What we've learned about life on Mars from Curiosity for the past decade

NASA's Jet Propulsion Lab celebrated the successful landing of its fourth robot on Mars ten years ago. The Curiosity rover, now in fifth grade, was sent to Mars in 2012 to investigate whether life could have existed there.

A robot the size of a car is packed with scientific instruments that study the climate and geology of the planet. The mission was a success, so how did it go? Is there anything that the Curiosity rover can teach us about the past and possible future of space exploration?

The Curiosity team's head scientist, Dr. Ashwin Vasavada, says that the mission was a great success.' Mars was habitable at one point in its history, but probably for millions, or tens of millions, of years,' he said.

While Mars rover could detect life, that didn't necessarily mean the planet itself was alive. Initially, Vasavada said, they simply wanted to figure out if life could even exist on the planet. We've explored Mars enough to know that dinosaur footprints don't exist there.

 The life that took hold probably never progressed past microbial stages.'How did life on Mars differ from that on Earth? Were there any specific events that led to its uninhabitability? The events are likely to be combined, according to Vasavada.

'The surface of Mars was likely once covered with rivers, and there may even have been an ocean there at one time. Three or four billion years ago, Mars looked a lot more like Earth than it does today,' he claimed. Possibly, the size of the planet ended life on earth.

As a smaller planet, it cooled quicker. Once it cooled faster, it lost its ability to generate a magnetic field.' After the magnetic field stopped, the atmosphere was stripped away by radiation in space, and it was no longer able to stay warm and have liquid water.'

A spot where the Curiosity rover first landed 10 years ago provided new insight for the Mars exploration team. It landed in Gale Crater. The cavity was formed when a large space rock hit the surface. As sediment was deposited in lakes, layers of mud built up on the mountain's sides.

We would be able to land there, and see if sediment had indeed been deposited in liquid water environments, such as lakes and streams,' Vasavada said. 'We could determine whether any of the periods of Mars' early history had these habitable conditions by driving up these rock layers.'

The success of the mission still surprises the scientist after ten years.' We have now climbed over 2,000 vertical feet on the mountain, and for the most part, every layer we have seen formed in a wet environment.