MGS MOC Release No. MOC2-221, 12 March 2000
Changes between 1 February 1998 and 18 November 1999 MOC2-221-A (425 KBytes)
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Crater at 6°S, 184°W on 01 FEB 1998 MOC2-221-B (370 KBytes)
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3-D Anaglyph View MOC2-221-C (320 KBytes)
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The picture at the lower left (above) shows a shallow crater located near Apollinaris Patera at 6°S, 184°W, that was photographed by MOC in February 1998. The walls of this crater exhibit approximately 100 dark streaks running down its slopes. These streaks have formed as small landslides or avalanches and are probably composed of sand and/or silt. The image is illuminated by sunlight from the lower left, and the crater is about 5 kilometers (3 miles) across. The white box shows the location of a section of the crater that was photographed again in mid-November 1999, about 92% of a Martian Year later.
The top picture shows a comparison of the southeastern crater wall as it appeared on Februrary 1, 1998, and again on November 18, 1999. (Note that the picture has been rotated relative to the context image at lower left). During the time between the two images, three new dark slope streaks formed (arrows, top right). The older streaks are lighter and fainter than these new, dark ones, suggesting that streaks fade with time. This means that, at least for the crater walls shown here, any streak that is dark is younger than any streak that is pale. The stereo anaglyph (requires red-blue "3-d glasses") at the lower right uses the two images of the crater rim to provide a 3-dimensional view. The anaglyph is helpful to see that the dark streaks really do occur on a slope. In addition, by viewing the anaglyph without 3-d glasses, one can easily identify the three new streaks because they appear as blue and have no red counterpart.
These three new slope streaks formed sometime between February 1998 and November 1999. Similar streaks were observed in the highest-resolution images from the Viking orbiters in the late 1970s, but for more than 20 years no one has known how recent these features might be, or how often they might form. Now, MOC is providing some exciting answers.
These pictures are released in conjunction with the 31st Lunar and Planetary Science Conference, being held in Houston, Texas, the week of March 13-17, 2000. These streaks are the subject of a poster presentation on the evening of March 16, 2000. To view a PDF copy of the abstract, CLICK HERE and note that it is ©2000 Lunar and Planetary Institute.
Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.
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