Saturn's moon Tethys has the large impact crater Odysseus. The crater is about 445 kilometres wide, nearly two-fifths of Tethys's diameter, making it one of the largest impact features known in the Solar System.
Odysseus is unusually flat for a crater of its size. Scientists think the icy crust of Tethys gradually relaxed after the impact, allowing the crater floor and central mountain structure to collapse toward the moon's rounded shape. Its rim still rises several kilometres above the surrounding surface, while the interior contains a central depression and elevated massifs.
The crater was revealed in detail by Voyager 2 during its 1981 flyby of Saturn. It is named after Odysseus, the Greek hero associated with Homer's epic poems. The feature lies on Tethys's leading hemisphere, where its immense size dominates the moon's otherwise heavily cratered terrain.
It is easy to confuse Odysseus with Herschel, the enormous crater on Mimas. Herschel is also a famous Saturnian impact feature, but Odysseus belongs to Tethys. Tethys also has Ithaca Chasma, a vast valley that may be geologically connected to the crater-forming impact.