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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 163 records · Page 9
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NASA NTRS1979

Vertical resolving power of a satellite temperature sounding system

The paper examines the vertical resolving power of satellite temperature retrieval systems. Attention is given to sounding instrument proposed by Kaplan, et al., (1977) which has been conceived to have greatly improved vertical resolving capabilities. Two types of tests are reported. The first, based on the work of Conrath (1972), involves a theoretical assessment of the manner by which the ambient temperature profile is averaged over height in order to produce an estimate of temperature at a given level. The second test is empirical involving the actual retrieval of temperature signals superimposed on a standard atmosphere with an emphasis on determining the minimum separation of the signals for which the sounder system is still capable of distinguishing individual signals.

Thompson, O. E.↗
NASA NTRS1979

The condensation and fractionation of refractory lithophile elements

It is noted that Cr, Mg, and Si are fractionated in chondritic material along with, but to a lesser extent than, a large group of more refractory elements. These patterns are reexamined with the reasoning that this might imply some unique distribution at the time of fractionation. It is shown that apparently two distinct fractionization patterns can be resolved: one involving ordinary and enstatite chondrites and the other involving carbonaceous chondrites, the earth, the moon, and the eucrite parent body. It is noted that the two trends intersect at C1 composition. Attention is given to the range in which the largest fraction of planetary matter condenses. It is concluded that the appearance of large amounts of condensed materials is conceivably in some way related to the fractionization process, although the exact relationship cannot be specified.

Larimer, J. W.↗
NASA NTRS1980

Collisional growth of planetesimals

Safronov's (1972) demonstration that relative velocities of planetesimals would be comparable to the dominant size bodies' escape velocities, combined with a plausible size distribution that has most mass in the largest bodies, yielded his evolution model with limited growth of the largest planetesimal with respect to its next largest neighbors. A numerical simulation of planetesimal accretion (Greenberg et al., 1978) suggests that at least over one stage of collisional accretion, velocities were much lower than the escape velocity of the largest bodies, because the bulk of the mass still resided in km-scale bodies. The low velocities at this early stage may conceivably have permitted early runaway growth, which, in turn, would have kept the velocities low and permitted continued runaway growth of the largest bodies.

Greenberg, R.↗
NASA NTRS1979

The International Ultraviolet Explorer: Case study in spacecraft design

The International Ultraviolet Explorer (IUE) is a geosynchronous scientific satellite that was conceived as an international space observatory capable of measuring UV spectra of faint celestial bodies. Simple operational procedures allow the astronomers to joystick the spaceborne telescope about the sky, using familiar ground-based observatory techniques. The present paper deals with the IUE project objectives, the technical problems, constraints, trade-offs, and the problem solving techniques used in the IUE program.

Freeman, H. R.↗
NASA NTRS1980

Atmospheric drag as the cause of the secular decrease in the semimajor axis of LAGEOS's orbit

An unmodeled acceleration is causing the semimajor axis of LAGEOS to decrease at the rate of about 1.1 mm/day. Drag from charged particles or neutral helium or both is the most probable cause. The rate of orbital decay is conceivably explained by the theories of charged particle drag. Unfortunately, these theories are not yet developed to the point where a definitive statement as to the importance of charged particle drag can be made. Neutral helium may also be the cause of the orbital decay. While the abundance required to account for the secular decrease is high, it also helps solve the 'helium problem'. Neutral hydrogen probably accounts for no more than 12 percent of the observed decay.

Rubincam, D. P.↗
NASA NTRS1980

The potential for damage from the accidental release of conductive carbon fibers from aircraft composites

Carbon and graphite fibers are known to be electrically conductive. The rapidly accelerating use of carbon fibers as the reinforcement in filamentary composite materials brought up the possibility of accidental release of carbon fibers from the burning of crashed commercial airliners with carbon composite parts. Such release could conceivably cause widespread damage to electrical and electronic equipment. The experimental and analytical results of a comprehensive investigation of the various elements necessary to assess the extent of such potential damage in terms of annual expected costs and maximum losses at low probabilities of occurrence are presented. A review of NASA materials research program to provide alternate or modified composite materials to overcome any electrical hazards from the use of carbon composites in aircraft structures is described.

Bell, V. L.↗
NASA NTRS1980

Thermal protection of reentry vehicles by actively cooled nosetips

Analytical modeling efforts and clear-air ground test results of a transportation-cooled nosetips (TCNT) design are presented. The discrete water injection platelet TCNT described was conceived and created to achieve the performance requirements for severe reentry vehicle trajectories. Thermal performance computer modeling techniques, combing both local heat blockage and boundary layer recovery enthalpy reduction are outlined.

Walker, R. E.↗
NASA NTRS1980

Environmental impacts of the satellite power system (SPS) on the middle atmosphere

The heavy lift launch vehicles (HLLV) proposed for use in constructing satellite power systems (SPS) would deposit various contaminants in the middle atmosphere, contaminants that would conceivable have adverse effects on climate and upper air structure. These contaminants consist of the major constitutents of water vapor, hydrogen, carbon dioxide, and carbon monoxide, and the minor constituents of sulfur dioxide and nitric oxide in the rocket effluent, as well as nitric oxide formed during reentry. To assess the magnitudes of the effects, new models or modified existing models were constructed.

Source record↗
NASA NTRS1980

FBI fingerprint identification automation study: AIDS 3 evaluation report. Volume 8: Measures of effectiveness

The development of both quantitative criteria that were used to evaluate conceptional systems for automating the functions for the FBI Identification Division is described. Specific alternative systems for automation were compared by using these developed criteria, defined as Measures of Effectiveness (MOE), to gauge system's performance in attempting to achieve certain goals. The MOE, essentially measurement tools that were developed through the combination of suitable parameters, pertain to each conceivable area of system operation. The methods and approaches used, both in selecting the parameters and in using the resulting MOE, are described.

Mulhall, B. D. L.↗
NASA NTRS1981

Analysis of IUE spectra using the interactive data language

The Interactive Data Language (IDL) is used to analyze high resolution spectra from the IUE. Like other interactive languages, IDL is designed for use by the scientist rather than the professional programmer, allowing him to conceive of his data as simple entities and to operate on this data with minimal difficulty. A package of programs created to analyze interstellar absorption lines is presented as an example of the graphical power of IDL.

Joseph, C. L.↗
NASA NTRS1978

Shuttle/tethered satellite system

A tethered satellite system was conceived as a device to extend the capability of the Space Shuttle to perform scientific/applications investigations and operational activities. The concept envisions a multiple-use tethered system with closed-loop control, capable of supporting a payload or satellite suspended from the Shuttle cargo bay, toward or away from the Earth, at distances up to 100 kilometers from the Shuttle. The background and results of early analyses and feasibility studies are discussed and a design and operational description of the system are presented. Also presented are a discussion of potential applications of the Tethered Satellite System, and plans for an operational verification flight in 1982.

Rupp, C. C.↗
NASA NTRS1980

Shuttle-era experiments in the area of plasma flow interactions with bodies in space

A new experimental approach is discussed that can be adopted for studies in the area of plasma flow interactions with bodies in space. The potential use of the Space Shuttle/Orbiter as a near-earth plasma laboratory for studies in space plasma physics and particularly in solar system plasmas is discussed. This new experimental approach holds great promise for studies in the supersonic and sub-Alfvenic flow regime which has applications to the motion of natural satellites around their mother planets in the solar-system (e.g., the satellite Io around the planet Jupiter). A well conceived experimental and theoretical program can lead to a better physical understanding regarding the validity and range of applicability of using gasdynamic, kinetic, and fluid approaches in describing collisionless plasma flow interactions with bodies in a variety of flow regimes. In addition to the above scientific aspects of the program, significant technological advances can be achieved regarding the interaction of space probes in planetary atmospheres/ionospheres and the reliability of using various plasma diagnostic devices on board spacecraft and large space platforms.

Samir, U.↗
NASA NTRS1980

SPIRIT - A high resolution cosmic ray isotope spectrometer for Spacelab

An instrument to measure the isotopic abundances of cosmic ray nuclei with Z in the range 20-30 and A in the range 40-70 has been conceived. The instrument, named SPIRIT (Superconducting Passive Iron Isotope Telescope), will have the mass resolution (sigma less than 0.15 amu) and collecting power (151 sq m ster h for a 10 day flight) to detect and convincingly resolve isotopes as rare as 0.5% of the total abundance of each element. Both range and magnetic rigidity are measured by following tracks through an array of sheets of CR-39, a sensitive new track-recording plastic, which had been kept in fixed position at uniform temperature within the uniform field region of a large superconducting magnet.

Tarle, G.↗
NASA NTRS1979

Avionics and displays in a future airspace system

The terminal configured vehicle (TCV) program was conceived to address the problems of (1) operation in the crowded terminal area airspace, and (2) integration of airborne avionics systems necessary to improve the efficiency of these operations. The program and its interaction with industry task groups are summarized, including elements of research and data collection. New technology is discussed which may be useful in implementing some defined avionics and display requirements.

Salmirs, S.↗
NASA NTRS1981

Discovery of phase-locked variable polarization in an RS Canum Venaticorum-like star, HR 5110

Using measurements on 79 nights in 1980 January-August, it is established that the polarization in the ultraviolet (U band) varies synchronously on the known binary period of 2.6132 days, with a peak-to-peak amplitude of 0.03%. The pattern is mainly second harmonic in character, as typical of binary star examples such as Algol and Upsilon Her. Reflection by the cooler star, by a plasma concentration, or both, is suggested. The scale of the polarization seems to be consistent with Rayleigh scattering by neutral hydrogen on the cooler star, and a roughly lambda to the -4th wavelength dependence should be searched for. The QU curve suggests a sizeable inclination for the system, of about 45 deg, but this is preliminary. Separately, a possible weak periodicity might be present on a subsidiary period, conceivably related to a rotating star spot.

Barbour, M. S.↗
NASA NTRS1981

NASA five-ball fatigue tester - Over 20 years of research

The paper reviews, from both a technical and historic perspective, the results of research conducted using the NASA Five-Ball Fatigue Tester. The test rig was conceived by W. J. Anderson in late 1958. The first data was generated in March 1959. Since then a total of approximately 500,000 test hours have been accumulated on a group of eight test rigs which are capable of running 24 hours a day, 7 days a week. Studies have been conducted to determine the effect on rolling-element fatigue life of contact angle, material hardness, chemistry, heat treatment, and processing, lubricant type and chemistry, elastohydrodynamic film thickness, deformation and wear, vacuum, and temperature as well as Hertzian and residual stresses. Correlation was established between the results obtained using the five-ball tester and those obtained with full-scale rolling-element bearings.

Zaretsky, E. V.↗
NASA NTRS1981

Systems overview and design methodology

The mission hardware to support a quarantine procedure for a proposed unmanned Mars sample return mission is described. There are several current options for acquiring a sample from the surface of Mars, ranging from a 'grab-and-run', or undocumented, sample return to a fully documented, selected-site, multisample mission. Although the Orbiting Quarantine Facility conceived was designed for one of the more likely mission plans (a documented collection of many subsamples), the facility is suitable for quarantine testing of the sample regardless of how it is acquired on Mars.

Source record↗
NASA NTRS1981

Operational procedures relative to severe weather

Severe weather impact on both safety and the economics of all types of aviation, and reduction of elimination are discussed. The functions and responsibilities of the dispatcher are outlined. All surface weather reports showing inclement weather, SIGMET REPORTS, forecasting turbulence or icing, convective SIGMETS: (1) tornadoes; (2) hail 3/4 of an inch or greater; (3) imbedded thunderstorms; (4) squall lines or (5) an area of level four or greater thunderstorms. This information along with PIREPs of severe weather are relayed to affected flights. It is concluded that operational procedures must be timely and well conceived to assure the least amount of impact on airline operations.

Sullivan, J. F.↗