Sep 21 2007
From The Space Library
The journal Science published a special issue about water on Mars. The issue included five reports that had used the scientific results derived from the detailed images that NASA’s Mars Reconnaissance Orbiter (MRO) had captured during the first 100 days of its mission. MRO’s primary mission was to study Mars’s hydrologic history, using six scientific instruments, including the High-Resolution Imaging Science Experiment camera (HiRISE), which provided 10 times the resolution of any previous Mars imager. The papers published in this special issue of Science indicated that evidence for liquid water on Mars was rare and difficult to discern. NASA’s Mars Global Surveyor (MGS), which had visited Mars in 1999, had raised researchers’ hopes that the probe had detected modern flows of liquid water on Mars. However, MRO’s observations suggested otherwise—that landslides of loose, dry materials had created the deposits that scientists had interpreted as evidence of liquid water. In addition, MRO had captured images suggesting that flowing lava, rather than water, had shaped some Martian landforms, such as branched channels and fan-like deposits. Moreover, MRO images indicated that, although certain gullies and rims of craters did indeed contain liquid water, the presence of water at these locations did not reveal the presence of a water table. Rather, the images suggested that objects impacting Mars had triggered trickles of water at these sites. Radar and gravity data indicated that the cap on Mars’s south pole held the largest reservoir of water ice on the planet.
NASA, “NASA Orbiter Provides Insights About Mars Water and Climate,” news release 07-206, 20 September 2007, http://www.nasa.gov/home/hqnews/2007/sep/HQ_07206_Mars_Water.html (accessed 4 August 2010); Joanne Baker, “Introduction to Special Issue: Water, Water, Not Everywhere?” Science 317, no. 5845 (21 September 2007): 1705, Science Mag (DOI: 10.1126/science.317.5845.1705; accessed 10 August 2010); Jeanna Bryner, “Hope for Water on Mars Dims with Sharp New Images,” Space.com, 20 September 2007, http://www.space.com/scienceastronomy/070920_mars_tale.html (accessed 10 August 2010).
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