eldavojohn writes "After Huygens & Cassini corrected our assumptions about Titan (a moon of Saturn), scientists are now debating about their next mission, and one of the choices is the Titan and Saturn System Mission. What makes Titan a good choice? 'Although the atmosphere of Titan is filled with a smoggy orange hydrocarbon haze, it is primarily composed of nitrogen — just like Earth's. In fact, Astrobiologists think Titan's atmosphere may be quite similar to how the Earth's was billions of years ago, before life on our planet generated oxygen.' We also discussed its liquid hydrocarbons earlier this year."