Curiosity (rover) counted. Previous NASA Mars rovers became active only after the successful entry, descent and landing on the Martian surface. "Curiosity", on the other hand, was active when it touched down on the surface of Mars, employing the rover suspension system for the final set-down. "Curiosity" transformed from its stowed flight configuration to a landing configuration while the MSL spacecraft simultaneously lowered it beneath the spacecraft descent stage with a tether from the "sky crane" system to a soft landing—wheels down—on the surface of Mars. After the rover touched down it waited 2 seconds to confirm that it was on solid
Curiosity (rover) ("Mount Sharp"), at the center of the wide crater. Thus, it is believed that the rover may have the opportunity to study two billion years of Martian history in the sediments exposed in the mountain. Additionally, its landing site is near an alluvial fan, which is hypothesized to be the result of a flow of ground water, either before the deposition of the eroded sediments or else in relatively recent geologic history. According to NASA, an estimated 20,000 to 40,000 heat-resistant bacterial spores were on "Curiosity" at launch, and as much as 1,000 times that number may not have been