Four thousand Martian days after landing on August 5, 2012, NASA’s Curiosity rover is still hard at work performing fascinating scientific research in Gale Crater. After drilling its 39th sample, the rover dropped the ground-up rock into its belly for a thorough examination.
The rover has been gradually climbing the base of 3-mile-tall (5-kilometer-tall) Mount Sharp, whose layers formed in different periods of Martian history and provide a record of how the planet’s climate changed over time, in order to study whether ancient Mars had the conditions to support microbial life.
The most recent sample was taken from a target known as “Sequoia” (the names of all of the mission’s current science targets are derived from places in the Sierra Nevada of California). As this region became enriched in sulfates—minerals that most likely formed in salty water that was evaporating as Mars first began to dry up billions of years ago—scientists hope the sample will reveal more about how the climate and habitability of Mars evolved. Mars’ liquid water eventually vanished permanently.