Image of the Day: November 2011
Topography and albedo image of different preservations states of craters (Nov. 30, 2011): These Dawn FC (framing camera) images show many craters, which have different states of preservation, in Vesta’s Bellicia quadrangle in the northern hemisphere. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, allowing stereo reconstruction. The various colors correspond to the height of the area. The red area in the left and center of the image is the highest area and the blue area in the right of the image is the lowest area. The large crater in the right of the image is seen to have a fresh rim in the albedo image. The freshness of this rim is also shown in the topography image as a sharp contrast between a higher (colored green) and lower (colored blue) height. The more degraded craters in the center of the left of the image have smoother rims and do not have such a sharp height contrast along their rims. Also, these images display the varying roughness across Vesta’s surface. The area next to the large crater in the right of the image is smoother and the rest of the area in the image is rougher. The area next to the large crater is probably an area of ejecta from the large, fresh crater because ejecta blankets are generally smoother than the areas surrounding them. These images are centered in Vesta’s Bellicia quadrangle and the center latitude and longitude of the image is 24.8°N, 65.6°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 27, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 700 km and the image has a resolution of about 60 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. The images are lambert-azimuthal map projected. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography and albedo image of grooved terrain on Vesta (Nov. 29, 2011): These Dawn FC (framing camera) images show part of the grooved terrain in Vesta’s Pinaria quadrangle, which is in the southern hemisphere. Large-scale grooves and depressions can be seen running diagonally across the image. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, allowing stereo reconstruction. The various colors correspond to the height of the area. The red area at the top of the image is the highest area and the blue area at the bottom of the image is the lowest area. The topography image does not show major height differences between the grooves and depressions; a higher resolution topography image may be necessary for this. However, the topography image does show that there is a decrease in height from the top to the bottom of the image, which is not clear in the albedo image. Visible in the bottom half of both images are narrow linear scars, which are probably formed by boulders ejected by impacts scouring across Vesta’s surface. These images are centered in Vesta’s Pinaria quadrangle and the center latitude and longitude of the image is 49.7°S, 47.3°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 26, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 700 km and the image has a resolution of about 60 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. The images are lambert-azimuthal map projected. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography and albedo image of hummocky-mantled terrain on Vesta (Nov. 28, 2011): These Dawn FC (framing camera) images show part of the ejecta blanket from Vesta’s “Snowman” craters in the northern hemisphere. The ejecta blanket fills the whole image and is identified by its hummocky yet smooth texture. The hummocky texture is due to the undulating hills and depressions across the image. But apart from these hills and depressions the surface is rather smooth. This smoothness is due to the generally small size of particles in ejecta blankets. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, allowing stereo reconstruction. The various colors correspond to the height of the area. The white area in the center of the image is the highest area and the blue area in the top of the image is the lowest area. The topography image shows that there are not large height differences between the hills and depressions. But, the topographically high area of ejecta, which is colored white, does become apparent in the topography image. These images are centered on the border between Vesta’s Caparronia and Domitia quadrangles, and also shows part of Marcia quadrangle. The center latitude and longitude of the image is 29.0°N, 179.9°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 26, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 700 km and the image has a resolution of about 60 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. The images are lambert-azimuthal map projected. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
opography and albedo image of ancient terrain with ruined crater (Nov. 27, 2011): These Dawn FC (framing camera) images show an old, heavily cratered terrain around Vesta’s equator. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, allowing stereo reconstruction. The various colors correspond to the height of the area. The red areas in the left of the image are the highest areas and the blue areas in the right of the image are the lowest areas. The heavily cratered nature of this terrain is clear in the albedo image. However, there is a roughly elliptical depression visible in the right of the topography image (colored blue) that is not as clear in the albedo image. This depression is probably a very old, ruined crater. It does not show up as well in the albedo image because it has been covered by later impact craters and has had its rim eroded. Another smaller, younger crater is visible as a blue depression in the lower left of the topography image. It is not as old or degraded/ eroded as the ruined crater so shows up better in the albedo image. These images are centered in Vesta’s Numisia quadrangle and the center latitude and longitude of the image is 1.3°N, 243.6°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 26, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 700 km and the image has a resolution of about 60 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. The images are lambert-azimuthal map projected. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography and albedo image of central complex and hummocky terrain (Nov. 26, 2011): These Dawn FC (framing camera) images show part of Rheasilvia quadrangle in Vesta’s southern hemisphere. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, allowing stereo reconstruction. The various colors correspond to the height of the area. The white and red areas in the left of the image are the highest areas and the blue area in the right of the image is the lowest area. The area denoted by the roughly circular white and red areas is the central complex feature of Vesta’s Rheasilvia basin. The high relief of the central complex is much clearer in the topography image than in the albedo image. Also clear in the topography image is the hummocky terrain, which surrounds the central complex feature. This is an undulating terrain, which consists of ridges and grooves. The height differences between the ridges and grooves are clear in the topography image: the grooves are low and colored blue and the ridges are high and colored green, yellow and red. These images are centered in Vesta’s Rheasilvia quadrangle and the center latitude and longitude of the image is 73.4°S, 297.0°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 25, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 700 km and the image has a resolution of about 60 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. The images are lambert-azimuthal map projected. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/DLR/ IDA
Topography and albedo image of part of Lucaria Tholus quadrangle (Nov. 25, 2011): These Dawn FC (framing camera) images show part of Lucaria Tholus quadrangle in Vesta’s northern hemisphere. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, allowing stereo reconstruction. The various colors correspond to the height of the area. The white area in the bottom of the image is the highest area and the blue area in the top of the image is the lowest area. Lucaria Tholus quadrangle is in Vesta’s heavily cratered northern hemisphere. Many craters, with different preservation states from fresh through degraded to ruined, are visible in these images. Two large ruined craters are partially visible in the top of the albedo image. These craters show up more clearly as the large, roughly circular, blue depressions in the top of the topography image. This image is centered in Vesta’s Lucaria Tholus quadrangle and the center latitude and longitude of the image is 16.5°N, 82.0°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 23, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Recent impact on the rim of Tuccia crater (Nov. 24, 2011): This Dawn FC (framing camera) image is dominated by the approximately 8 km diameter bright ray crater, which is roughly in the center of the image. This crater has been named Tuccia and the quadrangle in which it is located is named after it. Tuccia crater has a slightly degraded and rounded rim and is not as fresh as the approximately 3 km diameter crater located on its rim. This smaller, fresher crater must be younger than the more degraded Tuccia crater. These craters are located approximately 40 km northward of the rim of Vesta’s large south polar basin. The hummocky (i.e. wavy/ undulating) terrain of Vesta’s south polar region is seen in the bottom part of this image. The November 16 Image of the Day, “Bright rayed craters in Tuccia quadrangle” shows roughly the same part of Vesta’s surface as this image. But, today’s image was acquired from a lower orbit and consequently has better spatial resolution, which means that smaller objects are now visible. Thus, tiny craters around Tuccia crater, which could not be seen in the November 16 image, are visible in this image. This image is centered in Vesta’s Tuccia quadrangle and the center latitude and longitude of the image is 36.8°S, 194.6°E. NASA’s Dawn spacecraft obtained this image with its framing camera on November 8, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 488 km and the image has a resolution of about 46 meters per pixel. This image was acquired during the transfer to LAMO (Low Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Vesta’s cratered landscape: double crater and craters with bright ejecta (Nov. 23, 2011): This Dawn FC (framing camera) image is dominated by a double crater, which is located in the top of the image. The left side crater is 18 km in diameter and the right side crater is 23 km in diameter. This double crater may have been formed by the simultaneous impact of a binary asteroid. Binary asteroids are asteroids that orbit their mutual center of mass. As they orbit a mutual center of mass they move on a nearly identical path through the solar system. Thus, when they are on a collision course with another body in the solar system, such as Vesta, they will both impact the body and create overlapping craters. It is unlikely that this double crater was formed by one impact and then another because both of the craters seem to have a similar freshness and hence a similar age. It is unlikely that two non-binary asteroids would impact nearly the same spot on Vesta at a similar time. Other remarkable features across the image are young, small craters featuring bright ejecta rays. The bright linear rays at the bottom of the image originate from craters outside of the imaged area. This image is centered in Vesta’s Tuccia quadrangle and the center latitude and longitude of the image is 31.2°S, 203.7°E. NASA’s Dawn spacecraft obtained this image with its framing camera on November 8, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 483 km and the image has a resolution of about 45 meters per pixel. This image was acquired during the transfer to LAMO (Low Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Large blocks of rocky material in a young ray crater (Nov. 22, 2011): This Dawn FC (framing camera) image shows a young, fresh crater, which is about 7 km in diameter, in the lower right part of the image. This crater has both dark and bright rays fanning out from it. The bright rays extend much farther from the crater than the dark rays, which are located close to the crater rim. Rays around a crater are formed when relatively small sized pieces of material are ejected by the impact that formed the crater. When larger pieces of material are ejected they can form secondary craters. Clusters and chains of sub-kilometer diameter secondary craters occur roughly 15 km to 20 km away from the rim of the 7 km crater. They are called secondary craters because the blocks that formed them were ejected from a crater formed by a primary impact. Sometimes blocks fall back into the initial crater. Many of these blocks can be seen on the floor and walls of the 7 km diameter crater. These blocks are several tens of meters in size. This image is centered in Vesta’s Tuccia quadrangle and the center latitude and longitude of the image is 22.8°S, 217.3°E. NASA’s Dawn spacecraft obtained this image with its framing camera on November 8, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 478 km and the image has a resolution of about 45 meters per pixel. This image was acquired during the transfer to LAMO (Low Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Ejecta from Vesta’s “Snowman” craters (Nov. 21, 2011): This Dawn FC (framing camera) image shows ejecta from two of the large “Snowman” craters on the left of the image. This ejecta smooths out Vesta’s surface in the rest of the image. When an impact creates a crater lots of small, loose material is commonly thrown out onto the surrounding surface. This small, loose material is called ejecta and is often identified by its distinguishingly smooth appearance. This ejecta only has a few, small, fresh impact craters on its surface and there are no visible older craters buried underneath it. As there are no craters visible underneath it, this ejecta must be reasonably thick. The bumpy texture in the ejecta in the top right of the image is probably caused by movement in the ejecta due to slumping. Near to the “Snowman” craters there are some lumpy structures in the ejecta. These may be larger pieces of debris that were thrown out during the impact which formed the ejecta and the “Snowman” craters. This image is in Vesta’s Domitia quadrangle and the center latitude and longitude of the image is 29.8°N, 203.3°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 17, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Sextilia crater and surroundings (Nov. 20, 2011): This Dawn FC (framing camera) image is centered on the Sextilia crater in Vesta’s southern hemisphere. Craters on Vesta are named after Vestal virgins, priestesses of the Roman goddess Vesta. The Sextilia crater is a large, approximately 15km diameter, and distinctive crater so its name is used to name the quadrangle in which it is located. Sextilia crater is distinctive because it has a fresh, sharp rim which is also scalloped in shape. It also contains outcrops of both bright and dark material. These originate along its rim and sides and slump towards the center of the crater. There are some especially large slumps of material on the right side of the crater. Surrounding Sextilia crater is the hummocky (i.e. wavy/ undulating) terrain of Vesta’s southern hemisphere and some dark and bright rayed craters. The small dark rayed crater, and its larger neighbor, in the top of the image are the same craters which are in the bottom right of the “Dark material associated with and between craters” Image of the Day. This image is in Vesta’s Sextilia quadrangle and the center latitude and longitude of the image is 39.5°S, 155.7°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 10, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography and albedo image of Domitia crater (Nov. 19, 2011): These Dawn FC (framing camera) images show the Domitia crater in Vesta’s northern hemisphere and the topography of the surrounding region, which includes the “Snowman” craters. Domitia crater is the roughly 50km diameter crater in the top of the image, slightly offset from the center of the image. It is a highly degraded crater and its rim is nearly totally obscured by smaller, younger impact craters. Domitia crater is both large and distinctive so its name is used to name the quadrangle in which it is located. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, called stereo images. The various colors correspond to the height of the area that they color. For example, the white area in the bottom right of the image is the highest area and the dark blue top edge of the image is the lowest area. The bottom edge of Domitia crater is located on the boundary between the dark and light blue so it defines a sharp topography/ height boundary. This image is in Vesta’s Domitia, Marcia and Numisia quadrangles and the center latitude and longitude of the image is 22.3°N, 198.7°E. NASA’s Dawn spacecraft obtained this image with its framing camera on August 29, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km and the image has a resolution of about 250 meters per pixel. This image was acquired during the Survey phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Dark material associated with and between craters (Nov. 18, 2011): This Dawn FC (framing camera) image shows areas of dark material which are both associated with impact craters and between these craters. Dark material is seen cropping out of the rims and sides of the larger craters in this image. Then it frequently slumps down towards the centers of these craters. Also, there are some small dark rayed craters such as the crater near the bottom of the right edge of the image. But, many of the spots of dark material in this image appear to not be associated with any impact craters. These spots are frequently only a few pixels across so it is possible that they are in fact associated with impact craters which are just not visible at this resolution. It will be interesting to see if such tiny impact craters become visible when Dawn reaches its higher resolution LAMO (Low Altitude Mapping Orbit) phase. There is also bright material visible in this image, most noticeably in the part of the large crater visible in the top right of the image. This image is in Vesta’s Sextilia quadrangle and the center latitude and longitude of the image is 36.6°S, 135.5°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 17, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Features on Vesta’s regolith (Nov. 17, 2011): This Dawn FC (framing camera) image shows different features that form in the regolith covering Vesta’s surface. Regolith is the layer of loose, small sized material which often covers the bedrock of planets. Sinuous features in the top of the image are probably due to slumping of this regolith on a slope, similar to the way that sand slumps on the sides of sand dunes. Many of the narrow linear features in the bottom of the image are also probably due to some sort of slumping in the regolith. However, some of these linear features appear to be originating from the roughly 6km diameter crater, in the bottom left of the image, so they may have been formed by debris ejected from this crater scouring across Vesta’s surface. Also, the large crater on the bottom right side of the image has both bright and dark material cropping out in its interior and slumping towards its center. This image is in Vesta’s Numisia and Tuccia quadrangles and the center latitude and longitude of the image is 23.4°S, 227.9°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 17, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Bright rayed craters in Tuccia quadrangle (Nov. 16, 2011): This Dawn FC (framing camera) image is dominated by bright rayed craters of different sizes. The most prominent bright rayed crater is the approximately 8km diameter crater in roughly the center of the image. This crater is named Tuccia and the quadrangle in which it is located is named after it. Towards the bottom of the image its bright rays extend for over 10km but towards the top the rays are much less extensive. Tuccia crater has a smaller, fresher, younger crater on its rim which also seems to have bright rays emanating from it. It is clear that this smaller crater is younger because it overprints the larger crater and has a fresher, sharper rim than Tuccia crater. Slightly above these craters is a much smaller, roughly 2km diameter, bright rayed crater. To the left of this crater there is a patch of bright material that is associated with craters that are only a few pixels in diameter. There is also a good example of the hummocky (i.e. wavy/ undulating) terrain of Vesta’s south polar region in the bottom left of the image. Tuccia crater has been emplaced onto this hummocky terrain. This image is in Vesta’s Tuccia quadrangle and the center latitude and longitude of the image is 38.8°S, 200.2°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 17, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Hummocky terrain in Vesta’s Rheasilvia quadrangle (Nov. 15, 2011): This Dawn FC (framing camera) image shows the hummocky (i.e. wavy/ undulating) terrain of Vesta’s Rheasilvia quadrangle, which is the south polar region. This hummocky terrain is clearly seen as the pattern of hills and depressions that extends across the image. Some of these hills terminate abruptly and have scarps (i.e. cliffs) along their margins. Due to the direction of sunlight in this image these scarps are visible as linear shadowed regions. There are also narrow, linear grooves running obliquely across the image, most noticeably in the top of the image. There is a range of crater sizes from less than 1km to around 15km in diameter. The smaller craters tend to be fresher with sharper rims and the larger craters tend to be more degraded with rounder rims. A large, roughly 10km diameter, crater in the top left of the image contains linear features which are probably due to slumping towards the center of the crater. This image is in Vesta’s Rheasilvia quadrangle and the center latitude and longitude of the image is 74.8°S, 207.4°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 17, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Impact craters with different preservation states (Nov. 14, 2011): This Dawn FC (framing camera) image shows four large impact craters close to one another on Vesta’s surface. Interestingly, each of these four has a distinct preservation state. The crater on the right is the freshest: its rim is clear and sharp and material can be distinctly seen slumping into the center of the crater. The crater in the bottom is partially degraded: its rim is less clear and more rounded and material slumping into the center is only somewhat visible. The crater on the left is more degraded again: its rim is less distinct and very rounded and there is no slumping material visible. It has also has been partially covered by some younger impacts. The crater in the top is the most degraded: its rim is extremely rounded and it has been well covered by many younger impacts. It is so degraded that it may be called a ruin crater. It is clear from this image that as craters get older their rims get less sharp and more rounded, slumping material blends in with the rest of the material on Vesta’s surface and the number of younger impacts increases. This image is in Vesta’s Bellicia quadrangle and the center latitude and longitude of the image is 43.6°N, 83.6°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 16th 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Mantled surface of Vesta with secondaries (Nov. 13, 2011): This Dawn FC (framing camera) image shows a part of the surface of Vesta, which is mantled (i.e. covered) by an ejecta blanket. This ejecta blanket is evident as the smoothly textured surface visible across the image. Ejecta blankets consist of small debris, which are ejected as impacts form craters. The crater from which this ejecta blanket originates may be the large shadowed crater in the top left of the image, or may be another nearby large crater outside of the image. There are a number of smaller, younger craters and irregularly shaped, small depressions on top of this ejecta blanket, particularly in the right side of the image. Solitary impact craters are formed by impacts of material from space. But the crater chains and irregularly shaped depressions are probably formed by boulders and other debris re-impacting the surface of Vesta after they are ejected from a nearby large impact. As they are impacting Vesta for the second time these crater chains and irregular depressions are called secondaries. This image is in Vesta’s Domitia quadrangle and the center latitude and longitude of the image is 56.7°N, 190.1°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 19, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 702 km and the image has a resolution of about 70 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Grooves and crater chains on Vesta (Nov. 12, 2011): This Dawn FC (framing camera) image shows numerous grooves (i.e. linear depressions) and crater chains, especially in the right hand side of the image. These grooves and crater chains are less than 1km wide and have two dominant orientations, which crisscross one another in some areas to form an ‘X’ pattern. These grooves and crater chains were probably formed by impacts of material which originated in impacts outside of the region in this image. The grooves likely formed by material scouring across Vesta’s surface, leaving a linear depression. The crater chains likely formed due to secondary impacts, when material thrown out of previous impacts re-impacted Vesta. These grooves and crater chains lie on top of a smooth layer of ejecta blanket, which probably originates from the large crater in the left side of the image. Another narrow crater chain is seen extending from the inner wall of this crater to its base. This image is in Vesta’s Oppia quadrangle and the center latitude and longitude of the image is 18.5°N, 299.4°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 22, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 666 km and the image has a resolution of about 62 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Fresh crater with bright and dark rays (Nov. 11, 2011): This Dawn FC (framing camera) image shows a small, young, fresh crater with bright and dark rays extending from it. This crater is located in the center of the image, it is approximately 5km wide and its rays extend for up to 10km. The bright and dark rays also slump into the center of this crater, giving it an impressively mottled appearance. To the left of this crater is a larger, older, more degraded crater into which some of the bright and dark rays appear to be slumping. There is one particularly clear white ray, flanked by two dark rays, which slumps from the edge of the degraded crater to its center, a distance of nearly 10km. Bright and dark material also slumps into another degraded crater in the lower right of the image. But in this case the source of the material seems to be the crater rim rather than a neighboring crater. This image is in Vesta’s Sextilia quadrangle and the center latitude and longitude of the image is 23.6°S, 128.3°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 23, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 675 km and the image has a resolution of about 63 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Ejecta from a fresh crater covering older craters and crater chains (Nov. 10, 2011): This Dawn FC (framing camera) image is dominated by an approximately 20km wide, young, fresh crater in the top of the image. Surrounding this crater is its ejecta blanket, which is a covering of small particles that were thrown out during the impact that formed the crater. The ejecta blanket is the cause of the smooth surface around the 20km crater in this image. This ejecta blanket buries many older, degraded craters and some can be seen poking through the blanket in the bottom and right of the image. Degraded craters are less clear or not visible directly next to the 20km crater. This suggests that the ejecta blanket is thicker, and consequently more deeply buries older craters, closer to the 20km crater. There are several distinctive chains of small craters running obliquely across the image on top of the ejecta blanket. They are not buried by the ejecta blanket so must be younger than it. These crater chains likely formed due to secondary impacts, when material thrown out of previous impacts re-impacted Vesta. Similarly, material ejected from the 20km crater has fallen back into the crater and created densely packed pits on its floor. This image is in Vesta’s Floronia quadrangle and the center latitude and longitude of the image is 32.5°N, 1.2°E. NASA’s Dawn spacecraft obtained this image with its framing camera on October 24, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 662 km and the image has a resolution of about 62 meters per pixel. This image was acquired during the HAMO (High Altitude Mapping Orbit) phase of the mission. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of Vesta’s equatorial region III (Nov. 9, 2011): These Dawn FC (framing camera) images show part of Vesta’s equatorial region, which contains impact craters and troughs (linear depressions). The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, called stereo images. The various colors correspond to the height of the area that they color. For example, the white area in the bottom of the image is the highest area and the blue area in the top right of the image is the lowest. This blue area corresponds to a large circular depression, which is perhaps a very eroded ancient crater. The troughs, which run across the bottom of the image, do not have a continuous height along their lengths. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of Vesta’s equatorial region II (Nov. 8, 2011): These Dawn FC (framing camera) images show part of Vesta’s equatorial region, which contains many different sizes of impact craters. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, called stereo images. The various colors correspond to the height of the area that they color. For example, the white and red areas along the bottom of the image are the highest areas and the blue areas along the top of the image are the lowest. There is a long low area running obliquely across the image (color-coded blue and green in the topography image), which is not as clear in the albedo image. This long low area appears to be made up of three old, large, eroded craters. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11th 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of Vesta’s equatorial region I (Nov. 7, 2011): These Dawn FC (framing camera) images show part of Vesta’s equatorial region, which contains a prominent, deep impact crater (lower center of image) and large troughs (linear depressions). The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, called stereo images. The various colors correspond to the height of the area that they color. For example, the white areas in the bottom corners of the image are the highest areas and the blue areas along the top of the image are the lowest. The prominent impact crater is set into a topographically high area defined by the red and white color-coding. Above this area there are a number of deep troughs represented by green and blue color-coding. A conspicuous trough on the left, which looks like it could be quite deep in the albedo image, is shown by the color-coding in the topography image to be only a little shallower than the area surrounding it. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of a scarp and hummocky terrain in Vesta’s south polar region (Nov. 6, 2011): These Dawn FC (framing camera) images show part of the rim of the south polar basin, which is dominated by a large scarp (eg. cliff) that runs vertically across the center of the images. The piled-up material at the scarp’s base is likely due to landsliding. There is also some hummocky (eg. wavy/ undulating) terrain to the left of the scarp. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The topography is calculated from a set of images that were observed from different viewing directions, called stereo images. The various colors correspond to the height of the area that they color. For example, white and red areas on the right are the highest regions and the blue areas on the left are the lowest. The change in color-coded height on the scarp from red to green illustrates its dramatic topographic profile. The blue color-coded hummocky terrain is located on the base of the south polar basin, which is the lowest region in this image. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of Vesta’s south polar region IV (Nov. 5, 2011): These Dawn FC (framing camera) images show the central area of the south polar basin. They provide a view of the same region as yesterday’s Image of the Day but here the view is rotated by approximately 90°. These image show the mountain/ central complex as a roughly circular feature in the right of the image and there are grooves, scarps and hummocky (eg. wavy/ undulating) terrane around and on this feature. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The various colors correspond to the height of the area that they color. For example, red in the left and top of the right image is the highest area and the blue areas in the center of the image are the lowest. This color-coding greatly enhances the topography contrast between the mountain/ central complex (colored yellow and green) and the depression surrounding it (colored blue). The topography is calculated from a set of images that were observed from different viewing directions, these are called stereo images. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA /JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of Vesta’s south polar region III (Nov. 4, 2011): These Dawn FC (framing camera) images show the central area of the south polar basin. They provide a view of the same region as yesterday’s Image of the Day but here the view is rotated by approximately 60°. As before the mountain/ central complex is the roughly circular feature in the center of the image and there are grooves, scarps and hummocky (eg. wavy/ undulating) terrane around and on this feature. The large scarp in the center of the mountain/ central complex shows up better than in the previous Image of the Day. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The various colors correspond to the height of the area that they color. For example, the white and red in the top left of the right image is the highest area and the blue areas towards the bottom of the image are the lowest. This color-coding clearly shows how the side of the depression and the mountain/ central complex in the top of the image, colored green, is higher than the side in the bottom of the image, colored blue. The topography is calculated from a set of images that were observed from different viewing directions, these are called stereo images. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of Vesta’s south polar region II (Nov. 3, 2011): These Dawn FC (framing camera) images show the central area of the south polar basin. The mountain/ central complex is the roughly circular feature in the center of the image. There are grooves, scarps and hummocky (eg. wavy/ undulating) terrane around and on this feature. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The various colors correspond to the height of the area that they color. For example, the white and red on the top edge of the right image is the highest area and the blue areas in the bottom of the image is the lowest. This color-coding shows the topography of the region well: the mountain/ central complex (colored green and yellow) is higher than the roughly circular depression surrounding it (colored blue and green), which is all lower than the red and white region in the top of the image. The topography is calculated from a set of images that were observed from different viewing directions, these are called stereo images. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of Vesta’s south polar region I (Nov. 2, 2011): These Dawn FC (framing camera) images show part of the south polar basin. A large scarp (eg. cliff) is visible in the top right of the images, grooves and hummocky (eg. wavy/undulating) terrane are visible in the center of the images and the mountain/central complex is visible in the bottom left of the images. The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The various colors correspond to the height of the area that they color. For example, the white in the top left of the right image is the highest area and the blue areas in the bottom right of the image are the lowest. The scarp and surrounding area are some of the highest regions in the image. Then there is a blue colored depression in between this area and the mountain/ central complex. This is a green color which corresponds to a height in between that of the scarp area and the depression area. The topography is calculated from a set of images that were observed from different viewing directions, these are called stereo images. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Topography of Vesta’s equatorial region (Nov. 1, 2011): These Dawn FC (framing camera) images show part of Vesta’s equatorial region, which contains impact craters and troughs (linear depressions). The left image is an albedo image, which is taken directly through the clear filter of the FC. Such an image shows the albedo (eg. brightness/ darkness) of the surface. The right image uses the same albedo image as its base but then a color-coded height representation of the topography is overlain onto it. The various colors correspond to the height of the area that they color. For example, the white in the bottom right of the right image is the highest area and the blue areas in the central crater and the top of the right image are the lowest. Below the central crater there is a long low area running obliquely across the image (blue and green colors), which is not as clear in the left albedo image. The topography is calculated from a set of images that were observed from different viewing directions, these are called stereo images. NASA’s Dawn spacecraft obtained the albedo image with its framing camera on August 11, 2011. This image was taken through the camera’s clear filter. The distance to the surface of Vesta is 2740 km the image has a resolution of about 250 meters per pixel. The images are projected using a lambert-azimuthal map projection. Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Science
The targets of the Dawn mission could not be more different: While Vesta once had a hot, molten interior that produced lava flows, Ceres has always been a cold body, under whose surface possibly frozen water can be found. In addition, both bodies allow for a look back into an early phase of our solar system. Both asteroids are among the largest survivors from this early phase of planet formation. more...
Mission
Dawn is a NASA mission managed by the Jet Propulaion Laboratory (JPL) that will reach the asteroids Vesta and Ceres within the next years. The space probe will encounter its first destination, the asteroid Vesta, in the summer of 2011. Presumably at the end of July, Dawn will start orbiting Vesta and deliver its first high-resolution images of the surface. more...
Cameras
The mission's success crucially depends on the two cameras, Dawn's eyes. The cameras were developed and built under the leadership of the Max Planck Institute for Solar System Research with significant contributions by the Institute for Planetary Research of the German Aerospace Center (DLR) and in coordination with the Institute of Computer and Communication Network Engineering of the Technical University Braunschweig. more...