Free trajectory - didn't even go into orbit.

自由轨道—还没有进入轨道。

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Messenger is the first spacecraft to go into orbit around the planet.

信使号探测器是第一进入行星轨道的航天器。

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NASA's Mercury probe Messenger last Thursday became the first spacecraft to go into orbit around Mercury.

上周，美国宇航局的信使号水星探测器成为历史上第一个进入水星轨道的飞行器。

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"We will use the tremendous capabilities of this ion propulsion system to climb out of orbit around Vesta, travel for almost another three years through the asteroid belt to dwarf planet Ceres and then go into orbit around Ceres and undertake the same kind of measurements there that we'll be doing at Vesta.

VOA: special.2011.07.27

Near's encounter with Eros is its second chance to go into orbit around the rock.

BBC: Probe nears its rocky target

That is, until US satellite company Iridium decided to sell real estate on a portion of its next-generation global satellites, which are set to go into orbit starting in 2015 and be fully operational by 2018.

BBC: The key to preventing lost planes

It's supposed to go into orbit for a couple of years, taking these incredible close-up pictures, and you probably remember, Madeleine, that there's two little rovers that are still roving around on the surface of Mars, and they're still working great and sending back pictures.

NPR: Shuttle Landing Delayed Due to Poor Weather