Diagrams show how comet will approach Mars.

The Mars Reconnaissance Orbiter captures images of Comet C/2013 A1, also known as Sliding Spring after the observatory which discovered it, as it flies past Mars on October 19th. The comet originated in the Oort Cloud, which is located in the distant reaches of our solar system.

These images were taken by the Orbiter’s High Resolution Imaging Science Experiment (HiRISE) camera while the comet flew approximately 86,000 miles from Mars at a speed of 35,700 miles per hour (57,400 km/h) relative to the planet.
Greg Giles