... Both Opportunity and its sister rover Spirit are in their sixth year on Mars, exploring the red planet for years longer than original expectations. The Seahorse of the Large Magellanic Cloud . ... Martian Moon Deimos from MRO . ... Pictured above, in a recently release image by HiRISE camera onboard the Mars-orbiting Mars Reconnaissance Orbiter (MRO), is Deimos, the smaller moon of Mars. Deimos is one of the smallest known moons in the Solar System measuring only about 15 kilometers across. ...