WASHINGTON, Jan. 10 (Xinhua) -- NASA's MESSENGER spacecraft will make a flyby of Mercury on Jan. 14, which makes it the first to visit the planet in almost 33 years, NASA announced on Thursday.

    MESSENGER will explore and snap close-up images of never-before-seen terrain of Mercury. These findings could open new theories and answer old questions in the study of the solar system, said NASA scientists.

    NASA's MESSENGER is the first mission sent to orbit Mercury, the planet closest to our sun. Before that orbit begins in 2011, the probe will make three flights past the small planet, skimming as close as 124 miles above Mercury's cratered, rocky surface.

    MESSENGER's cameras and other sophisticated, high-tech instruments will collect more than 1,200 images and make other observations during Monday's flyby. It will make the first up-close measurements since Mariner 10 spacecraft's third and final flyby on March 16, 1975.

    This encounter will provide a critical gravity assist needed to keep the spacecraft on track for its March 2011 orbit insertion, beginning an unprecedented yearlong study of Mercury.

    Launched Aug. 3, 2004, MESSENGER is slightly more than halfway through its 4.9-billion mile journey. It already has flown past Earth once and Venus twice.