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The surface of Mercury is dominated by impact craters, so it is not surprising that every so often one crater forms atop another. In this image, a small crater formed close to the southern margin of Mercury's northern volcanic plains, before being superposed by a slightly larger and deeper crater. This second impact removed over a third of the smaller, pre-existing crater. Yet both craters show evidence of post-formation modification, notably where their walls meet their floors. For example, a hill lies at the base of the right-hand-side wall of the larger crater. This is likely a landslide deposit that formed when material slumped off the wall.
This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.
Date acquired: July 10, 2014
Image Mission Elapsed Time (MET): 47351839
Image ID: 6659618
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 52.3°
Center Longitude: 31.6° E
Resolution: 22 meters/pixel
Scale: The crater at center-right is approximately 10 km (6.2 miles) across
Incidence Angle: 54.1°
Emission Angle: 28.3°
Phase Angle: 45.2°
Orientation: North is to the right in this image.
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This image features a simple crater in the northern smooth plains. Superimposed on the wall of this crater is another impact crater. The smaller crater is elliptical in shape, which is most likely due to being formed on a slope on the larger crater's wall. It also appears that this impact event caused material to slide down the crater wall, which can be seen in this high-resolution image.
This image was acquired as part of the MDIS low-altitude imaging campaign. During MESSENGER's second extended mission, the spacecraft makes a progressively closer approach to Mercury's surface than at any previous point in the mission, enabling the acquisition of high-spatial-resolution data. For spacecraft altitudes below 350 kilometers, NAC images are acquired with pixel scales ranging from 20 meters to as little as 2 meters.
Date acquired: July 19, 2014
Image Mission Elapsed Time (MET): 48103544
Image ID: 6712882
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 72.72°
Center Longitude: 313.7° E
Resolution: 17 meters/pixel
Scale: This image is about 9 km (5.5 miles) across.
Incidence Angle: 78.6°
Emission Angle: 0.3°
Phase Angle: 78.9°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Today's image features the sharp rim of an unnamed complex crater on Mercury. Both the terrain outside the crater's rim and the floor of the crater are marked with small craters, easy to spot in this high-resolution image at a pixel scale of 15 meters. The wall of the crater, however, is relatively smooth, as material has slumped onto the floor.
This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.
Date acquired: May 05, 2012
Image Mission Elapsed Time (MET): 244718181
Image ID: 1769016
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 66.99°
Center Longitude: 227.6° E
Resolution: 15 meters/pixel
Scale: The image is approximately 7.7 km (4.8 miles) across
Incidence Angle: 68.6°
Emission Angle: 1.6°
Phase Angle: 70.3°
Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
This image brings us back to the vicinity of Matisse, the subject of several recent Gallery images. The unnamed impact crater with the bright pyroclastic deposit on its southern floor also has two arcuate scallops on its northern wall. These were the sites of massive landslides that took place when the oversteepened crater wall collapsed. The ultimate cause of the collapse is the topography of the area where the crater formed: the northern part of the crater formed on the wall of Matisse.
This image was acquired as part of MDIS's high-resolution albedo base map. The best images for discerning variations in albedo, or brightness, on the surface are acquired when the Sun is overhead, so these images typically are taken at low incidence angles. The albedo base map covers Mercury's surface at an average resolution of 200 meters/pixel.
Date acquired: April 05, 2012
Image Mission Elapsed Time (MET): 242124773
Image ID: 1609270
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -22.85°
Center Longitude: 267.3° E
Resolution: 196 meters/pixel
Scale: The crater with the bright floor is about 70 km (44 mi.) in diameter
Incidence Angle: 40.8°
Emission Angle: 30.0°
Phase Angle: 70.8°
Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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