Journey to the Iron Planet

Europe is sending its first mission to Mercury, the planet nearest the Sun. It's actually a joint venture with Japan and they've each built a probe.

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Together the probes are known as BepiColombo, after a famous Italian scientist, and they’ll be launched on their way by Europe's huge Ariane rocket.

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It's tricky going to Mercury because the Sun's gravity pulls you in and speeds you up. You have to put your foot on the brake all the way, or you'll fly straight past.

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In charge of the driving, and the parking once it gets there, is spacecraft operations manager Elsa Montagnon, seen here in the main control room.

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She'll fly Bepi close to Venus twice on the way, using its gravity to take out some speed.

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But it will also slow down with the help of the gentle thrust of “electric engines” like this. The force they apply is equivalent to a canary flapping its wings, but it's enough.

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After launch on 20 October, it's a long journey with a series of flybys before arrival, so be patient.

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Once it does finally get there, the BepiColombo scientists are hoping to solve many of Mercury’s mysteries.

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Top of the list, they want to learn more about the giant iron core that makes up more than 60% of its mass.

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The probes will have to take extreme care, however. It’s very hot at Mercury, hence all the insulation that’s had to be sewn on.

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The spacecraft will be toasted on one side by the Sun, and on the other by the radiant heat coming up from the “hot potato” planet itself.

BBC science correspondent Jonathan Amos says: “Mercury is not just some BBQ rock close to the Sun, but a fascinating world with stories to tell about how all the planets formed.” Follow him at @BBCAmos