Lyot Crater on Mars, with lines indicating data swaths taken by the Mars Express OMEGA sensor, and NASA Mars Reconnaissance Orbiter CRISM instrument data.. The stars show where hydrated mineerals have been detected. Credits: NASA/ESA/JPL-Caltech/JHU-APL/IAS.
A neat piece of news caught my eye this week — an announcement from the European Space Agency that mineral studies of Mars taken by ESA’s Mars Express mission and NASA’s Mars Reconnaissance Mission show that liquid water was once very widespread on Mars. The evidence lies inside craters spread around the planet, apparently just beneath the surface. It’s in the form of deposits of what are called hydrated silicates — minerals that have been in contact with water sometime in the past.
Lyot Crater (at left) was one of 91 impact craters the missions studied in a search for evidence of water. At least nine of the craters have strong evidence of hydrated silicates. Those minerals form in wet environments either on the surface or underground — and they have now been identified in both the north and south parts of Mars.
Why study craters? Because the impacting objects (asteroid chunks, for example) punched down through the surface of the planet and exposed very ancient surface crust that would have been in contact with water. This means that water was widespread on the Martian surface sometime in the past. This is great news for scientists who are working to understand the role that water played on Mars early in its history. The presence of water means that conditions could have been favorable for life. It doesn’t prove that life existed on Mars — that takes other studies and will very likely require us to visit the planet to prove it for sure. But, the existence of water is a big thing. There are hints of it all over Mars, not just in the hydrated silicates, but in the landforms that seem to be carved by the action of water. This is a fascinating story that is still unfolding for planetary scientists. I, for one, think that we’ll find substantial reservoirs of water (probably locked away in subsurface aquifers and permafrost) on Mars when our first explorers set foot on that dry and dusty desert surface.
Two images of the Phoenix Mars lander taken from Martian orbit in 2008 and 2010. The 2008 lander image (left) shows two relatively blue spots on either side corresponding to the spacecraft’s clean circular solar panels. In the 2010 (right) image scientists see a dark shadow that could be the lander body and eastern solar panel, but no shadow from the western solar panel. Image Credit: NASA/JPL-Caltech/University of Arizona
The Phoenix Mars Lander is officially a thing of the past. NASA’s Jet Propulsion Laboratory announced on May 24 that controllers had given up trying to contact the lander. They had been trying since Martian winter abated, by using the Mars Odyssey orbiter to make radio contact with the lander.
If you look at the “before-and-after” image to the left (taken by the Mars Reconnaissance Orbiter) you should be able to figure out why: it doesn’t look like it’s in very good shape in the right-hand image. The lander did not survive the harsh Martian winter. Hundreds of pounds of carbon dioxide ice probably coated the lander throughout the winter, and that would have destroyed the solar panels, at the very least.
While it was “alive” the lander returned data about the Martian polar region where it landed — enough data to keep scientists busy analyzing it for years. The information the spacecraft sent back is revising scientists’ understanding of Mars, particularly the ice-bearing regions which had never been explored in situ before Phoenix arrived. (In situ is a latin term meaning “in the place”.) We still have orbiters and landers on Mars, and there are new missions in planning and being built. Next to fly to Mars will be the Mars Science Laboratory — recently named Curiousity –, which I had the chance to see in its clean room at JPL this past week. It will launch in 2011. Once it lands on Mars, the laboratory will do what its name implies — do laboratory studies on the surface of the Red Planet. Our exploration of Mars continues on, and Phoenix was a large part of it. Remember her well!
