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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Short-term hot-hardness characteristics of five case hardened steels

Short-term hot-hardness studies were performed with carburized and hardened AISI 8620, CBS 1000, CBS 1000M, CBS 600, and Vasco X-2 steels. Case and core hardness measurements were made at temperatures from 294 to 811 K (70 to 1000 F). The data were compared with data for high-speed tool steels and AISI 52100. The materials tested can be ranked as follows in order of decreasing hot-hardness retention: (1) Vasco X-2; equivalent to through-hardened tool steels up to 644 K (700 F) above which Vasco X-2 is inferior; (2) CBS 1000, (3) CBS 1000M; (4) CBS 6000; better hardness retention at elevated temperatures than through-hardened AISI 52100; and (5) AISI 8620. For the carburized steels, the change in hardness with temperature of the case and core are similar for a given material. The short-term hot hardness of these materials can be predicted with + or - 1 point Rockwell C.

Anderson, N. E.↗
NASA NTRS1974

Minor planets and related objects. XVII - Five-color photometry of four asteroids

Asteroids (6), (14), (39), and (51) were observed at the Leiden Southern Station. Only (39) Laetitia seems to show some variation in color (3% in visual-ultraviolet) correlated to the light curve. If a similar effect is present for (6) Hebe, it should only be present at small phase angles. The light curves of (14) Irene and (39) Laetitia show light variations of a few percent of the rotational period indicating probable surface macrostructure.

Wamsteker, W.↗
NASA NTRS1976

Low subsonic aerodynamic characteristics of five irregular planform wings with systematically varying wing fillet geometry tested in the NASA/Ames 12 foot pressure tunnel (LA65)

An experimental and analytical aerodynamic program to develop predesign guides for irregular planform wings (also referred to as cranked leading edge or double delta wings is reported; the benefits are linearization of subsonic lift curve slope to high angles of attack and avoidance of subsonic pitch instabilities at high lift by proper tailoring of the planform-fillet-wing combination while providing the desired hypersonic trim angle and stability. Because subsonic and hypersonic conditions were the two prime areas of concern in the initial application of this program to optimize shuttle orbiter landing and entry characteristics, the study was designated the Subsonic/Hypersonic Irregular Planforms Study (SHIPS).

Ball, J. W.↗
NASA NTRS1976

Five meter diameter conical furlable antenna

An investigation was made to demonstrate that a 5-meter-diameter, furlable, conical reflector antenna utilizing a line source feed can be fabricated utilizing composite materials and to prove that the antenna can function mechanically and electrically as prototype flight hardware. The design, analysis, and testing of the antenna are described. An RF efficiency of 55% at 8.5 GHz and a surface error of 0.64 mm rms were chosen as basic design requirements. Actual test measurements yielded an efficiency of 53% (49.77 dB gain) and a surface error of 0.61 mm rms. Atmospherically induced corrosion of the reflector mesh resulted in the RF performance degradation. An assessment of the antenna as compared to the current state of the art technology was made. This assessment included cost, surface accuracy and RF performance, structural and mechanical characteristics, and possible applications.

Fortenberry, J. W.↗
NASA NTRS1976

Observations of interaction regions and corotating shocks between one and five AU - Pioneers 10 and 11

Interaction regions between adjacent solar-wind streams have been identified between 1 and 5 AU by Pioneer 10 and 11 magnetic-field and plasma measurements. Beyond 1 AU, a relatively large fraction of the interaction regions have been found to be accompanied by either forward shocks, reverse shocks, or shock pairs. The observations are consistent with previous theoretical proposals that the interaction between adjacent streams leads to the development of corotating interplanetary shocks.

Smith, E. J.↗
NASA NTRS1976

Arctic odyssey - Five years of data buoys in AIDJEX

The Arctic Ice Dynamics Joint Experiment of 1975-1976 used data bouys in conjunction with tracking satellites to study the interaction of Arctic Sea ice with the environment, and, more specifically, to define the motion of ice on the perimeter of the area of interest and to measure surface barometeric pressure over the same area. Charts are presented, indicating the position of the buoy array along with a table detailing buoy characteristics. The position fix accuracy of RAMS (Random Access Measurement System) buoys is discussed together with position errors due to the along-track motion of the observing satellites. Polar satellite data collection and tracking efficiency is assessed together with satellite system flexibility concepts.

Martin, P.↗
NASA NTRS1976

Jupiter at five microns

The paper summarizes the information obtained in recent maps of Jupiter at 5 microns, a frequency at which the gases in Jupiter have a relatively low opacity. It is highly possible that 5-micron hot spots are breaks in the cloud deck permitting observation of the hot lower layers of the atmosphere. Many 5-micron sources coincide with blue visual features, but the details of the correspondence need further investigation. Large-scale changes in the appearance of the planet occur at 5 microns on time scales of months; these changes are sufficiently dramatic to produce detectable variations in the whole-disk flux from the planet. Their correspondence to large-scale changes in visual features is not yet determined.

Armstrong, K. R.↗
NASA NTRS1976

High supersonic aerodynamic characteristics of five irregular planform wings with systematically varying wing fillet geometry tested in the NASA/LaRC 4-foot UPWT (LEG 2) (LA45A/B)

An experimental and analytical aerodynamic program to develop predesign guides for irregular planform wings is reported. The benefits are linearization of subsonic lift curve slope to high angles of attack and avoidance of subsonic pitch instabilities at high lift by proper tailoring of the planform fillet wing combination while providing the desired hypersonic trim angle and stability. The two prime areas of concern are to optimize shuttle orbiter landing and entry characteristics. Basic longitudinal aerodynamic characteristics at high supersonic speeds are developed.

Source record↗
NASA NTRS1976

The C-12/C-13 ratio in stellar atmospheres. VI - Five luminous cool stars

A simple curve-of-growth technique is described for extracting the C-12/C-13 ratio for M stars from high-resolution spectra of CO infrared vibration-rotation lines. The technique is applied to the CO lines at 1.6 and 2.3 microns in spectra of two M supergiants (Alpha Ori and Alpha Sco), two M giants (Alpha Her and Beta Peg), and a Mira-type variable (Chi Cyg). As a check on the CO analysis, the C-12/C-13 ratio is derived from the red CN system at 8000 A for Alpha Sco, Alpha Ori, and Beta Peg. The CO analysis is also applied to the K giant Alpha Boo as a check. The CN and CO results are found to be in general agreement, and the C-12/C-13 ratio in all the examined stars is shown to be considerably lower than the solar-system value. It is suggested that these stars were formed from clouds with a C-12/C-13 ratio of 40 to 89 and that their atmospheres now exhibit an enhancement of C-13 abundance due to internal production and mixing to the surface.

Hinkle, K. H.↗
NASA NTRS1977

Ar-40 intercept values and young apparent /K-40/-/Ar-40/ ages of five Apollo 15 fines

Correlations between Ar-40 and Ar-36 from size fractions of three Apollo 15 fines (15071, 15421, 15501) have been obtained. The Ar-40 intercept values of these fines and of 15091 and 15601 are generally lower than what one would expect for fines resulting from the comminution of rocks having ages of about 3.3 billion yr, typical for basalts of the landing site. This is interpreted to be the result of contamination by ray material from the Copernican age (equal or less than about 1 billion yr) craters, Autolycus and Aristillus, north of the landing site.

Jordan, J. L.↗
NASA NTRS1977

A search for hard X-rays from five strong extragalactic radio sources

Data from the University of California at San Diego (UCSD) hard X-ray instrument on OSO-7 have been used to search the regions containing 3C 390.3, M87, 3C 273, 3C 111, and 3C 129. We have a weak detection of 3C 390.3 and a possible detection of 3C 111. Sensitive upper limits on hard X-rays have been obtained for the other objects. The available observational data indicate a correlation between hard X-ray emission, self-absorbed gigahertz radio emission, and strong optical emission lines in extragalactic sources. Self-Compton X-ray models have been calculated for the sources observed in this paper, and the angular sizes, lifetimes, and B fields in these sources have been estimated. These model calculations agree with existing VLBI and time variability data.

Mushotzky, R. F.↗
NASA NTRS1977

Report on NASA five-year planning, fiscal years 1978 through 1982

This plan is NASA's initial description of its projected research and development activities for the years 1978 through 1982. Stated goals are: (1) assurance of U.S. Preeminence in aviation, (2) scientific exploration of the universe, (3) global information services, and (4) permanent U.S. presence in space. The program represents a budget increase in NASA's aeronautical and space research and development of between three and four percent per year in terms of FY 1978 dollars.

Culbertson, P. E.↗
NASA NTRS1977

Reliability analysis of forty-five strain-gage systems mounted on the first fan stage of a YF-100 engine

The reliability of 45 state-of-the-art strain gage systems under full scale engine testing was investigated. The flame spray process was used to install 23 systems on the first fan rotor of a YF-100 engine; the others were epoxy cemented. A total of 56 percent of the systems failed in 11 hours of engine operation. Flame spray system failures were primarily due to high gage resistance, probably caused by high stress levels. Epoxy system failures were principally erosion failures, but only on the concave side of the blade. Lead-wire failures between the blade-to-disk jump and the control room could not be analyzed.

Holanda, R.↗
NASA NTRS1978

Mutual phenomena of Jupiter's five inner satellites in 1979

In this paper, we first predict eclipses and occultations of the Galilean satellites in 1979 and find that, although circumstances are generally poor, about 75 events are observable. We have then made a special point of including 40 eclipses of J5 (Amalthea) by the Galilean satellites in the hope that both visual and far-infrared light curves can be obtained - the former giving accurate astrometric information for J5, and the latter possible bearing on its surface structure or composition.

Aksnes, K.↗
NASA NTRS1978

Observations of five moderate-luminosity far-infrared sources in Orion and Monoceros

Far-infrared and submillimeter observations of Orion Molecular Cloud-2 (OMC-2), OMC-1, OMC-3, NGC 2024 and Monoceros R2 are reported. The areas surveyed include far-infrared sources with luminosities between 100 and 250,000 solar luminosities. The data are employed to estimate masses and column densities for the radiating clouds, the radial dependence of the density in the clouds, and the masses of the stellar clusters. Brightness temperatures of both the extended and compact far-infrared sources in OMC-2 are found to be lower than the brightness temperature of the extended (C-12)O emission, indicating an important role in (C-12)O heating for stars external to the compact center.

Thronson, H. A., Jr.↗