Comet 67P/Churyumov–Gerasimenko nucleus prints conveniently on a flatbed FDM-type machine. This is a remix of thing http://www.thingiverse.com/thing:529408 which is from the ESA source file: http://blogs.esa.int/rosetta/2014/10/03/measuring-comet-67pc-g

All I did was cut it in half so it can print conveniently on flatbed FDM-type machines, which are very common in many institutions and homes. Glue the two halves together. And don't forget to visit the ESA Rosetta Mission page (http://sci.esa.int/rosetta/14615-comet-67p) and the JPL page (http://www.jpl.nasa.gov) for the folks who track and navigate this most extraordinary mission.

"Crater"-like circular features on the comet are not impact craters. They are holes, some of them deep, from which the cometary ejecta comes. The two lobes of the actual body have very different densities, confirming that they aggregated, and complicating gravitational models used in navigation.

The "selfie" space photograph is from the Rosetta Spacecraft, which itself appears in the field of view, and the comet about 50 km away; see caption here: http://sservi.nasa.gov/articles/rosetta-snaps-selfie-at-comet-67pchuryumov-gerasimenko/