This thread is intended for comments and questions regarding the [URL=http://messenger.jhuapl.edu/]MErcury Surface, Space ENvironment, Geochemistry, and Ranging[/URL] (MESSENGER) mission and the updates published under the topic:
NASA's MESSENGER to planet Mercury.
MESSENGER is only the second spacecraft to set sights on Mercury. Mariner 10 sailed past it three times in 1974 and 1975 and gathered detailed data on less than half the surface.
Carrying seven scientific instruments on its compact and durable composite frame, MESSENGER will provide the first images of the entire planet. The mission will also collect detailed information on the composition and structure of Mercury's crust, its geologic history, the nature of its thin atmosphere and active magnetosphere, and the makeup of its core and polar materials.
MESSENGER's science team will shape its investigation around several questions, including: Why is Mercury — the densest planet in the solar system — mostly made of iron? Why is it the only inner planet besides Earth with a global magnetic field? How can the planet closest to the sun, with daytime temperatures near 450 degrees Celsius (840 F), have what appears to be ice in its polar craters?