What you’re seeing here is a topographical model of a small part of the Gale Crater floor. This image was taken by the HiRISE instrument on the Mars Reconnaissance Orbiter (MRO). The Mars Reconnaissance Orbiter is a satellite designed to conduct research of Mars from orbit. The satellite was built by Lockheed Martin under the supervision of the Jet Propulsion Laboratory (JPL). Just as the Mars Science Lab rover is under the supervision of JPL The mission is managed by the Jet Propulsion Laboratory for the NASA Science Mission Directorate, Washington, D.C. MRO was launched on August 12, 2005, and attained Martian orbit on March 10, 2006. It took 5 months of aerobraking in the Martian atmosphere before it started to do its science research from its final science orbit.
In November 2006 when MRO started its science work there were five other active spacecraft which were either in orbit or on the planet surface: Mars Global Surveyor, Mars Express, Mars Odyssey, and two Mars Exploration Rovers. Since then we lost contact with the MGS satellite (in november 2007, after 10 years of operation) and with the MER Spirit, which stopped responding about mid 2011 (after 7 years of operation).
MRO contains a number of scientific instruments such as cameras, spectrometers, and radar, which are used to analyze the landforms, stratigraphy, minerals, and ice of Mars. It is monitoring the weather of Mars daily and its surface conditions. MRO is also studying potential landing sites, like for Curiosity. All satellites around Mars, including MRO are hosting telecommunications with Earth. The HiRISE (High Resolution Imaging Science Experiment) camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo, is operated by the University of Arizona, Tucson.
At the center of Gale Crater rises a 5.5 kilometer high mountain. Such a central peak is common in large impact craters and Gale Crater is 140 km wide and so big enough for this feature. ). It’s not entirely clear how this center mountain formed however. Some theories suggest that there was a time when the entire crater was filled with material and that most of it has eroded away, leaving just that lopsided formed mountain. On Earth we have a similar eroding of material on a large scale in the Grand Canyon. In Gale Crater like in the Grand Canyon the exposed layers tell a history of Mars’s geologic past. However bear in mind that this stack of rocks is more than twice as high as the layers of rock making up the Grand Canyon.
Scientists have been studying those layers using images from the HiRISE camera on MRO have discovered that clays in Gale Crater can only be found lower down in the crater. Which is to say that these layers are older than the sulfates, deposited by salty water,
Clays are only seen where water is abundant and the sulfates tell us that Gale Crater went through a period when water evaporated away.
What the floor of Gale Crater appears to be telling us is that standing water, at least locally, existed long ago on Mars, but later evaporated away. This is consistent with what we have seen in other parts of Mars, of course. Ever since the rovers landed on Mars we’ve seen one piece of evidence after another of standing water or even of running water in the Red Planet’s distant past.
That the Grand Canyon and the floor of Gale Crater have much in common can be seen on the HiRISE image we have used for the picture of the day. What we see really is a canyon with dunes rippling accross it. Whatever carved this canyon tore away the deposited material and revealed all those layers of rock showing us the deep past of Mars.