NASA's MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) probe will make a close approach to Mercury on Monday, one of three scheduled passes before slipping into a stable orbit around the hot planet in 2011.
The probe will be the first to enter orbit there, although the Mariner 10 previously visited the planet in the mid-1970s. But with an approach as close as 124 miles this time, MESSENGER will be able to send back more data, and images of higher resolution, than were achieved by the earlier craft.
According to NASA, the probe will take more than 1200 pictures, and make other observations of the planet's surface mineralogical and chemical composition, gravity field, and magnetic field during its flyby. It will take ultraviolet observations of the atmosphere, and document the particle and plasma composition of Mercury's magnetosphere.
Scientists are particularly interested in seeing the giant Caloris basin, an impact crater about 800 miles in diameter, or nearly a quarter of the planet's diameter itself, with rings of mountains around it that reach more than two miles high.
MESSENGER was launched in late 2004. It will use Mercury's gravity during this flyby, and during two others in October 2008 and September
2009, to help guide it to its final orbit around the planet in 2011.
Updated information about the probe can be found here.
NASA Spacecraft to Make Historic Flyby of Mercury [NASA]
(Image: A mosaic created from photos taken by the Mariner 10 Mercury probe, showing the hot planet's cratered surface. Credit: Mariner 10,
Astrogeology Team, U.S. Geological Survey)
