Mars Express closed in on the intriguing martian moon Phobos at 6:50 CEST on 23 July, flying past at 2.96 km/s, only 100 km from the centre of the moon. The ESA spacecraft’s fly-bys of the moon have returned its most detailed full-disc images ever, also in 3-D, using the High Resolution Stereo Camera on board.
Phobos is what scientists call a ‘small irregular body’. Measuring 27 km × 22 km × 19 km, it is one of the least reflective objects in the Solar System, thought to be a captured asteroid or a remnant of the material that formed the planets.