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The Scientific Context for Exploration of the Moon B Glossary, Acronyms, and Abbreviations ALSEP—Apollo Lunar Surface Experiments Package anorthosite—a type of rock made up mainly of plagioclase feldspar, which has been found in all the Apollo lunar samples and constitutes most of the light-colored crust on the Moon Archaea—a recently recognized domain of prokaryotic life. Single-celled microorganisms that lack a nucleus, are morphologically similar to bacteria but not closely related, having features such as genetic transcription and translation that are different. They are found in very high temperature environments, and include methanogens and hyperthermophiles that may be similar to the first life on Earth ASTP—Apollo-Soyuz Test Project, a joint U.S.–U.S.S.R. mission ATP—Advanced Technology Program of the National Aeronautics and Space Administration (NASA) bacteria—single-celled micro-organisms lacking a nucleus, morphologically similar to Archaea, but not closely related breccia—a rock composed of angular fragments of rocks and minerals in a matrix CAPTEM—Curation and Analysis Planning Team for Extraterrestrial Materials Chang’e—a Chinese National Space Administration lunar orbiter Chesapeake—an ancient subsurface impact crater located in the Chesapeake Bay CHEX—National Research Council’s Committee on Human Exploration Chicxulub—an ancient subsurface impact crater located near Chicxulub, Mexico
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The Scientific Context for Exploration of the Moon chondrite—a type of stony meteorite containing chondrules, roughly spherical bodies containing pyroxene or olivine embedded in the matrix chronostratigraphy—the branch of stratigraphy that studies the absolute age of rocks cool early Earth—hypothesis that the surface of Earth cooled relatively quickly after the formation of the core and the Moon, such that oceans and conditions hospitable for life could exist by 4.3 Ga Copernican—the lunar geologic period from about 1.1 Ga ago to the present Cretaceous/Tertiary boundary—on Earth, the boundary between rocks of the Cretaceous and Tertiary periods, about 65.5 million years ago, around the time of a major extinction event cumulates—igneous rocks formed by the accumulation of crystals from a magma detrital zircons—zircon crystals found in erosional deposits. Some grains are as old as 4.4 Ga and are the oldest known samples of Earth differentiated planetary body—a planetary body whose interior is formed of separate internal geologic units with distinct mineralogical characteristics, e.g., core, mantle, crust Erastosthenian—the lunar geologic period from 1.1 Ga to 3.2 Ga ago ESMD—NASA’s Exploration Systems Mission Directorate EVA—extravehicular activity Exosphere—the highest layer of an atmosphere feldspathic—pertaining to rocks rich in feldspar minerals Ga—one billion years geochronology—determination of the time at which a rock crystallized, usually by radioactive decay of parent-daughter isotope pairs: U-Pb, Sm-Nd, K-Ar, or Rb-Sr hyperthermophile—microorganisms that live in hot environments, above 60°C igneous rocks—rocks crystallized from a magma ISRU—in situ resource utilization Isua greenstone rocks—a geological formation in southwestern Greenland (Isua) composed of ancient surface rocks KREEP—lunar basalts and breccias that are rich in potassium (K), rare-earth elements (REE), and phosphorus (P) Kuiper Belt—a region of the solar system distributed in a roughly circular disk extending from 40 to 100 astronomical units from the Sun
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The Scientific Context for Exploration of the Moon Late Heavy Bombardment (LHB) hypothesis—the theory that meteorite bombardment of the inner solar system declined after accretion of the planets and then peaked again at 3.9 Ga. This event is proposed to have limited the emergence of life on Earth LCROSS—the Lunar Crater Observation and Sensing Satellite, a secondary payload to be launched with the Lunar Reconnaissance Orbiter LEAG—the NASA Lunar Exploration Analysis Group (LEAG) is responsible for analyzing scientific, technical, commercial, and operational issues associated with lunar exploration LPRP—the Lunar Precursor and Robotic Program of the Exploration Systems Mission Directorate LRO—NASA’s Lunar Reconnaissance Orbiter LSAM—NASA’s Lunar Surface Access Module Lunar A—a Japanese Aerospace Exploration Agency lunar mission lunar dynamo—for the ancient Moon, the possibility that a lunar magnetic field might have been generated by the internal motion of an iron-rich molten core Lunar Magma Ocean hypothesis—the hypothesis that when the Moon formed, it was molten to a depth of hundreds of kilometers; its crystallization produced the primary crust and mantle mafic materials—a dark-colored, igneous rocks rich in ferromagnesian minerals magma—molten rock from the interior of a planetary body mantle—the geologic zone above the core and below the crust MER—NASA’s Mars Exploration Rover obliquity—the angle between the orbital plane of an object and the plane of its rotational equator olivine—a magnesium iron silicate mineral (FeMg)2SiO4 parautochthonous—a rock type intermediate in tectonic character between those found at the site of their formation and those that come from another site Permian/Triassic boundary—on Earth, the layer of rocks between the Permian and Triassic periods, about 251 million years ago, the time of a major extinction event petrology—a branch of geology dealing with the composition, mineralogy, origin, occurrence, history, and structure of rocks plagioclase—a type of feldspar and one of the most common rock-forming minerals, (CaNa)(AlSi)4O8 pluton—a large body of igneous rock created by the subsurface intrusion of magma pre-Nectarian period—the lunar geologic period from the formation of the Moon to about 3.9 Ga ago
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The Scientific Context for Exploration of the Moon protolith—the original rocks from which igneous, metamorphic, or sedimentary rocks were formed pyroclastic—a type of rock material formed by volcanic explosion pyroxene—a group of common ferromagnesian rock-forming minerals regolith—on the Moon, the surface rock debris that overlies bedrock remanent magnetization—also called paleomagnetism, the component of a rock’s magnetism that has a fixed direction and is independent of Earth’s magnetic field rheology—the study of the deformation and flow of matter SBE—surface boundary exosphere SELENE—Selenological and Engineering Explorer, a Japanese Aerospace Exploration Agency lunar orbiter SIM—the Apollo Scientific Instrument Module, which contained panoramic and mapping cameras, a gamma-ray spectrometer, a laser altimeter, and a mass spectrometer SIMS—secondary-ion mass spectrometry SMART-1—Small Missions for Advanced Research in Technology, a European Space Agency lunar mission SMD—NASA’s Science Mission Directorate SPA—the lunar South Pole-Aitken Basin stratigraphy—the study of rock layers TEM—transmission electron microscopy U-Pb geochronology—the determination of the age of a rock based on radioactive decay of isotopes of U and Th to Pb, usually in the mineral zircon VSE—NASA’s Vision for Space Exploration xenolith—a foreign inclusion in an igneous rock zircon—a silicate mineral (ZrSiO4)
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