vesmír.info

First Color HiRISE Image of Mars

     This is the first color image of Mars from the High Resolution Imaging Science Experiment on NASA's Mars Reconnaissance Orbiter. At the center portion of the camera's array of light detectors there are extra detectors to image in green and near-infrared color bandpasses, to be combined with the black-and-white images (from red-bandpass detectors) to create color images. This is not natural color as seen by human eyes, but infrared color -- shifted to longer wavelengths. This image also has been processed to enhance subtle color variations. The southern half of the scene is brighter and bluer than the northern half, perhaps due to early-morning fog in the atmosphere. Large-scale streaks in the northern half are due to the action of wind on surface materials. The blankets of material ejected from the many small fresh craters are generally brighter and redder than the surrounding surface, but a few are darker and less red. Two greenish spots in the middle right of the scene may have an unusual composition, and are good future targets for the Compact Reconnaissance Imaging Spectrometer for Mars, a mineral-identifying instrument on Mars Reconnaissance Orbiter ( http://crism.jhuapl.edu/). In the bottom half of the image we see a redder color in the rough areas, where wind and sublimation of water or carbon dioxide ice have partially eroded patches of smooth-textured deposits.

     This image was taken by HiRISE on March 24, 2006. The image is centered at 33.65 degrees south latitude, 305.07 degrees east longitude. It is oriented such that north is 7 degrees to the left of up. The range to the target was 2,493 kilometers (1,549 miles). At this distance the image scale is 2.49 meters (8.17 feet) per pixel, so objects as small as 7.5 meters (24.6 feet) are resolved. In total this image is 49.92 kilometers (31.02 miles) or 20,081 pixels wide and 23.66 kilometers (14.70 miles) or 9,523 pixels long. The image was taken at a local Mars time of 07:33 and the scene is illuminated from the upper right with a solar incidence angle of 78 degrees, thus the sun was 12 degrees above the horizon. At an Ls of 29 degrees (with Ls an indicator of Mars' position in its orbit around the sun), the season on Mars is southern autumn.

     Image Credit: NASA/JPL-Caltech/University of Arizona

Perspective View of HiRISE First Image

     This perspective view generated from digital topography provides an overview of the Mars terrain covered in the first color image of Mars from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. It has a field of view 55 degrees wide, and no vertical exaggeration. The overview illustrates how the ridge has deformed several valleys and impact craters.

Sample of the Argyre Impact Basin Rim

     This image shows part of a low mountain belt that rings the Argyre impact basin in Mars' southern hemisphere. The mountains or hills seen here are located in the northwestern part of the Charitum Montes. Taken just minutes after the sun had risen over the horizon, only the sun-facing slopes are well illuminated and much of the scene is in shadow, but the camera has nevertheless captured many details of the surface that are only dimly illuminated. There are terrains that are both smooth and rough at this scale (2.94 meters or 9.65 feet per pixel). The rough terrain is littered with blocks roughly 10 meters (30 feet) across, and the smooth material has a uniform appearance broken by subtle, undulating ridges. The rough terrains usually occur at relatively high elevations, and smooth material occupies the lowest areas. In some locations it is evident that boulders from the rough terrain have tumbled downhill onto the smooth material. The smooth material is younger than the rough terrain, and some of it may have formed when water-rich or ice-rich debris flooded low-lying areas. In other areas the smooth material mantles the topography like deposits of airborne dust. Further upslope, the mountain flanks have a variety of rough textures. In places the terrain has been eroded into streamlined forms and striations, suggestive of glacial erosion. Gullies formed in one spot near bottom center. Perhaps the most striking aspect of this image is the dearth of fresh impact craters. The Argyre basin is thought to be billions of years old, but much more recent processes have greatly modified the surface.

     This image was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard NASA's Mars Reconnaissance Orbiter spacecraft on March 24, 2006. The image is centered at 52.20 degrees south latitude, 300.75 degrees east longitude. It is oriented such that north is 7 degrees to the left of up. The range to the target was 1,470 kilometers (913 miles). With 2x2 pixel binning, the scale of the image is 2.94 meters (9.65 feet) per pixel, so objects as small as 8.82 meters (28.94 feet) are resolved. In total this image is 29.47 kilometers (18.31 miles) or 10,040 pixels wide and 76.44 kilometers (47.50 miles) or 26,011 pixels long. The image was taken at a local Mars time of 07:24 and the scene is illuminated from the upper right with a solar incidence angle of 87.1 degrees, thus the sun was about 2.9 degrees above the horizon. At an Ls of 29 degrees (with Ls an indicator of Mars' position in its orbit around the sun), the season on Mars is southern autumn.