If they were combined into a single body the object would rotate once every 4 h! All these features can be understood if the Moon formed as the result of an oblique impact between Earth and another large, differentiated body, sometimes referred to as Theia, late in Earth's formation. In addition, the Earth–Moon system has a large amount of angular momentum per unit mass. The Moon is depleted in volatile materials such as water. It has a low density compared to the inner planets and it has only a very small core.
Halliday, in Encyclopedia of the Solar System (Third Edition), 2014 9 Planetary SatellitesĮarth's moon possesses a number of unusual features. Although the abundance of water appeared to increase with depth, a possible contamination of the sample on Earth could not be excluded. In the Luna 24 drill core, there is also evidence for about 0.1 wt% of water at a depth of 143 cm. Mare basalts and soils of Luna 24 contain similar concentrations of FeO and this observation indicates that only minor amounts of non-mare material occur at the landing site. The basaltic fragments from this core are very low in TiO 2, low in MgO, and high in Al 2O 3 and FeO and are 3.6–3.4 Ga old. On the basis of color and grain size differences, four layers were identified. In contrast to the drill cores of Luna 16 and Luna 20, stratification was well preserved in the Luna 24 core sample. Luna 24 returned a 1.6-m-long drill core that contained 170 g of mostly fine-grained mare regolith. Several bright patches and rays imply that non-mare material has been dispersed across the basin by impacts such as Giordano Bruno and Proclus. The thickness of these basalts was estimated to be ∼1–2 km. The landing site is characterized by wrinkle ridges, and several distinctive basalt types of Mare Crisium were identified by remote sensing techniques. Luna 24 landed in southern Mare Crisium (12.714° N, 62.213° E) ( Figures 23.9, 23.36, 23.37), about 40 km north of the main basin ring, which is ∼3.5–4.0 km higher than the landing site. Luna 24 was the last and most successful Luna mission. Harald Hiesinger, Ralf Jaumann, in Encyclopedia of the Solar System (Third Edition), 2014 12.10 Luna 24 (August 1976)
Studies revealed medium-titanium fine- and coarse-grained basalts in the Mare Fecunditatis, low-titanium and high-aluminum basalts in the Mare Crisium, and rocks of anorthosite-troctolite-norite series in a Highland region.
The full cycle of lunar samples return is considered: drilling and soil sampling on the lunar surface, delivery, acceptance and primary processing of lunar soil in the ground-based receiving complex, research methods and the major scientific results. However, these are also lunar samples return by Luna-16, Luna-20 and Luna-24. The Luna program is not only the first artificial planet (Luna-1), the first hard landing on the surface of another celestial body (Luna-2), the first images of the Moon Far Side (Luna-3), the first soft landing and the first panoramas of the lunar landscape (Luna-9), the first artificial Moon satellite and the first gamma-ray survey of the lunar surface (Luna-10, Luna-12), and the first lunokhods (Luna-17, Luna-21). Evgeny Slyuta, in Sample Return Missions, 2021 Abstract