Apollo 11 drive-tube core samples: an initial physical analysis of lunar surface sediment

Two drive-tube core samples were obtained at Tranquillity Base. Fines include much glass, are unweathered, medium gray, loose, nonstructured, very weakly coherent, and demonstrate both accumulation and mixing in a waterless vacuum environment. In contrast to chemical weathering characteristic on the earth, lunar alteration processes are primarily mechanical. We infer that environmental processes of the lunar surface may be expressed as follows: R (regolith) = f(cl, p, r, t, b, a, . . .), in which climate (cl) is constant and the time (t)-de-pendent processes of bombardment (b) and accumulation (a) assume significance unparalleled on the earth because of their effects on parent material (p) and relief (r).     

Apollo 11: exposure of lower animals to lunar material

Lunar material returned from the first manned landing on the moon was assayed for the presence of replicating agents possibly harmful to life on earth. Ten species of lower animals were exposed to lunar material for 28 days. No pathological effects attributable to contact with lunar material were detected.     

Apollo 17 seismic profiling: probing the lunar crust

Apollo 17 seismic data are interpreted to determine the structure of the lunar crust to a depth of several kilometers. Seismic velocity increases in a marked stepwise manner beneath the Taurus-Littrow region at the Apollo 17 site. A thickness of about 1200 meters is indicated for the infilling mare basalts at Taurus-Littrow. The apparent velocity is high (about 4 kilomleters per second) in the material immediately underlying the basalts.     

Light Flashes Observed by Astronauts on Apollo 11 through Apollo 17

The crew members on the last seven Apollo flights observed light flashes that are tentatively attributed to cosmic ray nuclei (atomic number >/= 6) penetrating the head and eyes of the observers. Analyses of the event rates for all missions has revealed an anomalously low rate for transearth coast observations with respect to translunar coast observations.     

Radioactivity of the lunar surface

Diffusion of radon and thoron from the Ilunar surface provides a mechanism for production of a radioactive surface layer on the moon. If the radon and thoron flux from the lunar surface is equal to that measured at the earth's surface, the equilibrium activity of this surface layet is estimated as approximately 1 microcurie per square meter, due to radon and its decay products. This activity consists of alpha particles and gamnmna rays at well-defined energies and of beta rays.     

Apollo 12 lunar material: effects on lipid levels of tobacco tissue cultures

Tobacco tissue cultures grown in contact with lunar material from Apollo 12, for a 12-week period, resulted in fluctuations of both the relative and absolute concentrations of endogenous sterols and fatty acids. The experimental tissues contained higher concentrations of sterols than the controls did. The ratio of campesterol to stigmasterol was greater than 1 in control tissues, but less than 1 in the experimental tissues after 3 weeks. High relative concentrations (17.1 to 22.2 percent) of an unidentified compound or compounds were found only in control tissues that were 3 to 9 weeks of age.     

Apollo 12 lunar samples: trace element analysis of a core and the uniformity of the regolith

Four core and soil samples from Apollo 12 are enriched in a number of trace elements of meteoritic origin to virtually the same degree as Apollo 11 soil. An average meteoritic influx rate of about 4 x 10(-9) gram per square centimeter per year thus seems to be valid for the entire moon. A sample from a light gray, coarse-grained layer in the core resembles lunar basalts in composition, but is enriched by factors of 10(4) to 10(5) in bismuth and cadmium.     

Radioactivity induced in apollo 11 lunar surface material by solar flare protons

Comparison of values of the specific radioactivities reported for lunar surface material from the Apollo 11 mission with analogous data for stone meteorites suggests that energetic particles from the solar flare of 12 April 1969 may have produced most of the cobalt-56 observed.     

Gas analysis of the lunar surface

The rare gas analysis of the lunar surface has lead to important conclusions concerning the moon. The large amounts of rare gases found in the lunar soil and breccia indicate that the solar atmosphere is trapped in the lunar soil as no other source of such large amounts of gas is known. The cosmogenic products indicate that the exposure ages of the 17 lunar rocks measured vary from 20 to 400 million years with some grouping of the ages. The most striking feature is the old potassium-argon age which for the 14 rocks analyzed varies from 2.5 to 3.8 billion years. It is concluded that Mare Tranquillitatis crystallized about 4 billion years ago from a molten state produced by a large meteorite impact or volcanic flow.     

Gravity: first measurement on the lunar surface

The gravity at the landing site of the first lunar-landing mission has been determined to be 162,821.680 milligals from data telemetered to earth by the lunar module on the lunar surface. The gravity was measured with a pulsed integrating pendulous accelerometer. These measurements were used to compute the gravity anomaly and radius at the landing site.     

Luminescence of apollo 11 lunar samples

Luminescence measurements were made of four lunar rocks, two terrestrial rocks (granite and gabbro), and one terrestrial mineral (willemite) by comparing the spectral curves with the curve of a barium sulfate standard. Efficiencies with 3000 angstrom excitation were < 6 x 10(-5) for the lunar samples, < 8 x 10(-5) for gabbro of very similar composition to the lunar samples, approximately 10(-4) for granite, and approximately 2 X 10(-2) for willemite. If these are typical values for other ultraviolet excitation wavelengths, the Apollo 11 site appears to contribute little to the observed lunar luminescence.     

Apollo 12 magnetometer: measurement of a steady magnetic field on the surface of the moon

The Apollo 12 magnetometer has measured a steady magnetic field of 36 +/- 5 gammas on the lunar surface. Surface gradient measurements and data from a lunar orbiting satellite indicate that this steady field is localized rather than global in its extent. These data suggest that the source is a large, magnetized body which acquired a field during an epoch in which the inducing field was much stronger than any that presently exists at the moon.     

Chondritic meteorites and the lunar surface

The landing dynamics of and soil penetration by Surveyor I indicated that the lunar soil has a porosity in the range 0.35 to 0.45. Experiments with Surveyor III's surface sampler for soil mechanics show that the lunar soil is approximately incompressible (as the word is used in soil mechanics) and that it has an angle of internal friction of 35 to 37 degrees; these results likewise point to a porosity of 0.35 to 0.45 for the lunar soil. Combination of these porosity measurements with the already-determined radar reflectivity fixes limits to the dielectric constant of the grains of the lunar soil. The highest possible value is about 5.9, relative to vacuum; a more plausible value is near 4.3. Either figure is inconsistent with the idea that the lunar surface is covered by chondritic meteorites or other ultrabasic rocks. The data point to acid rocks, or possibly vesicular basalts; carbonaceous chondrites are not excluded.     

Impact metamorphism of lunar surface materials

Silicate grains from Tranquillity Base have shock-induced features ranging from internal fragmentation through complete disruption of the lattice to thermal melting. Half the crystalline grains with diameters less than 125 micrometers have features of shock equivalent to those produced in the laboratory at pressures greater than about 40 kilobars. One quarter have features indicative of pressures greater than 90 kilobars. These properties together with great quantities of melt glass and aluminum-26 in the fine-grained material are indicative of repeated shock-loading by meteoritic bombardment over long periods of time.     

Elemental composition of lunar surface material

Elemental abundances, so far obtained, derived from the analysis of Apollo 11 lunar material are reported. Similarities and differences exist between lunar material, the eucritic achondrites, and the augite achondrite Angra dos Reis, the analysis of which is also reported.     

Apollo 11 Laser Ranging Retro-Reflector: Initial Measurements from the McDonald Observatory

Acquisition measurements of the round-trip travel time of light, from the McDonald Observatory to the Laser Ranging Retro-Reflector deployed on the moon by the Apollo 11 astronauts, were made on 20 August and on 3, 4, and 22 September 1969. The uncertainty in the round-trip travel time was +/- 15 nanoseconds, with the pulsed ruby laser and timing system used for the acquisition. The uncertainty in later measurements of a planned long-term sequence from this observatory is expected to be an order of magnitude smaller. The successful performance of the retro-reflector at several angles of solar illumination, as well as during and after a lunar night, confirms the prediction of thermal design analyses.