When the spacecraft flew past the planet on January 14, 2008, it took about 1,200 images of the planet. It flew as close as 124 miles (200 kilometers) from the planet’s surface.
When it was about 21,000 miles (33,000 kilometers) from the planet (after its closest approach) it snapped an image—using its Narrow Angle Camera of its Mercury Dual Imaging System (MDIS)—the first one released for public viewing. It showed irregularly shaped and discolored areas elevated above the crusty surface of the planet’s southern polar area—a never-before-area of the planet.
In the January 21, 2008 New Scientist article “Has Messenger revealed lava flows on Mercury?” British planetary scientist David Rothery, of Open University, is quoted to have said, “Those dark splotchy regions look like lava flows to me,” [New Scientist article: subscription required]
Scientists surmise that volcanic lava may have flowed after most of meteors, asteroids, and other space debris had crashed into the planet, forming craters over the first 500,000 years of the planet, which we are now seeing today.
This first image was one of forty-two images that will be pieced together by MESSENGER scientists to eventually give a global geological picture of Mercury.
The spacecraft will make another flyby of Mercury later in the year—on October 6, 2008—and will hopefully get a chance to get closer images of the planet’s surface in order to better distinguish the lava-flow areas with the older crustal areas.
After this second flyby, a third flyby will be performed on September 29, 2009. The spacecraft will then be inserted into orbit about the planet in March 2011.
An earlier iTWire article “Historic return to planet Mercury set for January 14, 2008” discusses the mission plans of MESSENGER, which is an acronym for MErcury Surface, Space ENvironment, GEochemistry, and Ranging.
A third mission to Mercury (NASA’s Mariner 10 was the first in the mid-1970s) is being planned by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA). Called the BepiColombo mission, it is scheduled to be launched in August 2013, with an orbital insertion date of June 2019.
The BepiColombo mission is intended to add to the information gathered by the MESSENGER mission. Its three components are the ESA Mercury Transfer Module (MTM), the ESA Mercury Planetary Orbiter (MPO), and the JAXA Mercury Magnetospheric Orbiter (MMO).
Additional information about the MESSENGER mission is found at The Johns Hopkins University Applied Physics Laboratory website: http://messenger.jhuapl.edu/mer_flyby1.html.
Additional information about the BepiColombo mission is found at the ESA website: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=30.