What is the name of the large canyon on Saturn's moon Tethys?

The large canyon on Saturn’s moon Tethys is called Ithaca Chasma. It is a huge graben, or trough system, stretching roughly 2,000 kilometers across the icy moon—about three-quarters of Tethys’s circumference.

Ithaca Chasma can reach around 100 kilometers in width and about 3–5 kilometers in depth. Its course is approximately aligned with a great circle running through Tethys’s poles, and it lies broadly concentric with the enormous Odysseus impact crater.

One leading explanation is that Tethys once contained a global liquid-water ocean. As that interior ocean froze, the moon’s volume may have increased, placing the crust under tension and causing it to fracture. Another hypothesis links the chasma to the impact that formed Odysseus, although crater counts suggest Ithaca Chasma is older than the crater.

Voyager 1 discovered the feature in 1980, while Voyager 2 helped reveal its full extent in 1981. The name refers to Ithaca, the Greek island associated with Homer’s Odyssey.