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NASA NTRS1973

Observations of interactions between interplanetary and geomagnetic fields

Magnetospheric effects associated with variations of the north-south component of the interplanetary magnetic field are examined in light of recent recent experimental and theoretical results. Although the occurrence of magnetospheric substorms is statistically related to periods of southward interplanetary magnetic field, the details of the interaction are not understood. In particular, attempts to separate effects resulting directly from the interaction between the interplanetary and geomagnetic fields from those associated with substorms have produced conflicting results. The transfer of magnetic flux from the dayside to the nightside magnetosphere is evidenced by equatorward motion of the polar cusp and increases of the magnetic energy density in the lobes of the geomagnetic tail. The formation of a macroscopic X-type neutral line at tail distances less than 35 R sub E appears to be a substorm phenomenon.

Burch, J. L.↗

NASA NTRS1973

Air traffic control surveillance accuracy and update rate study

The results of an air traffic control surveillance accuracy and update rate study are presented. The objective of the study was to establish quantitative relationships between the surveillance accuracies, update rates, and the communication load associated with the tactical control of aircraft for conflict resolution. The relationships are established for typical types of aircraft, phases of flight, and types of airspace. Specific cases are analyzed to determine the surveillance accuracies and update rates required to prevent two aircraft from approaching each other too closely.

Craigie, J. H.↗

NASA NTRS1973

Detonation propulsion for high pressure environments

One limitation encountered by chemical rocket propulsion in high pressure planetary atmospheres is illustrated by the conflict between the dependence of specific impulse on the ratio of chamber pressure to ambient pressure and the dependence of the motor structural design on the difference between the pressures. This work proposes to resolve the difficulty by employing detonating propellant in which the high pressures necessary for efficient propulsion are developed over a short time and need not be contained statically. Experimental results are presented to substantiate this claim of relatively high performance, together with an analytical development that approximately describes the flow dynamics.

Varsi, G.↗

NASA NTRS1973

On the distance to Cygnus X-1

Interstellar extinction of 50 stars in the immediate vicinity of Cyg X-1 is compared with color excess of HDE 226868. The fact that HDE 226868 has extinction drastically exceeding that of all stars in the field at less than 1 kpc is believed to be in conflict with the model of Trimble et al. (1973) in which the primary is a luminous undermassive star and with other similar models. Uniform extrapolation of the reddening yields a distance estimate of (2.5 plus or minus 0.4) kpc for Cygnus X-1, in agreement with the spectroscopic modulus for an O9 star.

Margon, B.↗

NASA NTRS1973

Origin of the cell - Experiments and premises

Theories and component concepts of the origin of life, i.e., primordial life, have emerged from (1) constructionistic studies on model materials and systems, and (2) reductionistic studies of contemporary cells. The resultant views conflict in a number of aspects; many of the differences are analyzed in this article. Constructionistic experiments are appropriate to asking questions about origins since they are in the same direction as evolution itself. These experiments have revealed self-ordering properties and associated emergent functions, which were not predictable.

Fox, S. W.↗

NASA NTRS1974

Putting all our noise technology to work

An assessment of the present state of the art in noise reduction technology indicates that this technology has the potential for effectively attaining this goal - a conclusion that is in apparent conflict with the frequently voiced complaints on intolerable noise levels near airports. Measures are suggested for a more vigorous implementation of available technology in practice to combat the aircraft noise problem.

Jackson, R. P.↗

NASA NTRS1974

Surface properties of the Orgueil meteorite - Implications for the early history of solar system volatiles

The Kr and H2O adsorption properties of Orgueil were studied. Dehydration by stepwise calcination produced a tenfold change in its B.E.T. surface area, which increased to 120 and then fell to 40 square meters per gram. Water exchangeability was measured by water regain from lab air between calcination cycles. Dehydration at room temperature showed that Orgueil contained 6 per cent by weight of water adsorbed on free surfaces. These results are consistent with an identification of Orgueil as montmorillonite, although chemical data conflict with this. High D/H ratios in CI carbonaceous chondrites may result from D enrichment in OH- groups during equilibration of dispersed phyllosilicate dust with preplanetary nebula gas at temperatures much less than 0 C.

Fanale, F. P.↗

NASA NTRS1974

Observations of interactions between interplanetary and geomagnetic fields

Magnetospheric effects associated with variations of the north-south component of the interplanetary magnetic field (IMF) are examined in light of recent experimental and theoretical results. Although the occurrence of magnetospheric substorms is statistically related to periods of southward IMF, the details of the interaction are not understood. In particular, attempts to separate effects resulting directly from the interaction between interplanetary and geomagnetic fields from those associated with substorms have produced conflicting results. It is possible, however, to say with some assurance that the transfer of magnetic flux from the dayside to the nightside magnetosphere, as evidenced by equatorward motion of the polar cusp and increases of the magnetic energy density in the lobes of the geomagnetic tail, is a direct consequence of the southward IMF. On the other hand, the formation of a macroscopic X-type neutral line at tail distances less than 35 earth radii appears to be a substorm phenomenon.

Burch, J. L.↗

NASA NTRS1974

On a fundamental problem in radiation biology

Experimental evidence indicates that the radiation dose required to reduce a surviving population to a certain fraction of its original population is lower for vertebrate cells than for viruses. On the other hand, the number of ionizations per cell required to inactivate that cell is greater for vertebrate cells than for viruses. The apparent conflict between these two findings is investigated. It is found that the apparent contradiction is probably a result of the fractional power dependence of the radiation-dose value on the nucleic acid weight.

Dugan, V.↗

NASA NTRS1974

Is Jupiter's magnetosphere like a pulsar's or earth's?

The application of pulsar physics to determine the magnetic structure in the planet Jupiter outer magnetosphere is discussed. A variety of theoretical models are developed to illuminate broad areas of consistency and conflict between theory and experiment. Two possible models of Jupiter's magnetosphere, a pulsar-like radial outflow model and an earth-like convection model, are examined. A compilation of the simple order of magnitude estimates derivable from the various models is provided.

Kennel, C. F.↗

NASA NTRS1974

Space charge effects in current transport

Developments on the subject of noise in single and double injection currents in solids are reviewed. Results are discussed in detail and a bibliography of published work in the field is provided. Conflicting findings and opinions are examined in the light of the present understanding of the subject.

Source record↗

NASA NTRS1974

Structure of Saturn's rings: Optical and dynamical considerations

The photometric phase curves of Saturn's rings are considered, as well as a conflict between dynamical and photometric models of the rings. The dependence of ring brightness on angular separation of the earth and sun as viewed from Saturn is discussed. The nonlinear brightness surge is interpreted. Some quantitative calculations were carried out for bodies in and near the asteroidal belt. Predicted density profiles of the ring obtained with Mimas in an eccentric orbit and in a circular orbit are also included.

Franklin, F. A.↗

NASA NTRS1974

Cooperative efforts by industry and government to develop geothermal resources

The Federal government's current plans for participation in the geothermal field appear to affect four major areas of interest: (1) resources exploration and assessment, (2) resources utilization projects, (3) advanced research and technology, and (4) environmental, legal, and institutional research. Private industry is also actively involved in these same areas of interest. Because of lack of coordination and communication between the private and public sector, it appears that there will be considerable duplication of effort, and, in some cases, serious conflict. It is also likely that this lack of coordination and communication may result in lack of effort in some key areas. Close coordination and communication between government and industry may resolve some of the major problems that are clearly evident.

Butler, D. R.↗

NASA NTRS1972

Apollo 17 photographic processing control document

The control parameters are defined which are to be used by the Photographic Technology Division for the processing of all films flown on Apollo Mission J-3. The procedures necessary for establishment of processing control are given along with information for denoting and solving any problem areas or conflicts which may occur prior to the mission.

Weinstein, M. S.↗

NASA NTRS1975

Downward continuation of gravity information from satellite to satellite tracking or satellite gradiometry in local areas

Integral formulas in the parameter domain are used instead of a representation by spherical harmonics. The neglected regions will cause a truncation error. The application of the discrete form of the integral equations connecting the satellite observations with surface gravity anomalies is discussed in comparison with the least squares prediction method. One critical point of downward continuation is the proper choice of the boundary surface. Practical feasibilities are in conflict with theoretical considerations. The properties of different approaches for this question are analyzed.

Rummel, R.↗

NASA NTRS1975

SS/RCS surface tension propellant acquisition/expulsion tankage technology

The analysis, design, fabrication, and testing of a propellant tank that satisfies the requirements of the space shuttle is presented. This mission presents very stringent and sometimes conflicting requirements. A compartmented-tank device was developed and various ground and drop tower test techniques were employed to verify the design using both subscale and full-scale hardware. Performance was established with scale models and further substantiation was obtained with the full-scale tankage. Fabrication, acceptance, fill and drain, inspection, and other ground handling procedures were developed.

Source record↗

NASA NTRS1975

The total and spectral solar irradiance and its possible variations

The present status of knowledge of the total and spectral irradiance of the sun is briefly reviewed. Currently accepted values of the solar constant and the extraterrestrial solar spectral irradiance are presented along with a discussion of how they were derived. Data on the variability of the solar constant are shown to be conflicting and inconclusive. Some of the alleged sun-weather relationships are cited in support of the need of knowing more precisely the variations in total and spectral solar irradiance. An overview of a solar monitoring program is discussed, with special emphasis on the Solar Energy Monitor in Space experiment which was proposed for several spacecraft missions. It is a combination of a solar constant detector and a prism monochromator. The determination of absolute values and the possible variations of the total and spectral solar irradiance, from measurements outside of the atmosphere is discussed.

Thekaekara, M. P.↗

NASA NTRS1974

Planning and management of science programs on Skylab

Discussion of the experience gained in experiment operation planning during the Skylab mission. The Skylab flight planning activity allowed the experimenters to interact with the system and provided the flexibility to respond to contingencies both major and minor. Both these aspects contributed to make efficient use of crew time thus helping to increase the science return from the mission. Examples of the need for real time scheduling response and of the tradeoffs considered between conflicting experiment requirements are presented. General management principles derived from this experience are developed. The Skylab mission experiences, together with previous Apollo mission experiences, are shown to provide a good background for Shuttle flight planning.

Parker, R. A. R.↗