right-front wheel, might prevent it from ever being able to leave the crater if a wheel failed. Project scientist Bruce Banerdt also said, "We've done everything we entered Victoria Crater to do and more." Opportunity will return to the plains in order to characterize Meridiani Planum's vast diversity of rocks—some of which may have been blasted out of craters such as Victoria. The rover had been exploring Victoria Crater since September 11, 2007. As of January 2009, the two rovers had collectively sent back 250,000 images and traveled over . After driving about since it left Victoria crater, Opportunity first saw the rim of Endeavour crater on March 7, 2009. It passed the mark along the way on sol 1897. Meanwhile, at Gusev crater, Spirit was dug in deep into the Martian sand, much as Opportunity was at Purgatory Dune in 2005. In November 2009, Washington University in St. Louis Professor Raymond Arvidson was named deputy principal investigator for the MER Mission. 2010 onwards On January 3 and 24, 2010, Spirit and Opportunity respectively marked six years on Mars. On January 26, NASA announced that Spirit will be used as a stationary research platform after several months of unsuccessful attempts to free the rover from soft sand. NASA announced on March 24, 2010, that Opportunity, which has an estimated remaining drive distance of 12 km to Endeavour Crater, has traveled over 20 km since the start of its mission. Each rover was designed with a mission driving distance goal of just 600 meters. One week later, they announced that Spirit may have gone into hibernation for the Martian winter and might not wake up again for months. On September 8, 2010, it was announced that Opportunity had reached the halfway point of the 19-kilometer journey between Victoria crater and Endeavour crater. On May 22, 2011, NASA announced that it would cease attempts to contact Spirit, which had been stuck in a sand trap for two years. The last successful communication with the rover was on March 22, 2010. The final transmission to the rover was on May 25, 2011. In April 2013, a photo sent back by one of the rovers became widely circulated on social networking and news sites such as Reddit that appeared to depict a human penis carved into the Martian dirt. On May 16, 2013, NASA announced that Opportunity had driven further than any other NASA