NASA Spacecraft Reaches Mercury

The unmanned Messenger probe took six and a half years to reach the solar system’s innermost planet.

After a 7.9-billion-kilometre journey, Messenger entered Mercury’s orbit Thursday night and began a one-year reconnaissance mission that will involve photographing every inch of the planet’s fiery surface. Scientists hope the $446-million spacecraft will help them determine why the planet has a super-dense iron core and what happened to its terrestrial surface, which is very thin and may have been blown away in a catastrophic blast billions of years ago. Messenger is the first spacecraft to orbit Mercury but not the first to reach the planet; the Mariner 10 probe performed three flybys of Mercury in 1974 and 1975 in preparation for an orbiting mission that NASA took more than 30 years to get around to executing.

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