Hello Mercury!!

The MESSENGER spacecraft will make its first flyby of Mercury today at 2:04:39 pm EST!! This image of Mercury was taken yesterday on January 13 when the spacecraft was at a distance of about 760,000 kilometers (470,000 miles) from Mercury. Mercury is about 4880 kilometers (about 3030 miles) in diameter, and the smallest feature visible in this image is about 20 kilometers (12 miles) across.

During the historic encounter today, extensive scientific data will be gathered. The Mercury Dual Imaging System cameras will acquire more than 1,200 images of Mercury, including images of portions of the surface never before viewed by a spacecraft. The Mercury Atmospheric and Surface Composition Spectrometer will observe Mercury's surface as well as its tenuous atmosphere. The Magnetometer will accurately measure Mercury's magnetic field, and the Energetic Particle and Plasma Spectrometer will characterize Mercury's space environment and interactions with the solar wind. The Mercury Laser Altimeter will sense surface topography along a narrow profile. The Gamma-Ray and Neutron Spectrometer and X-Ray Spectrometer will make the first measurements of Mercury’s surface elemental composition.

MESSENGER will begin to transmit the new data to Earth once all of the scientific measurements are completed, about 22 hours after the spacecraft's closest approach to Mercury. These flyby data will shed light on fundamental scientific questions related to the formation and evolution of the planet Mercury. As scientists analyze the data, the MESSENGER spacecraft will continue on its planned journey, which includes two more encounters of Mercury in October 2008 and September 2009, before entering an orbit around Mercury in March 2011.

Additional information and features from this first flyby will be available online at http://messenger.jhuapl.edu/mer_flyby1.html, so check back frequently. Following the flyby, be sure to check for the latest released images and science results!