Do you love to look up at the Moon? Well so does NASA’s Curiosity rover! Feel free to correct me if I’m wrong (I have not confirmed this) but this appears to be an image of Phobos, the larger of Mars’ two small moons, imaged by Curiosity’s Mastcam on mission Sol 1002 (June 1, 2015). I spotted it while looking though some raw images on JPL’s MSL mission page.
Phobos is a very small world, only about 16 miles (26 km) across, and orbits Mars at about 3,700 miles (6,000 km) altitude. Curiosity has imaged it before, once actually crossing in front of the Sun during an eclipse event on Aug. 20, 2013.
Both Phobos and its smaller, more distant sibling Deimos have been imaged together by Curiosity as well, during an occultation on Aug. 1, 2013. See an animation of those observations here.
Planned observations of Phobos help scientists more precisely determine its orbit.
See a color image of Phobos acquired by the HiRISE camera aboard Mars Reconnaissance Orbiter here.