Apollo 11 drive-tube core samples - An initial physical analysis of lunar surface sediment
Apollo 11 drive-tube core samples from Tranquillity Base, expressing lunar surface environmental processes
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Apollo 11 drive-tube core samples from Tranquillity Base, expressing lunar surface environmental processes
Properties, photometry, and dynamic processes of comets, lunar morphology, and Tungusk meteorite blast
Lunar fines transportation process in mare surface evolution, suggesting electrostatics role from photographic and seismic evidence
Discussion of the nature and properties of lunar rock as deduced from the examination of Apollo lunar rock samples. The topics include the lunar crust, the Fra Mauro formation, the interior of the moon, lunar chronology, surface processes, and earth-moon environment.
As a simulation of erosion processes on the lunar surface, impact craters were formed in dust targets by 2- to 5-micron-diameter polystyrene spheres with velocities between 2.5 and 12 km/sec. For weakly cohesive, thick targets of basalt dust with a maximum grain size comparable to the projectile diameter, the craters had an average projectile-to-diameter diameter ratio of 25, and the displaced mass was 3 orders of magnitude greater than the projectile mass. In a simulation of the effect of a dust covering on lunar rocks, a layer of cohesive, fine-grained basalt dust with a thickness nearly twice the projectile diameter protected a glass substrate from damage, but an area about 50 times the cross-sectional area of the projectile was cleared of all but a few grains. Impact damage was produced in glass under a thinner dust layer.
There is much evidence that the surface transportation of lunar soil has been a major process in the shaping of the lunar surface. Some such transportation has taken place as a result of meteoritic impacts, but theory and laboratory experiments indicate that electrostatic effects resulting from secondary electron emission are the dominant cause of movement of small grains on the surface. The various electrostatic actions are discussed, and a host of unexpected phenomena are described that have turned up in the course of the laboratory experiments.
Single crystal X-ray and energy dispersive electron-probe techniques are used to study the mineralogy and track history of Ibitira. The mineralogical features of the Ibitire eucrite are described and examined in relation to data for other eucrites and howardites and lunar samples. The processes which transformed a presumed igneous texture into a more complex one are discussed.
Laser altimetry data from the Apollo 15, 16, and 17 missions show that the ringed maria surfaces lie on one particular reference surface and that the center of gravity is definitely displaced from the optical center. If these extensive surfaces are assumed to be near-hydrostatic surfaces, then there must have existed a time in lunar history when lunar tides, internal processes, or both were much different than they are today.
Radiographs of the Apollo 15 deepdrill drive tubes were analyzed on an SDS electronic enhancer to determine sedimentary structures in the core samples. The data obtained were compared with all other Apollo mission radiographs and used to make inferences on the character of sedimentary depositional processes on the lunar surface.
A satellite formation model is extended to include evolution of planetary ring material and elliptic orbital motion. In this model the formation of the moon begins at a later time in the growth of the earth, and a significant fraction of the lunar material is processed through a circumterrestrial debris cloud where volatiles might have been lost. Thus, the chemical differences between the earth and moon are more plausibly accounted for. Satellites of the outer planets probably formed in large numbers throughout the growth of those planets. Because of rapid inward evolution of the orbits of small satellites, the present satellite systems represent only satellites formed in the last few percent of the growths of their primaries. The rings of Saturn and Uranus are most plausibly explained as the debris of satellites disrupted within the Roche limit. Because such a ring would collapse onto the planet in the course of any significant further accretion by the planet, the rings must have formed very near or even after the conclusion of accretion.
It is shown that the interdisciplinary study of the nonmare lunar rocks based on trace element, major element, and isotopic data plus petrographic evidence can succeed in amassing a large suite of demonstrably pristine rocks, and that the relative numbers of these rocks are not in accord with statistics amassed on soil fragments and glasses. The term 'pristine' is taken to mean rocks with primary compositions (albeit not necessarily textures) produced by lunar endogenous igneous processes. Melt rocks and crystalline matrix breccias produced by impact processes are excluded. A petrographic synonym for pristine would be 'unremelted, monomict'. It is found that anorthositic norites and noritic anorthosites were rare as primary nonmare rocks. Mechanical mixing appears to have been the dominant petrogenetic process on the highlands.
Results on lunar volatile transport processes have been obtained by studying green and brown glass droplets, orange and black core tube samples and the surface sample 74241 with the Scanning Auger Microprobe (SAM) and by Flameless Atomic Absorption Analysis (FLAA). SAM analyses show that the most dominant volatiles in the top few atomic layers of droplets are Zn and S, confirming that the surface Zn and S are good indicators of pyroclastic origin, and they are not entirely present as ZnS. In addition, FLAA thermal release profiles show that almost all the Zn and Cd are on grain surfaces, indicating that Zn and Cd were completely outgassed from lava fountain products during the volcanic eruption, were recondensed during or after the eruptions, and are thus present as surface coating.
Hadley Rille appears to be a collapsed lava tube/channel, whose formation history may be more intimately related to the mare units sampled at 15 than was previously thought. More work is needed relating samples and observations from Apollo 15 to the rille and its geologic evolution. As the only sinuous rille visited during the Apollo missions, Hadley Rille represents a data source that is directly applicable to the deciphering of processes involved in lunar mare volcanism.
Papers are presented on lunar highlands and lunar geology, igneous processes on the moon, and achondrites. Also considered are the geology, geochemistry, and atmosphere of Venus and Mars. Other topics include comets, cosmic dust, and primitive nebular materials. Experimental and theoretical studies on impact cratering are discussed, along with geological and geochemical studies of impact products.
A workshop entitled, Production and Uses of Simulated Lunar Materials, was convened to define the need for simulated lunar materials and examine related issues in support of extended space exploration and development. Lunar samples are a national treasure and cannot be sacrificed in sufficient quantity to test lunar resource utilization process adequately. Hence, the workshop focused on a detailed examination of the variety of potential simulants and the methods for their production.
The topics are presented in viewgraph form and include the following: (1) mission design choices - implications to a heavy-lift launch vehicle (HLLV); (2) Space Exploration Initiative (SEI) reference launch vehicles; (3) lunar mission profile; (4) Saturn 5 derived HLLV with 2 liquid oxygen (LOX)/RP boosters; (5) National Launch System (NLS) derived HLLV with 4 LOX/RP boosters; (6) first lunar outpost mission performance; (7) future trade studies; and (8) the first lunar outpost definition process.
The process of stationary lunar occultations is considered for observers in LEO. The orbit of the Hubble Space Telescope (HST) is used as a prototype. The noncoplanarity of the HST and lunar orbits disrupts many of the expected stationary events, and orbital drag complicates the prediction problem. In a typical year, the apparent speed of the lunar limb seen by the HST is slower than a typical ground-based event only about 0.7 percent of the time. The orbit prediction can be wrong by as much as 20 deg in 53 days, with most of the error lying in the plane of the orbit.
Previous spectra lead to disparate conclusions about Phobos' composition: primitive (like D- and T-asteroids) and processed materials (like lunar soils). Thermal-IR spectra of Phobos obtained by TES are consistent with materials like lunar soils.