Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2011 January 29



Explanation: Celebrating 7 years on the surface of the Red Planet, Mars exploration rover Opportunity now stands near the rim of 90 meter wide Santa Maria crater. Remarkably, Opportunity and its fellow rover Spirit were initially intended for a 3 month long primary mission. Still exploring, the golf cart-sized robot and shadow (far right) appear in the foreground of this panoramic view of its current location. The mosaic was constructed using images from the rover's navigation camera. On its 7 year anniversary, Opportunity can boast traversing a total of 26.7 kilometers along the martian surface. After investigating Santa Maria crater, controllers plan to have Opportunity resume a long-term trek toward Endeavour crater, a large, 22 kilometer diameter crater about 6 kilometers from Santa Maria. The rim of Endeavour is visible in the mosaic on the horizon at the right, just above the shadow of the rover's mast. During coming days, communication with the rover will be more difficult as Mars moves close to alignment with the Sun as seen from planet Earth's perspective.