Phoenix Candor Chasma EndeavourNASA eventually made its choice for the landing site of Mars Science Laboratory: it's Gale Crater
Mars Society Switzerland
Image Credit: NASA/JPL-Caltech/ASU/UA This oblique view of Gale crater shows the landing site and the mound of layered rocks that NASA's Mars Science Laboratory will investigate. The landing site is in the smooth area in front of the mound (marked by a yellow ellipse, which is 12.4 miles [20 kilometers] by 15.5 miles [25 kilometers]). Gale crater is 96 miles (154 kilometers) in diameter and holds a layered mountain rising about 3 miles (5 kilometers) above the crater floor. The landing site contains material washed down from the wall of the crater, which will provide scientists with the opportunity to investigate the rocks that form the bedrock in this area. The landing ellipse also contains a rock type that is very dense and very bright colored; it is unlike any rock type previously investigated on Mars. It may be an ancient playa lake deposit, and it will likely be the mission's first target in checking for the presence of organic molecules. The area of top scientific interest for Mars Science Laboratory is at the base of the mound, just at the edge of the landing ellipse and beyond a dark dune field. Here, orbiting instruments have detected signatures of both clay minerals and sulfate salts. Scientists studying Mars have several important hypotheses about how these minerals reflect changes in the Martian environment, particularly changes in the amount of water on the surface of Mars. The Mars Science Laboratory rover, Curiosity, will use its full instrument suite to study these minerals and how they formed to give us insights into those ancient Martian environments. These rocks are also a prime target in checking for organic molecules, since these environments may have been habitable -- able to support microbial life. Two canyons (marked by arrows) were cut in the mound through the layers containing the clay minerals and sulfate salts after deposition of the layers. These canyons, much like the Grand Canyon in Arizona, expose layers of rock representing tens or hundreds of millions of years of environmental change. The rover may be able to investigate these layers in the canyon closest to the landing ellipse, gaining access to a long history of environmental change on the planet. The canyons also contain sediment that was transported by the water that cut the canyons. This sediment interacted with the water, and the environment at that time may have been habitable. Thus, the rocks deposited at the mouth of the canyon closest to the landing ellipse form the third target in the search for organic molecules. This three-dimensional perspective view was created using visible-light imaging by the Thermal Emission Imaging System camera on NASA's Mars Odyssey orbiter. Three-dimensional information was derived from observations by the Mars Orbiter Laser Altimeter, which flew on NASA's Mars Global Surveyor orbiter. Color information is derived from color imaging of portions of the scene by the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter. The vertical dimension is not exaggerated.
PASADENA, Calif. -- NASA's next Mars rover will land at the foot of a layered mountain inside the planet’s Gale Crater. The car-sized Mars Science Laboratory, or Curiosity, is scheduled to launch late this year and land in August 2012. The target crater spans 96 miles (154 kilometers) in diameter and holds a mountain rising higher from the crater floor than Mount Rainier rises above Seattle. Gale is about the combined area of Connecticut and Rhode Island. Layering in the mound suggests it is the surviving remnant of an extensive sequence of deposits. The crater is named for Australian astronomer Walter F. Gale. "Mars is firmly in our sights," said NASA Administrator Charles Bolden. "Curiosity not only will return a wealth of important science data, but it will serve as a precursor mission for human exploration to the Red Planet." During a prime mission lasting one Martian year -- nearly two Earth years -- researchers will use the rover's tools to study whether the landing region had favorable environmental conditions for supporting microbial life and for preserving clues about whether life ever existed. "Scientists identified Gale as their top choice to pursue the ambitious goals of this new rover mission," said Jim Green, director for the Planetary Science Division at NASA Headquarters in Washington. "The site offers a visually dramatic landscape and also great potential for significant science findings." In 2006, more than 100 scientists began to consider about 30 potential landing sites during worldwide workshops. Four candidates were selected in 2008. An abundance of targeted images enabled thorough analysis of the safety concerns and scientific attractions of each site. A team of senior NASA science officials then conducted a detailed review and unanimously agreed to move forward with the MSL Science Team's recommendation. The team is comprised of a host of principal and co-investigators on the project. Curiosity is about twice as long and more than five times as heavy as any previous Mars rover. Its 10 science instruments include two for ingesting and analyzing samples of powdered rock that the rover's robotic arm collects. A radioisotope power source will provide heat and electric power to the rover. A rocket-powered sky crane suspending Curiosity on tethers will lower the rover directly to the Martian surface. The portion of the crater where Curiosity will land has an alluvial fan likely formed by water-carried sediments. The layers at the base of the mountain contain clays and sulfates, both known to form in water. "One fascination with Gale is that it's a huge crater sitting in a very low-elevation position on Mars, and we all know that water runs downhill," said John Grotzinger, the mission's project scientist at the California Institute of Technology in Pasadena, Calif. "In terms of the total vertical profile exposed and the low elevation, Gale offers attractions similar to Mars' famous Valles Marineris, the largest canyon in the solar system." Curiosity will go beyond the "follow-the-water" strategy of recent Mars exploration. The rover's science payload can identify other ingredients of life, such as the carbon-based building blocks of biology called organic compounds. Long-term preservation of organic compounds requires special conditions. Certain minerals, including some Curiosity may find in the clay and sulfate-rich layers near the bottom of Gale's mountain, are good at latching onto organic compounds and protecting them from oxidation. "Gale gives us attractive possibilities for finding organics, but that is still a long shot," said Michael Meyer, lead scientist for NASA's Mars Exploration Program at agency headquarters. "What adds to Gale's appeal is that, organics or not, the site holds a diversity of features and layers for investigating changing environmental conditions, some of which could inform a broader understanding of habitability on ancient Mars." The rover and other spacecraft components are being assembled and are undergoing final testing. The mission is targeted to launch from Cape Canaveral Air Force Station in Florida between Nov. 25 and Dec. 18. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. JPL is a division of Caltech. To view the landing site and for more information about the mission, visit: http://www.nasa.gov/msl and http://marsprogram.jpl.nasa.gov/msl/.
Image Credit: NASA/JPL-Caltech The area in and near the landing site selected for landing of NASA's Mars Science Laboratory offers a diversity of possible targets for examination by the mission's rover, Curiosity. For scale, the landing target ellipse indicated on this image is 12.4 miles (20 kilometers) by 15.5 miles (25 kilometers).
Comments: While sending a robotic mission cannot, of course, cause the same interest as would the launching of a manned exploratory mission, we should not shun our pleasure. Curiosity is a wonderful machine far more powerful and capable than our two "friends" Spirit and Opportunity, the landing site chosen is actually extremely rich in geological terms. Many experts questioned by Space.com immediately after the announcement of NASA’s choice, have also all expressed their satisfaction. Let us hope now that the launch goes well, that the EDL (Entry Descent Landing) goes well despite the rather delicate nature of the chosen site (wedged between the mountains and the crater rim), the very important mass of Curiosity and the very unusual landing technique to be used, finally, once on the ground, let us hope also that the delicate instruments aboard the rover (despite their claimed "robustness"), function well. Experience has highlighted the difficulties of the success of such robotic missions. While NASA is increasingly accustomed to them and know more and more how to deal with them, we can be sure that this mission will be another thrilling experience! Pierre Brisson
Exploration
NASA Press Release 2011-222 Guy Webster (Jet Propulsion Laboratory, Pasadena, Calif.) & Dwayne Brown (NASA's Headquarters, Washington). July 22nd 2011. Comments by Pierre Brisson
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