Tethys Behind Titan . ... Credit Copyright: Cassini Imaging Team , ISS , JPL , ESA , NASA Explanation: What's that behind Titan? It's another of Saturn's moons: Tethys . The robotic Cassini spacecraft orbiting Saturn captured the heavily cratered Tethys slipping behind Saturn's atmosphere-shrouded Titan late last year. The largest crater on Tethys , Odysseus , is easily visible on the distant moon. ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ...