Next week NASA's MESSENGER probe will skim just 124 miles (200 km) above Mercury's uncharted hemisphere. The craft's closest pass will occur at 2:04 p.m. EST (1904 GMT) on Monday. It will conduct three flybys that will help it reduce speed and ultimately enter Mercury's atmosphere. Launched in August of 2004 MESSENGER will be the first spacecraft to visit Mercury since NASA's Mariner 10 probe swung past the planet three times between 1974 and 1975. MESSENGER will enter orbit in 2011 for a one-year science campaign. The mission will have a total price tag of around $446 million and will probe the secrets of Mercury, from its wispy thin atmosphere to an unusually dense interior. The mission will also generate the first maps of some 55 percent of the planet's rocky surface. The craft will travel a total distance of 4.9 billion miles to get to Mercury. Over half of the planet hasn't been mapped and the flyby will take the first photos of it in 33 years. The team from NASA is anxious for the first of the nearly 1200 photos to start flowing in.
Here is a picture MESSENGER took from around 3 million miles away from Mercury:

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