{
    "id": 4175,
    "url": "https://svs.gsfc.nasa.gov/4175/",
    "page_type": "Visualization",
    "title": "GRAIL Gravity Map for the Cover of <i>Geophysical Research Letters</i>",
    "description": "This print-resolution still image was created for the cover of the May 28, 2014 issue of Geophysical Research Letters. It features a free-air gravity map of the Moon's southern latitudes developed by S. Goossens et al. from data returned by the Gravity Recovery and Interior Laboratory (GRAIL) mission.If the Moon were a perfectly smooth sphere of uniform density, the gravity map would be a single, featureless color, indicating that the force of gravity at a given elevation was the same everywhere. But like other rocky bodies in the solar system, including Earth, the Moon has both a bumpy surface and a lumpy interior. Spacecraft in orbit around the Moon experience slight variations in gravity caused by both of these irregularities.The free-air gravity map shows deviations from the mean gravity that a cueball Moon would have. The deviations are measured in milliGals, a unit of acceleration. On the map, purple is at the low end of the range, at around -400 mGals, and red is at the high end near +400 mGals. Yellow denotes the mean.The map shown here extends from the south pole of the Moon up to 50°S and reveals the gravity for that region in even finer detail than the global gravity maps published previously. The image illustrates the very good correlation between the gravity map and topographic features such as peaks and craters, as well as the mass concentration lying beneath the large Schrödinger basin in the center of the frame. The terrain in the image is based on Lunar Reconnaissance Orbiter (LRO) altimeter and camera data. || ",
    "release_date": "2014-06-17T00:00:00-04:00",
    "update_date": "2025-01-06T00:06:42.447616-05:00",
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        "alt_text": "A high-resolution free-air gravity map based on GRAIL data, overlaid on terrain based on LRO altimeter (LOLA) and camera (LROC) data. The view is south-up, with the south pole near the horizon in the upper left and the crescent Earth in the distance. The terminator crosses the eastern rim of the Schrödinger basin. Gravity is painted onto the areas that are in or near the night side. Red corresponds to mass excesses and blue to mass deficits.",
        "width": 750,
        "height": 900,
        "pixels": 675000
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    "main_video": null,
    "main_credits": {
        "Visualizations by": [
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                "name": "Ernie Wright",
                "employer": "USRA"
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        ]
    },
    "progress": "Complete",
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            "description": "This print-resolution still image was created for the cover of the May 28, 2014 issue of <i><a href=\"http://agupubs.onlinelibrary.wiley.com/hub/issue/10.1002/grl.v41.10/\">Geophysical Research Letters</a></i>. It features a free-air gravity map of the Moon's southern latitudes developed by S. Goossens et al. from data returned by the Gravity Recovery and Interior Laboratory (<a href=\"http://www.nasa.gov/grail\">GRAIL</a>) mission.<br><br>If the Moon were a perfectly smooth sphere of uniform density, the gravity map would be a single, featureless color, indicating that the force of gravity at a given elevation was the same everywhere. But like other rocky bodies in the solar system, including Earth, the Moon has both a bumpy surface and a lumpy interior. Spacecraft in orbit around the Moon experience slight variations in gravity caused by both of these irregularities.<br><br>The free-air gravity map shows deviations from the mean gravity that a cueball Moon would have. The deviations are measured in <a href=\"https://en.wikipedia.org/wiki/Gal_(unit)\">milliGals</a>, a unit of acceleration. On the map, purple is at the low end of the range, at around -400 mGals, and red is at the high end near +400 mGals. Yellow denotes the mean.<br><br>The map shown here extends from the south pole of the Moon up to 50°S and reveals the gravity for that region in even finer detail than the global gravity maps <a href=\"http://www.nasa.gov/home/hqnews/2012/dec/HQ_12-417_GRAIL.html\">published previously</a>. The image illustrates the very good correlation between the gravity map and topographic features such as peaks and craters, as well as the mass concentration lying beneath the large Schrödinger basin in the center of the frame. The terrain in the image is based on Lunar Reconnaissance Orbiter (<a href=\"http://www.nasa.gov/lro\">LRO</a>) altimeter and camera data.",
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            "description": "A high-resolution free-air gravity map based on GRAIL data, overlaid on terrain based on LRO altimeter (LOLA) and camera (LROC) data. The view is south-up, with the south pole near the horizon in the upper left and the crescent Earth in the distance. The terminator crosses the eastern rim of the Schrödinger basin. Gravity is painted onto the areas that are in or near the night side. Red corresponds to mass excesses and blue to mass deficits.",
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                        "media_type": "Image",
                        "alt_text": "A high-resolution free-air gravity map based on GRAIL data, overlaid on terrain based on LRO altimeter (LOLA) and camera (LROC) data. The view is south-up, with the south pole near the horizon in the upper left and the crescent Earth in the distance. The terminator crosses the eastern rim of the Schrödinger basin. Gravity is painted onto the areas that are in or near the night side. Red corresponds to mass excesses and blue to mass deficits.",
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                        "filename": "schrodinger_grail.tif",
                        "media_type": "Image",
                        "alt_text": "A high-resolution free-air gravity map based on GRAIL data, overlaid on terrain based on LRO altimeter (LOLA) and camera (LROC) data. The view is south-up, with the south pole near the horizon in the upper left and the crescent Earth in the distance. The terminator crosses the eastern rim of the Schrödinger basin. Gravity is painted onto the areas that are in or near the night side. Red corresponds to mass excesses and blue to mass deficits.",
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                        "alt_text": "A high-resolution free-air gravity map based on GRAIL data, overlaid on terrain based on LRO altimeter (LOLA) and camera (LROC) data. The view is south-up, with the south pole near the horizon in the upper left and the crescent Earth in the distance. The terminator crosses the eastern rim of the Schrödinger basin. Gravity is painted onto the areas that are in or near the night side. Red corresponds to mass excesses and blue to mass deficits.",
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                        "filename": "schrodinger_ulcn.tif",
                        "media_type": "Image",
                        "alt_text": "A high-resolution free-air gravity map based on GRAIL data, overlaid on terrain based on LRO altimeter (LOLA) and camera (LROC) data. The view is south-up, with the south pole near the horizon in the upper left and the crescent Earth in the distance. The terminator crosses the eastern rim of the Schrödinger basin. Gravity is painted onto the areas that are in or near the night side. Red corresponds to mass excesses and blue to mass deficits.",
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    "studio": "svs",
    "funding_sources": [
        "LRO"
    ],
    "credits": [
        {
            "role": "Animator",
            "people": [
                {
                    "name": "Ernie Wright",
                    "employer": "USRA"
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            ]
        },
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            "role": "Scientist",
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                    "name": "Sander Goossens",
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                {
                    "name": "Erwan M. Mazarico",
                    "employer": "Massachusetts Institute of Technology"
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            "role": "Project support",
            "people": [
                {
                    "name": "Laurence Schuler",
                    "employer": "ADNET Systems, Inc."
                },
                {
                    "name": "Ian Jones",
                    "employer": "ADNET Systems, Inc."
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    "series": [
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        "<a href=\"http://onlinelibrary.wiley.com/doi/10.1002/2014GL060178/abstract\">High-resolution local gravity model of the south pole of the Moon from GRAIL extended mission data</a>",
        "<a href=\"http://onlinelibrary.wiley.com/doi/10.1002/2014GL060178/abstract\">High-resolution local gravity model of the south pole of the Moon from GRAIL extended mission data</a>"
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            "description": "",
            "credit": "",
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            "sensor": "Lunar Gravity Ranging System",
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            "organizations": [
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            "organizations": [],
            "description": "",
            "credit": "",
            "url": "",
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        }
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    "nasa_science_categories": [
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    "keywords": [
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        "Gravity Recovery and Interior Laboratory",
        "Hyperwall",
        "Lunar",
        "Lunar Elevation Map",
        "Lunar Topography",
        "Moon"
    ],
    "recommended_pages": [],
    "related": [
        {
            "id": 5029,
            "url": "https://svs.gsfc.nasa.gov/5029/",
            "page_type": "Visualization",
            "title": "Illumination at Schrödinger Basin",
            "description": "An overhead view of Schrödinger basin showing both the inner peak ring and outer rim. The view is centered on 75°S 133°E with a vertical FOV of 5.8° from a distance of 2 Moon radii. || sp_illum.0002_print.jpg (1024x576) [245.3 KB] || sp_illum.0001_searchweb.png (320x180) [106.0 KB] || sp_illum.0001_thm.png (80x40) [7.1 KB] || schrodinger_2024_2025_720p30.mp4 (1280x720) [58.6 MB] || outer (1920x1080) [0 Item(s)] || schrodinger_2024_2025_720p30.webm (1280x720) [17.2 MB] || schrodinger_2024_2025_1080p30.mp4 (1920x1080) [105.2 MB] || schrodinger_2024_2025_360p30.mp4 (640x360) [20.1 MB] || schrodinger_2024_2025_1080p30.mp4.hwshow || ",
            "release_date": "2022-10-05T16:10:00-04:00",
            "update_date": "2025-02-18T00:12:07.530142-05:00",
            "main_image": {
                "id": 369259,
                "url": "https://svs.gsfc.nasa.gov/vis/a000000/a005000/a005029/sp_illum.0002_print.jpg",
                "filename": "sp_illum.0002_print.jpg",
                "media_type": "Image",
                "alt_text": "An overhead view of Schrödinger basin showing both the inner peak ring and outer rim. The view is centered on 75°S 133°E with a vertical FOV of 5.8° from a distance of 2 Moon radii.",
                "width": 1024,
                "height": 576,
                "pixels": 589824
            }
        },
        {
            "id": 4499,
            "url": "https://svs.gsfc.nasa.gov/4499/",
            "page_type": "Visualization",
            "title": "Orientale Impact Basin for the Cover of <i>Science</i>",
            "description": "This print-resolution still image was created for the cover of the October 28, 2016 issue of Science. It features a free-air gravity map of the Orientale impact basin based on data returned by the Gravity Recovery and Interior Laboratory (GRAIL) mission.Orientale is about 930 kilometers wide and lies on the western limb of the Moon as viewed from Earth. It's the Moon's youngest and best-preserved large impact basin, formed about 3.8 billion years ago at the end of the conjectured Late Heavy Bombardment. A paper in Science by Maria Zuber et al. uses the GRAIL data to shed new light on the basin's geology, while a second paper by Brandon Johnson et al. describes a computer simulation of the basin's formation constrained by that data.The shaded relief in this image is not a photograph. It's a very accurate computer rendering based on a digital model of the terrain. The model is derived from a digital elevation map called SLDEM2015. This map combines data from the laser altimeter (LOLA) on NASA's Lunar Reconnaissance Orbiter (LRO) with stereo imagery from the Terrain Camera on the Japan Space Agency's SELENE spacecraft.The angle of the virtual Sun was chosen to throw Orientale's terrain into high relief — it's just after sunrise at Orientale, about a day past full Moon. The camera is on the western terminator (day/night line) looking north.The colorful part is the gravity anomaly based on measurements by GRAIL. Red indicates areas of higher gravity, or excess mass, and blue indicates lower gravity or areas of mass deficits. The GRAIL data reveals the structure of the basin beneath the surface. The red in the center of the basin, for example, shows that the crust is particularly thin there, and that denser mantle material is closer to the surface. || ",
            "release_date": "2016-10-21T00:00:00-04:00",
            "update_date": "2023-05-03T13:48:10.312241-04:00",
            "main_image": {
                "id": 420055,
                "url": "https://svs.gsfc.nasa.gov/vis/a000000/a004400/a004499/orientale_preview.jpg",
                "filename": "orientale_preview.jpg",
                "media_type": "Image",
                "alt_text": "The Orientale impact basin, combining shaded relief with free air gravity.",
                "width": 1024,
                "height": 768,
                "pixels": 786432
            }
        },
        {
            "id": 4218,
            "url": "https://svs.gsfc.nasa.gov/4218/",
            "page_type": "Visualization",
            "title": "Procellarum Rifts for the Cover of <i>Nature</i>",
            "description": "Oceanus Procellarum, or the Ocean of Storms, is the largest of the dark maria visible to the naked eye on the near side of the Moon. Its relatively flat surface of basaltic lava covers most of the northwest quadrant of the Moon's disk.The leading explanation of Procellarum's origin is that it is a large, ancient impact basin. But the authors of a paper in the October 2, 2014 edition of the journal Nature suggest instead that this region is the result of the way the lunar crust cooled billions of years ago.The red in the image shown here is part of a pattern of gravity anomalies revealed by data from the Gravity Recovery and Interior Laboratory (GRAIL) mission. Jeffrey Andrews-Hanna and his coathors interpret this rectangular feature as a remnant of the plumbing system that moved magma to the surface of the Moon's near side, flooding low-lying areas with lava.The rectangular shape differs from the circular shape expected for an impact basin. It more closely resembles the pattern of cracks that form in materials subjected to thermal stress. In fact, the paper compares the shape of the Procellarum gravity anomaly with a feature spanning the south pole of Enceladus, the ice-covered moon of Saturn. || ",
            "release_date": "2014-10-01T00:00:00-04:00",
            "update_date": "2023-05-03T13:50:29.953711-04:00",
            "main_image": {
                "id": 451025,
                "url": "https://svs.gsfc.nasa.gov/vis/a000000/a004200/a004218/nature_cover_print.jpg",
                "filename": "nature_cover_print.jpg",
                "media_type": "Image",
                "alt_text": "Gravity anomalies (red) bordering the Procellarum region are overlaid on a global elevation map.",
                "width": 1024,
                "height": 576,
                "pixels": 589824
            }
        },
        {
            "id": 4023,
            "url": "https://svs.gsfc.nasa.gov/4023/",
            "page_type": "Visualization",
            "title": "GRAIL Impacts the Moon",
            "description": "The Gravity Recovery and Interior Laboratory (GRAIL) mission comprises a pair of satellites launched in September, 2011 and placed in orbit around the Moon in January, 2012. The two satellites, named Ebb and Flow, used radio signals to precisely measure their separation as they flew in formation, one following the other in the same nearly circular polar orbit. These measurements allowed mission scientists to build up an accurate and detailed gravity map of the Moon.GRAIL ends its successful mission by impacting the Moon on December 17, 2012 at approximately 5:27 p.m. EST (22:27 UT). The two spacecraft were placed in an orbit that takes them within a kilometer of the surface, so low that they will hit the side of an unnamed mountain that lies between Mouchez and Philolaus craters, near the north pole at 75°45'N, 26°11'W. Ebb strikes first, followed 24 seconds later by Flow.This animation shows the last three orbits of the two spacecraft, with views of the impact site. The impact occurs on the night side of a waxing crescent Moon, so the view shifts from a natural color Moon to a false-color elevation map. || ",
            "release_date": "2012-12-17T09:00:00-05:00",
            "update_date": "2025-01-05T22:18:52.416447-05:00",
            "main_image": {
                "id": 469813,
                "url": "https://svs.gsfc.nasa.gov/vis/a000000/a004000/a004023/grail.0850.jpg",
                "filename": "grail.0850.jpg",
                "media_type": "Image",
                "alt_text": "GRAIL's final three orbits, with close-ups of the impact site.",
                "width": 1920,
                "height": 1080,
                "pixels": 2073600
            }
        },
        {
            "id": 4014,
            "url": "https://svs.gsfc.nasa.gov/4014/",
            "page_type": "Visualization",
            "title": "GRAIL Primary Mission Gravity Maps (AGU 2012)",
            "description": "The Gravity Recovery and Interior Laboratory (GRAIL) mission comprises a pair of satellites launched in September, 2011 and placed in orbit around the Moon in January, 2012. The two satellites, named Ebb and Flow, used radio signals to precisely measure their separation as they flew in formation, one following the other in the same nearly circular polar orbit. These measurements allowed mission scientists to build up an accurate and detailed gravity map of the Moon.If the Moon were a perfectly smooth sphere of uniform density, the gravity experienced by the spacecraft would be exactly the same everywhere. But like other rocky bodies in the solar system, including the Earth, the Moon has both a bumpy surface and a lumpy interior. As the spacecraft fly in their orbits, they experience slight variations in gravity caused by both of these irregularities, variations which show up as small changes in the separation of the two spacecraft.The free-air gravity map shows these variations directly. (Free-air is a historical term; there is, of course, no air on the Moon.) The Bouguer gravity map subtracts the effect of the bumpy surface to show the lumpiness underneath. The elevation maps from the laser altimeter on Lunar Reconnaissance Orbiter (LRO) were used to create a model of what the gravity would be if the Moon were bumpy but not lumpy. This model was then subtracted from the free-air map to produce the Bouguer map. (Note: The Bouguer map shown here was filtered to emphasize smaller features; harmonic degrees 1 to 6 were excluded.)The crustal thickness map is inferred from the Bouguer map: If the density of the crust is assumed to be uniform, then the gravity anomalies visible in the Bouguer gravity map can be explained by variations in the thickness of the crust. Highs in gravity indicate places where the denser mantle is closer to the surface, and hence where the crust is thinner.While aiding navigation for future lunar missions, GRAIL's gravity measurements reveal information about the internal structure of the Moon, improving our understanding of the origin and development of not just the Moon, but also the Earth and the rest of the inner solar system. || ",
            "release_date": "2012-12-05T12:00:00-05:00",
            "update_date": "2017-01-23T12:22:42-05:00",
            "main_image": {
                "id": 470169,
                "url": "https://svs.gsfc.nasa.gov/vis/a000000/a004000/a004014/topo_free.0200_preview.jpg",
                "filename": "topo_free.0200_preview.jpg",
                "media_type": "Image",
                "alt_text": "Side-by-side rotating Moon globes showing LOLA elevation and GRAIL free-air gravity.This video is also available on our YouTube channel.",
                "width": 1920,
                "height": 1080,
                "pixels": 2073600
            }
        }
    ],
    "sources": [],
    "products": [],
    "newer_versions": [],
    "older_versions": [],
    "alternate_versions": []
}