Gale (crater) about above the floor of Gale—three times higher than the Grand Canyon is deep. At 10:32 p.m. PDT on Aug. 5, 2012 (1:32 a.m. EDT on Aug. 6, 2012), the Mars Science Laboratory rover "Curiosity" landed on Mars at , at the foot of the layered mountain inside Gale crater. "Curiosity" landed within a landing ellipse approximately by . The landing ellipse is about below Martian "sea level" (defined as the average elevation around the equator). The expected near-surface atmospheric temperatures at the landing site during "Curiosity"s primary mission (1 Martian year or 687 Earth days) are from to .
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