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Results are briefly described of efforts undertaken to assign proper electron transitions to the Auger lines of copper. Based on these investigations, using X-ray excitation and higher resolution, all three prominent Auger peaks of copper were determined to be L3MM type rather than L2MM type.
The lunar surface was mapped with respect to Mg, Al, and Si, as Al/Si and Mg/Si ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The Al/Si and Mg/Si chemical ratios correspond to that for anorthositic gabbro through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust or material similar to it as the Descartes landing site.
The effects of lifting rotor blade torsion, blade flap bending flexibility and rotor support flexibility on rotor stability and random response are described. The subjects discussed are: (1) blade representation and method of analysis, (2) random gust response statistics for coupled torsion-flapping rotor blade vibrations, (3) flap bending corrections to the rigid blade analysis of lifting rotors, and (4) effects of rotor support flexibility. The response of linear periodically time varying systems to random excitation is examined.
Experimental intensity ratios of Auger transitions for Co, Ni, Cu, and Zn as well as the relative L sub 2 and L sub 3 level widths of Cu and Zn, derived from their photoelectron spectra, are presented. Evidence is presented that a great deal of vacancy reorganization took place following photoionization and prior to Auger emission. These reorganizations are assumed to be due to Coster-Kronig transitions f sub 23. These results are compared with theoretical calculations and agree with predicted discontinuity at Z = 30 where f sub 23 transitions become energetically impossible.
The lunar surface was mapped with respect to Mg, Al and Si as Al/Si and Mg/Si ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The Al/Si and Mg/Si chemical ratios correspond to those for anorthositic gabbro through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust, or material similar to it, at the Descartes landing site.
Although only part of the information from the X-ray fluorescence geochemical experiment has been analyzed, it is clear that the experiment was highly successful. Significant compositional differences among and possibly within the maria and highlands have been detected. When viewed in the light of analyzed lunar rocks and soil samples, and the data from other lunar orbital experiments (in particular, the Apollo 15 gamma-ray spectroscopy experiment), the results indicate the existence of a differential lunar highland crust, probably feldspathic. This crust appears to be related to the plagioclase-rich materials previously found in the samples from Apollo 11, Apollo 12, Apollo 14, Apollo 15, and Luna 16.
Detailed sequential study by photoelectron spectroscopy of the change in valence states of iron in Fe2O3, Fe3O4, FeO, and Fe foil samples, showing that chemical reduction does take place on the sample surface when argon ion bombardment occurs. These spectra give evidence that, after prolonged ion bombardment, the surface of all four samples consisted predominantly of iron in the metallic state. Argon ion sputtering of 15 silicate and oxide samples under similar experimental conditions produced surface darkening only in samples containing iron. Monitoring of the photoelectron peak of carbon during the experiment indicates that ion-bombardment darkening is not due to the buildup of hydrocarbon surface contaminants in the oil-free high-vacuum system used by the authors. On the basis of these studies, it is concluded that solar-wind bombardment should be included as one of the possible mechanisms for producing darkening of the lunar surface.
Some preliminary results are presented of X-ray photoelectron spectroscopic measurements of various valence states of Fe and Cu in several compounds using a novel method, ion-sputtering reduction. The potential usefulness of this method for other chemical-physical studies such as multiplet splitting, shakeup satellites, and isoelectronic shifts is emphasized.
Mapping of the lunar surface with respect to magnesium, aluminum, and silicon as aluminum/silicon and magnesium/silicon intensity ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide new data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The aluminum/silicon and magnesium/silicon concentration ratios correspond to those for anorthositic gabbros through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust or material similar to it at the Descartes landing site.
High-resolution LMM Auger spectra of Cu and Zn obtained by X-ray excitation are shown to contain fine structures which have not been reported previously. An attempt has been made to classify these fine structures in terms of pure L-S coupling of the final vacancies of the atom. The agreement between the calculated and the observed energy separations of the fine-structure lines is good within the accuracy of the Hartree-Fock approximation.
Several spectrometers carried in the Service Module of the Apollo 15 and Apollo 16 spacecraft were employed for the compositional mapping of the lunar surface. The observations involved the measurements of secondary (fluorescent) X-rays, gamma rays and alpha particle emissions. A large scale compositional map of over 20 percent of the lunar surface was obtained for the first time. It was possible to demonstrate interesting chemical differences between the mare and the highlands, to find specific areas of high radioactivity and to learn something about the composition of the moon's hidden side. Further the same devices were used to obtain useful astronomical data during the return to earth.
The X-ray fluorescence spectrometer, carried in the scientific instrument module bay of the command and service module, was used for orbital mapping of the lunar surface composition and X-ray galactic observations during transearth coast. The lunar surface measurements involved observations of the intensity and characteristic energy distribution of the secondary or fluorescent X-rays produced by the interaction of solar X-rays with the lunar surface. The astronomical observations consisted of relatively long periods of X-ray measurement of preselected galactic sources such as Cygnus (Cyg X-1) and Scorpius (Sco X-1).
An analysis of coupled torsion-flapping rotor blade vibrations in response to atmospheric turbulence revealed that at high rotor advance ratios anticipated for future high speed pure or convertible rotorcraft both flapping and torsional vibrations can be severe. While appropriate feedback systems can alleviate flapping, they have little effect on torsion. Dynamic stability margins have also no substantial influence on dynamic torsion loads. The only effective means found to alleviate turbulence caused torsional vibrations and loads at high advance ratio was a substantial torsional stiffness margin with respect to local static torsional divergence of the retreating blade.
The prime purpose of the X-ray fluorescence spectrometer carried in the Scientific Instrument Module of the Command-Service Module was to map the lunar surface with respect to its chemical composition. Results are presented for Al, Mg, and Si as Al/Si and Mg/Si ratios for the various features overflow by the spacecraft. The lunar surface measurements involved observations of the intensity and characteristic energy distribution of the secondary or fluorescent X rays produced by the interaction of solar X rays with the lunar surface. The results showed that the highlands and maria are chemically different, with the highlands having considerably more Al and less Mg than the maria. The mare-highland contact is quite sharp and puts a limit on the amount of horizontal transport of material. The X-ray data suggest that the dominant rock type of the lunar highlands is a plagioclase-rich pyroxene bearing rock probably anorthositic gabbro or feldspathic basalt.
Results of an investigation of the discontinuity in the L2 level width and the L3-M45M45/L2-M45M45 Auger intensity ratio at Z=30. The afore-mentioned intensity ratio is found to undergo a sudden decrease at Z=30. Relative L2 and L3 level widths of Cu and Zn are derived from photoelectron spectra; while the L3 width increases from Cu to Zn, the L2 width of Cu is greater than that of Zn, contrary to the general trend. The above-mentioned discontinuity is traced to a discontinuity in the Coster-Kronig transition probability f sub 23 predicted in earlier calculations.
The somewhat controversial question of which elastic blade modes are essential in the flight mechanics of hingeless rotorcraft is studied on the basis of quasi-steady linear aerodynamics including reversed flow effects and uniform inflow. The modes are for the rotating blade, and intermode aerodynamic coupling terms are retained. The criteria for judging elastic mode effects include 19 hub moment and force derivatives, rotor trim data, rotor stability charts for lagged hub moment feedback, step gust and random gust responses. Fixed hub and constant chord blades with widely differing elasticity and inertia and with moderate twist are assumed.
A number of experiments carried in orbit on the Apollo 15 and 16 spacecraft were used in the compositional mapping of the lunar surface. The observations involved measurements of secondary (fluorescent) X-rays, gamma rays and alpha particle emissions. A large scale compositional map of over 20% of the lunar surface was obtained for the first time. It was possible to demonstrate significant chemical differences between the mare and the highlands, to find specific areas of high radioactivity and to learn something about the composition of the moon's hidden side.
The effects of three gyroless rotor feedback systems: (1) coning feedback, (2) proportional tilting feedback, and (3) a combination of these on the rotor-body dynamics of hingeless rotorcraft are studied with a simplified analytical model in the advance ratio range from 0 to .8. Combinations of feedback phase angles and control phase angles are selected to minimize control cross coupling and control sensitivity changes between low and high speed flight. For the feedback systems thus selected the effects of feedback gain and control actuator time lag on the stability both with fixed hub and in free flight is studied, whereby the rotorcraft is free in pitch, roll and vertical motion but otherwise restrained. For the free flight is studied, whereby the rotorcraft is free in pitch, roll and vertical motion but otherwise restrained. For the free flight conditions the effects of a horizontal tail are also determined in itself and in combination with the rotor feedback systems.