Curiosity succeeded in this main task quickly, finding evidence near its landing site that a habitable lake-and-stream system existed within the (Gale) crater about 3.5 billion years ago.
Curiosity has been exploring the spacious interior of Gale Crater since August 2012, when the car-size rover landed on a mission to determine if the area could ever have supported microbial life.
Those photos contain copious evidence of river, delta and lake environments within Gale, which is thought to have formed after a massive impact about 3.8 billion years ago. Streams carried sediments from the crater's northern rim and walls down to the floor, where the intermittent lake existed, study team members said.