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End of Rosetta

September 5, 2016

After keeping company with a comet for the last two years, a spacecraft is about to get a whole lot closer to it. Engineers will nudge it to a gentle touchdown at the end of the month. That’ll provide the sharpest views of any comet to date.

Rosetta entered orbit around Comet 67P Churyumov-Gerasimenko in August of 2014. It dropped a probe a few months later, but the probe landed awkwardly and soon expired.

Even so, Rosetta revealed a great deal about the comet. It found that 67P is shaped like a rubber duck, with two lobes joined by a narrow neck. A recent study found that the two lobes may have split apart and come back together many times over the comet’s history.

Rosetta also measured the comet’s composition. It detected an amino acid and other compounds that are important for life, suggesting that comets might have delivered some of the ingredients for life to Earth. But it found that the water on 67P doesn’t match that found on Earth. That might mean that Earth’s water did not come from comets, as scientists have long suggested.

Over the next few weeks, Rosetta will drop closer and closer to the comet, then touch down, snapping pictures and taking other readings along the way. But it’s not designed as a lander, so its solar arrays won’t be able to gather sunlight, and its radio antenna won’t be able to aim at Earth — bringing its mission to an end.

A mission to an asteroid is just about to get started. More about that tomorrow.

Script by Damond Benningfield

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