WASHINGTON - NASA's best effort to find a missing Mars space probe have failed, scientists said Tuesday as they began to lose hope for the 10-year-old planet-mapping workhorse. After more than two weeks of silence from the Mars Global Surveyor, NASA will make other tries to locate it, but scientists were pessimistic. "We may have lost a dear old friend and teacher," Michael Meyer, the lead scientist for NASA's Mars Exploration Program said in a news conference. The $154 million surveyor, which was supposed to last only two years but continued sending data for almost a decade, is the oldest...