Real time digital videomagnetograph at the Aerospace San Fernando Solar Observatory
Design criteria for real time digital videomagnetograph at Aerospace San Fernando Solar Observatory
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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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Hydrogen-maser time and frequency standard at Agassiz Observatory
Hydrogen maser time and frequency standards at Agassiz observatory for long baseline interferometry via radio telescope, discussing Loran C
Levine, M. W.↗
Skylab as factory, worksite and observatory
Skylab as orbital factory, worksite and observatory for experiments in science, technology, materials science and manufacturing
Lundholm, J. G.↗
A description of the lunar ranging station at McDonald Observatory
McDonald Observatory lunar ranging station including telescope matching optics, guiding, timing equipment, pulsed ruby laser system and calibration procedures
Currie, D. G.↗
Crab Nebula pulsar radio pulse arrival times at Arecibo Observatory
Tables of Crab Nebula pulsar radio pulse arrival times at Arecibo observatory
Counselman, C. C., III↗
Delta-85 Orbiting Solar Observatory-H (OSO-H) Operations summary
The objectives of the Orbiting Solar Observatory (OSO-H) are discussed. Subjects considered are the: (1) mission objectives, (2) mission plan, (3) post launch operations, (4) communications, and (5) test operations. Illustrations of the satellite configuration and the Delta 85 launch vehicle are included.
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Haystack Observatory
Radio astronomy programs comprise three very-long-baseline interferometer projects, ten spectral line investigations, one continuum mapping in the 0.8 cm region, and one monitoring of variable sources. A low-noise mixer was used in mapping observations of 3C273 at 31 GHz and in detecting of a new methyl alcohol line at 36,169 MHz in Sgr B2. The new Mark 2 VLBI recording terminal was used in galactic H2O source observations using Haystack and the Crimean Observatory, USSR. One feature in W29 appears to have a diameter of 0.3 millisec of arc and a brightness temperature of 1.4 x 10 to the 15th power K. Geodetic baseline measurements via VLBI between Green Bank and Haystack are mutually consistent within a few meters. Radar investigations of Mercury, Venus, Mars, and the Moon have continued. The favorable opposition of Mars and improvements in the radar permit measurements on a number of topographic features with unprecedented accuracy, including scarps and crater walls. The floor of Mare Serenitatis slopes upward towards the northeast and is also the location of a strong gravitational anomaly.
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High Energy Astronomy Observatory, Mission C, Phase A. Volume 2: Preliminary analyses and conceptual design
An analysis and conceptual design of a baseline mission and spacecraft are presented. Aspects of the HEAO-C discussed include: baseline experiments with X-ray observations of space, analysis of mission requirements, observatory design, structural analysis, thermal control, attitude sensing and control system, communication and data handling, and space shuttle launch and retrieval of HEAO-C.
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High Energy Astronomy Observatory, Mission C, Phase A. Volume 3: Appendices
Technical data, and experiment and spacecraft alternatives are presented in support of the HEAO-C, whose primary objective is a detailed study of the more interesting high energy sources, using grazing incidence X-ray telescopes and a spacecraft pointing accuracy of + or - 1 arc minute. The analyses presented cover the mission analysis and launch vehicle; thermal control trade studies and supporting analyses; attitude sensing and control analyses; electrical systems; and reliability analysis. The alternate experiments which were considered are listed, and the advantages and disadvantages of several alternate observatory configurations are assessed.
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Orbit selection considerations for earth observatory satellites
All the possible circular sun-synchronous orbits for earth observatory satellites are displayed, which have orbital altitudes between 740 and 1,115 kilometers (approximately 400 to 600 nautical miles) and have either a 16, 17, or 18 day repeat cycle for the ground trace. It was found that there are 9 orbits with a 16 day repeat cycle, 17 orbits with a 17 day repeat cycle, and 7 orbits with an 18 day repeat cycle meeting the requirements. For each of these, various characteristics such as ideal ground trace patterns, swathing patterns, and daily drift are displayed. The solar elevation angle along the orbit and the change in the solar elevation angle with season are given. This presentation of general orbital characteristics has application to finding approximate orbital elements and selecting orbits for many types of earth sensing satellite missions.
Cooley, J. L.↗
High Energy Astronomy Observatory star tracker search program
The development of a control system to accommodate the scientific payload of the High Energy Astronomy Observatory (HEAO) is discussed. One of the critical elements of the system is the star tracker subsystem, which defines an accurate three-axis attitude reference. A digital computer program has been developed to evaluate the ability of a particular star tracker configuration to meet the requirements for attitude reference at various vehicle orientations. Used in conjuction with an adequate star catalog, the computer program provides information on availability of stars for each tracker and on the ability of the system to maintain three-axis attitude reference throughout a representative sequence of vehicle orientations.
Weiler, W. J.↗
Sensor lighting considerations for earth observatory satellite missions
Facets of sensor lighting conditions for Earth observatory satellite missions are considered. Assuming onboard sensors of a given width viewing perpendicular to the subsatellite ground track along sun-synchronous orbits with various nodes, the ground trace of the ends of the sensor coverage were found, as well as the variation in solar illumination on the ground across the line covered by the sensor during the day for any point along the orbit. The changes with season and variation during the year were also found.
Cooley, J. L.↗
Geomagnetic survey by the polar-Orbiting Geophysical Observatories.
Summary of reduced data from the polar Orbiting Geophysical Observatories OGO 2 and 4, spanning the time period from Oct. 14, 1965 to the end of 1967. A brief discussion of the accuracy of the observations is followed by a description of the data extent. It is shown that the quantity of data acquired by the OGO magnetometers far exceeds the total for all other magnetic survey sources. Data acquisition for only about a two-week interval gives virtually complete global coverage. Procedures and considerations underlying the data analysis performed are discussed. Suggestions for further work are presented.
Cain, J. C.↗
Experiment to measure hard solar and celestial X-rays from the fifth Orbiting Solar Observatory.
In this paper we describe an experiment designed to measure solar and celestial X-rays in the energy range between 15 to 250 keV. The experiment was flown on the fifth Orbiting Solar Observatory which was launched on Jan. 22, 1969. Up to the time of this writing the instrument continues to operate satisfactorily.
Frost, K. J.↗
Ultraviolet photometry from the Orbiting Astronomical Observatory. II Interstellar extinction.
Evaluation of interstellar extinction curves over the region from 3600 to 1100 A for 17 stars. The observations were made by the two Wisconsin spectrometers on board the Orbiting Astronomical Observatory 2, with spectral resolutions of 10 and 20 A. The extinction curves generally show a pronounced maximum at 2175 plus or minus 25 A, a broad minimum in the region from 1800 to 1350 A, and finally a rapid rise to the far-ultraviolet. Large extinction variations from star to star are found, especially in the far-ultraviolet; however, with only two possible exceptions in this sample, the wavelength at the maximum of the extinction bump is essentially constant. These data are combined with visual and infrared observations to display the extinction behavior over a range in wavelength of about a factor of 20. The observations appear to require a multicomponent model of the interstellar dust.
Bless, R. C.↗
The radio astronomy explorer satellite, a low-frequency observatory.
The RAE-1 is the first spacecraft designed exclusively for radio astronomical studies. It is a small, but relatively complex, observatory including two 229-meter antennas, several radiometer systems covering a frequency range of 0.2 to 9.2 MHz, and a variety of supporting experiments such as antenna impedance probes and TV cameras to monitor antenna shape. Since its launch in July, 1968, RAE-1 has sent back some 10 billion data bits per year on measurements of long-wavelength radio phenomena in the magnetosphere, the solar corona, and the Galaxy. In this paper we describe the design, calibration, and performance of the RAE-1 experiments in detail.
Weber, R. R.↗
Dimensional stability and micromechanical properties of materials for use in an Orbiting Astronomical Observatory.
This paper considers the problem of irreversible dimensional changes of the order of one thousandth of an inch per inch in several candidate materials for orbiting observatories. Although there are a number of potential sources for such dimensional changes, those given major consideration here are applied stresses and residual stresses. Results of room-temperature microyield strength (MYS) and microcreep tests to detect permanent strains associated with both short- and long-duration loading are reported for several engineering materials, including four aluminum alloys (2024, 5456, 6061, and 2014), I400 beryllium, TZM molybdenum, AZ31 magnesium, two titanium alloys (Ti-6Al-4V and Ti-5Al-2.5Sn), 321 stainless steel, a graphite/epoxy composite, and low-expansion glass ceramics. The data indicate that: metallic materials have no true elastic limit; the MYS cannot be predicted reliably from, and is appreciably less than, the conventional yield strength: significant microcreep and stress relaxation can occur at stresses somewhat below the MYS.
Marschall, C. W.↗
Minor constituents in planetary atmospheres - Ultraviolet spectroscopy from the Orbiting Astronomical Observatory.
Orbiting Astronomical Observatory data between 2000 and 3600 A, obtained by the Wisconsin Experimental Package objective grating scanning spectrometer, are used to set upper limits to the abundances of many minor constituents in the atmospheres of Mars, Jupiter, Saturn, and Venus.
Owen, T.↗