This is a composite of images from NASA's Deep Space 1 spacecraft showing "features of comet Borrelly's nucleus, dust jets escaping the nucleus and the cloud-like coma of dust and gases surrounding the nucleus,” according to JPL. “False color is used to reveal details of the jets and coma.” (A coma is the nebulous envelope around the nucleus of a comet.) This image was taken on a Sept. 22, 2001, flyby as part of the Deep Space 1 mission. Deep Space 1 (DS1) was launched in 1998 and is credited with creating some of the best images of a comet. The mission was part of NASA’s New Millennium Program, which was managed by JPL. DS1 was retired in 2001.