"Phase-locked" Mimas!

Caption NASA originale:"Cassini's ability to remain precisely and steadily pointed at targets, such as Saturn's moon Mimas (seen here) yields sharp images despite the relatively high speed at which the spacecraft moves.
Cassini was traveling at more than 13 Km per second when it acquired this view, which shows crisp detail on Mimas against the backdrop of Saturn's Northern Hemisphere. Shadows of the icy rings stretch across the atmosphere and appear to be blurred because of the spacecraft motion.
The part of Mimas visible here always faces away from Saturn as the moon orbits the Gas Giant. In scientific language (jargon...), Mimas is said to be "phase-locked".
The image has been rotated so that North on Mimas (and Saturn) is up. This view was obtained with the Cassini spacecraft narrow angle camera on Jan. 18, 2005, at a distance of approx. 1,25 MKM from Mimas and at a phase angle of 114°. The image was taken using filters sensitive to wavelengths of infrared and polarized light. Res. is 7 Km/pixel".