The Curiosity rover has been hanging out on the surface of Mars for a year now, and over that time has accumulated enough evidence to strongly suggest the planet could have supported microbial life at some point in its history.

A ceremony was held at NASA's Jet Propulsion Laboratory in Pasadena, California, to mark the rover's first anniversary on Mars. Scientists involved in the inter-planetary project have taken stock of the year that has passed and all they have learned.

"The stunning thing is that we found it all so quickly," says California Institute of Technology geologist and lead project scientist John Grotzinger, “if you asked me a year ago, 'What are you going to find in the first year?' I wouldn't have ever said we were going to find what we went looking for.”

A year on and the work is getting much less speculative, with teams now looking for possible life-friendly niches on Mars and investigating whether any organic carbon has been preserved in the planet's ancient rocks. Next up on Curiosity’s to-do list is a trip to Mount Sharp, a five-kilometre high mound of layered sediment rising from the floor of Gale Crater, where the one-tonne rover touched down on 6 August 2012.

It can be lonely for such an intelligent robot so far away, luckily NASA will send a companion next year. Another robotic probe named MAVEN will be launched at Cape Canaveral in November, and should reach the Martian orbit by September 2014.