Water Abundance Dependent on Temperature

This chart highlights observations from NASA's Deep Impact mission of the northern polar regions of the moon acquired on June 9, 2009. The image at left is a map of the moon taken by the U.S. Clementine satellite -- the rest of the images are different representations of Deep Impact data, including measurements of brightness, temperature, and strength of a signature for water and hydroxyl molecules. The water signature varies significantly across the lunar surface; the strength of the signature is not correlated with terrain type but is highly dependent on temperature.

Since successfully carrying out its spectacular impact experiment at comet Tempel 1 on July 4, 2005, the Deep Impact spacecraft has been on an extended mission, called Epoxi, which culminates in a flyby of comet Hartley 2 on November 4, 2010. The spacecraft observed the moon for calibration purposes on several occasions en route to the second comet.