Virtual expedition to the moon. Practical guide



    By the beginning of the 21st century, humanity has accumulated a huge array of data about our natural satellite - the Moon. However, the search for these materials for non-professionals may be difficult due to their scatter over various highly specialized resources. In this review, I suggest you familiarize yourself with a very interesting LROC resource , which is a high resolution moon map (1-0.5 m / pixel). The map is supplemented with solid scientific tools and 3D display of the desired area. Thanks to the Lunar Orbital Scout , anyone can go on a journey across the surface of our natural satellite.

    The map is composed of a synthesis of various images of the moon, taken both from the Earth (low resolution) and from the lunar orbit. Scientific information includes data from the LRO, GRAIL, Clementina, and Chandrayan 1 probes. The LRO lunar probe chamber, LROC, is a modified version of the photographic equipment installed on the Martian counterpart of the MRO probe. Includes a 1-0.5m / pixel high-resolution camera (NAC) and a 100m / pixel wide-angle (WAC) camera.

    The resource LROC at the first acquaintance gives us the visible hemisphere of the moon in orthographic projection (that is, the same as we see it from the Earth). By default, a layer of an array of high-resolution images is superimposed (up to 1-0.5 m / pixel) made by LRO for most of the lunar surface.


    1 - layer menu; 2 - menu of geodetic study of the surface topography; 3 - navigation menu (coordinates, navigation); 4 - scale

    If you want to have "the whole area of ​​the Moon" at hand ", I recommend that you change the projection to cylindrical (equidistant cylindrical), which can be done in the layer menu 1 - Cylindrical projection (entire surface of the moon); 2 and 3 - orthographic projection of the south and north poles; 4 and 5 - orthographic projection of the visible and inverse hemispheres of the moon. Let's start by exploring the various scientific “layers” available on the LROC resource. The imposition of these layers works on a similar principle as in adobe Photoshop - select the desired layer with a tick and adjust the transparency for the convenience of superimposing them on top of each other. It should be noted that different layers have different resolutions.







    The first activated layer is just an array of high-resolution orbital images. It is thanks to him that the main potential of the resource is revealed. On the map we see cobblestones rolling down from the mountain in the resolution of 0.5 m / p and a thin dark line of tracks under it. The same pieces of cracked stone taken by the expedition of Apollo 17. But still, we will not stop in this group of layers, looking ahead, all in order.











    The first group of layers: 1 - coordinate grid; 2 - the lunar surface area illuminated at a given moment of time; 3 - satellite position LRO; 4 - regions shot in stereo mode (double click on the desired point and load the map); 5 - marks the zones, the pictures of which were posted on the LRO website; 6 - the nomenclature of objects on the surface of the moon (with a resolution of 500 m / pixel or more). In the nomenclature submenu is a search that is very reluctant to search for most of the artificial objects on the surface of the moon. In the submenu of most layers, you can adjust their transparency.



    Two subsequent groups of layers: 1 - the area of ​​mineralogical studies carried out by the apparatus Chandrayan 1; 2 - published surface images (actually displays areas shot in high resolution); 3 - surface areas that must be taken again (with a resolution of the map above 1km / p); 4 and 5 - surface area taken at the zenith of the Sun (small shadows) or at its low position (long shadows).

    We pass directly to the geological layers.

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    Clementine's lunar probe in the 90s created a mineralogical map of the moon, based on various color ratios of its surface. Her data is presented in this layer. The most ancient regions (up to 4.5 billion years) are marked in red. Lunar seas (3.9-1 billion years), rich in iron at various ratios of titanium, are marked by gradations of yellow / orange (rich in iron, poor in titanium) and blue (rich in iron with a maximum impurity of titanium). In general, the oldest regions are marked in dark red, the youngest in dark blue.

    “Magnetic sunblock”



    In this part of the image, the region of the selenomagnetic anomaly is visible - Reiner Gamma (with a superimposed layer of Clementine). It corresponds to the local concentration of heavy metals. In the visible range, the region is also clearly visible from the Earth, since it is brighter than the surrounding surface. Local magnetic fields protected regolith from the solar wind, which tends to obscure the lunar seas. This predetermined the unusual "turbulent" view of the region.

    Chandrayaan 1 Products Indian Chandrayan probe mapped the lunar surface reflectance at a wavelength of 1489nm. The most obvious is the albedo layer of the polar regions (it is necessary to switch to the desired polar projection), the brightest zones of the poles correspond to the local concentration of water ice.







    GRAIL, a layer of the gravitational gradient of the surface of the moon, composed by two probes of the same name program. Dark blue indicates zones with high gravity, dark red indicates zones with the lowest gravity. However, in terms of mass concentration, the map should be interpreted the other way around - the crust on the far side of the moon is much thicker and more massive than on the visible. Features of the tidal capture of the Moon by the Earth have led to the fact that we see precisely the least massive, rich in seas, hemisphere of a natural satellite.

    Lunaserv access These layers can help if you need alternative surface illumination, or if you need pictures of areas not affected by LRO. LRO diviner map products








    Temperature and geological layers. The first two show the difference in nighttime temperatures on the lunar surface. Green indicates the average value (about -153 ° C), dark blue indicates a colder deviation from this value (up to -180 °), red, the warmest (up to -120 °). The third activated layer is a map of rock accumulations on the surface of the moon. These rocks usually cool more slowly than the surrounding soil, which is what automatic stations use to find them. 4 - Christiansen scale for silicate rock composition. Dark blue indicates silicates characteristic of plagioclase (composed of sodium, calcium, aluminum, silicon and oxygen), dark blue, silicates rich in olivine (composed of magnesia, iron, silicon and oxygen).

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    Another albedo map of the polar regions (visible in the polar projection) used to search for water ice.

    LROC Global DTM For choice, two layers visually showing the surface relief of the satellite. As in most other layers, in the submenu you can adjust the transparency of the map in projection onto other layers. LROC NAC (High Resolution Camera Layers)








    LRO was shooting the surface of the moon at different angles of incidence of sunlight. Smaller resolution cameras were also shot at different angles to the satellite surface. In this group of layers, you can select a map of zones shot at different lighting angles (zones are visible at a resolution higher than 2km / pixel). Often the same regions were shot at different angles of illumination: east - lighting falls from the east side, west - from the west. Large - the sun is low over the horizon, long shadows; medium - the sun is located approximately between the horizon and the zenith, moderately long shadows; small - the sun is high above the horizon, minimal shadows.


    The place of work of the Apollo 12 expedition, filmed at different lighting angles.

    LROC WAC Basemaps (wide-angle camera layers)

    The last group of layers, and the first that we saw. 1 - Map of polar lighting, the dark areas of this layer show areas of "eternal darkness" where sunlight never gets. Bright areas, on the contrary, are constantly lit by the sun. These regions are most interesting for future manned or automatic expeditions. 2-5, low resolution cars (100-500 m / pixel): 2 - Color map of the moon; 3 - Map of the moon without shadows; 4-5 - Maps of the back and the visible side of the moon with long shadows; 5 - Map of the moon with moderate shadows; 6 - Base layer of WAC snapshots with integrated NAC high-resolution layer.






    Change of various layers displaying the lunar surface. Let me remind you that these layers, like many others, have a transparency setting.

    The Moon in 3D

    Of course, it’s sometimes very interesting to stroll through the lunar expanses using 2D high-resolution images of the Moon. But it is no less interesting to look at the moon in the third dimension. For this we use a geodetic menu.



    The first line performs two functions - calculating the distance / size and simultaneously compiling a geodetic graph of the elevation from point "A" to point "B". The flexibility of the ruler allows you to measure dimensions (and elevation) for objects of irregular, circular or distorted shapes. To do this, at the last point, double-click the left mouse button.



    Geodesic graph of the heights of the endogenous Huygens catena (geological layer superimposed). Catenas are chains of craters on the surface of celestial bodies. Distinguish between endogenous catenas (appearing due to rock collapse in soil cracks) and shock caused by the simultaneous fall of a group of objects (large meteorites often collapse when approaching massive objects, due to the tidal action of the latter).

    The length of the graph is limited only by the surface of the moon. Resolution from tens to hundreds of meters / pixel.

    The second option offers a full 3D projection of the selected area of ​​the Moon, with a similar geodetic scale, resolution. The maximum area available for 3D rendering is approximately 1 million km2 (1000x1000km). This function also works simultaneously with any scientific layer.



    To obtain a 3D projection, select the desired zone, left-click and select 3D Live in the menu.



    We wait until the program loads the region, and in the pop-up window, click on the link. On the left is a 3D model of Davy's shock catena, with an overlay of night temperature. Now the region can be inspected from all sides, turn on automatic rotation, change the elevation difference (up to x10) and the display mode (perspective and orthographic) for clarity. On the right, the Dream Sea with a superimposed geological layer, accumulations of heavy metals and selenomagnetic anomalies similar to Reiner Gamma are visible. The LROC server allows you to download source data about the 3D landscape, which can be useful for developers of scientific applications or computer games.







    The third item is a bookmark where you can save the coordinates of interesting finds on the surface of the moon.

    At the same time as this server, I advise you to use google moon maps . Although google lunar maps are inferior to LROC in functionality and resolution, they surpass it in terms of searching for artificial objects. These cards will greatly simplify your search for traces of American and Soviet missions.

    Have a nice expedition!

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