This image layout depicts changes in the surface of comet Tempel 1, observed first by NASA Deep Impact Mission in 2005 top right and again by NASA Stardust-NExT mission on Feb. 14, 2011 bottom right.

NASA Stardust-NExT mission transmitted the first image it took during its approach to comet Tempel 1 at 8:35 p.m. PST 11:35 p.m. EST on Feb. 14, 2011.

This pair of images shows the before-and-after comparison of the part of comet Tempel 1 that was hit by the impactor from NASA Deep Impact spacecraft.

This pair of images shows the area affected by the impactor released by NASA Deep Impact spacecraft in July 2005.

Artist concept of NASA Stardust-NExT mission, which will fly by comet Tempel 1 on Feb. 14, 2011.

Reversed stereo image pair covering the region of NASA Deep Impact site from the Stardust-NExT mission.

This image shows the location of the newly discovered planet-like object, dubbed Sedna, in relation to the rest of the solar system in 2004.

This image obtained by NASA Stardust spacecraft shows a side of the nucleus of comet Tempel 1 that has never been seen before; three terraces of different elevations are visible, with dark, banded scarps, or slopes, separating them.

This image layout depicts changes in the surface of comet Tempel 1, observed first by NASA Deep Impact Mission in 2005 top right and again by NASA Stardust-NExT mission on Feb. 14, 2011 bottom right.

This pair of images shows the before-and-after comparison of the part of comet Tempel 1 that was hit by the impactor from NASA Deep Impact spacecraft.

This series of images shows the area where NASA Deep Impact probe collided with the surface of comet Tempel 1 in 2005. The view zooms in as the images progress from top left to right, and then bottom left to right.

This composite image was taken by NASA Stardust navigation camera 42 hours before its encounter with comet Tempel 1. The spacecraft is due to encounter the comet in the evening hours of Feb. 14, 2011.

This pair of images shows the before-and-after comparison of the part of comet Tempel 1 that was hit by the impactor from NASA Deep Impact spacecraft.

This anaglyph shows the region where NASA Deep Impact mission sent a probe into the surface of comet Tempel 1 in 2005. 3D glasses are necessary to view this image.

This image shows the surface of comet Tempel 1 before and after NASA Deep Impact mission sent a probe into the comet in 2005. The region was imaged by Deep Impact before the collision left, then six years later on by NASA Stardust-NExT mission.

This image mosaic shows four different views of comet Tempel 1 as seen by NASA Stardust spacecraft as it flew by on Feb. 14, 2011. The images progress in time beginning at upper left, upper right, to lower left, then lower right.

This pair of images shows a before-and-after comparison of the area on comet Tempel 1 targeted by an impactor from NASA Deep Impact spacecraft in July 2005.

These two images show the different views of comet Tempel 1 seen by NASA Deep Impact spacecraft left and NASA Stardust spacecraft right.

This composite image is the first taken by NASA Stardust spacecraft navigation camera. The observations were made on Jan. 18 and 19, 2011. Stardust will fly within about 200 kilometers 124 miles of the comet nucleus.

This pair of images shows the area affected by the impactor released by NASA Deep Impact spacecraft in July 2005.