A nuclear-powered submarine that was lost in the Atlantic 17 years ago was found and photographed last month, Navy sources confirmed. The sources said the research ship Knorr, operating a new deep-diving submersible named the Argo, located and shot color video and still photos of the attack submarine Scorpion on Aug. 17. The unmanned submersible Argo is the same one that photographed the Titanic earlier this month. The Scorpion sank under mysterious circumstances in 1968, with the loss of its entire 99-man crew, about 400 miles southeast of the Azores. Another Navy submersible, the Trieste, managed to photograph the Scorpion just one year after it sank.