Thursday, July 31, 2014

Oblong Impact Crater


This image features an elongated impact crater north of Rembrandt impact basin. This crater was most likely formed by a oblique impact (less than 15 degrees from the horizontal), which created the crater's distinct elongated shape and central peak. This crater's rays have faded over time due to space weathering, but when they were still visible, they would have formed a butterfly pattern from the crater's rim.

This image was acquired as part of MDIS's high-resolution surface morphology base map. The surface morphology base map covers more than 99% of Mercury's surface with an average resolution of 200 meters/pixel. Images acquired for the surface morphology base map typically are obtained at off-vertical Sun angles (i.e., high incidence angles) and have visible shadows so as to reveal clearly the topographic form of geologic features.

Date acquired: July 04, 2014
Image Mission Elapsed Time (MET): 46777429
Image ID: 6618818
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -18.60°
Center Longitude: 95.44° E
Resolution: 162 meters/pixel
Scale: The oblong impact is about 34.2 km (21.3 miles) long and 19.3 km (12 miles) wide.
Incidence Angle: 65.0°
Emission Angle: 31.8°
Phase Angle: 41.1°

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Tuesday, July 29, 2014

Secondary Craters in the Northern Plains


This image is one of the highest resolution images taken by the MESSENGER spacecraft to date. It features a field of secondary craters in Mercury's northern smooth plains. Secondary craters are formed by the re-impact of debris strewn from a larger crater. The largest secondary craters in this image are roughly a few hundred meters across. If you look closely, you can see some small craters that are only tens of meters across. All of these craters are simple craters.

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.

On 25 July 2014, MESSENGER moved closer to Mercury than any spacecraft has before, dropping to an altitude of 100 kilometers (60 miles) above the planet's surface. By 19 August 2014, the minimum altitude will be cut in half, to only 50 kilometers (31 miles)! MESSENGER will execute three more orbit-correction maneuvers in order to delay the end of mission to late March 2015. For more details on this event, read this news story.

Date acquired: June 11, 2014
Image Mission Elapsed Time (MET): 44779109
Image ID: 6477542
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 69.84°
Center Longitude: 48.47° E
Resolution: 2.9 meters/pixel
Scale: This image is about 3 km (1.8 miles) across.
Incidence Angle: 79.4°
Emission Angle: 0.1°
Phase Angle: 79.6°

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Saturday, July 26, 2014

Raditladi Basin


This color view of Raditladi gives us a fresh view of the peak-ring basin. The bright hollows of Raditladi stand out in white along the peak ring against the smooth crater floor. These shallow depressions may result from the loss of volatile materials. Today's image also shows the darker ejecta of a crater that impacted the basin just above the southern peak-ring structure. The darker material was likely excavated during the small crater's impact.

This image was acquired as a targeted high-resolution 11-color image set. Acquiring 11-color targets is a new campaign that began in March 2013 and that utilizes all of the WAC's 11 narrow-band color filters. Because of the large data volume involved, only features of special scientific interest are targeted for imaging in all 11 colors.

Date acquired: June 22, 2014
Image Mission Elapsed Time (MET): 45761752, 45761748, 45761746
Image ID: 6547149, 6547147, 6547146
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: 28.37°
Center Longitude: 120.3° E
Resolution: 732 meters/pixel
Scale: Raditladi crater has a diameter of 257.7 km (160.1 miles)
Incidence Angle: 57.3°
Emission Angle: 38.5°
Phase Angle: 89.4°

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Thursday, July 24, 2014

Laxness Crater's Topographical Profile


Today's image features Laxness, a crater on Mercury's northern plains named for Halldör Laxness, a twentieth-century Icelandic writer. The overlain MLA track bisecting Laxness reveals the crater's topography, which is difficult to resolve in images because of the crater's persistently shadowed interior. On the right of the image is a cross-section of Laxness showing how the crater's depth changes from point A to point B. The MLA data show that Laxness is a complex crater with a central peak (light blue). While the crater's central peak is not obvious in the Mercury Dual Imaging System (MDIS), it is clearly distinguishable to MLA.

Instrument: Mercury Laser Altimeter (MLA)
MLA Track: MLASCIRDRAPLFN1202071801
Crater's Center Latitude: 83.3°
Crater's Center Longitude: 310.0° E
Scale: The crater has a diameter of 25.9 km (16.1 miles)

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Tuesday, July 22, 2014

Landslides Below an Impact Crater Rim


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

Saturday, July 19, 2014

Craters Munch, Sander and Poe


The top image is a MASCS VIRS interpolated color composite of craters Munch and Sander (center), with Poe toward the east. These craters are in the north of Caloris basin. The center image is a MASCS color composite showing individual spectral footprints. The bottom image is a monochrome MDIS mosaic of the same area. The three crater rims are blue, indicating low reflectance. Sander's floor is yellow, however, which is high reflectance and indicative of fresh material.

The VIRS composite shows hundreds of individual footprints tracks (minimum 100-200 m across and 3-4 km long) taken from different directions and altitudes. In locations where multiple footprints cover the same area, the footprint with the best illumination for mineralogical interpretation (usually the lowest incidence angle where shadows are minimized) is used for making the map. In areas where footprints are sparse (separated by tens of km), observations are interpolated for complete coverage of the surface. This is particularly true in the northern hemisphere, where Caloris is located. In the MDIS mosaic, some brightness variations are due to tiling of images taken at different illuminations.

Date Created: June 16, 2014
Instruments: Visible and Infrared Spectrograph (VIRS) of the Mercury Atmosphere and Surface Composition Spectrometer (MASCS) and Mercury Dual Imaging System (MDIS)
VIRS Color Composite Wavelengths: 575 nm as red, 415 nm/750 nm as green, 310 nm/390 nm as blue
Center Latitude: 42.5°
Center Longitude: 154.5° E
Resolution: 1 km/pixel
Scale: Sander crater (center) is about 50 km (31 mi.) in diameter.

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Thursday, July 17, 2014

Waters Crater Impact Melt and Ejecta Blanket


The top image is a MASCS VIRS color composite of Waters crater (center) in Mercury's mid latitudes. The bottom image is a monochrome MDIS mosaic of the same area. The central blue area corresponds to both Waters and its impact melt flow. The encompassing yellow area likely relates to Waters' ejecta blanket. Blue areas indicate low reflectance, while yellow areas relate to high reflectance and newer material.

The VIRS composite shows hundreds of individual footprints tracks (minimum 100-200 m across and 3-4 km long) taken from different directions and altitudes. In locations where multiple footprints cover the same area, the footprint with the best illumination for mineralogical interpretation (usually the lowest incidence angle where shadows are minimized) is used for making the map. In the MDIS mosaic, some brightness variations are due to tiling of images taken at different illuminations.

Date Created: July 7, 2014
Instruments: Visible and Infrared Spectrograph (VIRS) of the Mercury Atmosphere and Surface Composition Spectrometer (MASCS) and Mercury Dual Imaging System (MDIS)
VIRS Color Composite Wavelengths: 575 nm as red, 415 nm/750 nm as green, 310 nm/390 nm as blue
Center Latitude: -9.1°
Center Longitude: 254.6° E
Resolution: 0.5 km/pixel
Scale: Waters crater (center) is about 15 km (9.3 mi.) in diameter.

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Tuesday, July 15, 2014

Craters Eminescu, Xiao Zhao and Eastman by VIRS and MDIS


The top image is a MASCS VIRS interpolated color composite of craters Eminescu (center), with Xiao Zhao and Eastman toward the east and in Mercury's mid-latitudes. The bottom image is a monochrome MDIS mosaic of the same area. Yellow areas correspond to high values in both the red and green channels, that is, high reflectance (at 575 nm) and high values of the 415-nm/575-nm reflectance ratio. In some cases these spectral characteristics are associated with fresh material (like the rays of Xiao Zhao) that has been less affected by space weathering. Hollows, such as those found on and around the central peak of Eminescu, have similar colors.

The VIRS composite shows hundreds of individual footprints tracks (minimum 100-200 m across and 3-4 km long) taken from different directions and altitudes. In locations where multiple footprints cover the same area, the footprint with the best illumination for mineralogical interpretation (usually the lowest incidence angle where shadows are minimized) is used for making the map. In areas where footprints are sparse (separated by tens of km), observations are interpolated for complete coverage of the surface. In the MDIS mosaic, some brightness variations are due to tiling of images taken at different illuminations.

Date Created: June 16, 2014
Instruments: Visible and Infrared Spectrograph (VIRS) of the Mercury Atmosphere and Surface Composition Spectrometer (MASCS) and Mercury Dual Imaging System (MDIS)
VIRS Color Composite Wavelengths: 575 nm as red, 415 nm/750 nm as green, 310 nm/390 nm as blue
Center Latitude: 10.0°
Center Longitude: 114.3° E
Resolution: 1 km/pixel
Scale: Eminescu crater(center) is about 130 km (80 mi.) in diameter

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Saturday, July 12, 2014

Crater on a Ridge


Today's image is one of the highest resolution images MESSENGER has taken to date at only 3 meters per pixel. It features a small ridge with a crater on its crest. The small crater is a simple crater. If you look at the area around the crater, you can spy many craters that are even smaller! As MESSENGER continues passing close to the surface of Mercury, high resolution images such as this one will be taken, allowing scientists (and the public) to see Mercury as it has never been seen before!

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: June 09, 2014
Image Mission Elapsed Time (MET): 44663950
Image ID: 6469301
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 75.38°
Center Longitude: 64.46° E
Resolution: 3 meters/pixel
Scale: The central crater is 366 m (1200 ft) in diameter.
Incidence Angle: 80.0°
Emission Angle: 1.2°
Phase Angle: 81.1°

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Thursday, July 10, 2014

Sunrise Near the South Pole


Today's image features a large area near the south pole of Mercury. On the right side of this image, going from top to bottom are both the Terror Rupes and Eltanin Rupes. In the middle of the right edge is Alver, a peak-ring crater. Below Alver is Disney, a crater named after the animator Walt Disney.

Date acquired: June 16, 2014
Image Mission Elapsed Time (MET): 45232494, 45232490, 45232488
Image ID: 6510119, 6510117, 6510116
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: -83.00°
Center Longitude: 40.17° E
Resolution: 2988 meters/pixel
Scale: This image is 1585 km (985 miles) across.
Center Incidence Angle: 85.3°
Center Emission Angle: 14.1°
Center Phase Angle: 99.4°

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Tuesday, July 8, 2014

Egonu Crater


This image is a high-resolution view of the polar crater Egonu. The 'flower' in the crater is Egonu's central peak. Egonu is named after Uzo Egonu, a Nigerian artist (1931-1996). He was known for crossing the boundary between Western and African painting, as he lived in England for most of his life.

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 05, 2012
Image Mission Elapsed Time (MET): 249988836
Image ID: 2143790
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 67.15°
Center Longitude: 61.80° E
Resolution: 13 meters/pixel
Scale: This image is about 14 km (8.7 miles) across
Incidence Angle: 75.6°
Emission Angle: 1.3°
Phase Angle: 74.3°

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Saturday, July 5, 2014

Bright Rayed Impact Crater


Today's image features an explosion of stunning rays, radiating from a crater located near Mercury's equator. The bright ejecta rays result from impacts ejecting subsurface material. Because the subsurface material is relatively unweathered compared to the nearby surface terrain, the rays appear a bright white in this color image.

This image was acquired as a targeted high-resolution 11-color image set. Acquiring 11-color targets is a new campaign that began in March 2013 and that utilizes all of the WAC's 11 narrow-band color filters. Because of the large data volume involved, only features of special scientific interest are targeted for imaging in all 11 colors.

Date acquired: December 10, 2013
Image Mission Elapsed Time (MET): 28990861, 28990857, 28990855
Image ID: 5355052, 5355050, 5355049
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: -0.68°
Center Longitude: 95.97° E
Resolution: 685 meters/pixel
Scale: The image is approximately 566 km (352 miles) across
Incidence Angle: 32.6°
Emission Angle: 49.5°
Phase Angle: 82.1°

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Thursday, July 3, 2014

Mercury's Terminator


Today's color image features both Mercury's terminator and limb. The terminator is the striking separation of night and day on Mercury. It is seen in this image with the change from dark, on the left of the image, to light. Mercury's limb is also captured, as we can see the edge between sunlit Mercury and space.

Date acquired: May 05, 2014
Image Mission Elapsed Time (MET): 41602341, 41602337, 41602335
Image ID: 6252070, 6252068, 6252067
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
WAC filters: 9, 7, 6 (996, 748, 433 nanometers) in red, green, and blue
Center Latitude: -57.08°
Center Longitude: 93.92° E
Resolution: 3227 meters/pixel
Scale: The bottom edge of this image is approximately 2530 km (1572 miles) in length.

Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington