NASA has released new images from a spacecraft showing a side of Mercury which has never been seen before.

Although NASA explored the planet previously in 1974 with the Mariner spacecraft, it only took pictures of Mercury partially allowing scientists to map 45 percent of the whole planet.

The images obtained by the $446 million MESSENGER mission (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) this week contain some of those unexplored areas. One image released Saturday was taken after Messenger made its closest approach to Mercury last week.

In the photos released this week, scientists have observed unexplored cratered areas of the planet.

On Monday, Messenger made its closest approach to Mercury yet, aiming for new discoveries. Among its goals is to discover if Mercury has ice water in its polar craters and to complete the mapping of the whole planet.

On Tuesday January 15, the Messenger spacecraft returned toward the direction of earth to transmit the photos.

The goal for the spacecraft is that it eventually reaches orbit around the plan in March of 2011.

During the flyby, Messenger stored 500 megabytes of data including 1,213 images, according to NASA. The information is now being decoded in the Science Operations Center at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland in the U.S.

Scientists involved in the space mission have begun to study Mercury's geological history. According to the Messenger mission, studying Mercury will help to develop a better understanding of how the planets formed and evolved. Mercury has the oldest surface, the densest mass, and is the smallest and least explored planet compared with Venus, Earth and Mars.

There are two more flybys of the planet scheduled.

For more information visit Messenger's website: