Mars Rover
NASA/JPL-Caltech
After seven months of roaming around the Red Planet, NASA's car-size robot, called Curiosity, has finally provided evidence that Mars could have once supported microbial life, the space agency announced in a press conference from Washington D.C. on Tuesday. The first powder rock sample ever collected on Mars had traces of sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, scientists found. These elements are considered necessary to support life on Earth.  
"We have found a habitable environment that is so benign and so supportive of life that if this water had been around and you had been on the planet, you would have been able to drink it," Curiosity project scientist John Grotzinger told reporters.  
The rover used the drill on her robotic arm to make a small hole in a flat rock named "John Klein" in early February. The drill churned up the rock into powder and extracted about a tablespoon of powder material. 
The sample was then delivered to two lab instruments on the rover — the Chemistry and Mineralogy instrument and the Sample Analysis at Mars instrument — to determine what it's made of.  
The drilling site was chosen because it had concretions that indicated the sediment was once water-soaked. The scientists found phyllosillicates, or clay minerals, at John Klein.
The first scoop showed that the ground underneath Mars' dusty orange-red surface is actually green-gray. Mars looks red because the top layer is mostly made of iron oxide, or iron that rusted after being exposed to oxygen.  
NASA's $2.5-billion rover landed in Mars' Gale Crater in August 2012. She's currently parked in an area called Yellowknife Bay inside of Gale crater. The robot is headed for a spot called Glenelg near the based of Mount Sharpe, which rises up from the center of Gale crater.