Tempel 1 and Hartley 2
This image shows the nuclei of comets Tempel 1 and Hartley 2, as imaged by NASA's Deep Impact spacecraft, which continued as an extended mission known as EPOXI.
Tempel 1 is five times larger than Hartley 2. Visible jets are easily seen in images of Hartley 2, but required extensive processing to be seen in images of Tempel 1.
Tempel 1 is 7.6 kilometers (4.7 miles) in the longest dimension. Hartley 2 is 2.2 km (1.4 miles) long.
The Tempel 1 image was built up from more than 25 images captured by the impactor targeting sensor on July 4, 2005. The Hartley 2 image was obtained by the Medium- Resolution Imager on Nov. 4, 2010.
NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the EPOXI mission for NASA's Science Mission Directorate, Washington. The University of Maryland, College Park, is home to the mission's principal investigator, Michael A'Hearn. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.
For more information about EPOXI visit http://www.nasa.gov/epoxi and http://epoxi.umd.edu/.
Image Credit: NASA/JPL-Caltech/UMD