This image provided by NASA shows a Nov. 4, 2010 image from NASA's EPOXI mission spacecraft showing part of the nucleus of comet Hartley 2. The sun is illuminating the nucleus from the right. A distinct cloud of individual particles is visible. Scientists say a NASA spacecraft braved a cosmic ice storm during this recent flight past the comet Hartley 2.(AP Photo/NASA)

This image provided by NASA shows a Nov. 4, 2010 image from NASA's EPOXI mission spacecraft showing part of the nucleus of comet Hartley 2. The sun is illuminating the nucleus from the right. A distinct cloud of individual particles is visible. Scientists say a NASA spacecraft braved a cosmic ice storm during this recent flight past the comet Hartley 2.(AP Photo/NASA)