems presently being operated by the Goddard Space Flight Center are described along with their range and accuracy capabilities. The major subsystems are outlined, operation of the fixed system and the two mobile systems is discussed, and the performance of all three systems is evaluated. It is noted that these systems have an accuracy of better than 10 cm on a carefully surveyed range as well as in regular satellite ranging operations and are capable of ranging to all currently launched retroreflector-equipped satellites with the exception of Timation III. Future improvements discussed include a third mobile system which will be able to range distant satellites, such as Timation III, with an accuracy of better than 5 cm and the use of a frequency-doubled Nd:YAG laser in place of the ruby lasers now being employed.

Mcgunigal, T. E.↗
NASA NTRS1975

Satellite laser ranging work at the Goddard Space Flight Center

The paper describes the satellite laser ranging system at the Goddard Space Flight Center, its range and accuracy capabilities, and planned improvements for future systems. Major subsystems are described, including the laser, optical/mechanical, receiver, computer/software, timing, and laser data preprocessing subsystems. Operational considerations are examined, with attention given the mobile station layout, manpower requirements, and transportability. System performance is considered, with emphasis on system accuracy (calibration, stability, clock synchronization, atmospheric propagation correction) and range capability.

Mcgunigal, T. E.↗
NASA NTRS1975

Regional myocardial shape and dimensions of the working isolated canine left ventricle

The extent to which the dynamic shape and dimensions of the isolated left ventricular myocardial wall differ throughout the myocardium and how these differences are characteristic of the anatomic location was demonstrated. The use of a biplane X-ray technique and a metabolically-supported isolated canine left ventricle preparation provided an angiographically ideal means of measuring mechanical dynamics of the myocardium while the intact left ventricular myocardial structure and electrical activation pattern retains most of the in situ ventricular characteristics.

Ritman, E. L.↗
NASA NTRS1976

Satellites for distress alerting and locating: Report by Interagency Committee for Search and Rescue Ad Hoc Working Group

The background behind the congressional legislation that led to the requirement for the Emergency Locator Transmitter (ELT) and the Emergency Position-Indicating Radio Beacon (EPIRB) to be installed on certain types of aircraft and inspected marine vessels respectively is discussed. The DAL problem is discussed for existing ELT and EPIRB equipped aircraft and ships. It is recognized that the DAL requirement for CONUS and Alaska and the maritime regions are not identical. In order to address the serious DAL problem which currently exists in CONUS and Alaska, a low orbiting satellite system evolves as the most viable and cost effective alternative that satisfies the overall SAR system design requirements. A satellite system designed to meet the needs of the maritime regions could be either low orbiting or geostationary. The conclusions drawn from this report support the recommendation to proceed with the implementation of a SAR orbiting satellite system.

Ehrlich, E.↗
NASA NTRS1977

Scientific rationale and strategies for a first comet mission: Report of the Comet Halley science working group

The science objectives of a first comet mission are reviewed and related to what is known or can be expected to be learned in the near future from ground-based and near earth observations. A set of instruments and their science objectives are defined for a mission to Comet Halley during its 1985/86 apparition. The benefits from a fast flyby, a slow flyby, or a rendezvous mission and the relative impact of each on the instrument payload were assessed. The relative scientific value of encounters with the comet at distances from the sun ranging from 1 AU to 2.5 AU, including possible tradeoffs between flyby velocity and distance was considered. Pre- and post-perihelion encounters were likewise evaluated.

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NASA NTRS1977

Scientific rationale and strategies for a first comet mission. Report of the Comet Halley science working group. An executive summary

The justification, scientific objectives, instrumentation, and strategy for a first comet mission are discussed. Topics include: mission target; rendezous, propulsion system requirements, measurement objectives, instrument capabilities for rendezvous and the tail probe payload, and backup missions if rendezvous with Halley's comet is not possible to achieve. Support research to be done by NASA is recommended.

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NASA NTRS1976

Collected works of Charles J. Donlan

Spin tests and wind tunnel tests for various types of experimental aircraft are discussed. The fighter aircraft and monoplanes of the World War II era are emphasized.

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NASA NTRS1977

DSN water vapor radiometer development: Recent work

A water vapor radiometer (WVR) was developed which measures the atmospheric noise temperature at two different frequencies. These noise temperatures are used in empirical-theoretical equations which yield tropospheric range delay, in centimeters, through the atmosphere along the beam of the WVR. This range correction is then applied to measurements concerning spacecraft range and to very long baseline interferometry determinations.

Slobin, S. D.↗
NASA NTRS1977

Shuttle Program. Euler angles, quaternions, and transformation matrices working relationships

A brief mathematical development of the relationship between the Euler angles and the transformation matrix, the quaternion and the transformation matrix, and the Euler angles and the quaternion is presented. The analysis and equations presented apply directly to current space shuttle problems. The twelve three-axis Euler transformation matrices are given as functions of the Euler angles, the equations for the quaternion as a funtion of the Euler angles, and the Euler angles as a function of the transformation matrix elements.

Henderson, D. M.↗
NASA NTRS1977

First works by K. E. Tsiolkovsky and I. V. Meshchersky on rocket dynamics

A study of rocket dynamics done by K. E. Tsiolkovsky in 1896 is reported. Problems in rectilinear movement of rockets were studied. Calculations were done on velocity efficiency, motion in free space, motion in a homogeneous gravitational field and motion with constant acceleration.

Kosmodemiansky, A. A.↗
NASA NTRS1977

On fundamentally new sources of energy for rockets in the early works of the pioneers of astronautics

The research for more efficient methods of propelling a spacecraft, than can be achieved with chemical energy, was studied. During a time when rockets for space flight had not actually been built pioneers in rocket technology were already concerned with this problem. Alternative sources proposed at that time, were nuclear and solar energy. Basic engineering problems of each source were investigated.

Melkumov, T. M.↗
NASA NTRS1977

Task and work performance on Skylab missions 2, 3, and 4: Time and motion study: Experiment M151

Human task performance was evaluated under weightlessness conditions during long duration space flight in order to study the characteristics of the adaptation function. Results show that despite pronounced variability in training schedules and in initial reaction to the Skylab environment, in-flight task performance was relatively equivalent among Skylab crews, and behavioral performance continued to improve from beginning to end of all missions.

Kubis, J. F.↗
NASA NTRS1977

Report of the Terrestrial Bodies Science Working Group. Volume 1: Executive summary

Current knowledge of Mercury, Venus, Mars, the Moon, asteroids, comets, and the Galilean satellites were reviewed along with related NASA programs and available mission concepts. Exploration plans for the 1980 to 1990 period are outlined and recommendations made. Topics discussed include: scientific objectives and goals, exploration strategy and recommended mission plans, supporting research and technology, Earth-based and Earth-orbital investigations, data analysis and synthesis, analysis of extraterrestrial materials, broadening the science support base, and international cooperation.

Source record↗
NASA NTRS1977

Report of the Terrestrial Bodies Science Working Group. Volume 2: Mercury

The objectives and rationale for scientific investigation of Mercury are explored. Knowledge already obtained by astronomical observations and Mariner 10 spacecraft is reviewed and measurements required for the principal scientific goals are described. The use of low thrust propulsion systems is recommended so that maximum scientific return may be achieved and the reconnaissance phase of Mercury exploration may be completed in a single mission. Accelerated development is recommended on solar electric propulsion, solar sails, passive and active cooling mechanisms, and single rough landers.

Albee, A. L.↗
NASA NTRS1977

Report of the Terrestrial Bodies Science Working Group. Volume 3: Venus

The science objectives of Pioneer Venus and future investigations of the planet are discussed. Concepts and payloads for proposed missions and the supporting research and technology required to obtain the desired measurements from space and Earth-based observations are examined, as well as mission priorities and schedules.

Kaula, W. M.↗