Titania is the fourth of the five biggest satellites of Uranus, in terms of increasing distance to Uranus; it is the biggest in terms of mass. It was discovered by Herschel in 1787. It orbits at a distance of 436,300 km (or 17 planetary radii) from Uranus. Its diameter is 1,580 km. The part of the satellite imaged by Voyager 2 in 1981 shows a smooth surface with large canyons and faults. The longest one is Messina Chasmata with an overall length of about 1,500 km. The only large crater, Gertrude, is 326 km in diameter. Titania probably consists of a rocky core and an icy mantle; it orbits inside Uranus’ magnetosphere.