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SSA-A spacecraft magnetic tests

In the initial magnetic tests the spacecraft perm moment as received was 43 milliampere-meter squared (pole-cm), which was reduced by deperm treatment to milliampere-meter squared. Facility fluxgate probe bias results indicated Z axis bias at the SSS-A fluxgate magnetometer position to be about one half nanotesla (gamma) after Z axis deperm. The ASCS magnetometers, 01 and 02, were successfully aligned and proper operation of the ASCS system were verified. The spacecraft fluxgate magnetometer was calibrated in both the high and low sensitivity modes after a defective 01 electronics card was replaced. Problems were encountered in the Z axis search coil during calibration and the test was re-scheduled. Final test results indicated that the total perm moment could not be reduced any lower than 35 milliampere-meter squared by deperm treatment. However, the Z axis moment decreased from 22 milliampere-meter squared to 6 milliampere-meter squared after deperm. Correct operation and calibration was verified for all three axes of the spacecraft fluxgate magnetometer and no significant bias was observed during stray field testing. Null and spot calibration of the ASCS magnetometer was completed and the measured spin and attitude coil moments were: 2535 and 9820 milliampere-meter squared respectively.

Roy, T. N.↗

Frequency dependence of ATS-1 observed micropulsations of some geophysical parameters

Low frequency oscillations in the earth's magnetic field at the synchronous orbit were observed with the magnetometer experiment on board the ATS 1 satellite since Dec. 1966. An analysis of oscillations in the range .002 f .02 H3 for the interval Dec. 1966 through Dec. 1968 is reported. It was found that the frequency of an event increases with the sum of Kp for 24 hours prior to the event midpoint. For events with duration greater than 6 hours, the product moment correlation coefficient for frequency f, and the sum Kp was R = 0.87. The best least squares linear fit to the data for these events was f = (0.32) sum Kp = 5.1. For the same events the correlation coefficient for frequency and Dst was R = -0.83.

Mason, F.↗

Spectral and polarization analysis of micropulsations observed at ATS-1

Results are reported for an analysis of low frequency oscillations in the earth's magnetic field as observed at the synchronous orbit by the magnetometer experiment on board ATS 1. Oscillations in the range .002 f .02 H3 for the period Dec. 1966 through Dec. 1967 were studied. The analysis combines a detailed, computer-processed, spectral analysis of selected events with a less detailed manual analysis of all events in the two year time interval from Dec. 1966 to Dec. 1968. The computer analysis revealed that a given event is often characterized by a dominat, narrow, spectral peak whose associated oscillations are almost entirely limited to a plane, together with several minor peaks. Dynamic spectral analyses revealed that minor spectral peaks appear as short isolated bursts. The sense of rotation of the perturbation vector tends to change from right-handed elliptical at the beginning of a burst to left-handed elliptical at the end. The major axis of the polarization ellipse is inclined by typically 30 deg east of radial.

Morris, W.↗

Some characteristics of low-frequency oscillations observed at ATS 1.

Analysis of low-frequency oscillations of the magnetic field at ATS 1 for the 25-month data interval from December 1966 to December 1968. Irregular oscillations and oscillations associated with magnetic storms were excluded from the analysis. Of the 222 events identified, 170 events were oscillating predominantly transverse to the background magnetic field. The oscillations were observed to occur most frequently in the early afternoon hours. They also seemed to occur more frequently during December, January, and February than at other times of the year. During a given individual event the frequency was fairly constant and it varied between .0015 and .02 Hz with a broad peak near .01 Hz. The event duration varied between a minimum of 10 min and a maximum of 14 hours and 26 min. During a given event the amplitude varied. The average maximum amplitude of an event was about 3 gamma.

Cummings, W. D.↗

Possible variation of the gravitational constant over the elements.

We re-examine the theory and data of the Kreuzer experiment to measure the relative difference in the gravitational constant between two elements. Significant errors appear in the statistical analysis of Kreuzer which vitiate his conclusions. The upper bound for the relative difference of F and Br from his experimental data correctly becomes .02, about 10 times the limit already set on the general variation of the gravitational constant over the elements by direct use of a Cavendish balance.

Gilvarry, J. J.↗

Shock tube study of the reaction H plus O2 plus Ar yields HO2 plus Ar

Rate coefficient data for the recombination reaction H + 02 + Ar yields H02 + Ar have been determined from studies of lean hydrogen-oxygen mixtures behind incident shock waves over the temperature range of 948 to 1125 K. Hydroxyl radical concentration profiles were measured by ultraviolet absorption spectroscopy, and rate data were obtained through analysis of induction time and exponential growth parameter data. Analysis of the data yielded a rate coefficient which was generally lower than most of the more recent values obtained from shock tube studies. The effect of boundary layer formation on the conditions behind the shock was also examined and found to be negligible.

Jachimowski, C. J.↗

Further development and testing of the metabolic gas analyzer

Continued development of a metabolic monitor utilizing a mass spectrometer and digital computer to perform measurements and data reduction, is reported. The device prints-out breath-by-breath values for 02 consumption, C02 production, minute volume and tidal volume. The flow is measured by introduction of a tracer gas to the expired gas stream. Design modifications to reduce pressure drop in the flow splitter to one inch of water at 600 liters/min flow and to extend the range of linear flow measurement to 1000 liters/min are discussed.

Source record↗

Eleventh order resonance terms in the geopotential from the orbit of Vanguard 3

The orbit of Vanguard 3 (1959-7A) is strongly resonant with 11th order and odd degree terms in the geopotential. It affords an excellent opportunity to determine a significant linear constraint between these terms. Tracking data on this satellite (in the form of mean Kepler elements) are analyzed over a 3 1/2 year period in the early 1960's, which ends with the orbit having just passed through perfect commensurability. The eccentricity and inclination show the deep resonance variations (up to 0.0002 in e and .02 deg in i) with great clarity. Previous and current geopotential solutions fail to explain these perturbations.

Wagner, C. A.↗

Spectrophotometric results from the Copernicus satellite. I - Instrumentation and performance.

The Princeton telescope-spectrometer on the OAO spacecraft Copernicus scans stellar spectra with a resolution of about 0.05 A between 950 and 1450 A, and twice this in first order between 1650 and 3000 A. The pointing during several minutes is steady within .02 sec, and the measured photometric precision in the shorter wavelength range is limited only by the statistics of photon counts, with 14-sec counts of about 1000 on an unreddened B1 star, m(v) = 5.0, at 1100 A. In the 1650-3000 A wavelength range, phototube noise resulting from cosmic rays makes observations difficult on stars fainter than m(v) = 3.0.

Rogerson, J. B.↗

Induced magnetosphere of the moon. II - Experimental results from Apollo 12 and Explorer 35.

The asymmetric lunar electromagnetic induction theory of Schubert et al. (1973) is tested by using data from the Apollo 12 Lunar Surface Magnetometer and from the Ames magnetometer on Explorer 35. The comparison of data and theory shows that the moon displays an induction asymmetry due to the flow of the solar wind and the formation of the diamagnetic cavity on the darkside. It is inferred that the induced field forms a magnetospheric-like configuration, with the field confined mostly to the crust of the moon. Although the magnetospheric spectrum is time-dependent for all frequencies examined, the distance traveled by the solar wind is so large that a quasi-static magnetospheric configuration can be assumed. The differential power spectrum of the interplanetary magnetic field that excites the moon is compared with the resulting induction spectrum, which has a linear differential power frequency dependence over the frequency range from .0002 to .02 Hz, falling off on either side of these limits. The integrated power in this band is about 5 gamma squared for the interplanetary field local north-south component and about 12 gamma squared for the induced spectrum of this component on the lunar surface.

Smith, B. F.↗

Remote sensing of atmospheric and surface temperatures with microwaves.

Solids, liquids, and gases emit at microwave wavelengths measurable amounts of black-body thermal radiation. Receiver sensitivities readily approach 0.01 K, and permit accurate measurements of land, sea, and atmospheric temperatures. Sea and land temperature measurements must be corrected for the effects of surface emissivity, but these effects can often be measured or estimated. Observations near the 5 mm wavelength 02 resonances can yield atmospheric temperature profiles with an approximate accuracy of 2 K for altitudes 0-80 km. Such measurements from balloons and aircraft suggest that the planned earth-orbital satellite experiments will yield data valuable for numerical weather prediction. Ground-based radio telescopes and planetary-probes have yielded similar information about the surfaces and atmospheres of other planets.

Staelin, D. H.↗

Detection of moisture and moisture related phenomena from Skylab

The author had identified the following significant results. Soil moisture and precipitation variations were not detectable as tonal variations on the S19OA IR B and W photography. Some light tonal areas contained high precipitation .83 inches and high moisture content 21.1% while other light tonal areas contained only .02 inches precipitation and as little as 0.7% moisture. Similar variations were observed in dark tonal areas. This inconsistency may be caused by a lapse of 3 to 4 days from the time precipitation occurred until the photographs were taken and the fact that in the first inch of soil the measured soil moisture was generally less than 5.0%. For overall tonal contrast, the aerial color, color IR and aerial B and W appear to be the best. Cities stand out from the landscape best in the aerial color and color IR, however, to see major street patterns a combination of the two aerial B and W bands and the two IR B and W bands may be desirable. For mapping roads it is best use all 6 bands. For lake detection, the IR B and W bands would be the best but for streams the aerial B and W band would be better. The aerial color, color IR, and the two IR B and W bands are best for distinguishing cultivated and non-cultivated areas, whereas the two aerial B and W bands are better for seeing local relief. Clouds may be best seen in the aerial color and color IR bands.

Eagleman, J. R.↗

Temperature and electrical conductivity of the lunar interior from magnetic transient measurements in the geomagnetic tail

Magnetometers were deployed at four Apollo sites on the moon to measure remanent and induced lunar magnetic fields. Measurements from this network of instruments were used to calculate the electrical conductivity, temperature, magnetic permeability, and iron abundance of the lunar interior. Global lunar fields due to eddy currents, induced in the lunar interior by magnetic transients in the geomagnetic tail field, were analyzed to calculate an electrical conductivity profile for the moon: the conductivity increases rapidly with depth from 10 to the minus 9 power mhos/meter at the lunar surface to .0001 mhos/meter at 200 km depth, then less rapidly to .02 mhos/meter at 1000 km depth. A temperature profile is calculated from conductivity: temperature rises rapidly with depth to 1100 K at 200 km depth, then less rapidly to 1800 K at 1000 km depth. Velocities and thicknesses of the earth's magnetopause and bow shock are estimated from simultaneous magnetometer measurements. Average speeds are determined to be about 50 km/sec for the magnetopause and 70 km/sec for the bow shock, although there are large variations in the measurements for any particular boundary crossing.

Dyal, P.↗

Measurements of NH3 absorption coefficients with a C-13/O-16/2 laser

Measurements of NH3 absorption coefficients are presented for several transitions of a C-13(O-16)2 laser for small concentrations of NH3(p less than 1 torr) for absorption lines broadened to 1 atm with N2. NH3 absorption coefficients were determined for laser transitions R(8)(920.2194 wavelengths/cm) to R(28)(933.8808 wavelengths/cm) of the 00 1 - (10 0,02 0)I band. The strongest absorption coefficient K = 36.09 + or - 1.43 per (atm-cm) was measured for the R(18) transition for the NH3 line, aQ(6,6), and is larger than has been found in any previous measurements with a CO2 laser. The dependence of K on total pressure was also obtained for select transitions, and the frequency separation between the R(18) laser transition and the neighboring NH3 line aQ(6,6) was determined to be 550 + or - 50 MHz. These results are significant for long path absorption monitoring of NH3 with CO2 lasers since the path length can be reduced by approximately 40% and for heterodyne detection of NH3 since the relative position of the laser transition to the NH3 absorption line is well within the bandpass of Hg-Cd-Te photomixers.

Allario, F.↗

Synoptic maps of solar coronal hole boundaries derived from He 2 304 A spectroheliograms from the manned skylab missions

The disk boundaries of coronal holes have been determined from He II 304 A spectroheliograms which were taken with the Naval Research Laboratory slitless XUV spectrograph during the manned Skylab missions. These boundaries are plotted by Carrington rotation as synoptic charts in both the standard rectangular as well as polar-view projections. The periods of time for which boundaries were determined are 24 May through 28 June 1973 (first manned Skylab mission), 2 August through 24 September 1973 (second manned mission), and 21 November 1973 through 2 February 1974 (third manned mission); the Carrington rotations covered (in part or totally) are 1601 and 02; 160r, 1604, 05 and 06; and 1608, 09 and 10, respectively.

Bohlin, J. D.↗