{
    "count": 7,
    "next": null,
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    "results": [
        {
            "id": 3621,
            "url": "https://svs.gsfc.nasa.gov/3621/",
            "result_type": "Visualization",
            "release_date": "2009-07-27T00:00:00-04:00",
            "title": "LRO Transition from Earth-Centered to Moon-Centered Coordinates",
            "description": "This animation illustrates the solution to a human factors problem in the visualization of an orbit path, in this case the launch and lunar orbit insertion of the Lunar Reconnaissance Orbiter satellite.The visualization (found HERE) shows LRO orbiting the Earth, traveling from the Earth to the moon, and entering lunar orbit. Throughout the visualization, a trail is drawn to show LRO's path. This trail is a history of LRO's motion.The viewer's expectation is that LRO first travels in a circular orbit centered on the Earth, then follows a smoothly curving path connecting the Earth to the moon, and finally enters an elliptical orbit around the moon. The problem for the animator is that an accurate trail satisfying all of these expectations is impossible to draw in a single coordinate system. A trail drawn in Earth-centered coordinates forms a looping, spring-like path when LRO enters lunar orbit, and a trail drawn in moon body-fixed coordinates becomes disconnected from the Earth and precesses through space.Simply switching from one coordinate system to the other would make the trail appear to jump suddenly and dramatically. Creating a hybrid trail would leave a visually confusing elbow in LRO's path.The solution illustrated here is to morph the trail from one coordinate system to the other. The blue trail is the Earth-centered path, the orange trail is the moon body-fixed path, and the white trail is the morph between the two. In the visualization, the Earth trail shortens, disconnecting it from the Earth, and then morphs over about 400 frames into the moon body-fixed trail. With careful timing, the result is a visually seamless transition from one coordinate system to the other.Notice that the difference in coordinate systems creates no ambiguity about the present position of LRO at any given time. LRO is always at the intersection of the trails. The problem arises when attempting to depict the history of its motion. That history takes different shapes in coordinate systems that move relative to one another.An animation showing LRO's entire path in both coordinate systems simultaneously can be found HERE. || ",
            "hits": 91
        },
        {
            "id": 3618,
            "url": "https://svs.gsfc.nasa.gov/3618/",
            "result_type": "Visualization",
            "release_date": "2009-07-17T00:00:00-04:00",
            "title": "LRO in Earth Centered and Moon Centered Coordinates",
            "description": "This visualization shows the Lunar Reconnaissance Orbiter (LRO) orbit insertion from two different points of view (i.e., coordinate systems): Earth centered inertial coordinates and moon centered fixed coordinates. Orbit trails are shown in bright colors where the orbits have been and in darker colors for where the orbits will be. At any particular time, LRO is exactly at the intersection of the two orbit trail curves. The Earth centered coordinates are in blue and the moon centered coordinate are in orange.Why are there two different trails?Because the moon is moving, the moon centered coordinate system is moving. If the moon was stationary with respect to the Earth, both trails would look the same; but since the moon is moving, the moon's trail is always moving and the trails look different.Think of LRO orbiting the moon. From the moon's perspective, it's just going in an ellipse around the moon. In this case, the observation point (the moon) is moving with LRO. But, from the Earth's perspective, if you plotted out the trail of LRO, you would get a series of loops as LRO goes around the moon and as the moon moves through the sky.Animating an orbit trail that changes between two discrete coordinate systems is a challenge. A discontinuity arises if you just switch over from one trail to another. To animate a smooth transition one solution is to carefully select sections of the Earth centered and moon centered curves and then morph from the Earth centered curve section to the moon centered curve section while the animation was playing. This technique was used here as well. || ",
            "hits": 157
        },
        {
            "id": 3577,
            "url": "https://svs.gsfc.nasa.gov/3577/",
            "result_type": "Visualization",
            "release_date": "2009-05-12T00:00:00-04:00",
            "title": "Permanent Shadows on the Moon",
            "description": "As the Earth and Moon orbit around the Sun, there are places on the Moon that never receive direct sunlight. Most of these permanently shadowed regions are at the lunar poles. This animation approximates the permanently shadowned regions pertaining to the Moon's south pole by maintaining a maximum sun angle to the surface of 1.5 degrees. These permanently shadowed areas are of interest because they could hold water ice. (NOTE: South Pole Digital Elevation Maps [DEM] based on publically released JAXA/Selene data.) || ",
            "hits": 550
        },
        {
            "id": 3443,
            "url": "https://svs.gsfc.nasa.gov/3443/",
            "result_type": "Visualization",
            "release_date": "2007-08-27T00:00:00-04:00",
            "title": "Clementine Lunar South Pole",
            "description": "NASA's next moon mission, the Lunar Reconaissance Orbiter (LRO), will pave the way for future lunar missions by taking high resolution data of the entire lunar body. This animation zooms into one region of high interest, the lunar south pole, as seen by the 1994 Clementine mission. The possibility of frozen water is one of many reasons NASA is interested in this potential landing site. However, many of the craters in this area where frozen water sources are most likely to be found are in constant shadow which inhibited Clementine's ability to see into these craters. These shadows are the very dark areas at the poles center as seen in this animation, and one of the moon's secrets on which LRO should shed some light. || ",
            "hits": 168
        },
        {
            "id": 3444,
            "url": "https://svs.gsfc.nasa.gov/3444/",
            "result_type": "Visualization",
            "release_date": "2007-08-27T00:00:00-04:00",
            "title": "Clementine Moon Spin",
            "description": "This animation rotates around a virtual moon showing Clementine data. The first frame and last frame of the animation match up to allow continuous cycling of the rotation. || ",
            "hits": 139
        },
        {
            "id": 3275,
            "url": "https://svs.gsfc.nasa.gov/3275/",
            "result_type": "Visualization",
            "release_date": "2005-10-18T00:00:00-04:00",
            "title": "Hubble Space Telescope Looks at the Moon to Prospect for Resources (Aristarchus Crater - gray)",
            "description": "My edit: The Hubble Space Telescope was used to gather high resolution multi spectral data of the moon's Aristarchus Crater in order to investigate the possibility of potential oxygen producing minerals on the surface. Identifying such minerals could aid in planning future sustained human missions on the moon. Initial analysis of the data indicate the likely presence of titanium and iron oxides. Both these minerals could be used as oxygen sources essential for human exploration.This visualization starts with a view of the moon as seen from Earth using a USGS Apollo derived artist rendered texture (airbrushed). The camera then zooms into the Aristarchus Crater region. Simulated topography derived from Clementine data is used for relief and high resolution HST data is used for the area of interest. After investigating Aristarchus Crater, the camera then moves over to Schroter's Valley for a brief investigation.This visualization is match rendered with id 3275 so that the color version can be dissolved in or out as needed.Exposure Time: 2.5 minutesFilters: F250W (250nm), F344N (344nm), F502N (502nm), F658N (658nm) || ",
            "hits": 117
        },
        {
            "id": 3276,
            "url": "https://svs.gsfc.nasa.gov/3276/",
            "result_type": "Visualization",
            "release_date": "2005-10-17T00:00:00-04:00",
            "title": "Hubble Space Telescope Looks at the Moon to Prospect for Resources (Aristarchus Crater - color)",
            "description": "The Hubble Space Telescope looked at specific areas of the moon prospecting for important minerals that may aid future sustained human presence on the moon. Initial analysis of the data indicate the likely presence of titanium and iron oxides. These minerals can be sources of oxygen, essential for human exploration. This visualization starts with a view of the moon as seen from Earth using a USGS Apollo derived artist rendered texture (airbrushed). The camera then zooms into the Aristarchus crater region. Clementine derived simulated topography is shown around the outside and HST color imagery is shown filling most of the view. The camera then flies into the crater site using using simulated topgraphy and then over to Schroter's Valley. This visualization is match rendered with animation 3274 so that the color version can be dissolved in or out as needed. The colors are from these HST filter bands: RED = 502/250 nm ratio, GREEN = 502 nm (green), BLUE = 250/502 nm ratio. In the image, blues are—in principle—higher in ilmenite. || ",
            "hits": 54
        }
    ]
}