Titania (moon) an extended mission. Another mission concept proposed was the Uranus orbiter and probe concept, evaluated around 2010. Uranus was also examined as part of one trajectory for a precursor interstellar probe concept, Innovative Interstellar Explorer. A Uranus orbiter was listed as the third priority for a NASA Flagship mission by the NASA Planetary Science Decadal Survey, and conceptual designs for such a mission are currently being analyzed. Titania (moon) Titania is the largest of the moons of Uranus and the eighth largest moon in the Solar System at a diameter of . Discovered by William Herschel in 1787, Titania is
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