Rosetta's first close-ups of comet 67P

Rosetta made its first close flyby of comet 67P Saturday, taking images from an unprecedented distance of just 6 km, less than 4 miles away.

In one set of images, taken from 8.9 km away, the European Space Agency (ESA) said it got the most "stunning" details yet of the comet's contrasting terrains. In one series of pictures, you can clearly make out boulders, tens or hundreds of feet in diameter, scattered all around.

The ESA was happy that Rosetta passed through the "zero phase" angle during its flyby, a term that means the sun was directly behind the spacecraft, which offers ideal lighting conditions for photographing.

Rosetta, which has been tailing the comet 67P since August, is no longer orbiting the rock, but going in for periodic flybys. The spacecraft is now moving further from its target to capture some wider views.