New Scientist watches the Messenger probe prepare to take a final spin around the hottest planet – with one last firing of its engines:
Engineers expect the 120-second engine burn to give the craft an 80-kilometre lift that will keep it aloft until March. But before then, as Messenger swoops low over the planet, it will heat up so much that the solder holding some instruments together could melt.
Messenger’s sunshade was designed to withstand temperatures of 350 °C. The problem is that the planet radiates heat back toward the instruments hiding behind that shade, says Messenger engineer Dan O’Shaughnessy. The solder will melt when the shaded regions warm to 185 °C, which will happen as Messenger’s altitude dips below 26 kilometres.
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The planet’s uneven gravity makes the site of Messenger’s eventual crash-landing uncertain. But it will probably land on the far side, where it will be out of view until 2024, when the European Space Agency’s BepiColombo mission arrives.
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To mark its impending demise, the Messenger team is running a public contest to name five of Mercury’s craters after any artist, composer, or writer who has been famous for more than 50 years and dead for more than three.
Here’s where you send your name suggestions. (I put an application in for Tristan Tzara, the founder of Dada. Dali already has Mercury crater named after him.)