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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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Implications of Lunar 9 moon probe, sputtering yield reduction due to surface roughness, water formation by solar wind bombardment, photometric function of moon, and chemical sputtering
Tracking data for Lunar Orbiter I producing first estimate of overall gravitational field of Moon, noting spacecraft will not impact on Moon before completing photographic mission
Plasma shadow formation on dark side of moon, using solar wind-moon interaction model
The use of the earth-moon system for radio tracking has several potentially useful aspects, from a scientific standpoint: extension of the baseline by two orders of magnitude, absence of lunar atmosphere, higher-velocity parallax with a longer period, and the moon's more modellable rotation. The facility would be a convenient base station for other research, not directly involving the tracking capability, but utilizing its orbiting data link features.
Results concerning the distribution of mascons on the moon have been obtained from an analysis of Apollo 8, 10, 11, and 12 lunar orbit missions. It was concluded that the tugging and pulling by the moon on the orbit plane of the Apollo spacecraft yields qualitative information concerning the distribution of the mascons.
A search was made for the possible existence of magnetic monopoles on the moon using magnetic observations from magnetometer experiments on Explorer 33 and 35. A series of 37 orbital plots were analyzed and it was determined that the net number of magnetic monopoles was less than 1 per 10 to the 7th power cc. This is equivalent to the difference in the number of northern and southern magnetic monopoles within the moon being less than 1 per 10 to the 31st power nucleons. Searches for monopoles from lunar samples have also proven negative.
Electromagnetic induction in the moon driven by fluctuations of the interplanetary magnetic field is used to determine the lunar bulk electrical conductivity. The present data clearly show the north-south and east-west transfer function difference as well as high frequency rollover. The difference is shown to be compatible over the mid-frequency range with a noise source associated with the compression of the local remanent field by solar wind dynamic pressure fluctuations. Models for two, three, and four layer; current layer, double current layer, and core plus current layer moons are generated by inversion of the data using a theory which incorporates higher order multipoles. Core radii conductivities generally are in the range 1200 to 1300 km and 0.001 to 0.003 mhos/m; and for the conducting shell 1500 to 1700 km with 0.0001 to 0.0007 mhos/m with an outer layer taken as nonconducting. Core temperature based on available olivine data is 700 to 1000 C.
The need for a task that would collate and interpret Apollo results and provide a synthesized view of the moon is discussed. Comparisons are made between earth and moon structure and history.
Measurements of the microwave emission from the moon and their interpretation in terms of the thermophysics of that body are reviewed. Variations of the brightness temperatures of the moon during a lunation and during eclipses when combined with infrared and radar measurements yield a precise set of physical parameters for the upper few meters of the lunar soil. These parameters include the density, thermal conductivity, dielectric constant, radio absorption coefficients, and the mean temperature gradiant.
The objective of the passive seismic experiment is to measure vibrations of the lunar surface produced by all natural and artificial sources of seismic energy and to use these data to deduce the internal structure and constitution of the moon and the nature of tectonic processes which may be active within the moon. Lunar seismic signals are discussed together with the sources of these signals, and aspects of lunar structure and dynamics. Seismic signals from approximately 250 natural events and from two man-made impacts have been recorded during seven months of operation of the two seismic stations installed during Apollo missions 11 and 12.
The papers describe earth-based and in situ surface measurements of the thermal characteristics of lunar-type materials. A geophysical interpretation of the thermal history of the moon is given. Microwave emission from the moon and radar mapping of lunar surface roughness are studied. Lunar thermal aspects from Surveyor data, lunar surface temperatures from Apollo 11 data, the development of an in situ thermal conductivity measurement for the lunar heat flow experiment, and the Apollo 15 lunar heat flow measurement are reviewed. Thermal properties of granulated materials, thermal property measurements on lunar material returned by Apollo 11 and 12 missions, and thermal characteristics of lunar surface roughness are discussed. Individual items are abstracted in this issue.
Consideration of those aspects of the radio emission from the moon which are directly important in interpreting the emission observations. Thermophysical models of the moon can be constructed which explain the emission to the accuracy of the measurements. The variations during lunations of the radio brightness temperatures measured in the wavelength range from 1 mm to about 5 cm can be reproduced by homogeneous models with a thermal parameter in the range from 800 to 1200 cgs units, a dielectric constant about equal to 2, and a loss tangent of about 0.008.
Boundary condition asymmetries inherent in the solar wind flow past the moon are included in a cylindrical model of the interplanetary magnetic field-moon interaction. Numerical examinations of the sunward side response of this model are compared in the frequency domain with those of symmetrically excited spherical and cylindrical models and two characteristic differences are observed: the response of the asymmetric model is depressed at low frequencies due to magnetic diffusion around a conducting core, and is flattened at high frequencies because of the finite application time of the incident interplanetary magnetic field. The diffusion of field lines around the core is also evident in the time response of the model in the antisolar cavity. The above features of the lunar response resulting from boundary condition asymmetries are shown to be evident in observational measurements.
This paper reports some preliminary results from the suprathermal ion detectors deployed on the lunar surface by the Apollo 12 and 14 astronauts. Salient features of these results include: the possible observation of sporadic venting of gas from the lunar surface; evidence for a prompt ionization and acceleration mechanism operating in the lunar exosphere; and a preliminary measurement yielding approximately 1 month for the e-folding decay time for the heavier components of the exhaust gases from the Apollo lunar landing systems. Prominent phenomena from which these results have been derived are: (1) ion bursts of low to moderate energy seen in conjunction with lunar sunrise and sunset; (2) solar wind energy ions detected on the night side of the moon; (3) ions of several keV energy seen during the lunar sunset to midnight quadrant of the moon's orbit; (4) magnetosheath ion flux enhancements; (5) ion bursts generated by the lunar impact of the Apollo 13 Saturn upper stage; and (6) geomagnetic storm associated ion flux variations in the earth's magnetotail.
The selenographic positions of the observed lunar features are solved for, or estimated directly from, angular measurements made from the orbiting spacecraft (Apollo missions 8, 10, 11, 12, 14, and 15) to the landmark, using least-squares techniques. It appears that the radius values derived from the Apollo landmark data provide some proof of the existence of a displacement between the center of figure and center of mass of the moon along the earth-moon line. In addition, all three components of the estimated crater locations should be useful toward establishing a selenodetic reference system for interpreting or reducing earth-based observation data.
The analysis of lunar samples has shown that the carbon chemistry of the moon is entirely different from the carbon chemistry of the earth. Lunar carbon chemistry is more closely related to cosmic physics than to conventional organic chemistry. Sources of carbon on the moon are considered, giving attention to meteorites and the solar wind. The approaches used in the analysis of the samples are discussed, taking into account the method of gas chromatography employed and procedures used by bioscience investigators in the study of the lunar fines. The presence of indigenous methane and carbide in the lunar fines was established. Reactions and processes taking place on the lunar surface are discussed.
The electromagnetic response of the Moon to excitation by the time dependent fluctuations of the interplanetary magnetic field is given for the dark or antisolar hemisphere of the Moon. Six hours of time series data from the Explorer 35 magnetometer and the lunar surface magnetometer on Apollo 12 are used to obtain the Fourier spectral amplitudes of the surface and interplanetary fields from which transfer functions are calculated for the east-west, north-south, and vertical directions at the Apollo site. A critical discussion of lunar conductivity profiles derived from night side radial magnetic field data and vacuum scattering theory is presented. Limitations are shown that there is no evidence for a lunar core as conducting as 0.01 mhos/m.
An analytic solution for the magnetic field in the space defined by a spherical moon and its downstream cylindrical cavity formed by the solar wind is derived for interplanetary magnetic fields both parallel and perpendicular to the cavity axis. By superposition, the solution is obtained for arbitrary orientations of the interplanetary field. The theory is quasi-static and is formulated in terms of a scalar magnetic potential. Thus the moon model consists of a core of arbitrary size and infinite electrical conductivity surrounded by a nonconducting shell; the cavity volume is assumed to be nonconducting. The variation of the magnetic field on the lunar surface, both on the sunlit and on the dark side hemispheres, and on the cavity boundary is presented for various values of core radius. The solution yields the distribution of currents on the lunar sunlit surface and the surface of the cavity. Theoretical transfer functions are presented and their variations with position on the lunar surface and with core size are discussed.