Search NASA⌕ Search

SEARCH · Search NASA

Results for “LUNAR EVOLUTION”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Evolution of the lunar orbit with temperature- and frequency-dependent dissipation

The importance of the thermal evolution of the earth and the moon for the dynamical history of the earth-moon system is investigated using a model of coupled thermal-dynamical evolution of this system, in which the sun's gravity is ignored and only the gravitational interaction of the earth-moon system is included, along with oceanic dissipation. Results suggest that most of the lunar angular momentum was received from the earth via solid tides within the first few 100 million years after the formation of the earth and the moon, indicating that oceanic dissipation plays a minor role. It is suggested that solid tides, rather than ocean tides, might be most important to the lunar-orbit evolution.

Ross, M. N.↗
NASA NTRS1990

Exploration initiatives: Post-Apollo manned spaceflight thrusts

Post-Apollo manned spaceflight thrusts; pre-July 20, 1989 studies; Space Station, Moon, and Mars pathway; possible mission scenarios; lunar transportation vehicles; lunar evolution summary; Mars spacecraft; Shuttle derived launch vehicles; and critical areas of technology/advanced development for lunar and Mars missions are outlined. The presentation is represented by viewgraphs only.

Source record↗
NASA NTRS1975

Origin and evolution of the lunar regolith; Proceedings of the Symposium, Houston, Tex., November 13-15, 1974

The papers consider the origin and evolution of the lunar regolith utilizing data obtained during American and Soviet manned and unmanned lunar missions as well as surface and orbital observations, photography, sample collections, and experimental studies. Topics include the transport and emplacement of crater and basin deposits, development of the mare regolith, the shallow lunar structure as determined from the passive seismic experiment, horizontal transport of the regolith, the origin of the exotic component and KREEP-rich materials, the influx of interplanetary materials onto the moon, stratification in the lunar regolith, catastrophic rupture of lunar rocks, cosmic-ray exposure ages of surface features, breccia formation by sintering and crystallization, evolution of the lunar soil, and effects of maturation on the reflectance of the regolith. Individual items are announced in this issue.

Source record↗
NASA NTRS1980

Lunar asymmetry and palaeomagnetism

A model is proposed for the early lunar evolution which accounts for the compositional asymmetry between the nearside and farside of the moon and the natural remanent magnetism of lunar rocks. According to the model, the preferred gravitational energy state consisted of an asymmetric accumulation of a liquid iron alloy (Fe-Ni and a small amount of sulfur) which displaces upwards the cold primordial undifferentiated core. The resulting depth asymmetry of the outer partially molten zone leads eventually to the subcrustal accumulation of light magnesium-rich pyroxenes and olivine, preferentially in one hemisphere, sufficient to explain the offset and also indirectly providing a possible explanation for the nearside concentration of KREEP and mass basalt. Slow downward migration of iron releases gravitational energy sufficient for convection and dynamo generation in an iron layer for about a billion years.

Stevenson, D. J.↗
NASA NTRS1984

Conference on the Origin of the Moon

Various topics relating to lunar evolution are discussed. The Moon's ancient orbital history, geophysical and geochemical constraints favoring the capture hypothesis, the site of the lunar core, chemical and petrological constraints, dynamical constraints, and mathematical models are among the topics discussed.

Source record↗
NASA NTRS1986

Origin of the moon; Proceedings of the Conference, Kona, HI, October 13-16, 1984

Various topics relating to lunar evolution are discussed. The moon's ancient orbital history, geophysical and geochemical constraints favoring the capture hypothesis, the site of the lunar core, chemical and petrological constraints, dynamical constraints, and mathematical models are among the topics discussed.

Hartmann, W. K.↗
NASA NTRS1977

Origin and evolution of the lunar surface - The major questions remaining

The major factors in the evolution of the lunar surface have not been determined yet. Huge lava flows and lunar differentiation, though commonly assumed, is in discord with much of the evidence. The alternative is for most of the surface to represent the last stages of accretion of the moon only, with the chemical differentiation having taken place previously in the source material. Radar, seismic, surface exposure, and mascon evidence can then be accounted for. A large-scale surface transport mechanism of soil must then have been present.

Gold, T.↗
NASA NTRS2016

Subsurface Morphology and Scaling of Lunar Impact Basins

Impact bombardment during the first billion years after the formation of the Moon produced at least several tens of basins. The Gravity Recovery and Interior Laboratory (GRAIL) mission mapped the gravity field of these impact structures at significantly higher spatial resolution than previous missions, allowing for detailed subsurface and morphological analyses to be made across the entire globe. GRAIL-derived crustal thickness maps were used to define the regions of crustal thinning observed in centers of lunar impact basins, which represents a less unambiguous measure of a basin size than those based on topographic features. The formation of lunar impact basins was modeled numerically by using the iSALE-2D hydrocode, with a large range of impact and target conditions typical for the first billion years of lunar evolution. In the investigated range of impactor and target conditions, the target temperature had the dominant effect on the basin subsurface morphology. Model results were also used to update current impact scaling relationships applicable to the lunar setting (based on assumed target temperature). Our new temperature-dependent impact-scaling relationships provide estimates of impact conditions and transient crater diameters for the majority of impact basins mapped by GRAIL. As the formation of lunar impact basins is associated with the first approximately 700 Myr of the solar system evolution when the impact flux was considerably larger than the present day, our revised impact scaling relationships can aid further analyses and understanding of the extent of impact bombardment on the Moon and terrestrial planets in the early solar system.

Miljkovic, K.↗
NASA NTRS1997

Planetary Geophysics and Tectonics

Research supported by grant NAGW-1928 has addressed a variety of problems related to planetary evolution. One important focus has been on questions related to the role of chemical buoyancy in planetary evolution with application to both Venus and the Moon. We have developed a model for the evolution of the Moon (Hess and Parmentier, 1995) in which dense, highly radioactive, late stage magma ocean cumulates sink forming a core. This core heats the overlying, chemically layered mantle giving rise to a heated, chemically well-mixed layer that thickens with time. This Mixed layer eventually becomes hot enough and thick enough that its top begins to melt at a pressure low enough that melt is buoyant, thus creating mare basalts from a high pressure source of the correct composition and at an appropriate time in lunar evolution. In work completed during the last year, numerical experiments on convection in a chemically stably stratified fluid layer heated from below have been completed. These results show us how to calculate the evolution of a mixed layer in the Moon, depending on the heat production in the ilmenite- cumulate core and the chemical stratification of the overlying mantle. Chemical stratification of the mantle after its initial differentiation is would trap heat in the deep interior and prevent the rapid rise of plumes with accompanying volcanism. This trapping of heat in the interior can explain the thickness of the lunar lithosphere as a function of time as well as the magmatic evolution. We show that heat transported to the base of the lithosphere at a rate determined by current estimates of radioactivity in the Moon would not satisfy constraints on elastic lithosphere thickness from tectonic feature associated with basin loading. Trapping heat at depth by a chemically stratified mantle may also explain the absence of global compressional features on the surface that previous models predict for an initially hot lunar interior. For Venus, we developed a model in which the chemical buoyancy of crust and a depleted mantle layer stabilizes the lithosphere for long periods of time and provides a mechanism of episodic planetary evolution (Parmentier and Hess, 1992). Continued thickening of a residual depleted mantle layer eventually suppresses pressure release melting and the creation of depleted mantle. Continued cooling then allows the lithosphere to become heavier than the underlying hotter, undepleted mantle. This repeated instability can occur on time scales appropriate for episodic global resurfacing on Venus. We have also examined the role of the gabbro-eclogite phase transformation on crust and lithosphere stability and as a mechanism of crustal recycling in the absence of plate tectonics. Our work thus far concentrates on the scale of instability that would occur due to cooling or crustal thickening associated with horizontal shortening. Whether repeated overturn can explain the evolution of Venus depends in part on whether sufficient heat transfer can occur between overturns and on constraints provided by understanding observed surface features and evolution.

Parmentier, E. M.↗
NASA NTRS2012

Experimental Fractional Crystallization of the Lunar Magma Ocean

The current paradigm for lunar evolution is of crystallization of a global scale magma ocean, giving rise to the anorthositic crust and mafic cumulate interior. It is thought that all other lunar rocks have arisen from this differentiated interior. However, until recently this paradigm has remained untested experimentally. Presented here are the first experimental results of fractional crystallization of a Lunar Magma Ocean (LMO) using the Taylor Whole Moon (TWM) bulk lunar composition [1].

Rapp, J. F.↗
NASA NTRS2023

Assessing the Relocation of Artemis Foundational Lunar Surface Concepts

The National Aeronautics and Space Administration (NASA) has defined a functionally based Moon to Mars (M2M) architecture consisting of four key human exploration segments: human lunar return (HLR), foundational exploration (FE), sustained lunar evolution (SLE), and humans to Mars (H2M). These segments are portions of the architecture which represent a stepwise increase in complexity and achievement of M2M objectives [1]. As systems are deployed during the FE segment, it may be desired or even necessary to relocate these elements on the lunar surface as the architecture transitions into the SLE segment. While some Artemis elements under development, such as rovers, are being designed for mobility during both crewed and uncrewed/dormant periods, other architectural concepts do not currently carry a mobility capability. In preparation for the Agency’s 2023 Architecture Concept Review (ACR), a team was assembled to establish a methodology for assessing the relocation feasibility of normally stationary elements. Such a capability could be applied locally or regionally, and might allow for re-purposing previously occupied terrain, expansion of exploration range, aggregation of habitation elements, or retiring systems at the end of their useful service life. The assembled NASA team investigated the relocation trade space through defining a representative concept of operations (ConOps) and assessing possible system impacts. The team focused predominately on the relocation of medium and large surface habitat architectural concepts through surface-based traverses utilizing separable mobility platforms (SMP). A representative mobility platform model was placed through simulation to analyze the possible energy requirements and dynamic illumination impacts. Preliminary assessment indicated that element relocation might be achievable, however significant system and architectural-level risks still need to be quantified. Future analysis will assist in determining what degree of element relocation provides the greatest benefit to achieving a sustained lunar presence. [1] NASA. (2022). Moon to Mars Objectives. Retrieved from: https://www.nasa.gov/sites/default/files/atoms/files/m2m-objectives-exec-summary.pdf

Artemis↗
NASA NTRSDate not supplied

Assessing the Relocation of Artemis Foundational Lunar Surface Concepts

The National Aeronautics and Space Administration (NASA) has defined a functionally based Moon to Mars (M2M) architecture consisting of four key human exploration segments: human lunar return (HLR), foundational exploration (FE), sustained lunar evolution (SLE), and humans to Mars (H2M). These segments are portions of the architecture which represent a stepwise increase in complexity and achievement of M2M objectives [1]. As systems are deployed during the FE segment, it may be desired or even necessary to relocate these elements on the lunar surface as the architecture transitions into the SLE segment. While some Artemis elements under development, such as rovers, are being designed for mobility during both crewed and uncrewed/dormant periods, other architectural concepts do not currently carry a mobility capability. In preparation for the Agency’s 2023 Architecture Concept Review (ACR), a team was assembled to establish a methodology for assessing the relocation feasibility of normally stationary elements. Such a capability could be applied locally or regionally, and might allow for re-purposing previously occupied terrain, expansion of exploration range, aggregation of habitation elements, or retiring systems at the end of their useful service life. The assembled NASA team investigated the relocation trade space through defining a representative concept of operations (ConOps) and assessing possible system impacts. The team focused predominately on the relocation of medium and large surface habitat architectural concepts through surface-based traverses utilizing separable mobility platforms (SMP). A representative mobility platform model was placed through simulation to analyze the possible energy requirements and dynamic illumination impacts. Preliminary assessment indicated that element relocation might be achievable, however significant system and architectural-level risks still need to be quantified. Future analysis will assist in determining what degree of element relocation provides the greatest benefit to achieving a sustained lunar presence. [1] NASA. (2022). Moon to Mars Objectives. Retrieved from: https://www.nasa.gov/sites/default/files/atoms/files/m2m-objectives-exec-summary.pdf

Artemis↗
NASA NTRS1980

The lunar regolith - Comparative petrology of the Apollo sites

A description is presented of the modal petrology of eight surface soils from the Apollo 11, 12, 14, 15, and 16 landing sites. One of the most striking features of the petrology of the considered soils is found to be the similarity in distribution of pyroxene composition between the soil and the local rock types. The considered investigation is concerned with certain difficulties with respect to an understanding of regolith evolution. Lunar soils contain material foreign to the local geology. The foreign material must have been transported over long distances. However, models of regolith formation on the moon indicate that lateral transport is inefficient. It is found in the investigation that the soil is predominantly of local derivation, that lateral homogenization is a minor process, that foreign material is present in the amounts indicated by bulk chemical mixing models, and that preferential transport of fine-grained material does not occur.

Labotka, T. C.↗
NASA NTRS1984

A testable gravitational capture model for the origin of the Earth's Moon

A gravitational capture model is proposed to explain lunar evolution. The model is divided into five orbital eras. In the first era, it is postulated that the pre-capture Moon formed as a small planetary unit on the inner edge of the Asteroid Zone. Orbital era 2 commenced when the Moon's orbit became Earth-crossing. As the Moon underwent periodic gravitational encounters with Earth in a near Earth orbit (orbital era 3), the lunar body because warmer and thus more easily capture. Era 4 saw the Moon inserted into a geocentric orbit that gradually became more circular. Following orbital circulation, the lunar orbit gradually expanded to its present dimensions (era 5).

Malcuit, R. J.↗
NASA NTRS1992

Lunar impact basins and crustal heterogeneity - New western limb and far side data from Galileo

Multispectral images of the lunar western limb and far side obtained from Galileo reveal the compositional nature of several prominent lunar features and provide new information on lunar evolution. The data reveal that the ejecta from the Orientale impact basin (900 kilometers in diameter) lying outside the Cordillera Mountains was excavated from the crust, not the mantle, and covers pre-Orientale terrain that consisted of both highland materials and relatively large expanses of ancient mare basalts. The inside of the far side South Pole-Aitken basin (greater than 2000 kilometers in diameter) has low albedo, red color, and a relatively high abundance of iron- and magnesium-rich materials. These features suggest that the impact may have penetrated into the deep crust or lunar mantle or that the basin contains ancient mare basalts that were later covered by highlands ejecta.

Belton, Michael J. S.↗
NASA NTRS1993

Magnetic fields and nonuniform structures of the Moon

Direct magnetic measurements performed by space probes demonstrated the existence of small-scale, stationary surface magnetic fields on the Moon. The magnetic field averaged over a region of approximately 600 km was found to be no larger than approximately 10(exp -5) G, that of the regions approximately 100-200 km is approximately 10(exp -5) to 10(exp -4) G, and that of approximately 10-100 km reaches approximately 10(exp -3) G. Investigations of certain lunar rocks reveal stable residual magnetization, which could have been acquired during the crystallization of the rocks in the presence of the outer magnetic field, provided such a field existed at the initial stage of lunar evolution. Estimates show that 4 x 10(exp 9) yr ago the field was small, then it rose to approximately 1.3 G at the beginning of 3.9 x 10(exp 9) yr with a subsequent exponential decrease during the period of 3.9 x 10(exp 9) yr to 3.2 x 10(exp 9) yr ago. Small-scale fields have been explained by some authors as due to mechanical impacts produced by meteors. The theory of this effect is not elaborated in detail. This can in no way explain the paleomagnetic data. These data are commonly explained as a result of the dynamo action in the liquid lunar core.

Dolginov, A. Z.↗