Over the past 10 years, NASA's Curiosity rover has revealed that Mars was once a habitable world with long-lived rivers and lakes billions of years ago.
Why it matters: These discoveries have fundamentally transformed how scientists understand the habitability of Mars, with research now pointing to the idea that the planet could have supported life for a good portion of its history.
When did the Curiosity rover land on Mars?
Curiosity had a prime mission for just two years when it landed on the Red Planet on Aug. 5, 2012.
- But 10 years later, the mission continues, with the car-sized rover currently exploring Mount Sharp and getting a good look at the various layers of sediment set down within the large mountain's location in Gale Crater, the spacecraft's landing site.
- So far, Curiosity has driven 17.58 miles since landing in the crater.
- "It was not at all a sure thing that we would be here 10 years, and especially in such good shape," Ashwin Vasavada, Curiosity's project scientist tells Axios. "We're right on the verge of accomplishing some of the last things we ever envisioned accomplishing at Mount Sharp and Gale Crater."
Curiosity's discoveries
Curiosity discovered what used to be an ancient stream bed that was home to a river that was once ankle to hip deep, according to a NASA report from 2013.
- The rover has shown that the planet hosts organic molecules, which aren't themselves signs of life but are the building blocks of it.
- It also discovered that there is methane being released into the atmosphere of the world, a possible sign of life or the result of normal geological processes.
The big picture: Curiosity represents a culmination of decades of hardware sent to Mars over the years.
- Earlier rovers, like Opportunity and Sojourner, were relatively simple machines that gathered important science but didn't have the analytical abilities of more complicated tools.
- Curiosity is effectively a full science laboratory, with the ability to sample the Martian rock and parse out exactly what it is and even how it formed.
- Even Perseverance, the newest rover sent to Mars by NASA, is more focused on gathering samples for an eventual return to Earth instead of analyzing these samples just from the Martian surface.
What's next for the Curiosity rover
Curiosity will build on its past successes over the next three years on its newly extended mission.
- In the immediate future, the rover is continuing its climb up Mount Sharp, with plans to go to an area where the geology of the mountain changes.
- "Pretty much everywhere we've explored on Mount Sharp to this point, there has been evidence of a lot of water in the ancient past. Most of the layers we've explored, formed as mud at the bottom of ancient lakes," Vasavada says.
- "Now we're about to switch maybe to something more like the opposite. Maybe the lakes will disappear forever in the historical record of Mount Sharp."
- If that is the case and Curiosity finds that these layers have always been dry, the question then becomes whether Mars could have still been habitable for microbial life — perhaps below the surface of the planet — even after those lakes disappeared.
What to watch: Curiosity runs on nuclear power, and eventually that will deplete, ending its long, scientifically productive stint on Mars.
- "Things could change tomorrow, but we could have, five to eight years," Andy Mishkin, of NASA's Jet Propulsion Laboratory, tells Axios.
