Here is closeup of Enceladus, a moon of Saturn, taken by Cassini on an October 9 flyby of the body.
Why the close up? Like Jupiter's volcanic Io and Neptune's Triton, Enceladus is notable for its geological activity, as well as the organic compounds, including water ice, spewing from vents at the southern pole, which in some pictures give the moon the appearance of a comet. If, as speculated, the interior of the moon contains a liquid ocean, it's an extremely attractive target for astrobiologists.
So in a daring mission last Friday, the doughty little spacecraft Cassini flew into the vented plume to directly sample its composition, coming within 16 miles of the surface of the Enceladus.
Think that might make for some nervous moments for Cassini navigators? It did. In the right image, E5 represents the Oct. 9 flyby while E6 is the planned trajectory for a planned Oct. 31 rendezvous. Click to enlarge.
A nicely done video tour of the moon is here.
Image sources: NASA/JPL/Space Sciences Institute and NASA/JPL