Artist concept of NASA Deep Space 1 Encounter with Comet Borrelly.

This very long exposure was taken by NASA Deep Space 1 to show detailed structures in the faint parts of comet Borrelly inner coma. As a result, the nucleus has been greatly over-exposed and its shape appears distorted.

This image, taken by NASA Deep Space 1 on September 22, 2001, has been enhanced to reveal dust being ejected from the nucleus of comet Borrelly. As a result, the nucleus is bright white in the image.

Over 1300 energy spectra taken on September 22, 2001 from the ion and electron instruments on NASA Deep Space 1 span a region of 1,400,000 kilometers 870,000 miles centered on the closest approach to the nucleus of comet Borrelly.

The solid nucleus of comet Borrelly is barely resolved in this image from NASA Deep Space 1, enhanced to reveal the highly collimated dust extending towards the bottom left corner of the picture.

NASA Deep Space 1 flew by comet Borrelly on September 22, 2001 and took these measurements with its plasma instruments. These data show that the flow of ions around the comet rocky, icy nucleus.

Sunlight illuminates the bowling-pin shaped nucleus from directly below comet Borrelly as seen by NASA Deep Space 1. At this distance, many features become vivid on the surface of the nucleus, including a jagged line between day and night on the comet.

A composite of images from NASA Deep Space 1 spacecraft shows features of comet Borrelly nucleus, dust jets escaping the nucleus and the cloud-like coma of dust and gases surrounding the nucleus.

NASA's New Millennium Deep Space 1 spacecraft approaching the comet 19P/Borrelly. With its primary mission to serve as a technology demonstrator--testing ion propulsion and 11 other advanced technologies--successfully completed in September 1999, Deep Space 1 is now headed for a risky, exciting rendezvous with Comet Borrelly. NASA extended the mission, taking advantage of the ion propulsion and other systems to target the daring encounter with the comet in September 2001. Once a sci-fi dream, the ion propulsion engine has powered the spacecraft for over 12,000 hours. Another onboard experiment includes software that tracks celestial bodies so the spacecraft can make its own navigation decisions without the intervention of ground controllers. The first flight in NASA's New Millennium Program, Deep Space 1 was launched October 24, 1998 aboard a Boeing Delta 7326 rocket from Cape Canaveral Air Station, FL. Deep Space 1 successfully completed and exceeded its mission objectives in July 1999 and flew by a near-Earth asteroid, Braille (1992 KD), in September 1999. http://photojournal.jpl.nasa.gov/catalog/PIA04604

In this highest resolution view of the icy, rocky nucleus of comet Borrelly, (about 45 meters or 150 feet per pixel) a variety of terrains and surface textures, mountains and fault structures, and darkened material are visible over the nucleus's surface. This was the final image of the nucleus of comet Borrelly, taken just 160 seconds before Deep Space1's closest approach to it. This image shows the 8-km (5-mile) long nucleus about 3417 kilometers (over 2,000 miles) away. Smooth, rolling plains containing brighter regions are present in the middle of the nucleus and seem to be the source of dust jets seen in the coma. The rugged land found at both ends of the nucleus has many high ridges along the jagged line between day and night on the comet. This rough terrain contains very dark patches that appear to be elevated compared to surrounding areas. In some places the dark material accentuates grooves and apparent faults. Stereo analysis shows the smaller end of the nucleus (lower right) is tipped toward the viewer (out of frame). Sunlight is coming from the bottom of the frame. http://photojournal.jpl.nasa.gov/catalog/PIA03500