NASA: Messenger sends back never-before-seen Mercury images

NASA's Messenger spacecraft sent back images of Mercury Tuesday morning, giving scientists information about never-before-seen areas of the planet that's closest to the sun.

One of the first images to come back from the spacecraft shows the Kuiper crater, which was first identified during the Mariner 10 mission in the 1970s, according to NASA. That same image also shows what NASA is calling a large pattern of rays that extend from the northern pole of Mercury south past the Kuiper crater.

Early Monday morning, Messenger raced past Mercury and snapped hundreds of pictures. NASA announced Monday that the spacecraft, armed with an array of six analysis instruments, flew just 125 miles above the planet's cratered surface at 4:40 a.m. Eastern Time.

Monday was the second of three Messenger passes over Mercury. It made its first flyby in January.

While Messenger was taking photos and collecting other data from the planet, it used Mercury's gravity to give it a "critical" assist to keep the probe on course. NASA scientists hope to move the spacecraft into position to actually begin orbiting Mercury in March 2011.

NASA hopes that Messenger becomes the first spacecraft to orbit the planet, which is only 58 million kilometers from the sun. In comparison, the Earth is 149,600,000 kilometers from the sun.

Part of Messenger's mission is to help scientists figure out whether there is ice hidden on the poles of Mercury. Finding ice there would be a major discovery, since the planet is so close to the sun, its surface is 11 times brighter than Earth's. NASA noted in online documents that while Mercury's surface temperatures can reach about 840 degrees Fahrenheit, deep craters near its poles are in the shade, and there the temperature can plummet to minus 350 F.

Ice was one of the major discoveries that the Phoenix Mars Lander made this summer on the Martian north pole. Instruments on the lander conducted several tests on soil dug up by a robotic arm and discovered what scientists had been hoping to find -- elements that could support life.

Messenger is equipped with six of its own instruments to conduct tests on the Mercury trip.