



NASA’s Opportunity rover entered its 16th year roaming the surface of Mars. It landed on the red planet on 24 January 2004 in the Meridiani Planum region, and its initial mission was expected to consist of traveling just over 1 kilometre and exploring for 90 Martian days, called sols, which are slightly longer than a day on Earth – lasting 24 hours, 39 minutes and 35.24 seconds. Instead, the rover has traveled more than 45 kilometres, and for well over 5,000 Martian days.









"Fifteen years on the surface of Mars is testament not only to a magnificent machine of exploration but the dedicated and talented team behind it that has allowed us to expand our discovery space of the Red Planet," said John Callas, project manager for Opportunity at NASA's Jet Propulsion Laboratory. "However, this anniversary cannot help but be a little bittersweet as at present we don't know the rover's status. We are doing everything in our power to communicate with Opportunity, but as time goes on, the probability of a successful contact with the rover continues to diminish."





Opportunity last communicated with Earth in June of last year, after which the Perseverance Valley experienced a dust storm that covered the rover’s location and blocked out the sunlight the rover needs to charge its batteries. The storm has since cleared, but the rover’s communications have not resumed.





During its 15-year mission, the Opportunity rover has made multiple contributions to space science, including the discovery of argon in the Martian atmosphere, and information on the frequency and dynamics of the dust devils, tornado-like formations of dust and sand moved by wind in the Martian atmosphere. The rover also discovered that the wind-blown ripples on the Meridiani plains are probably the result of the red planet’s spin axis tilt from the past, when its winds were different. It also found several meteorites dispersed across the Meridiani plains, and that the Burns formation on the plains is sulfate-rich sandstones with hematitic concretions formed in ancient shallow lakes and cemented by rising groundwaters.













Perhaps most importantly, Opportunity found evidence that Mars may be have been a habitable environment in the past. It located and examined some of the oldest – approximately 4 billion years old – that had been exposed to waters that were much more habitable that the waters that resulted in the Burns formation.





To date, Opportunity is a record holder for the longest distance traveled by an off-Earth wheeled vehicle. Although contact with Opportunity is lost, NASA continues to study the Martian core and geology with its newest lander, Insight, which arrived to the red planet in November 2018, and has already successfully placed one of its scientific instruments for further investigation of the planet.