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Mariner 9 Television Reconnaissance of Mars and Its Satellites: Preliminary Results

Masursky, Harold and Murray, B. C. and Cutts, J. A. and Sharp, R. P. and Smith, Susan and Leighton, R. B. and Sagan, C. (1972) Mariner 9 Television Reconnaissance of Mars and Its Satellites: Preliminary Results. Science, 175 (4019). pp. 294-305. ISSN 0036-8075. doi:10.1126/science.175.4019.294.

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At orbit insertion on 14 November 1971 the Martian surface was largely obscured by a dust haze with an extinction optical depth that ranged from near unity in the south polar region to probably greater than 2 over most of the planet. The only features clearly visible were the south polar cap, one dark, spot in Nix Olympica, and three dark spots in the Tharsis region. During the third week the atmosphere began to clear and surface visibility improved, but contrasts remained a fraction of their normal value. Each of the dark spots that apparently protrude through most of the dust-filled atmosphere has a crater or crater complex in its center. The craters are rimless and have featureless floors that, in the crater complexes, are at different levels. The largest crater within the southernmost spot is approximately 100 kilometers wide. The craters apparently were formed by subsidence and resemble terrestrial calderas. The south polar cap has a regular margin, suggesting very flat topography. Two craters outside the cap have frost on their floors; an apparent crater rim within the cap is frost free, indicating preferential loss of frost from elevated ground. If this is so then the curvilinear streaks, which were frost covered in 1969 and are now clear of frost, may be low-relief ridges. Closeup pictures of Phobos and Deimos show that Phobos is about 25 ±5 by 21 ±1 kilometers and Deimos is about 13.5 ± 2 by 12.0 ±0.5 kilometers. Both have irregular shapes and are highly cratered, with some craters showing raised rims. The satellites are dark objects with geometric albedos of 0.05.

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Cutts, J. A.0000-0002-1765-8322
Additional Information:© 1972 American Association for the Advancement of Science. December 1971. We thank E. M. Shoemaker and A. P. Ingersoll for reviewing the manuscript. We also thank R. Tyner and S. Reed for making mosaics of the pictures during mission operations. This work was performed for the Jet Propulsion Laboratory, California Institute of Technology, under NASA contract NAS 7-100.
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Issue or Number:4019
Record Number:CaltechAUTHORS:20151111-080331134
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Official Citation:Mariner 9 Television Reconnaissance of Mars and Its Satellites: Preliminary Results Harold Masursky, R. M. Batson, J. F. McCauley, L. A. Soderblom, R. L. Wildey, M. H. Carr, D. J. Milton, D. E. Wilhelms, B. A. Smith, T. B. Kirby, J. C. Robinson, C. B. Leovy, G. A. Briggs, T. C. Duxbury, C. H. Acton Jr., B. C. Murray, J. A. Cutts, R. P. Sharp, Susan Smith, R. B. Leighton, C. Sagan, J. Veverka, M. Noland, J. Lederberg, E. Levinthal, J. B. Pollack, J. T. Moore Jr., W. K. Hartmann, E. N. Shipley, G. De Vaucouleurs, and M. E. Davies Science 21 January 1972: 175 (4019), 294-305. [DOI:10.1126/science.175.4019.294]
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:62048
Deposited By: Ruth Sustaita
Deposited On:11 Nov 2015 21:04
Last Modified:10 Nov 2021 22:57

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