NASA published images taken by its spacecraft that traveled to Mercury, the planet closest to the sun, on Tuesday. The published images provide a rare glance into this planet’s surface.

The Messenger aircraft is the first aircraft in history to orbit Mercury.

‘On Oct. 6, 2008, at roughly 4:40 a.m. ET, MESSENGER flew by Mercury for the second time this year. During the encounter, the probe swung just 125 miles (200 kilometers) above the cratered surface of Mercury, snapping hundreds of pictures and collecting a variety of other data from the planet as it gains a critical gravity assist that keeps the probe on track to become the first spacecraft ever to orbit the innermost planet beginning in March 2011,’ NASA announced.

On October 7, at 1.50 A ET, the images were received on earth. The image in the far right corner of the article is one taken by Messenger approximately 90 minutes after its closes approach to the small planet. ‘The bright crater just south of the center of the image is Kuiper, identified on images from the Mariner 10 mission in the 1970s. For most of the terrain east of Kuiper, toward the limb (edge) of the planet, the departing images are the first spacecraft views of that portion of Mercury’s surface. A striking characteristic of this newly imaged area is the large pattern of rays that extend from the northern region of Mercury to regions south of Kuiper,’ NASA explained.

Another image is the one to the left. It was taken approximately 58 minutes before Messenger’s closest approach to Mercury on Oct. 6, 2008. It was captured by Messenger’s Narrow Angle Camera. ‘The features in the foreground, near the right side of the image, are close to the terminator, the line between the sunlit dayside and dark night side of the planet, so shadows are long and prominent. Two very long scarps, or cliffs, are visible in this region, and the scarps appear to crosscut each other. The easternmost scarp also cuts through a crater, showing that it formed after the impact that created the crater. Other neighboring impact craters, such as in the upper left of this image, appear to be filled with smooth plains material,’ NASA explained on its website.

Many other images were sent down by Messenger, all enabling humans to look at Mercury in a way we were never able to do so before. The image to the right, for instance, shows ‘Mercury’s surface illuminated obliquely from the right by the Sun. The unnamed crater (52 kilometers, or 31 miles, in diameter) in the center of the image displays a telephone-shaped collapse feature on its floor. Such a collapse feature, not seen on the floors of other craters in this image, could reflect past volcanic activity at and just below the surface of this particular crater. MESSENGER team members are examining closely the more than 1200 images returned from this flyby for other surface features that can provide clues to the geological history of the innermost planet.’

The crater is ‘located in the southern hemisphere of Mercury, on the side that was not viewed by Mariner 10 during any of its three flybys (1974-1975). This scene was imaged while Messenger was departing from Mercury from a distance of about 19,300 kilometers (12,000 miles), about 1 hour after the spacecraft’s closest encounter with Mercury. The image is of a region approximately 236 kilometers (147 miles) across, and craters as small as 1.6 kilometers (1 mile) can be seen. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington,’ NASA said.

Messenger will continue its travel. It will fly around the sun approximately 15 times, if all goes well, and will be put it into the Mercury’s orbit in March 2011. Mercury was first approached in 1974 and 1975 by NASA and later by Messenger itself in January of this year, but the spacecraft will focus on parts of the planet not viewed during those missions.

If Messenger will succeed in entering Mercury’s orbit, it will be the first spacecraft to do so. This should help scientists understand the composition of the planet’s surface better.