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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Design of a one-year lifetime, spaceborne superfluid helium dewar

The Infrared Astronomical Satellite is an Explorer Mission and a joint venture of the Netherlands, the United Kingdom, and the United States scheduled for launch into earth orbit in 1981. The cryogenic system is a major part of the satellite; it incorporated many unique and state-of-the-art design features to satisfy the requirements of a one-year orbital lifetime, a focal plane temperature less than 4K, minimal launch weight, and zero-gravity operation. The 60-centimeter diameter telescope is contained within a superfluid helium dewar having a capacity of 540 liters. The telescope aperture cover employs an independent cryogenic system containing a 54-liter supercritical helium tank. The aperture cover, which is ejected two weeks after launch, protects the telescope from contamination and provides the low-temperature background needed to perform focal plane health checks. Design and predicted performance of the cryogenic systems are discussed in detail.

Hopkins, R. A.↗
NASA NTRS1980

Ultraviolet albedos of Uranus and Neptune

Observations on Uranus, Neptune, and four G-type stars which were obtained with the five channel ultraviolet spectrometer aboard the Astronomical Netherlands Satellite are reported. The paper uses these data to derive geometric albedos between 1800 and 3300 A for Uranus and between 2200 and 3300 A for Neptune. It is shown that the albedos are in good agreement with ground measurements near 3300 A and with OAO 2 measurements near 2500 A. In addition, it is noted that the albedos are smaller than theoretical predictions for deep pure H2 Rayleigh-Raman scattering atmospheres, which confirms earlier predictions that additional sources of ultraviolet absorption are required in the upper atmosphere of these planets. Consideration is given to the possibility that the Uranian atmosphere contains an extra absorber, noting that the identification of this absorber is difficult from broad-band spectrophotometric measurements.

Savage, B. D.↗
NASA NTRS1980

Transport jet aircraft noise abatement in foreign countries: Growth, structure, impact. Volume 1: Europe, July 1980

The development and implementation of aircraft noise control regulations in various European states are described. The countries include the United Kingdom, France, Switzerland, Federal Republic of Germany, Sweden, Denmark, and the Netherlands. Topics discussed include noise monitoring, airport curfews, land use planning, and the government structure for noise regulation.

Spencer, F. A.↗
NASA NTRS1981

NASA selects scientific investigations for Earth dynamics studies

Forty two domestic investigators affiliated with U.S. universities, governmental agencies, or private concerns and 14 investigators from France, West Germany, the Netherlands, Switzerland, Spain, Sweden, Australia, New Zealand, Venezuela, and Canada were selected to use precise geodetic data obtained by laser ranging and very long base interferometry in a study of the Earth's tectonic plate movement, crustal deformation, and rotational dynamics. The studies to be made and the principal investigators for each are listed.

Source record↗
NASA NTRS1981

Radio maps of Jupiter's radiation belts and planetary disk at lambda 6 cm

Two-dimensional maps of Jupiter's radio emission were made in April 1978 at a frequency of 4885 MHz (6 cm) using the Westerbork telescope in the Netherlands. Pictures in the Stokes parameters I, Q and U have been obtained every 15 deg in longitude, each smeared over 20 deg of the planet's rotation. The half power beam width was approximately 1/6 of the disk diameter in right ascension and approximately 1/2 in declination. The planetary disk shows little or no limb darkening at this wavelength and has a temperature of 220 + or - 8 K. The radiation belts clearly show a kind of plateau or flattening in intensity in the outer part of the belt. A comparison with 21 and 50 cm maps indicate no difference in the width and form of the emission regions with wavelength.

De Pater, I.↗
NASA NTRS1982

Time comparison via OTS-2

The time comparisons carried out via OTS-2 between the Technical University Graz (Austria) and the Van Swinden Laboratory Delft (Netherlands) are discussed. The method is based on the use of the synchronization pulse in the TV-frame of the daily evening broadcasting of a French TV-program to Northern Africa. Corrections, as a consequence of changes in the position of the satellite coordinates are applied weekly after reception of satellite coordinates. A description of the method is given as well as some of the particular techniques used in both the participating laboratories. Preliminary results are presented.

Dejong, G.↗
NASA NTRS1982

Heat Capacity Mapping Mission investigation no. 25 (Tellus project)

The TELLUS pilot project, utilizing 0.5 to 1.1 micron and 10.5 to 12.5 micron day and/or night imagery from the Heat Capacity Mapping Mission, is described. The application of remotely sensed data to synoptic evaluation of evapotranspiration and moisture in agricultural soils was considered. The influence of topography, soils, land use, and meteorology on surface temperature distribution was evaluated. Anthropogenic heat release was investigated. Test areas extended from semi-arid land in southern Italy to polders in the Netherlands, and from vine-growing hills in the Rhineland to grasslands in Buckinghamshire.

Deparatesi, S. G.↗
NASA NTRS1981

Sunshade/radiative cooler for IRAS infrared astronomical satellite

The Infrared Astronomical Satellite (IRAS) is a joint project shared by the United States and the Netherlands with the United Kingdom providing tracking and ground support services. IRAS features a cryogenically cooled telescope designed to perform an unbiased all-sky survey of the far infrared spectrum from 8 to 120 microns and to observe objects of special interest. The sunshade is designed to protect the telescope aperture and sunshade radiators from: direct solar radiation; direct earth radiation; radiation exchange with satellite structures; excessive aperture heating caused by sunshade inner cone emission. The sunshade three-stage radiative cooler design meets the listed requirements and, in addition, provides some contamination protection for the telescope aperture and optical surfaces during pointing maneuvers when the telescope is tilted in the direction of the velocity vector. Unless protected by the sunshade, the ram effect can cause molecules to enter the aperture and deposit on the cooled optical surfaces. This paper describes the sunshade design, the thermal analyses, and the results of thermal balance testing of the flight hardware.

Anderson, R. R.↗
NASA NTRS1981

Five-color band ultraviolet photometry of fourteen close binaries

Photometric observations obtained with the Astronomical Netherlands Satellite in five ultraviolet wavelength regions for 14 close binaries are presented. Strong excess far-ultraviolet flux is detected in four objects. The binaries TT Hya, RX Cas, and SX Cas exhibit a pronounced excess of far-ultraviolet flux, which is thought to be the result of mass transfer phenomena in these systems. Observations of the binary R Ara show very peculair variations; its far ultraviolet flux at 1550 A brightened by 0.4 mag between phases 0.7 and 0.8, while its near ultraviolet flux at 3300 A decreased by 0.5 mag over this same half-day interval. The A0 II-III component in the system RZ Sct is seen to dominate the ultraviolet spectrum.

Kondo, Y.↗
NASA NTRS1982

The early-type component in v1 Sagittarii

Four low-resolution UV spectra of v1 Sgr (cK2) were obtained with the IUE satellite to investigate the nature of the hot component in this object, which was detected in the Astronomical Netherlands Satellite UV photometric data. The IUE results show that the spectral energy distribution of v1 Sgr in the FUV is comparable to that of a B9 star. FUV flux level, when compared with that of the mid-ultraviolet flux level, indicates that the luminosity of the hot component is roughly equivalent to that of a main-sequence star, assuming that the mid-ultraviolet flux is dominated almost entirely by a K2 I object. No discernible spectral features are present in the FUV, contrary to what may be expected in a star of B9 spectral type. Two possible interpretations are suggested: the hot component is a rapidly rotating star, or an accretion disk surrounding a central object which could be a collapsed star is being observed.

Kondo, Y.↗
NASA NTRS1980

Government financial support for civil aircraft research, technology and development in four European countries and the United States

Data on the levels of government financial support for civil aircraft airframe and engine (CAAE) research and technology (R&T) in the United States and Europe (United Kingdom, West Germany, France and The Netherlands) and means of comparing these levels are provided. Data are presented for the years 1974-1977. European R&T expenditure data were obtained through visits to each of the four European countries, to the Washington office of the European Communities, and by a search of applicable literature. CAAE R&T expenditure data for the United States were obtained from NASA and Federal Aviation Administration (FAA).

Chandler, B.↗
NASA NTRS1983

LANN wing design

The LANN wing is the result of a joint effort between Lockheed, the Air Force, NASA, and the Netherlands to measure unsteady pressures at transonic speeds. It is a moderate-aspect-ratio transport wing configuration. The wing was machined from NITRONIC 40 and has 12 percent thick supercritical airfoil sections.

Firth, G. C.↗
NASA NTRS1982

Ultraviolet light curves of the dwarf novae U Geminorum and VW Hydri

The optical light curves of many dwarf novae show a prominent hump. This hump is attributed to a hot spot located where the gas stream from the cool secondary star strikes the accretion disk around the white dwarf primary. In the present investigation, the energy distribution of the hot spot is obtained from the amplitude of the hump in different wavelength regions. The color temperature of the hot spot is derived, and the temperature and optical thickness for thermal free-free emission models for the spot is discussed. The nature of the disk is studied by comparing its UV-optical energy distribution with computed accretion disk models. The ultraviolet light curves of two quiescent dwarf novae, U Gem and VW Hyi is derived by combining Astronomical Netherlands Satellite (ANS) photometry from several different epochs.

Wu, C.-C.↗
NASA NTRS1982

Observations of RR Lyrae with the ANS satellite

Photometric observations of RR Lyr in the ultraviolet have been obtained using the Astronomical Netherlands Satellite. The observations are compared with theoretical light curves calculated using synthetic spectra and angular diameters determined as a function of phase for RR Lyr by Manduca et al. from photometry at longer wavelengths. A good agreement is found. A bump in the observed light curves in the phase range 0.6 to 0.8 supports the existence of a shock as predicted by Hutchinson, Hill, and Lillie.

Bonnell, J.↗
NASA NTRS1983

Peculiar ultraviolet interstellar extinction

In connection with investigations of the physical characteristics of interstellar dust, a study of objects with peculiar extinction might provide new insights about the composition, size distribution, formation, and destruction of the particulate matter. Meyer and Savage (1981) have found that the dust toward many stars exhibits peculiar UV extinction. The present investigation is concerned with International Ultraviolet Explorer (IUE) spectrophotometric measurements for a sample of stars judged by Meyer and Savage to have highly anomalous UV extinction as inferred from the broad-band Astronomical Netherlands Satellite (ANS) data. The reported IUE measurements provide the opportunity to determine if the ANS photometry measurements of Meyer and Savage are anomalous because of peculiar extinction.

Massa, D.↗
NASA NTRS1983

The IRAS project organisation and mission operations

The project organisation of IRAS is described, showing the tasks assigned to each project group during post-launch operations. The satellite is described, emphasizing the detectors. In the task division, the role of the U.S. is to construct the telescope and survey instrument, launch the satellite, process final science data for the survey instrument, and provide certain standard satellite items. The Netherlands construct the spacecraft and three additional instruments, integrates and tests the overall satellite, and designs and participates in the development of the operational system. The U.K. provides the operational control center and primary tracking station, generates a system for preliminary science analysis of the survey data, provides housekeeping analysis software and science data distribution software, and staffs the control center operations. The teams involved in mission planning and operations, and their roles, are identified, and a block diagram of the operations organisation is presented.

Van Holtz, R. C.↗
NASA NTRS1983

Ultraviolet photometry of dwarf novae in outburst

Broad-band photometry from the Astronomical Netherlands Satellite of five dwarf novae at 1550, 1800, 2200, 2500, and 3300 A is presented. EM Cyg in standstill exhibits a flux excess at 3300 A. The lack of a strong extinction feature at 2200 A is seen as suggesting that the reddening is small toward all five systems. Using an independent estimate of the distances, mass flux rates are derived by fitting steady-state, optically thick accretion disk models to the observed UV luminosity. The rate is found to be 3 x 10 to the 17th g/s for Z Cam and EM Cyg in outburst and a factor of 3 smaller of Z Cam in standstill. The models, however, do not reproduce the slope of the Balmer continuum. Of special interest are the observations of outburst rises of SS Aur, SU UMa, and EM Cyg. SS Aur exhibits an exponential increase at a rate of 3.5 mag in 0.5 d. The outburst in EM Cyg also reveals an exponential rise, but at a rate of only 1.2 mag per day.

Wu, C.-C.↗