MESSENGER is the first spacecraft to orbit Mercury since Mariner 10 in 1974-75.

信使号是第一艘环绕水星轨道的飞船，自从1974 - 75年的水手号以来。

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Mercury was visited first by the Mariner 10 probe in the 1970s; and by Messenger currently

在1970年水手10号探测器第一次造访水星，目前信使号在执行水星探测任务。

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Messenger will become the first spacecraft to orbit Mercury and the first mission there since Mariner 10 in 1975.

“信使”号将成为第一个绕水星飞行的航天器，它也是1975年“水手10号”接近水星后的第一次近水星探测活动。

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Mariner 10, the last spacecraft to visit Mercury, imaged only about 40 percent of the planet, he said.

NPR: NASA Probe Glimpses Unseen Side of Mercury