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                    "instance": {
                        "id": 468290,
                        "url": "https://svs.gsfc.nasa.gov/vis/a010000/a011100/a011186/print_thickness.tif",
                        "filename": "print_thickness.tif",
                        "media_type": "Image",
                        "alt_text": "Using the gravity map, scientists created this map of the moon's crust. The different colors indicate variations in thickness.",
                        "width": 2400,
                        "height": 2400,
                        "pixels": 5760000
                    }
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            ],
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    "credits": [
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            "role": "Animator",
            "people": [
                {
                    "name": "Ernie Wright",
                    "employer": "USRA"
                }
            ]
        },
        {
            "role": "Video editor",
            "people": [
                {
                    "name": "Kayvon Sharghi",
                    "employer": "USRA"
                }
            ]
        },
        {
            "role": "Scientist",
            "people": [
                {
                    "name": "Maria Zuber",
                    "employer": "Massachusetts Institute of Technology"
                },
                {
                    "name": "Erwan M. Mazarico",
                    "employer": "Massachusetts Institute of Technology"
                }
            ]
        },
        {
            "role": "Writer",
            "people": [
                {
                    "name": "Alex Kasprak",
                    "employer": "USRA"
                }
            ]
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    "nasa_science_categories": [
        "Planets & Moons"
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    "keywords": [
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    "related": [
        {
            "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
            }
        }
    ],
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}