Professional Pilot, March 2016

PROFESSIONAL PILOT March 2016 17 ings Starting on the surface of Mars the working rovers have been marching on and finding more evidence of past liquid water having been where they are The Mars rover Opportunity is still working on the surface of the planet after more than 11 years It landed in a location originally chosen because of the presence of a mineral that on Earth forms primarily in the presence of liquid water Opportunity found this mineral course grained hematite in the form of small spheres nicknamed blueberries covering the surface where it landed Thought to have formed from concentration of minerals in the subsurface the blueberries were only the beginning Over the years Opportunity has found a variety of minerals and layered structures consistent with the presence of liquid water Much of what it has found is consistent with formation in salty acidic water at least some of which was in the subsurface The Curiosity rover landed on Mars in 2012 in a flat area inside a more than 100 km diameter crater The intention was to drive it to the layered terrains in a mountain in the center of the crater Long before it got there in fact right near its landing site Curiosity began to find evidence of past liquid water including delta type deposits from water flowing into the crater and stream and lake type deposits So theres ample geological layering and mineral evidence confirming that liquid water existed for significant amounts of time on the surface of Mars And based on the minerals found this was much more life friendly liquid water than most of what Opportunity found evidence of This was neutral pH fresh water that we could have happily drunk had we been there in the past One of the main goals of these rovers has been the search for and understanding of past habitable environments So habitable environments Check During 2015 Curiosity reached the base of Mount Sharp a huge mountain of materials in the center of the crater thought to be deposited there by water after the crater was formed This particular site was chosen for close study because of orbital spectral data that showed evidence of carbonates and sulfates in the mountains layers minerals formed in the presence of liquid water Curiosity is equipped with a complex set of science instruments to carry out its studies Several times it has drilled a few centimeters into rocks to get past the atmospheric dust and weathering that makes it hard to understand the composition of the rock from the outside This allows scientists to be particularly effective at determining what the rock is really made of and to infer the environment in which it formed As Curiosity drives into the canyons of Mt Sharp over the next couple years expect more great findings And rugged Opportunity is not only still exploring but it is now near clays seen from orbit that may be indicative of a past life friendly water environment This image from the NASA Curiosity rovers Mastcam shows an evenly layered rock This pattern is typical of lake floor sedimentary deposits not far from where flowing water entered a lake The pattern occurs at the lowest part of Mt Sharp in what is dubbed the Murray formation named after my PhD thesis advisor Caltech Professor Bruce Murray The color in this image has been white balanced to resemble approximate daytime lighting conditions on Earth Images courtesy NASA JPL MSSS This self portrait of NASAs Curiosity rover shows the vehicle at the Big Sky site Curiosity is in a large Martian crater whose rim can be seen in the distance At this site its drill collected the missions 5th sample of Mt Sharp the mountain in the center of the crater and the target for this mission Note the gray drill holes circled at left This image was taken on Oct 6 2015 the 1126th sol Martian day of the mission