NASA's MESSENGER reveals more hidden territory on Mercury

Washington, November 4 : NASA spacecraft MESSENGER's third and final flyby of Mercury has revealed more hidden territory on the planet and is providing new scientific findings about this relatively unknown world.

The Mercury Surface, Space Environment, Geochemistry and Ranging spacecraft, known as MESSENGER, flew by Mercury on September 29.

The probe completed a critical gravity assist to remain on course to enter into orbit around Mercury in 2011.

Despite shutting down temporarily because of a power system switchover during a solar eclipse, the spacecraft's cameras and instruments collected high-resolution and color images unveiling another 6 percent of the planet's surface never before seen at close range.

NASA spacecraft has now imaged approximately 98 percent of Mercury's surface.

After MESSENGER goes into orbit around Mercury, it will see the polar regions, which are the only unobserved areas of the planet.

"Although the area viewed for the first time by spacecraft was less than 350 miles across at the equator, the new images reminded us that Mercury continues to hold surprises," said Sean Solomon, principal investigator for the mission and director of the Department of Terrestrial Magnetism at the Carnegie Institution of Washington.

Many new features were revealed during the third flyby, including a region with a bright area surrounding an irregular depression, suspected to be volcanic in origin.

Other images revealed a double-ring impact basin approximately 180 miles across.

The basin is similar to a feature scientists call the Raditladi basin, which was viewed during the probe's first flyby of Mercury in January 2008.

"This double-ring basin, seen in detail for the first time, is remarkably well preserved," said Brett Denevi, a member of the probe's imaging team and a postdoctoral researcher at Arizona State University in Tempe.

"One similarity to Raditladi is its age, which has been estimated to be approximately one billion years old. Such an age is quite young for an impact basin, because most basins are about four times older," he said.

"The inner floor of this basin is even younger than the basin itself and differs in color from its surroundings. We may have found the youngest volcanic material on Mercury," he added.

The third flyby also revealed new information on the abundances of iron and titanium in Mercury's surface materials.

"Now we know Mercury's surface has an average iron and titanium abundance that is higher than most of us expected, similar to some lunar mare basalts," said David Lawrence, an APL participating mission scientist.

--ANI