Clementine begins moon-mapping mission.

The day before beginning a 2-month survey of the moon, the Clementine spacecraft trained its four cameras on a north polar region of the lunar surface that includes part of a 100-kilometer-wide crater called Nansen. These images, released last week at a Pentagon press briefing, show a section of the crater and its surroundings. Nansen, which lies on the limb of the moon, appears as a shadowy form in the lower left of the UV/visible and near-infrared pictures.

This multiwavelength portrait offers a prelude to the high-resolution map Clementine is expected to generate during its lunar sojourn. The first spacecraft to orbit the moon in 23 years, Clementine will map the entire lunar surface from a polar orbit. In contrast, previous U.S. missions mapped only the moons equatorial regions.

A joint mission of NASA and the Ballistic Missile Defense Organization (the former Star Wars office), Clementine will test several detectors for the military in a mission expected to include the first flyby of a near-Earth asteroid (SN: 1/15/94, p.40). Though it will use all four of its miniature cameras to image the moon, two of them - the near-infrared and UV/visible devices will play the major role. These cameras will map the moons surface at 11 wavelengths, resolving features as small as 200 meters across.

The color map, notes geologist Eugene M. Shoemaker, will help identify the composition of lunar rocks and provide new clues to the geological processes that shaped various parts of the lunar surface. Recently retired from the U.S. Geological Survey in Flagstaff, Ariz., he is helping to analyze the lunar images, some 40,000 of which had been generated as of March 1.

Shoemaker notes that cameras on the Apollo missions examined at high resolution both the front side of the moon and a narrow swath of the back. "But the images we're taking now are going to cover the entire moon. We'll get a global data set of very high photometric fidelity, ... That's a totally new step."