Titan was a major focus of the mission all along, since it's bigger than the planet Mercury and the only moon massive enough to have a significant atmosphere.

土卫六一直以来都是这项探测任务的主要聚焦点，因其体积比水星还要大，是唯一一颗拥有浓密大气层的卫星。

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Finally, planetary scientists are eager to learn where Titan's nitrogen and methane originated and why it is the only moon in the solar system that possesses a dense atmosphere.

最后，行星科学家急于了解土卫六的氮气及甲烷从何而来，又为什么只有它是太阳系唯一拥有浓密大气的卫星。

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Finally, planetary scientists are eager to learn where Titan's nitrogen and methane originated and why it is the only moon in the solar system that possesses a dense atmosphere.

最后，行星科学家急于了解土卫六的氮气及甲烷从何而来，又为什么只有它是太阳系唯一拥有浓密大气的卫星。

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