Titania (moon) have a spatial resolution of about 3.4 km (only Miranda and Ariel were imaged with a better resolution). The images cover about 40% of the surface, but only 24% was photographed with the precision required for geological mapping. At the time of the flyby, the southern hemisphere of Titania (like those of the other moons) was pointed towards the Sun, so the northern (dark) hemisphere could not be studied. No other spacecraft has ever visited the Uranian system or Titania, and no mission is currently planned. One possibility, now discarded, was to send "Cassini" on from Saturn to Uranus in
Moons of Uranus which is made primarily of ice. The ice component may include ammonia and carbon dioxide. Their surfaces are heavily cratered, though all of them (except Umbriel) show signs of endogenic resurfacing in the form of lineaments (canyons) and, in the case of Miranda, ovoid race-track like structures called coronae. Extensional processes associated with upwelling diapirs are likely responsible for the origin of the coronae. Ariel appears to have the youngest surface with the fewest impact craters, while Umbriel's appears oldest. A past 3:1 orbital resonance between Miranda and Umbriel and a past 4:1 resonance between Ariel and Titania are thought