After two years of doing the loop-the-loop around Mercury, MESSENGER has unveiled a bunch of surprises from Mercury — the closest planet to the Sun.
The spacecraft launched in 2004 and made three flybys of the planet before settling into orbit two years ago today. Incredibly, MESSENGER is only the second NASA probe to visit Mercury; the first one, Mariner 10, only flew by a few times in the 1970s. It was an incredible feat for the time, but we didn’t even have a complete map of Mercury before MESSENGER arrived at the planet.
So, what have scientists found in MESSENGER’s two years in orbit? Tales of sulfur, organic materials and iron, it turns out.