Mercury, As Never Seen Before: MESSENGER visits innermost planet

Mercury’s image problem is fading. On Jan. 14, NASA’s MESSENGER spacecraft flew within 200 kilometers of the solar system’s smallest—and oft-ignored—planet. The craft viewed one crater-pocked hemisphere, half of which had never before been seen close-up. When Mariner 10, the only other craft to visit Mercury, examined the surface 33 years ago, sunlight illuminated a different portion of the planet.