NASA's Cassini spacecraft will be turning a double play this week, visiting the geyser moon Enceladus and the hazy moon Titan. The alignment of the moons means that Cassini can catch glimpses of these two contrasting worlds within less than 48 hours, with no maneuver in between. The spacecraft will pass within 270 miles of the surface of Enceladus and within 750 miles of Titan.