Mars Express flybys 'within touching distance' of Red Planet's moon

London: Mars Express made its closest fly-by yet of Red Planet's moon, Phobos, skimming past at only 45 km above its surface, on Dec. 29.

However, the probe is going too fast to click images of the irregularly shaped moon that is 15 miles wide, the Daily Express reported.

Instead, researchers will measure the probe's speed reduction as it enters Phobos' gravitational field to provide clues to its mass and density.

Ground stations around the world are going to be tracking the precise location of the probe for 35 hours, looking for small deviations in it's path.