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
Stability of the Solar System essentially the distance from sun to earth). These are now known as the Kirkwood gaps. Some asteroids were later discovered to orbit in these gaps, but their orbits are unstable and they will eventually break out of the resonance due to close encounters with a major planet. Another common form of resonance in the Solar System is spin–orbit resonance, where the period of spin (the time it takes the planet or moon to rotate once about its axis) has a simple numerical relationship with its orbital period. An example is our own Moon, which is in a 1:1 spin–orbit resonance