Showing papers by "Frank G. Lemoine published in 2013"
Institut de Physique du Globe de Paris1, Goddard Space Flight Center2, University of California, Santa Cruz3, Lunar and Planetary Institute4, University of Hawaii5, Purdue University6, Southwest Research Institute7, Lamont–Doherty Earth Observatory8, Carnegie Institution for Science9, Colorado School of Mines10, California Institute of Technology11, Massachusetts Institute of Technology12
TL;DR: In this article, high-resolution gravity data obtained from the dual Gravity Recovery and Interior Laboratory (GRAIL) spacecraft show that the bulk density of the Moon's highlands crust is 2550 kilograms per cubic meter, substantially lower than generally assumed.
Abstract: High-resolution gravity data obtained from the dual Gravity Recovery and Interior Laboratory (GRAIL) spacecraft show that the bulk density of the Moon's highlands crust is 2550 kilograms per cubic meter, substantially lower than generally assumed. When combined with remote sensing and sample data, this density implies an average crustal porosity of 12% to depths of at least a few kilometers. Lateral variations in crustal porosity correlate with the largest impact basins, whereas lateral variations in crustal density correlate with crustal composition. The low-bulk crustal density allows construction of a global crustal thickness model that satisfies the Apollo seismic constraints, and with an average crustal thickness between 34 and 43 kilometers, the bulk refractory element composition of the Moon is not required to be enriched with respect to that of Earth.
675 citations
Massachusetts Institute of Technology1, Jet Propulsion Laboratory2, Goddard Space Flight Center3, Purdue University4, Southwest Research Institute5, Carnegie Institution for Science6, Lamont–Doherty Earth Observatory7, Institut de Physique du Globe de Paris8, University of Maryland, Baltimore County9
TL;DR: The Moon's gravity field reveals that impacts have homogenized the density of the crust and fractured it extensively, and GRAIL elucidates the role of impact bombardment in homogenizing the distribution of shallow density anomalies on terrestrial planetary bodies.
Abstract: Spacecraft-to-spacecraft tracking observations from the Gravity Recovery and Interior Laboratory (GRAIL) have been used to construct a gravitational field of the Moon to spherical harmonic degree and order 420. The GRAIL field reveals features not previously resolved, including tectonic structures, volcanic landforms, basin rings, crater central peaks, and numerous simple craters. From degrees 80 through 300, over 98% of the gravitational signature is associated with topography, a result that reflects the preservation of crater relief in highly fractured crust. The remaining 2% represents fine details of subsurface structure not previously resolved. GRAIL elucidates the role of impact bombardment in homogenizing the distribution of shallow density anomalies on terrestrial planetary bodies.
404 citations
Case Western Reserve University1, University of California, Los Angeles2, Lamont–Doherty Earth Observatory3, Carnegie Institution for Science4, Southwest Research Institute5, Planetary Science Institute6, University of British Columbia7, Goddard Space Flight Center8, Massachusetts Institute of Technology9, National Museum of Natural History10, University of California, Santa Barbara11, Johns Hopkins University Applied Physics Laboratory12
TL;DR: In this article, NASA MESSENGER Participating Scientist grant NNX07AR77G was used to conduct a study on the effects of solar arrays on the performance of the spacecraft.
Abstract: United States. National Aeronautics and Space Administration (NASA MESSENGER Participating Scientist grant NNX07AR77G)
259 citations
Colorado School of Mines1, Jet Propulsion Laboratory2, Brown University3, Lunar and Planetary Institute4, Goddard Space Flight Center5, University of Arizona6, Massachusetts Institute of Technology7, Purdue University8, University of California, Santa Cruz9, Southwest Research Institute10, Lamont–Doherty Earth Observatory11, Carnegie Institution for Science12, University of Hawaii13, Institut de Physique du Globe de Paris14
TL;DR: The Moon's gravity map shows that the crust is cut by extensive magmatic dikes, perhaps implying a period of early expansion, and application of gravity gradiometry to observations by the GRAIL mission results in the identification of a population of linear gravity anomalies with lengths of hundreds of kilometers.
Abstract: The earliest history of the Moon is poorly preserved in the surface geologic record due to the high flux of impactors, but aspects of that history may be preserved in subsurface structures. Application of gravity gradiometry to observations by the Gravity Recovery and Interior Laboratory (GRAIL) mission results in the identification of a population of linear gravity anomalies with lengths of hundreds of kilometers. Inversion of the gravity anomalies indicates elongated positive-density anomalies that are interpreted to be ancient vertical tabular intrusions or dikes formed by magmatism in combination with extension of the lithosphere. Crosscutting relationships support a pre-Nectarian to Nectarian age, preceding the end of the heavy bombardment of the Moon. The distribution, orientation, and dimensions of the intrusions indicate a globally isotropic extensional stress state arising from an increase in the Moon's radius by 0.6 to 4.9 kilometers early in lunar history, consistent with predictions of thermal models.
160 citations
TL;DR: In this paper, the authors derived gravity models of the Moon to degree 420, 540, and 660 in spherical harmonics using the data from the Gravity Recovery and Interior Laboratory (GRAIL) primary mission.
Abstract: We have analyzed Ka‒band range rate (KBRR) and Deep Space Network (DSN) data from the Gravity Recovery and Interior Laboratory (GRAIL) primary mission (1 March to 29 May 2012) to derive gravity models of the Moon to degree 420, 540, and 660 in spherical harmonics. For these models, GRGM420A, GRGM540A, and GRGM660PRIM, a Kaula constraint was applied only beyond degree 330. Variance‒component estimation (VCE) was used to adjust the a priori weights and obtain a calibrated error covariance. The global root‒mean‒square error in the gravity anomalies computed from the error covariance to 320×320 is 0.77 mGal, compared to 29.0 mGal with the pre‒GRAIL model derived with the SELENE mission data, SGM150J, only to 140×140. The global correlations with the Lunar Orbiter Laser Altimeter‒derived topography are larger than 0.985 between l = 120 and 330. The free‒air gravity anomalies, especially over the lunar farside, display a dramatic increase in detail compared to the pre‒GRAIL models (SGM150J and LP150Q) and, through degree 320, are free of the orbit‒track‒related artifacts present in the earlier models. For GRAIL, we obtain an a posteriori fit to the S‒band DSN data of 0.13 mm/s. The a posteriori fits to the KBRR data range from 0.08 to 1.5 micrometers/s for GRGM420A and from 0.03 to 0.06 micrometers/s for GRGM660PRIM. Using the GRAIL data, we obtain solutions for the degree 2 Love numbers, k20=0.024615+/-0.0000914, k21=0.023915+/-0.0000132, and k22=0.024852+/-0.0000167, and a preliminary solution for the k30 Love number of k30=0.00734+/-0.0015, where the Love number error sigmas are those obtained with VCE.
137 citations
Book•
07 Aug 2013
TL;DR: In this paper, the phase lag by which the earth's body tide follows the tidal potential is estimated for the principal lunar semidiurnal tide M(sub 2) by combining recent tidal solutions from satellite tracking data and from Topex/Poseidon satellite altimeter data.
Abstract: The phase lag by which the earth's body tide follows the tidal potential is estimated for the principal lunar semidiurnal tide M(sub 2). The estimate results from combining recent tidal solutions from satellite tracking data and from Topex/Poseidon satellite altimeter data. Each data type is sensitive to the body-tide lag: gravitationally for the tracking data, geometrically for the altimetry. Allowance is made for the lunar atmospheric tide. For the tidal potential Love number kappa(sub 2) we obtain a lag epsilon of 0.20 deg +/- 0.05 deg, implying an effective body-tide Q of 280 and body-tide energy dissipation of 110 +/- 25 gigawatts.
80 citations
TL;DR: In this paper, a series of Jason-2 GPS and SLR/DORIS-based orbits using ITRF2005 and the std0905 standards are computed and compared to two different geocenter motion models where biases and trends have been removed.
20 citations
TL;DR: In this article, the authors show that the pointmascon approach can stabilize the geographically correlated orbit errors which are of fundamental interest for the analysis of regional Mean Sea Level trends based on altimeter data, and can therefore provide an interim solution in the event of GRACE data loss.
18 citations
01 Mar 2013
11 citations
Massachusetts Institute of Technology1, California Institute of Technology2, Colorado School of Mines3, Brown University4, Lunar and Planetary Institute5, University of Arizona6, University of California, Santa Cruz7, Harvard University8, Marshall Space Flight Center9, University of Baltimore10, Goddard Space Flight Center11, Purdue University12, Southwest Research Institute13
TL;DR: The Gravity Recovery and Interior Laboratory (GRAIL) Extended Mission (XM) as mentioned in this paper provided an additional three months of gravity mapping at half the altitude (23 km) of the primary mission (55 km), and is providing higherresolution gravity models that are being used to map the upper crust of the Moon in unprecedented detail.
Abstract: The Gravity Recovery and Interior Laboratory (GRAIL) [1], NASA s eleventh Discovery mission, successfully executed its Primary Mission (PM) in lunar orbit between March 1, 2012 and May 29, 2012. GRAIL s Extended Mission (XM) initiated on August 30, 2012 and was successfully completed on December 14, 2012. The XM provided an additional three months of gravity mapping at half the altitude (23 km) of the PM (55 km), and is providing higherresolution gravity models that are being used to map the upper crust of the Moon in unprecedented detail.
6 citations
18 Mar 2013
TL;DR: In this paper, high-resolution gravity data from GRAIL have yielded new estimates of the bulk density and thickness of the lunar crust, and the average global crustal thickness is found to lie between 34 and 43 km, a value 10 to 20 km less than several previous estimates.
Abstract: High-resolution gravity data from GRAIL have yielded new estimates of the bulk density and thickness of the lunar crust. The bulk density of the highlands crust is 2550 kg m-3. From a comparison with crustal composition measured remotely, this density implies a mean porosity of 12%. With this bulk density and constraints from the Apollo seismic experiment, the average global crustal thickness is found to lie between 34 and 43 km, a value 10 to 20 km less than several previous estimates. Crustal thickness is a central parameter in estimating bulk lunar composition. Estimates of the concentrations of refractory elements in the Moon from heat flow, remote sensing and sample data, and geophysical data fall into two categories: those with refractory element abundances enriched by 50% or more relative to Earth, and those with abundances the same as Earth. Settling this issue has implications for processes operating during lunar formation. The crustal thickness resulting from analysis of GRAIL data is less than several previous estimates. We show here that a refractory-enriched Moon is not required