Comet hunter Robert McNaught at Siding Spring Observatory in New South Wales, Australia, discovered the object dubbed C/2013 Jan. 3.
Additional data on the comet's movements by the Catalina Sky Survey in Arizona allowed astronomers to trace the comet's likely orbit around the sun.
Its calculated trajectory has the comet crossing Mars's orbit on Oct. 19, 2014, Australian blogger Ian Musgrave said.
The best estimates have the comet passing Mars at a safe distance of 560,000 miles, much farther than the distance asteroid 2012 DA14 passed Earth last week when it came within 22,000 miles.
The comet's pass by Mars could make it visible to either rovers on the surface or several Mars-orbiting satellites, astronomers said.
"Over the next few months, we and other observers will take more images of it that will reduce our uncertainty on the orbit," Alex Gibbs at the Catalina Sky Survey told NewScientist.com. "The data will also help determine what probes might be able to see it."