Curiosity has been inspecting Mount Sharp, a three mile high mountain of sedimentary rocks inside Gale Crater. It's mission there is to decipher the record of the planet's earlier history stored inside the layers of rock. The rover has also found evidence of groundwater and freshwater existing on the planet. This was determined by the detection of the iron-oxide mineral hematite, which is created when water alters basaltic volcanic rock, as well as jarosite, a mineral that forms when volcanic rock interacts with mildly acidic water. One speculation by scientists is that a lake used to fill gale crater and is the reason for the fine grained sedimentary rocks which reside there, but this is still only a hypothesis which needs further testing by the …show more content…
Of these probes, NASA's Mars Odyssey has operated the longest since its arrival in 2001. Among its accomplishments, is the discovery of ice in the south polar cap, evidence that melting snow caused some of the gullies, and it has helped provide adequate landing sites for the rovers Spirit and Opportunity. NASA isn't the only one in on researching Mars though, the second oldest orbiter belongs to the European Space Agency, called Mars Express. It arrived in 2003 and has since, along with examining the atmospheric chemistry of the planet, has provided great topographic maps of the volcanoes, canyons, and craters on the