SEARCH · Engineering Papers

Results for “outer”

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.

SourceResearch connectionFrom yearThrough year

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

At least 163 records · Page 9

All sources NASA NTRS DOE OSTI

NASA NTRS1973

Orbit improvement from satellite imaging data obtainable from outer planet missions.

Equations of motion are established for a dynamical system in which a spacecraft flies close to and interacts with an outer planet and one or more of its satellites. For the computation of the state and mass partials needed in a simultaneous orbit correction of n interacting bodies, a notably compact set of variational equations is derived. The above system of differential equations is integrated numerically on a computer. Spacecraft-satellite direction measurements accurate to plus or minus 10 sec were simulated along three representative trajectories (Mariner/Jupiter/Saturn 1977 missions) approaching Io, Titan, and Iapetus to within 41000, 13000, and 7000 km, respectively. The paper concludes with a brief discussion of the need for future work on the orbits of the satellites of the outer planets.

Aksnes, K.↗

NASA NTRS1974

Ball motion and sliding friction in an arched outer-race ball bearing

The motion of the ball and sliding friction in an arched outer-race ball bearing under thrust load is analyzed. Fatigue life evaluations were made. The analysis is applied to a 150-millimeter-bore ball bearing. The results indicated that for high-speed light-load applications the arched bearing has significant improvement in fatigue life over that of a conventional bearing. An arching of 0.254 mm (0.01 in.) was found to be optimal. Also, for an arched bearing a considerable amount of spinning occurs at the outer-race contacts.

Hamrock, B. J.↗

NASA NTRS1974

A relation between ELF hiss amplitude and plasma density in the outer plasmasphere

Simultaneous observations of ELF hiss amplitude and plasma density on Ogo 5 have been investigated. Passes through the region of variable plasma density in the outer plasmasphere have yielded a quantitative relation between the hiss amplitude, the plasma density, and the plasma density corresponding to the threshold of wave detection. It is suggested that this dependence of wave amplitude on plasma density is a source effect and is related to the wave-particle interaction in the outer plasmasphere that gives rise to hiss.

Chan, K.-W.↗

NASA NTRS1974

The outer solar system - Perspectives for exobiology

An attempt is made to summarize the current knowledge about the composition and structures of outer planet atmospheres with special emphasis on Jupiter, Saturn, and Titan. The nature of the substances which are responsible for the yellow coloration observed on both Jupiter and Saturn is discussed. The analysis of planetary conditions conducted shows that the outer solar system offers a variety of environments in which natural experiments in prebiotic organic synthesis must be taking place at the present time.

Owen, T.↗

NASA NTRS1974

Outer planet probe cost estimates: First impressions

An examination was made of early estimates of outer planetary atmospheric probe cost by comparing the estimates with past planetary projects. Of particular interest is identification of project elements which are likely cost drivers for future probe missions. Data are divided into two parts: first, the description of a cost model developed by SAI for the Planetary Programs Office of NASA, and second, use of this model and its data base to evaluate estimates of probe costs. Several observations are offered in conclusion regarding the credibility of current estimates and specific areas of the outer planet probe concept most vulnerable to cost escalation.

Niehoff, J.↗

NASA NTRS1975

Correlation between the outer flow and the turbulent production in a boundary layer

Space-time velocity correlation measurements between fluctuations occurring in the convoluting outer edge of a flat boundary layer with fluctuations occurring near the viscous subregion were made. The correlations indicate that information is propagated from the outer region to the inner region. The migration of turbulence away from the wall was previously studied in the open literature. The results presented here along with the migration results lend support to the limit cycle model for turbulence production.

Cliff, W. C.↗

NASA NTRS1974

Ball motion and sliding friction in an arched outer race ball bearing

The motion of the ball and sliding friction in an arched outer-race ball bearing under thrust load is determined. Fatigue life evaluations were made. The analysis is applied to a 150 millimeter bore ball bearing. The results indicated that for high speed-light load applications the arched bearing has significant improvement in fatigue life over that of a conventional bearing. An arching of 0.254 mm (0.01 in.) was found to be an optimal. For an arched bearing it was also found that a considerable amount of spinning occurs at the outer race contacts.

Hamrock, B. J.↗

NASA NTRS1975

Particles and fields in the outer solar system

Use of the MJS77 and MJU missions to perform on site studies of the outer heliosphere and the local interstellar medium is discussed. Subjects for investigation are described, including fluctuations and instabilities of the solar wind in the outer solar system, profiles of the interstellar medium, and interactions between the solar wind and the interstellar medium. On site studies of interstellar cosmic rays are proposed, in particular obtaining interstellar spectra of cosmic ray nuclei and electrons and determining the cosmic-ray modulation region of the heliosphere. The general goals and requirements of the MJS77 and MJU missions are outlined.

Vogt, R. E.↗

NASA NTRS1976

Experimental performance of 75-millimeter-bore arched outer-race ball bearings to 2.1 million DN

An experimental investigation was performed to determine the operating characteristics of arched outer-race bearings and to compare the data with those for a similar, but conventional, deep-groove ball bearing. The bearings were tested over a range of shaft speeds up to 28,000 rpm at a thrust load of 2200 newtons (500 lb). One bearing was operated at 26,000 rpm with a range of thrust loads. The amounts of arching were 0.13, 0.25, and 0.51 millimeter (0.005, 0.010, and 0.020 in.). All bearings operated satisfactorily; the arched bearing outer-race temperatures and torques were consistently higher than those for the conventional bearing.

Coe, H. H.↗

NASA NTRS1976

Performance of 75 millimeter-bore arched outer-race ball bearings

An investigation was performed to determine the operating characteristics of 75-mm bore, arched outer-race bearings, and to compare the data with those for a similar, but conventional, deep groove ball bearing. Further, results of an analytical study, made using a computer program developed previously, were compared with the experimental data. Bearings were tested up to 28,000 rpm shaft speed with a load of 2200 N (500 lb). The amount of arching was 0.13, 0.25, and 0.51 mm (.005, .010, and .020 in.). All bearings operated satisfactorily. The outer-race temperatures and the torques, however, were consistently higher for the arched bearings than for the conventional bearing.

Coe, H. H.↗

NASA NTRS1975

Planets and satellites of the outer solar system, asteroids, and comets

The cosmogenic significance of outer solar system objects is evaluated with emphasis on planets and larger satellites of greatest biological interest; comets, asteroids, and the smaller satellites are also discussed. Principal physical and rudimentary photometric data for the five outer planets are presented in tables. Sufficient information on planetary motions is included for most calculations in physical planetology.

Newburn, R. L., Jr.↗

NASA NTRS1975

Electrostatic noise bands associated with the electron gyrofrequency and plasma frequency in the outer magnetosphere

Naturally occurring noise bands near the electron plasma frequency are frequently detected by the University of Iowa plasma wave experiment on the Imp 6 satellite in the region from just inside the plasmapause to radial distances of about 10 earth radii in the outer magnetosphere. The electric field strength of these noise bands is usually small with typical broad band electric field strengths of about 2 microvolts per m. A magnetic field has been detected only in a few unusually intense cases, and in these cases the magnetic field energy density is several orders of magnitude smaller than the electric field energy density. The bands are observed at all magnetic latitudes covered by the Imp 6 orbit and appear to be a permanent feature of the outer magnetosphere. They are found at all local times and occur least frequently in the quadrant from 18 to 24 hours. The bands appear to consist of two distinct spectral types called diffuse and narrow band. In both types the center frequency of the noise band is bounded by consecutive harmonics of the electron gyrofrequency, and these noise bands occur most often between harmonics that are near the local electron plasma frequency.

Shaw, R. R.↗

NASA NTRS1976

Expansion of an X-ray coronal arch into the outer corona

An asymmetric expanding arch photographed in the inner corona with an X-ray telescope on August 13, 1973, is identified as the source of the mass ejected in a white-light transient in the outer corona. The morphology, angular position, estimated mass, and apparent rate of upward acceleration of the lower coronal arch are similar to those of the arch seen passing through the outer corona. The mass of material removed from the lower corona is estimated to be 2 by 10 to the 15th power g, and the upward motion is consistent with a constant acceleration of 12.5 m/sec per sec between 1.3 and 5 solar radii.

Rust, D. M.↗

NASA NTRS1976

Performance of 75-millimeter bore arched outer-race ball bearings

An investigation was performed to determine the operating characteristics of 75-mm bore, arched outer-race bearings, and to compare the data with those for a similar, but conventional, deep groove ball bearing. Further, results of an analytical study, made using a computer program developed previously, were compared with the experimental data. Bearings were tested up to 28,000 rpm shaft speed with a load of 2,200 N (500 lb). The amount of arching was 0.13, 0.25, and 0.51 mm (0.005, 0.010, and 0.020 in). All bearings operated satisfactorily. The outer-race temperatures and the torques, however, were consistently higher for the arched bearings than for the conventional bearings

Coe, H. H.↗

NASA NTRS1977

Plasma electron measurements in the outer Jovian magnetosphere

The existence of the plasma electrons in the outer Jovian magnetosphere reported by Intriligator and Wolfe (1974) is consistent with (1) the additional pressure needed to supplement the magnetospheric magnetic field in the outer magnetosphere so as to balance the solar wind and interplanetary magnetic field dynamic pressure across the magnetopause, (2) the drastic change in the plasma electron spectrum as soon as Pioneer 10 crossed the magnetopause from the magnetosheath into the magnetosphere, (3) the fact that the instrument aperture was at spacecraft ground, and (4) the fact that beyond about 2 AU the continuous observations of all ambient electron fluxes (solar wind electrons, secondary electrons, photoelectrons, etc.) are below the instrument threshold.

Intriligator, D. S.↗

NASA NTRS1977

Identification of a new class of satellites in the outer solar system

From near-infrared photometry (JHKL) of small bodies in the outer solar system a previously unrecognized class of planetary satellites is identified which may have surfaces mostly free of frosts of water, methane, or ammonia. These bodies - including two satellites of Uranus (Titania and Oberon), and one each of Saturn (Hyperion) and Neptune (Triton) - have surfaces characterized by neutral reflectance between J and H (1.25 and 1.60 microns) and rapidly decreasing reflectance at K (2.2 microns) and L (3.5 microns). It is pointed out that the 15 solid bodies in the outer solar system that have been satisfactorily observed (excluding the asteroids) fall into six classes according to spectral reflectance. The presence of water frost or ice on the surface of Enceladus is established.

Cruikshank, D. P.↗

NASA NTRS1978

Acceleration of protons at 32 Jovian radii in the outer magnetosphere of Jupiter

A rapid ten-fold increase of proton flux was observed at 32 Jovian radii in Jupiter's outer magnetosphere. The total event lasted about 30 minutes and was composed of many individual events. Both before and after the event, proton flux was similar to the low-flux level found between crossings of the magnetic equator. Measurements of angular distributions and the time histories of proton and alpha particle channels at different energies indicate that the flux increase is caused by local acceleration. It is suggested that the average particle population in the outer magnetosphere is caused by a state of dynamic equilibrium between acceleration and loss processes.

Schardt, A. W.↗

NASA NTRS1978

Equation of state fits to the lower mantle and outer core

The lower mantle and outer core are subjected to tests for homogeneity and adiabaticity. An earth model is used which is based on the inversion of body waves and Q-corrected normal-mode data. Homogeneous regions are found at radii between 5125 and 4825 km, 4600 and 3850 km, and 3200 and 2200 km. The lower mantle and outer core are inhomogeneous on the whole and are only homogeneous in the above local regions. Finite-strain and atomistic equations of state are fit to the homogeneous regions. The apparent convergence of the finite-strain relations is examined to judge their applicability to a given region. In some cases the observed pressure derivatives of the elastic moduli are used as additional constraints. The effect of minor deviations from adiabaticity on the extrapolations is also considered. An ensemble of zero-pressure values of the density and seismic velocities are found for these regions. The range of extrapolated values from these several approaches provides a measure of uncertainties involved.

Butler, R.↗